Despite considerable reductions in mobile source emissions, annual average aerosol concentrations measured in Los Angeles using Federal Reference Methods (FRM) have not appreciably declined over the past decade. Here, we use submicron aerosol measurements and zero-dimensional modeling to quantify the impacts of these emission reductions on aerosol formation in Pasadena, CA, during the late spring and summer of 2022. Reductions in secondary organic aerosol (SOA) concentrations expected from reduced mobile source emissions appear to have been largely offset by increases in hydroxyl radical concentrations, an indirect effect of reduced nitrogen oxide (NOx) emissions. As a result, while the predicted contribution of mobile sources to the SOA burden has declined from ∼50% in 2010 to only ∼25% in 2022, concentrations of locally formed SOA have remained relatively constant. In contrast, reductions in mobile source NOx emissions have likely reduced overnight production of nitric acid and ammonium nitrate (AN) aerosol. We provide indirect evidence that FRM measurements may have failed to capture the reduction in AN since 2010 due to the evaporation of semivolatile species from FRM filter samples. Our results suggest that given the effectiveness of historical regulatory efforts aimed at mobile sources, and on-road sources in particular, additional reductions in submicron aerosol concentrations in Los Angeles will likely require increased focus on abating emissions from nonroad and area sources.
\nNew particle formation (NPF) represents a major source of tropospheric fine aerosols. A common viewpoint is that NPF hinges thermodynamically on the volatility of condensing species and is unfavorable at high temperatures. From an intensive field campaign, we observed frequent NPF events during a heat wave. Size-resolved chemical composition of nanoparticles down to 3 nanometers was first measured, unraveling a dominant presence of carboxylic acids. Our work uncovers a spontaneous mechanism to produce supramolecular nanoparticles through self-assembly of organic acids. This discovery explains not only the unexpected NPF at high temperatures but also its ubiquitous occurrence under diverse atmospheric conditions. As global warming leads to more frequent and intense heat waves, our findings open avenues for assessing the impacts of aerosols on cloud formation, public health, and climate.
", "doi": "10.1126/science.ady5192", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2026-02-12", "series_number": "6786", "volume": "391", "issue": "6786", "pages": "eady5192" }, { "id": "authors:3qtbf-x0x14", "collection": "authors", "collection_id": "3qtbf-x0x14", "cite_using_url": "https://authors.library.caltech.edu/records/3qtbf-x0x14", "type": "article", "title": "Poorly quantified trends in ammonium nitrate remain critical to understand future urban aerosol control strategies", "author": [ { "family_name": "Ward", "given_name": "Ryan X.", "orcid": "0000-0003-2317-3310", "clpid": "Ward-Ryan-X" }, { "family_name": "Baliaka", "given_name": "Haroula D.", "orcid": "0000-0001-7851-8449", "clpid": "Baliaka-Haroula-D" }, { "family_name": "Schulze", "given_name": "Benjamin C.", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Kerr", "given_name": "Gaige H.", "orcid": "0000-0001-8869-0752" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Hasheminassab", "given_name": "Sina", "clpid": "Hasheminassab-Sina" }, { "family_name": "Bahreini", "given_name": "Roya", "orcid": "0000-0001-8292-5338" }, { "family_name": "Dillner", "given_name": "Ann M.", "orcid": "0000-0001-8306-754X" }, { "family_name": "Russell", "given_name": "Armistead", "orcid": "0000-0003-2027-8870" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Heterogeneous oxidation of SO2 by NO2 on aerosols has recently been found to be one of the major formation pathways of sulfate in the polluted troposphere, but the chemical mechanisms and kinetics remain uncertain. By combining lab experiments, theoretical chemistry calculations, and field measurements, here we show that the SO2 oxidation by NO2 is critically dependent on anions at the air–aerosol aqueous interface. The reaction rate of NO2 with HSO\u207b\u2083 (1.1 × 108–1.6 × 109 M−1 s−1) is more than four orders of magnitude larger than the traditionally held value for the bulk phase due to the abundant occurrence of chloride, nitrate, and carboxylic anions at the air–aqueous interface, which remarkably accelerates sulfate formation during China haze periods by enhancing the uptake of NO2 through interfacial electrostatic attraction. Atmospheric models not accounting for this aerosol interfacial process likely produce major misrepresentations of tropospheric sulfate aerosols under polluted conditions.
", "doi": "10.1093/pnasnexus/pgaf058", "pmcid": "PMC11880798", "issn": "2752-6542", "publisher": "National Academy of Sciences", "publication": "PNAS Nexus", "publication_date": "2025-03", "series_number": "3", "volume": "4", "issue": "3", "pages": "pgaf058" }, { "id": "authors:yhbyd-3rn78", "collection": "authors", "collection_id": "yhbyd-3rn78", "cite_using_url": "https://authors.library.caltech.edu/records/yhbyd-3rn78", "type": "article", "title": "Kinetic Modeling of Secondary Organic Aerosol in a Weather-Chemistry Model: Parameterizations, Processes, and Predictions for GOAmazon", "author": [ { "family_name": "He", "given_name": "Yicong" }, { "family_name": "Bilsback", "given_name": "Kelsey R.", "orcid": "0000-0002-5996-1522" }, { "family_name": "Shrivastava", "given_name": "Manish", "orcid": "0000-0002-9053-2400" }, { "family_name": "Zaveri", "given_name": "Rahul A.", "orcid": "0000-0001-9874-8807" }, { "family_name": "Shilling", "given_name": "John E.", "orcid": "0000-0002-3728-0195" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Zhao", "given_name": "Bin", "orcid": "0000-0001-8438-9188" }, { "family_name": "Wang", "given_name": "Shuxiao", "orcid": "0000-0001-9727-1963" }, { "family_name": "Cappa", "given_name": "Christopher D.", "orcid": "0000-0002-3528-3368" }, { "family_name": "Pierce", "given_name": "Jeffrey R.", "orcid": "0000-0002-4241-838X" }, { "family_name": "Jathar", "given_name": "Shantanu H.", "orcid": "0000-0003-4106-2358" } ], "abstract": "Secondary organic aerosol (SOA) forms and evolves in the atmosphere through many pathways and processes, over diverse spatial and time scales. Hence, there is a need to represent these widely varying kinetic processes in large-scale atmospheric models to allow for accurate predictions of the abundance, properties, and impacts of SOA. In this work, we integrated a kinetic, process-level model (simpleSOM-MOSAIC) into a weather-chemistry model (WRF-Chem) to simulate the oxidation chemistry and microphysics of atmospheric SOA. simpleSOM-MOSAIC simulates multigenerational gas-phase chemistry, autoxidation reactions, aqueous chemistry, heterogeneous oxidation, oligomerization, and phase-state-influenced gas/particle partitioning of SOA. As a case study, the integrated WRF-Chem-simpleSOM-MOSAIC (WC-SSM) model was used to simulate the photochemical evolution downwind of a large city (Manaus, Brazil) in the Amazon and, in turn, study the anthropogenic and biogenic interactions in an otherwise pristine environment. Consistent with previous work, we found that OA was enhanced by up to a factor of 4 in the urban plume due to elevated hydroxyl radical (OH) concentrations, relative to the background, and that this OA was dominated by SOA from biogenic precursors (80%). In addition to accurately simulating the OA enhancement in the urban plume, the model reproduced the magnitude of the OA oxygen-to-carbon (O:C) ratio and broadly tracked the evolution of the aerosol number size distribution. Our work highlights the importance of including an integrated, kinetic representation of SOA processes in an atmospheric model.", "doi": "10.1021/acsestair.4c00240", "issn": "2837-1402", "publisher": "American Chemical Society", "publication": "ACS ES&T Air", "publication_date": "2025-02-14", "series_number": "2", "volume": "2", "issue": "2", "pages": "249\u2013263" }, { "id": "authors:b419g-02969", "collection": "authors", "collection_id": "b419g-02969", "cite_using_url": "https://authors.library.caltech.edu/records/b419g-02969", "type": "article", "title": "Quantifying primary oxidation products in the OH-initiated reaction of benzyl alcohol", "author": [ { "family_name": "Buenconsejo", "given_name": "Reina S.", "orcid": "0000-0002-0162-905X", "clpid": "Buenconsejo-Reina-S" }, { "family_name": "Charan", "given_name": "Sophia M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-Sophia-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "Benzyl alcohol is found in many volatile chemical products (VCPs) including a number of personal care products and industrial solvents. We report here on the products of the gas-phase oxidation of benzyl alcohol by OH and its dependence on nitric oxide (NO) levels. Using a gas chromatography in tandem with a chemical ionization mass spectrometer (CIMS) and gas chromatographer with a flame ionization detector (GC-FID), we measure the branching fractions to the major gas-phase oxidation products: hydroxybenzyl alcohol (HBA) and benzaldehyde. Later-generation oxidation products from both HBA and benzaldehyde pathways are also observed. In particular, catechol is a major gas-phase product of HBA. The fraction of H abstraction from benzyl alcohol leading to benzaldehyde formation is unaffected by [NO], with an average branching fraction of (21±10) %. The fraction of OH addition leading to HBA formation (36±18) % also does not appear to vary with [NO]. Consistent with the known high SOA yields of catechol, we find that HBA has a very high secondary organic aerosol (SOA) yield. Thus, benzyl alcohol and its oxidation products efficiently produce secondary organic aerosol – under some conditions approaching unity. Insights from the present study can help elucidate the chemistry of other atmospherically relevant aromatic compounds, especially those found in VCPs.
\nIn this paper, a four nested Weather Research and Forecasting-Community Multiscale Air Quality (WRF-CMAQ) model was applied to analyze ozone (O3) concentration reductions under the influence of extremely high NOx concentrations emitted from ships at the Hankou Jiangtan (HJ) station adjacent to the Yangtze River in Wuhan, China. By adding NO emissions along the waterway for the sensitivity experiments, the model successfully reproduced two cases of high NOx concentrations on April 9 and April 28, 2020, and one case of persistent and extremely high NOx concentrations on the night of May 3, 2020. During daytime, strong photochemical reactions generated new O3, while the high concentration NOx from ship emissions continuously reduced O3 through catalytic cycling. This led to the O3 concentrations at the HJ station being consistently lower than the surrounding stations in the afternoon, with the high NOx plume dropping O3 concentrations by 51 ppb in 1 h, and NO2 concentrations up to 110 ppb. The presence of large amounts of fresh NO (up to 265 ppb) in the ship emission plumes rapidly reduces O3 concentrations through titration reactions during night, resulting in a wide area of low O3 concentrations (2–4 ppb) over a long period of time. This study demonstrates that the pollution and impact of emissions from ships traveling in waterways on the atmosphere of the surrounding area cannot be ignored.
\nThe declining trend in vehicle emissions has underscored the growing significance of volatile organic compound (VOC) emissions from volatile chemical products (VCPs). However, accurately representing VOC chemistry in simplified chemical mechanisms remains challenging due to its chemical complexity including speciation and reactivity. Previous studies have predominantly focused on VOCs from fossil fuel sources, leading to an underrepresentation of VOC chemistry from VCP sources. We developed an integrated chemical mechanism, RACM2B-VCP, that is compatible with WRF-Chem and is aimed at enhancing the representation of VOC chemistry, particularly from VCP sources, within the present urban environment. Evaluation against the Air Quality System (AQS) network data demonstrates that our model configured with RACM2B-VCP reproduces both the magnitude and spatial variability of O3 and PM2.5 in Los Angeles. Furthermore, evaluation against comprehensive measurements of O3 and PM2.5 precursors from the Reevaluating the Chemistry of Air Pollutants in California (RECAP-CA) airborne campaign and the Southwest Urban NOx and VOC Experiment (SUNVEx) ground site and mobile laboratory campaign confirm the model's accuracy in representing NOx and many VOCs and highlight remaining biases. Although there exists an underprediction in the total VOC reactivity of observed VOC species, our model with RACM2B-VCP exhibits good agreement for VOC markers emitted from different sectors, including biogenic, fossil fuel, and VCP sources. Through sensitivity analyses, we probe the contributions of VCP and fossil fuel emissions to total VOC reactivity and O3. Our results reveal that 52 % of the VOC reactivity and 35 % of the local enhancement of MDA8 O3 arise from anthropogenic VOC emissions in Los Angeles. Significantly, over 50 % of this anthropogenic fraction of either VOC reactivity or O3 is attributed to VCP emissions. The RACM2B-VCP mechanism created, described, and evaluated in this work is ideally suited for accurately representing ozone for the right reasons in the present urban environment where mobile, biogenic, and VCP VOCs are all important contributors to ozone formation.
\nThis study describes a modeling framework, model evaluation, and source apportionment to understand the causes of Los Angeles (LA) air pollution. A few major updates are applied to the Community Multiscale Air Quality (CMAQ) model with a high spatial resolution (1 km × 1 km). The updates include dynamic traffic emissions based on real-time, on-road information and recent emission factors and secondary organic aerosol (SOA) schemes to represent volatile chemical products (VCPs). Meteorology is well predicted compared to ground-based observations, and the emission rates from multiple sources (i.e., on-road, volatile chemical products, area, point, biogenic, and sea spray) are quantified. Evaluation of the CMAQ model shows that ozone is well predicted despite inaccuracies in nitrogen oxide (NOx) predictions. Particle matter (PM) is underpredicted compared to concurrent measurements made with an aerosol mass spectrometer (AMS) in Pasadena. Inorganic aerosol is well predicted, while SOA is underpredicted. Modeled SOA consists of mostly organic nitrates and products from oxidation of alkane-like intermediate volatility organic compounds (IVOCs) and has missing components that behave like less-oxidized oxygenated organic aerosol (LO-OOA). Source apportionment demonstrates that the urban areas of the LA Basin and vicinity are NOx-saturated (VOC-sensitive), with the largest sensitivity of O3 to changes in VOCs in the urban core. Differing oxidative capacities in different regions impact the nonlinear chemistry leading to PM and SOA formation, which is quantified in this study.
", "doi": "10.5194/acp-24-2345-2024", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2024-02-23", "series_number": "4", "volume": "24", "issue": "4", "pages": "2345-2363" }, { "id": "authors:0hjg4-xtz88", "collection": "authors", "collection_id": "0hjg4-xtz88", "cite_using_url": "https://authors.library.caltech.edu/records/0hjg4-xtz88", "type": "article", "title": "Microphysical complexity of black carbon particles restricts their warming potential", "author": [ { "family_name": "Huang", "given_name": "Xiao-Feng" }, { "family_name": "Peng", "given_name": "Yan" }, { "family_name": "Wei", "given_name": "Jing" }, { "family_name": "Peng", "given_name": "Jianfei", "orcid": "0000-0003-4753-087X" }, { "family_name": "Lin", "given_name": "Xiao-Yu" }, { "family_name": "Tang", "given_name": "Meng-Xue" }, { "family_name": "Cheng", "given_name": "Yong", "orcid": "0000-0001-9590-9548" }, { "family_name": "Men", "given_name": "Zhengyu" }, { "family_name": "Fang", "given_name": "Tiange" }, { "family_name": "Zhang", "given_name": "Jinsheng" }, { "family_name": "He", "given_name": "Ling-Yan" }, { "family_name": "Cao", "given_name": "Li-Ming", "orcid": "0000-0001-7304-2891" }, { "family_name": "Liu", "given_name": "Chao", "orcid": "0000-0002-3509-5690" }, { "family_name": "Zhang", "given_name": "Chenchong" }, { "family_name": "Mao", "given_name": "Hongjun" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401" } ], "abstract": "Black carbon (BC) strongly absorbs solar radiation, but its warming effect on climate is poorly quantified. A key challenge is to accurately assess BC light absorption after BC is mixed with non-BC components. However, there has consistently been a large observation-modeling gap in BC light absorption estimation, reflecting the insufficient understanding of realistic BC complexity. Here, we conduct comprehensive in situ measurements of BC single-particle microphysics, e.g., size, coating amounts, density, and shape, along with optical closure calculation. Specifically, the observed particle-to-particle heterogeneities in size and coating and the non-spherical BC shape only explain the lower observed BC absorption by ∼20% and ∼30%, respectively. A remaining gap for fully aged spherical BC-containing particles is related to the off-center BC-core position. The global climate model assessment shows that fully accounting for the observed BC complexity in the aerosol microphysical representation reduces the global BC direct radiative forcing by up to 23%.
", "doi": "10.1016/j.oneear.2023.12.004", "issn": "2590-3322", "publisher": "Cell Press", "publication": "One Earth", "publication_date": "2024-01-19", "series_number": "1", "volume": "7", "issue": "1", "pages": "136-145" }, { "id": "authors:pcqb7-y7n82", "collection": "authors", "collection_id": "pcqb7-y7n82", "cite_using_url": "https://authors.library.caltech.edu/records/pcqb7-y7n82", "type": "article", "title": "Characterization of the aerosol vertical distributions and their impacts on warm clouds based on multi-year ARM observations", "author": [ { "family_name": "Lin", "given_name": "Yun", "clpid": "Lin-Yun" }, { "family_name": "Takano", "given_name": "Yoshihide", "orcid": "0000-0002-9937-7611", "clpid": "Takano-Yoshihide" }, { "family_name": "Gu", "given_name": "Yu", "orcid": "0000-0002-3412-0794", "clpid": "Gu-Yu" }, { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401", "clpid": "Wang-Yuan" }, { "family_name": "Zhou", "given_name": "Shujun", "clpid": "Zhou-Shujun" }, { "family_name": "Zhang", "given_name": "Tianhao", "orcid": "0000-0003-3456-8262", "clpid": "Zhang-Tianhao" }, { "family_name": "Zhu", "given_name": "Kuilin", "clpid": "Zhu-Kuilin" }, { "family_name": "Wang", "given_name": "Jingyu", "orcid": "0000-0002-4841-0872", "clpid": "Wang-Jingyu" }, { "family_name": "Zhao", "given_name": "Bin", "orcid": "0000-0001-8438-9188", "clpid": "Zhao-Bin" }, { "family_name": "Chen", "given_name": "Gang", "orcid": "0000-0003-4934-1909", "clpid": "Chen-Gang" }, { "family_name": "Zhang", "given_name": "Damao", "orcid": "0000-0002-3518-292X", "clpid": "Zhang-Damao" }, { "family_name": "Fu", "given_name": "Rong", "orcid": "0000-0002-4065-248X", "clpid": "Fu-Rong" }, { "family_name": "Seinfeld", "given_name": "John", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aerosol vertical distribution plays a crucial role in cloud development and thus precipitation since both aerosol indirect and semi-direct effects significantly depend on the relative position of aerosol layer in reference to cloud, but its precise influence on cloud remains unclear. In this study, we integrated multi-year Raman Lidar measurements of aerosol vertical profiles from the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) facility with available Value-Added Products of cloud features to characterize aerosol vertical distributions and their impacts on warm clouds over the continental and marine ARM atmospheric observatories, i.e., Southern Great Plains (SGP) and Eastern North Atlantic (ENA). A unimodal seasonal distribution of aerosol optical depths (AODs) with a peak in summer is found at upper boundary layer over SGP, while a bimodal distribution is observed at ENA for the AODs at lower levels with a major winter-spring maximum. The diurnal mean of upper-level AOD at SGP shows a maximum in the early evening. According to the relative positions of aerosol layers to clouds we further identify three primary types of aerosol vertical distribution, including Random, Decreasing, and Bottom. It is found that the impacts of aerosols on cloud may or may not vary with aerosol vertical distribution depending on environmental conditions, as reflected by the wide variations of the relations between AOD and cloud properties. For example, as AOD increases, the liquid water paths (LWPs) tend to be reduced at SGP but enhanced at ENA. The relations of cloud droplet effective radius with AOD largely depend on aerosol vertical distributions, particularly showing positive values in the Random type under low-LWP condition (<50 g m\u207b\u00b2). The distinct features of aerosol-cloud interactions in relation to aerosol vertical distribution are likely attributed to the continental-marine contrast in thermodynamic environments and aerosol conditions between SGP and ENA.
", "doi": "10.1016/j.scitotenv.2023.166582", "issn": "0048-9697", "publisher": "Elsevier", "publication": "Science of The Total Environment", "publication_date": "2023-12-15", "volume": "904", "pages": "166582" }, { "id": "authors:hnnwr-z0490", "collection": "authors", "collection_id": "hnnwr-z0490", "cite_using_url": "https://authors.library.caltech.edu/records/hnnwr-z0490", "type": "article", "title": "Methane Emissions from Dairy Operations in California's San Joaquin Valley Evaluated Using Airborne Flux Measurements", "author": [ { "family_name": "Schulze", "given_name": "Benjamin C.", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Ward", "given_name": "Ryan X.", "orcid": "0000-0003-2317-3310", "clpid": "Ward-Ryan-X" }, { "family_name": "Pfannerstill", "given_name": "Eva Y.", "orcid": "0000-0001-7715-1200", "clpid": "Pfannerstill-Eva-Y" }, { "family_name": "Zhu", "given_name": "Qindan", "orcid": "0000-0003-2173-4014", "clpid": "Zhu-Qindan" }, { "family_name": "Arata", "given_name": "Caleb", "orcid": "0000-0002-0170-8794", "clpid": "Arata-Caleb" }, { "family_name": "Place", "given_name": "Bryan", "orcid": "0000-0002-9224-2837", "clpid": "Place-Bryan-K" }, { "family_name": "Nussbaumer", "given_name": "Clara", "orcid": "0000-0002-5662-8476", "clpid": "Nussbaumer-Clara" }, { "family_name": "Wooldridge", "given_name": "Paul", "orcid": "0000-0003-2711-5900", "clpid": "Wooldridge-Paul" }, { "family_name": "Woods", "given_name": "Roy", "orcid": "0000-0002-3632-6374", "clpid": "Woods-Roy" }, { "family_name": "Bucholtz", "given_name": "Anthony", "clpid": "Bucholtz-Anthony" }, { "family_name": "Cohen", "given_name": "Ronald C.", "orcid": "0000-0001-6617-7691", "clpid": "Cohen-Ronald-C" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-Allen-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "State inventories indicate that dairy operations account for nearly half of California's methane budget. Recent analyses suggest, however, that these emissions may be underestimated, complicating efforts to develop emission reduction strategies. Here, we report estimates of dairy methane emissions in the southern San Joaquin Valley (SJV) of California in June 2021 using airborne flux measurements. We find average dairy methane fluxes of 512 \u00b1 178 mg m\u207b\u00b2 h\u207b\u00b9 from a region of 300+ dairies near Visalia, CA using a combination of eddy covariance and mass balance-based techniques, corresponding to 118 \u00b1 41 kg dairy\u207b\u00b9 h\u207b\u00b9. These values estimated during our June campaign are 39 \u00b1 48% larger than annual average estimates from the recently developed VISTA-CA inventory. We observed notable increases in emissions with temperature. Our estimates align well with inventory predictions when parametrizations for the temperature dependence of emissions are applied. Our measurements further demonstrate that the VISTA-CA emission inventory is considerably more accurate than the EPA GHG-I inventory in this region. Source apportionment analyses confirm that dairy operations produce the majority of methane emissions in the southern SJV (\u223c65%). Fugitive oil and gas (O&G) sources account for the remaining \u223c35%. Our results support the accuracy of the process-based models used to develop dairy emission inventories and highlight the need for additional investigation of the meteorological dependence of these emissions.
", "doi": "10.1021/acs.est.3c03940", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science & Technology", "publication_date": "2023-12-05", "series_number": "48", "volume": "57", "issue": "48", "pages": "19519-19531" }, { "id": "authors:k5ygt-7pr51", "collection": "authors", "collection_id": "k5ygt-7pr51", "cite_using_url": "https://authors.library.caltech.edu/records/k5ygt-7pr51", "type": "article", "title": "Particle-phase accretion forms dimer esters in pinene secondary organic aerosol", "author": [ { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Hafeman", "given_name": "Nicholas J.", "orcid": "0000-0001-7525-7597", "clpid": "Hafeman-Nicholas-J" }, { "family_name": "Rezgui", "given_name": "Samir P.", "orcid": "0000-0003-4080-9835", "clpid": "Rezgui-Samir-P" }, { "family_name": "Chen", "given_name": "Jing", "orcid": "0000-0001-6545-6197" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Kjaergaard", "given_name": "Henrik G.", "orcid": "0000-0002-7275-8297" }, { "family_name": "Stoltz", "given_name": "Brian M.", "orcid": "0000-0001-9837-1528", "clpid": "Stoltz-B-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "Secondary organic aerosol (SOA) is ubiquitous in the atmosphere and plays a pivotal role in climate, air quality, and health. The production of low-volatility dimeric compounds through accretion reactions is a key aspect of SOA formation. However, despite extensive study, the structures and thus the formation mechanisms of dimers in SOA remain largely uncharacterized. In this work, we elucidate the structures of several major dimer esters in SOA from ozonolysis of \u03b1-pinene and \u03b2-pinene\u2014substantial global SOA sources\u2014through independent synthesis of authentic standards. We show that these dimer esters are formed in the particle phase and propose a mechanism of nucleophilic addition of alcohols to a cyclic acylperoxyhemiacetal. This chemistry likely represents a general pathway to dimeric compounds in ambient SOA.", "doi": "10.1126/science.adi0857", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2023-11-17", "series_number": "6672", "volume": "382", "issue": "6672", "pages": "787-792" }, { "id": "authors:akfgq-xxc27", "collection": "authors", "collection_id": "akfgq-xxc27", "cite_using_url": "https://authors.library.caltech.edu/records/akfgq-xxc27", "type": "article", "title": "Measurement report: Airborne measurements of NOx fluxes over Los Angeles during the RECAP-CA 2021 campaign", "author": [ { "family_name": "Nussbaumer", "given_name": "Clara M.", "orcid": "0000-0002-5662-8476" }, { "family_name": "Place", "given_name": "Bryan K." }, { "family_name": "Zhu", "given_name": "Qindan", "orcid": "0000-0003-2173-4014" }, { "family_name": "Pfannerstill", "given_name": "Eva Y.", "orcid": "0000-0001-7715-1200" }, { "family_name": "Wooldridge", "given_name": "Paul", "orcid": "0000-0003-2711-5900" }, { "family_name": "Schulze", "given_name": "Benjamin C.", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Arata", "given_name": "Caleb" }, { "family_name": "Ward", "given_name": "Ryan", "orcid": "0000-0003-2317-3310", "clpid": "Ward-Ryan" }, { "family_name": "Bucholtz", "given_name": "Anthony" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896" }, { "family_name": "Cohen", "given_name": "Ronald C.", "orcid": "0000-0001-6617-7691" } ], "abstract": "
Nitrogen oxides (NOx≡NO+NO\u2082) are involved in most atmospheric photochemistry, including the formation of tropospheric ozone (O3). While various methods exist to accurately measure NOx concentrations, it is still a challenge to quantify the source and flux of NOx emissions. We present airborne measurements of NOx and winds used to infer the emission of NOx across Los Angeles. The measurements were obtained during the research aircraft campaign RECAP-CA (Re-Evaluating the Chemistry of Air Pollutants in CAlifornia) in June 2021. Geographic allocations of the fluxes are compared to the NOx emission inventory from the California Air Resources Board (CARB). We find that the NOx fluxes have a pronounced weekend effect and are highest in the eastern part of the San Bernardino Valley. The comparison of the RECAP-CA and the modeled CARB NOx fluxes suggests that the modeled emissions are higher than expected near the coast and in Downtown Los Angeles and lower than expected further inland in the eastern part of the San Bernardino Valley.
", "doi": "10.5194/acp-23-13015-2023", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2023-10-16", "series_number": "20", "volume": "23", "issue": "20", "pages": "13015-13028" }, { "id": "authors:0emr8-t2054", "collection": "authors", "collection_id": "0emr8-t2054", "cite_using_url": "https://authors.library.caltech.edu/records/0emr8-t2054", "type": "article", "title": "Volatile organic compound fluxes in the agricultural San Joaquin Valley \u2013 spatial distribution, source attribution, and inventory comparison", "author": [ { "family_name": "Pfannerstill", "given_name": "Eva Y.", "orcid": "0000-0001-7715-1200" }, { "family_name": "Arata", "given_name": "Caleb" }, { "family_name": "Zhu", "given_name": "Qindan", "orcid": "0000-0003-2173-4014" }, { "family_name": "Schulze", "given_name": "Benjamin C.", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Woods", "given_name": "Roy" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Bucholtz", "given_name": "Anthony" }, { "family_name": "Cohen", "given_name": "Ronald C.", "orcid": "0000-0001-6617-7691" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896" } ], "abstract": "The San Joaquin Valley is an agricultural region in California that suffers from poor air quality. Since traffic emissions are decreasing, other sources of volatile organic compounds (VOCs) are gaining importance in the formation of secondary air pollutants. Using airborne eddy covariance, we conducted direct, spatially resolved flux observations of a wide range of VOCs in the San Joaquin Valley during June 2021 at 23–36 \u2218C. Through land-cover-informed footprint disaggregation, we were able to attribute emissions to sources and identify tracers for distinct source types. VOC mass fluxes were dominated by alcohols, mainly from dairy farms, while oak isoprene and citrus monoterpenes were important sources of reactivity. Comparisons with two commonly used inventories showed that isoprene emissions in the croplands were overestimated, while dairy and highway VOC emissions were generally underestimated in the inventories, and important citrus and biofuel VOC point sources were missing from the inventories. This study thus presents unprecedented insights into the VOC sources in an intensive agricultural region and provides much needed information for the improvement of inventories, air quality predictions, and regulations.
", "doi": "10.5194/acp-23-12753-2023", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2023-10-12", "series_number": "19", "volume": "23", "issue": "19", "pages": "12753-12780" }, { "id": "authors:7ksgh-p5f86", "collection": "authors", "collection_id": "7ksgh-p5f86", "cite_using_url": "https://authors.library.caltech.edu/records/7ksgh-p5f86", "type": "article", "title": "Direct observations of NOx emissions over the San Joaquin Valley using airborne flux measurements during RECAP-CA 2021 field campaign", "author": [ { "family_name": "Zhu", "given_name": "Qindan", "orcid": "0000-0003-2173-4014" }, { "family_name": "Place", "given_name": "Bryan", "orcid": "0000-0002-9224-2837" }, { "family_name": "Pfannerstill", "given_name": "Eva Y.", "orcid": "0000-0001-7715-1200" }, { "family_name": "Tong", "given_name": "Sha" }, { "family_name": "Zhang", "given_name": "Huanxin", "orcid": "0000-0003-1090-7215" }, { "family_name": "Wang", "given_name": "Jun", "orcid": "0000-0002-7334-0490" }, { "family_name": "Nussbaumer", "given_name": "Clara M.", "orcid": "0000-0002-5662-8476" }, { "family_name": "Wooldridge", "given_name": "Paul", "orcid": "0000-0003-2711-5900" }, { "family_name": "Schulze", "given_name": "Benjamin C.", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Arata", "given_name": "Caleb", "orcid": "0000-0002-0170-8794" }, { "family_name": "Bucholtz", "given_name": "Anthony", "orcid": "0000-0002-7049-4005" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896" }, { "family_name": "Cohen", "given_name": "Ronald C.", "orcid": "0000-0001-6617-7691" } ], "abstract": "Nitrogen oxides (NOx) are principle components of air pollution and serve as important ozone precursors. As the San Joaquin Valley (SJV) experiences some of the worst air quality in the United States, reducing NOx emissions is a pressing need, yet quantifying current emissions is complicated due to a mixture of mobile and agriculture sources. We performed airborne eddy covariance flux measurements during the Re-Evaluating the Chemistry of Air Pollutants in California (RECAP-CA) field campaign in June 2021. Combining footprint calculations and land cover statistics, we disaggregate the observed fluxes into component fluxes characterized by three different land cover types. On average, we find emissions of 0.95 mg N m−2 h−1 over highways, 0.43 mg N m−2 h−1 over urban areas, and 0.30 mg N m−2 h−1 over croplands. The calculated NOx emissions using flux observations are utilized to evaluate anthropogenic emissions inventories and soil NOx emissions schemes. We show that two anthropogenic inventories for mobile sources, EMFAC (EMission FACtors) and FIVE (Fuel-based Inventory for Vehicle Emissions), yield strong agreement with emissions derived from measured fluxes over urban regions. Three soil NOx schemes, including the MEGAN v3 (Model of Emissions of Gases and Aerosols from Nature), BEIS v3.14 (Biogenic Emission Inventory System), and BDISNP (Berkeley–Dalhousie–Iowa Soil NO Parameterization), show substantial underestimates over the study domain. Compared to the cultivated soil NOx emissions derived from measured fluxes, MEGAN and BEIS are lower by more than 1 order of magnitude, and BDISNP is lower by a factor of 2.2. Despite the low bias, observed soil NOx emissions and BDISNP present a similar spatial pattern and temperature dependence. We conclude that soil NOx is a key feature of the NOx emissions in the SJV and that a biogeochemical-process-based model of these emissions is needed to simulate emissions for modeling air quality in the region.
", "doi": "10.5194/acp-23-9669-2023", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2023-08-31", "series_number": "17", "volume": "23", "issue": "17", "pages": "9669-9683" }, { "id": "authors:2681z-yrb91", "collection": "authors", "collection_id": "2681z-yrb91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230628-256974000.6", "type": "article", "title": "Overview of ICARUS\u2500A Curated, Open Access, Online Repository for Atmospheric Simulation Chamber Data", "author": [ { "family_name": "Nguyen", "given_name": "Tran B.", "orcid": "0000-0001-9206-4359", "clpid": "Nguyen-Tran-B" }, { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580" }, { "family_name": "Buenconsejo", "given_name": "Reina S.", "orcid": "0000-0002-0162-905X", "clpid": "Buenconsejo-Reina-S" }, { "family_name": "Charan", "given_name": "Sophia M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-Sophia-M" }, { "family_name": "Cavanna", "given_name": "Eric E." }, { "family_name": "Cocker", "given_name": "David R.", "orcid": "0000-0002-0586-0769" }, { "family_name": "Day", "given_name": "Douglas A.", "orcid": "0000-0003-3213-4233" }, { "family_name": "DeVault", "given_name": "Marla P.", "orcid": "0000-0002-9562-1920" }, { "family_name": "Donahue", "given_name": "Neil M.", "orcid": "0000-0003-3054-2364" }, { "family_name": "Finewax", "given_name": "Zachary", "orcid": "0000-0003-4225-5303" }, { "family_name": "Habib", "given_name": "Luke F.", "orcid": "0000-0002-1752-3102" }, { "family_name": "Handschy", "given_name": "Anne V.", "orcid": "0000-0003-2537-0019" }, { "family_name": "Hildebrandt Ruiz", "given_name": "Lea", "orcid": "0000-0001-8378-1882" }, { "family_name": "Hou", "given_name": "Chung-Yi S.", "orcid": "0000-0002-8087-1775" }, { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847" }, { "family_name": "Joo", "given_name": "Taekyu", "orcid": "0000-0002-8252-4232" }, { "family_name": "Klodt", "given_name": "Alexandra L.", "orcid": "0000-0002-3558-972X" }, { "family_name": "Kong", "given_name": "Weimeng", "orcid": "0000-0002-9432-2857", "clpid": "Kong-Weimeng" }, { "family_name": "Le", "given_name": "Chen", "orcid": "0000-0003-2605-0834" }, { "family_name": "Masoud", "given_name": "Catherine G.", "orcid": "0000-0003-1525-2561" }, { "family_name": "Mayernik", "given_name": "Matthew S.", "orcid": "0000-0002-4122-0910" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765" }, { "family_name": "Nienhouse", "given_name": "Eric J.", "orcid": "0000-0001-6508-5402" }, { "family_name": "Nizkorodov", "given_name": "Sergey A.", "orcid": "0000-0003-0891-0052" }, { "family_name": "Orlando", "given_name": "John J.", "orcid": "0000-0003-2879-0844" }, { "family_name": "Post", "given_name": "Jeroen J." }, { "family_name": "Sturm", "given_name": "Patrick O.", "orcid": "0000-0001-7361-9590" }, { "family_name": "Thrasher", "given_name": "Bridget L.", "orcid": "0000-0002-3961-1971" }, { "family_name": "Tyndall", "given_name": "Geoffrey S.", "orcid": "0000-0002-0695-5241" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Worley", "given_name": "Steven J.", "orcid": "0000-0003-2797-6284" }, { "family_name": "Zhang", "given_name": "Xuan", "orcid": "0000-0003-1548-8021" }, { "family_name": "Ziemann", "given_name": "Paul J.", "orcid": "0000-0001-7419-0044" } ], "abstract": "Atmospheric simulation chambers continue to be indispensable tools for research in the atmospheric sciences. Insights from chamber studies are integrated into atmospheric chemical transport models, which are used for science-informed policy decisions. However, a centralized data management and access infrastructure for their scientific products had not been available in the United States and many parts of the world. ICARUS (Integrated Chamber Atmospheric data Repository for Unified Science) is an open access, searchable, web-based infrastructure for storing, sharing, discovering, and utilizing atmospheric chamber data [https://icarus.ucdavis.edu]. ICARUS has two parts: a data intake portal and a search and discovery portal. Data in ICARUS are curated, uniform, interactive, indexed on popular search engines, mirrored by other repositories, version-tracked, vocabulary-controlled, and citable. ICARUS hosts both legacy data and new data in compliance with open access data mandates. Targeted data discovery is available based on key experimental parameters, including organic reactants and mixtures that are managed using the PubChem chemical database, oxidant information, nitrogen oxide (NOx) content, alkylperoxy radical (RO\u2082) fate, seed particle information, environmental conditions, and reaction categories. A discipline-specific repository such as ICARUS with high amounts of metadata works to support the evaluation and revision of atmospheric model mechanisms, intercomparison of data and models, and the development of new model frameworks that can have more predictive power in the current and future atmosphere. The open accessibility and interactive nature of ICARUS data may also be useful for teaching, data mining, and training machine learning models.", "doi": "10.1021/acsearthspacechem.3c00043", "pmcid": "PMC10278178", "issn": "2472-3452", "publisher": "American Chemical Society", "publication": "ACS Earth and Space Chemistry", "publication_date": "2023-06-15", "series_number": "6", "volume": "7", "issue": "6", "pages": "1235-1246" }, { "id": "authors:bp1m7-0np08", "collection": "authors", "collection_id": "bp1m7-0np08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230530-441700800.46", "type": "article", "title": "Toward a versatile spaceborne architecture for immediate monitoring of the global methane pledge", "author": [ { "family_name": "Wang", "given_name": "Yuchen", "clpid": "Wang-Yuchen" }, { "family_name": "Guo", "given_name": "Xvli", "clpid": "Guo-Xvli" }, { "family_name": "Huo", "given_name": "Yajie", "clpid": "Huo-Yajie" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Pan", "given_name": "Yuqing", "orcid": "0000-0003-2093-8197", "clpid": "Pan-Yuqing" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Baklanov", "given_name": "Alexander", "orcid": "0000-0002-5396-8440", "clpid": "Baklanov-Alexander" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Liu", "given_name": "Pengfei", "orcid": "0000-0002-6714-7387", "clpid": "Liu-Pengfei" } ], "abstract": "The global methane pledge paves a fresh, critical way toward carbon neutrality. However, it remains largely invisible and highly controversial due to the fact that planet-scale and plant-level methane retrievals have rarely been coordinated. This has never been more essential within the narrow window to reach the Paris target. Here we present a two-tiered spaceborne architecture to address this issue. Using this framework, we focused on the United States, China, the Middle East, and North Africa, and simultaneously uncovered methane-abundant regions and plumes. These include new super-emitters, potential leakages, and unprecedented multiple plumes in a single source. More importantly, this framework is shown to challenge official emission reports that possibly mislead estimates from global, regional, and site scales, particularly by missing super-emitters. Our results show that, in principle, the above framework can be extended to be multi-tiered by adding upcoming stereoscopic measurements and suitable artificial intelligence, and thus it is sufficiently versatile for immediate and future monitoring of the global methane pledge.", "doi": "10.5194/acp-23-5233-2023", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2023-05-10", "series_number": "9", "volume": "23", "issue": "9", "pages": "5233-5249" }, { "id": "authors:7vys3-pvr50", "collection": "authors", "collection_id": "7vys3-pvr50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230214-87190900.6", "type": "article", "title": "Widespread missing super-emitters of nitrogen oxides across China inferred from year-round satellite observations", "author": [ { "family_name": "Pan", "given_name": "Yuqing", "clpid": "Pan-Yuqing" }, { "family_name": "Duan", "given_name": "Lei", "orcid": "0000-0002-6540-1847", "clpid": "Duan-Lei" }, { "family_name": "Li", "given_name": "Mingqi", "clpid": "Li-Mingqi" }, { "family_name": "Song", "given_name": "Pinqing", "clpid": "Song-Pinqing" }, { "family_name": "Xv", "given_name": "Nan", "clpid": "Xv-Nan" }, { "family_name": "Liu", "given_name": "Jing", "clpid": "Liu-Jing" }, { "family_name": "Le", "given_name": "Yifei", "clpid": "Le-Yifei" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Wang", "given_name": "Cui", "clpid": "Wang-Cui" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" } ], "abstract": "Nitrogen oxides (NO\u2093 \u2261 NO + NO\u2082) play a central role in air pollution and are targeted for emission mitigation by environmental protection agencies globally. Unique challenges for mitigation are presented by super-emitters, typically with the potential to dominate localized NO\u2093 budgets. Nevertheless, identifying super-emitters still challenges emission mitigation, while the spatial resolution of emission monitoring rises continuously. Here we develop an efficient, super-resolution (1 \u00d7 1 km\u00b2) inverse model based on year-round TROPOMI satellite observations over China. Consequently, we resolve hundreds of super-emitters in virtually every corner of China, even in remote and mountainous areas. They are attributed to individual plants or parks, mostly associated with industrial sectors, like energy, petrochemical, and iron and steel industries. State-of-the-art bottom-up emission estimates (i.e., MEICv1.3 and HTAPv2), as well as classic top-down inverse methods (e.g., a CTM coupled with the Ensemble Kalman Filter), do not adequately identify these super-emitters. Remarkably, more than one hundred super-emitters are unambiguously missed, while the establishments or discontinuations of the super-emitters potentially lead to under- or over-estimates, respectively. Moreover, evidence shows that these super-emitters generally dominate the NO\u2093 budget in a localized area (e.g., equivalent to a spatial scale of a medium-sized county). Although our dataset is incomplete nationwide due to the undetectable super-emitters on top of high pollution, our results imply that super-emitters contribute significantly to national NO\u2093 budgets and thus suggest the necessity to address the NO\u2093 budget by revisiting super-emitters on a large scale. Integrating the results we obtain here with a multi-tiered observation system can lead to identification and mitigation of anomalous NO\u2093 emissions.", "doi": "10.1016/j.scitotenv.2022.161157", "issn": "0048-9697", "publisher": "Elsevier", "publication": "Science of the Total Environment", "publication_date": "2023-03-15", "volume": "864", "pages": "Art. No. 161157" }, { "id": "authors:4pjt6-73r14", "collection": "authors", "collection_id": "4pjt6-73r14", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230125-515005200.30", "type": "article", "title": "Vapors Are Lost to Walls, Not to Particles on the Wall: Artifact-Corrected Parameters from Chamber Experiments and Implications for Global Secondary Organic Aerosol", "author": [ { "family_name": "Bilsback", "given_name": "Kelsey R.", "orcid": "0000-0002-5996-1522", "clpid": "Bilsback-Kelsey-R" }, { "family_name": "He", "given_name": "Yicong", "orcid": "0000-0001-8969-1167", "clpid": "He-Yicong" }, { "family_name": "Cappa", "given_name": "Christopher D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-Christopher-D" }, { "family_name": "Chang", "given_name": "Rachel Ying-Wen", "orcid": "0000-0003-2337-098X", "clpid": "Chang-Rachel-Ying-Wen" }, { "family_name": "Croft", "given_name": "Betty", "orcid": "0000-0002-7009-1767", "clpid": "Croft-Betty" }, { "family_name": "Martin", "given_name": "Randall V.", "orcid": "0000-0003-2632-8402", "clpid": "Martin-Randall-V" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pierce", "given_name": "Jeffrey R.", "orcid": "0000-0002-4241-838X", "clpid": "Pierce-Jeffrey-R" }, { "family_name": "Jathar", "given_name": "Shantanu H.", "orcid": "0000-0003-4106-2358", "clpid": "Jathar-Shantanu-H" } ], "abstract": "Atmospheric models of secondary organic aerosol (OA) (SOA) typically rely on parameters derived from environmental chambers. Chambers are subject to experimental artifacts, including losses of (1) particles to the walls (PWL), (2) vapors to the particles on the wall (V2PWL), and (3) vapors to the wall directly (VWL). We present a method for deriving artifact-corrected SOA parameters and translating these to volatility basis set (VBS) parameters for use in chemical transport models (CTMs). Our process involves combining a box model that accounts for chamber artifacts (Statistical Oxidation Model with a TwO-Moment Aerosol Sectional model (SOM-TOMAS)) with a pseudo-atmospheric simulation to develop VBS parameters that are fit across a range of OA mass concentrations. We found that VWL led to the highest percentage change in chamber SOA mass yields (high NO\u2093: 36\u2013680%; low NO\u2093: 55\u2013250%), followed by PWL (high NO\u2093: 8\u201339%; low NO\u2093: 10\u201337%), while the effects of V2PWL are negligible. In contrast to earlier work that assumed that V2PWL was a meaningful loss pathway, we show that V2PWL is an unimportant SOA loss pathway and can be ignored when analyzing chamber data. Using our updated VBS parameters, we found that not accounting for VWL may lead surface-level OA to be underestimated by 24% (0.25 \u03bcg m\u207b\u00b3) as a global average or up to 130% (9.0 \u03bcg m\u207b\u00b3) in regions of high biogenic or anthropogenic activity. Finally, we found that accurately accounting for PWL and VWL improves model-measurement agreement for fine mode aerosol mass concentrations (PM\u2082.\u2085) in the GEOS-Chem model.", "doi": "10.1021/acs.est.2c03967", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2023-01-10", "series_number": "1", "volume": "57", "issue": "1", "pages": "53-63" }, { "id": "authors:49ka1-pe336", "collection": "authors", "collection_id": "49ka1-pe336", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220726-998075000", "type": "article", "title": "Quantifying on-road vehicle emissions during traffic congestion using updated emission factors of light-duty gasoline vehicles and real-world traffic monitoring big data", "author": [ { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Jiang", "given_name": "Linhui", "clpid": "Jiang-Linhui" }, { "family_name": "Xia", "given_name": "Yan", "clpid": "Xia-Yan" }, { "family_name": "Wang", "given_name": "Lu", "clpid": "Wang-Lu" }, { "family_name": "Ye", "given_name": "Jianjie", "clpid": "Ye-Jianjie" }, { "family_name": "Hou", "given_name": "Tangyan", "clpid": "Hou-Tangyan" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Li", "given_name": "Zhen", "orcid": "0000-0003-3802-7543", "clpid": "Li-Zhen" }, { "family_name": "Song", "given_name": "Zhe", "clpid": "Song-Zhe" }, { "family_name": "Li", "given_name": "Jiali", "clpid": "Li-Jiali" }, { "family_name": "Jiang", "given_name": "Yaping", "clpid": "Jiang-Yaping" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Zhang", "given_name": "Xiaoye", "clpid": "Zhang-Xiaoye" }, { "family_name": "Zhang", "given_name": "Yang", "clpid": "Zhang-Yang-ENV" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" } ], "abstract": "Light-duty gasoline vehicles (LDGVs) have made up >90 % of vehicle fleets in China since 2019, moreover, with a high annual growth rate (> 10 %) since 2017. Hence, accurate estimates of air pollutant emissions of these fast-changing LDGVs are vital for air quality management, human healthcare, and ecological protection. However, this issue is poorly quantified due to insufficient reserves of timely updated LDGV emission factors, which are dependent on real-world activity levels. Here we constructed a big dataset of explicit emission profiles (e.g., emission factors and accumulated mileages) for 159,051 LDGVs based on an official I/M database by matching real-time traffic dynamics via real-world traffic monitoring (e.g., traffic volumes and speeds). Consequently, we provide robust evidence that the emission factors of these LDGVs follow a clear heavy-tailed distribution. The top 10 % emitters contributed >60 % to the total fleet emissions, while the bottom 50 % contributed <10 %. Such emission factors were effectively reduced by 75.7\u201386.2 % as official emission standards upgraded gradually (i.e., from China 2 to China 5) within 13 years from 2004 to 2017. Nevertheless, such achievements would be offset once traffic congestion occurred. In the real world, the typical traffic congestions (i.e., vehicle speed <5 km/h) can lead to emissions 5\u2013 9 times higher than those on non-congested roads (i.e., vehicle speed >50 km/h). These empirical analyses enabled us to propose future traffic scenarios that could harmonize emission standards and traffic congestion. Practical approaches on vehicle emission controls under realistic conditions are proposed, which would provide new insights for future urban vehicle emission management.", "doi": "10.1016/j.scitotenv.2022.157581", "issn": "0048-9697", "publisher": "Elsevier", "publication": "Science of the Total Environment", "publication_date": "2022-11-15", "volume": "847", "pages": "Art. No. 157581" }, { "id": "authors:v3h1q-erq93", "collection": "authors", "collection_id": "v3h1q-erq93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230103-817548100.12", "type": "article", "title": "Notable impact of wildfires in the western United States on weather hazards in the central United States", "author": [ { "family_name": "Zhang", "given_name": "Yuwei", "orcid": "0000-0002-3260-6782", "clpid": "Zhang-Yuwei" }, { "family_name": "Fan", "given_name": "Jiwen", "orcid": "0000-0001-5280-4391", "clpid": "Fan-Jiwen" }, { "family_name": "Shrivastava", "given_name": "Manish", "orcid": "0000-0002-9053-2400", "clpid": "Shrivastava-M" }, { "family_name": "Homeyer", "given_name": "Cameron R.", "orcid": "0000-0002-4883-6670", "clpid": "Homeyer-Cameron-R" }, { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401", "clpid": "Wang-Yuan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Increased wildfire events constitute a significant threat to life and property in the United States. Wildfire impact on severe storms and weather hazards is another pathway that threatens society, and our understanding of which is very limited. Here, we use unique modeling developments to explore the effects of wildfires in the western US (mainly California and Oregon) on precipitation and hail in the central US. We find that the western US wildfires notably increase the occurrences of heavy precipitation rates by 38% and significant severe hail (\u22652 in.) by 34% in the central United States. Both heat and aerosols from wildfires play an important role. By enhancing surface high pressure and increasing westerly and southwesterly winds, wildfires in the western United States produce stronger moisture and aerosol transport to the central United States and larger wind shear and storm-relative helicity in the central United States. Both the meteorological environment more conducive to severe convective storms and increased aerosols contribute to the enhancements of heavy precipitation rates and large hail. Moreover, the local wildfires in the central US also enhance the severity of storms, but their impact is notably smaller than the impact of remote wildfires in California and Oregon because of the lessened severity of the local wildfires. As wildfires are projected to be more frequent and severe in a warmer climate, the influence of wildfires on severe weather in downwind regions may become increasingly important.", "doi": "10.1073/pnas.2207329119", "pmcid": "PMC9636965", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2022-11", "series_number": "44", "volume": "119", "issue": "44", "pages": "Art. No. e2207329119" }, { "id": "authors:wz38r-8z283", "collection": "authors", "collection_id": "wz38r-8z283", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220926-577339400.21", "type": "article", "title": "Impacts of condensable particulate matter on atmospheric organic aerosols and fine particulate matter (PM_(2.5)) in China", "author": [ { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Song", "given_name": "Zhe", "clpid": "Song-Zhe" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Liu", "given_name": "Pengfei", "orcid": "0000-0002-6714-7387", "clpid": "Liu-Pengfei" }, { "family_name": "Zhang", "given_name": "Xiaoye", "clpid": "Zhang-Xiaoye" }, { "family_name": "Zhang", "given_name": "Meigen", "orcid": "0000-0002-3318-6134", "clpid": "Zhang-Meigen" }, { "family_name": "Sun", "given_name": "Yele", "orcid": "0000-0003-2354-0221", "clpid": "Sun-Yele" }, { "family_name": "Liu", "given_name": "Zirui", "orcid": "0000-0002-1939-9715", "clpid": "Liu-Zirui" }, { "family_name": "Sun", "given_name": "Caiping", "clpid": "Sun-Caiping" }, { "family_name": "Jiang", "given_name": "Jingkun", "clpid": "Jiang-Jingkun" }, { "family_name": "Wang", "given_name": "Shuxiao", "orcid": "0000-0001-9727-1963", "clpid": "Wang-Shuxiao" }, { "family_name": "Murphy", "given_name": "Benjamin N.", "orcid": "0000-0003-3542-5378", "clpid": "Murphy-Benjamin-N" }, { "family_name": "Alapaty", "given_name": "Kiran", "clpid": "Alapaty-Kiran" }, { "family_name": "Mathur", "given_name": "Rohit", "orcid": "0000-0001-8927-5876", "clpid": "Mathur-Rohit" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Condensable particulate matter (CPM) emitted from stationary combustion and mobile sources exhibits high emissions and a large proportion of organic components. However, CPM is not generally measured when conducting emission surveys of PM in most countries, including China. Consequently, previous emission inventories have not included emission rates for CPM. Here, we construct an emission inventory of CPM in China with a focus on organic aerosols (OAs) based on collected CPM emission information. Results show that OA emissions are enhanced twofold after the inclusion of CPM in a new inventory for China for the years 2014 and 2017. Considering organic CPM emissions and model representations of secondary OA (SOA) formation from CPM, a series of sensitivity cases have been simulated here using the three-dimensional Community Multiscale Air Quality (CMAQ) model to estimate the contributions of CPM emissions to atmospheric OA and fine PM (PM_(2.5), particulate matter with aerodynamic diameter not exceeding 2.5\u2009\u00b5m) concentrations in China. Compared with observations at a Beijing site during a haze episode from 14 October to 14 November 2014, estimates of the temporal average primary OA (POA) and SOA concentrations were greatly improved after including the CPM effects. These scenarios demonstrated the significant contributions of CPM emissions from stationary combustion and mobile sources to the POA (51\u2009%\u201385\u2009%), SOA (42\u2009%\u201358\u2009%), and total OA concentrations (45\u2009%\u201375\u2009%). Furthermore, the contributions of CPM emissions to total OA concentrations were demonstrated over the 2 major cities and 26 other cities of the Beijing\u2013Tianjin\u2013Hebei region (hereafter referred to as the \"BTH2\u2009+\u200926 cities\") in December 2018, with average contributions of up to 49\u2009%, 53\u2009%, 54\u2009%, and 50\u2009% for Handan, Shijiazhuang, Xingtai, and Dezhou, respectively. Correspondingly, the inclusion of CPM emissions also narrowed the gap between simulated and observed PM_(2.5) concentrations over the BTH2\u2009+\u200926 cities. These results improve the simulation performance of atmospheric OA and PM_(2.5) and may also provide important implications for the sources of OA.", "doi": "10.5194/acp-22-11845-2022", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2022-09-13", "series_number": "17", "volume": "22", "issue": "17", "pages": "11845-11866" }, { "id": "authors:gda2b-4p107", "collection": "authors", "collection_id": "gda2b-4p107", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220803-536053000", "type": "article", "title": "Heterogeneous iodine-organic chemistry fast-tracks marine new particle formation", "author": [ { "family_name": "Huang", "given_name": "Ru-Jin", "orcid": "0000-0002-4907-9616", "clpid": "Huang-Ru-Jin" }, { "family_name": "Hoffmann", "given_name": "Thorsten", "orcid": "0000-0003-0939-271X", "clpid": "Hoffmann-Thorsten" }, { "family_name": "Ovadnevaite", "given_name": "Jurgita", "orcid": "0000-0001-7201-0118", "clpid": "Ovadnevaite-Jurgita" }, { "family_name": "Laaksonen", "given_name": "Ari", "orcid": "0000-0002-1657-2383", "clpid": "Laaksonen-Ari" }, { "family_name": "Kokkola", "given_name": "Harri", "orcid": "0000-0002-1404-6670", "clpid": "Kokkola-Harri" }, { "family_name": "Xu", "given_name": "Wen", "orcid": "0000-0002-2084-2630", "clpid": "Xu-Wen" }, { "family_name": "Xu", "given_name": "Wei", "orcid": "0000-0002-9590-1906", "clpid": "Wu-Wei" }, { "family_name": "Ceburnis", "given_name": "Darius", "orcid": "0000-0003-0231-5324", "clpid": "Ceburnis-Darius" }, { "family_name": "Zhang", "given_name": "Renyi", "orcid": "0000-0001-8708-3862", "clpid": "Zhang-Renyi" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "O'Dowd", "given_name": "Colin", "orcid": "0000-0002-3068-2212", "clpid": "O'Dowd-Colin" } ], "abstract": "The gas-phase formation of new particles less than 1 nm in size and their subsequent growth significantly alters the availability of cloud condensation nuclei (CCN, >30\u201350 nm), leading to impacts on cloud reflectance and the global radiative budget. However, this growth cannot be accounted for by condensation of typical species driving the initial nucleation. Here, we present evidence that nucleated iodine oxide clusters provide unique sites for the accelerated growth of organic vapors to overcome the coagulation sink. Heterogeneous reactions form low-volatility organic acids and alkylaminium salts in the particle phase, while further oligomerization of small \u03b1-dicarbonyls (e.g., glyoxal) drives the particle growth. This identified heterogeneous mechanism explains the occurrence of particle production events at organic vapor concentrations almost an order of magnitude lower than those required for growth via condensation alone. A notable fraction of iodine associated with these growing particles is recycled back into the gas phase, suggesting an effective transport mechanism for iodine to remote regions, acting as a \"catalyst\" for nucleation and subsequent new particle production in marine air.", "doi": "10.1073/pnas.2201729119", "pmcid": "PMC9371740", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2022-08-09", "series_number": "32", "volume": "119", "issue": "32", "pages": "Art. No. e2201729119" }, { "id": "authors:fq1wc-zev70", "collection": "authors", "collection_id": "fq1wc-zev70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220520-231670000", "type": "article", "title": "Process-Level Modeling Can Simultaneously Explain Secondary Organic Aerosol Evolution in Chambers and Flow Reactors", "author": [ { "family_name": "He", "given_name": "Yicong", "orcid": "0000-0001-8969-1167", "clpid": "He-Yicong" }, { "family_name": "Lambe", "given_name": "Andrew T.", "orcid": "0000-0003-3031-701X", "clpid": "Lambe-Andrew-T" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Cappa", "given_name": "Christopher D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-Christopher-D" }, { "family_name": "Pierce", "given_name": "Jeffrey R.", "orcid": "0000-0002-4241-838X", "clpid": "Pierce-Jeffrey-R" }, { "family_name": "Jathar", "given_name": "Shantanu H.", "orcid": "0000-0003-4106-2358", "clpid": "Jathar-Shantanu-H" } ], "abstract": "Secondary organic aerosol (SOA) data gathered in environmental chambers (ECs) have been used extensively to develop parameters to represent SOA formation and evolution. The EC-based parameters are usually constrained to less than one day of photochemical aging but extrapolated to predict SOA aging over much longer timescales in atmospheric models. Recently, SOA has been increasingly studied in oxidation flow reactors (OFRs) over aging timescales of one to multiple days. However, these OFR data have been rarely used to validate or update the EC-based parameters. The simultaneous use of EC and OFR data is challenging because the processes relevant to SOA formation and evolution proceed over very different timescales, and both reactor types exhibit distinct experimental artifacts. In this work, we show that a kinetic SOA chemistry and microphysics model that accounts for various processes, including wall losses, aerosol phase state, heterogeneous oxidation, oligomerization, and new particle formation, can simultaneously explain SOA evolution in EC and OFR experiments, using a single consistent set of SOA parameters. With \u03b1-pinene as an example, we first developed parameters by fitting the model output to the measured SOA mass concentration and oxygen-to-carbon (O:C) ratio from an EC experiment (<1 day of aging). We then used these parameters to simulate SOA formation in OFR experiments and found that the model overestimated SOA formation (by a factor of 3\u201316) over photochemical ages ranging from 0.4 to 13 days, when excluding the abovementioned processes. By comprehensively accounting for these processes, the model was able to explain the observed evolution in SOA mass, composition (i.e., O:C), and size distribution in the OFR experiments. This work suggests that EC and OFR SOA data can be modeled consistently, and a synergistic use of EC and OFR data can aid in developing more refined SOA parameters for use in atmospheric models.", "doi": "10.1021/acs.est.1c08520", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2022-05-17", "series_number": "10", "volume": "56", "issue": "10", "pages": "6262-6273" }, { "id": "authors:2phba-tvn02", "collection": "authors", "collection_id": "2phba-tvn02", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220520-231882000", "type": "article", "title": "Direct measurements of ozone response to emissions perturbations in California", "author": [ { "family_name": "Wu", "given_name": "Shenglun", "orcid": "0000-0002-2156-7968", "clpid": "Wu-Shenglun" }, { "family_name": "Lee", "given_name": "Hyung Joo", "clpid": "Lee-Hyung-Joo" }, { "family_name": "Anderson", "given_name": "Andrea", "clpid": "Anderson-Andrea" }, { "family_name": "Liu", "given_name": "Shang", "orcid": "0000-0002-3403-8651", "clpid": "Liu-Shang" }, { "family_name": "Kuwayama", "given_name": "Toshihiro", "orcid": "0000-0002-0540-0156", "clpid": "Kuwayama-Toshihiro" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Kleeman", "given_name": "Michael J.", "clpid": "Kleeman-Michael-J" } ], "abstract": "A new technique was used to directly measure O\u2083 response to changes in precursor NO\u2093 and volatile organic compound (VOC) concentrations in the atmosphere using three identical Teflon smog chambers equipped with UV lights. One chamber served as the baseline measurement for O\u2083 formation, one chamber added NO\u2093, and one chamber added surrogate VOCs (ethylene, m-xylene, n-hexane). Comparing the O\u2083 formation between chambers over a 3-hour UV cycle provides a direct measurement of O\u2083 sensitivity to precursor concentrations. Measurements made with this system at Sacramento, California, between April\u2013December 2020 revealed that the atmospheric chemical regime followed a seasonal cycle. O\u2083 formation was VOC-limited (NO\u2093-rich) during the early spring, transitioned to NO\u2093-limited during the summer due to increased concentrations of ambient VOCs with high O\u2083 formation potential, and then returned to VOC-limited (NO\u2093-rich) during the fall season as the concentrations of ambient VOCs decreased and NO\u2093 increased. This seasonal pattern of O\u2083 sensitivity is consistent with the cycle of biogenic emissions in California. The direct chamber O\u2083 sensitivity measurements matched semi-direct measurements of ratios from the TROPOspheric Monitoring Instrument (TROPOMI) aboard the Sentinel-5 Precursor (Sentinel-5P) satellite. Furthermore, the satellite observations showed that the same seasonal cycle in O\u2083 sensitivity occurred over most of the entire state of California, with only the urban cores of the very large cities remaining VOC-limited across all seasons. The O\u2083-nonattainment days (MDA8 O\u2083 > 70\u2009ppb) have O\u2083 sensitivity in the NO\u2093-limited regime, suggesting that a NO\u2093 emissions control strategy would be most effective at reducing these peak O\u2083 concentrations. In contrast, a large portion of the days with MDA8 O\u2083 concentrations below 55\u2009ppb were in the VOC-limited regime, suggesting that an emissions control strategy focusing on NO\u2093 reduction would increase O\u2083 concentrations. This challenging situation suggests that emissions control programs that focus on NO\u2093 reductions will immediately lower peak O\u2083 concentrations but slightly increase intermediate O\u2083 concentrations until NO\u2093 levels fall far enough to re-enter the NO\u2093-limited regime. The spatial pattern of increasing and decreasing O\u2083 concentrations in response to a NO\u2093 emissions control strategy should be carefully mapped in order to fully understand the public health implications.", "doi": "10.5194/acp-22-4929-2022", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2022-04-14", "series_number": "7", "volume": "22", "issue": "7", "pages": "4929-4949" }, { "id": "authors:3vv2c-e8p46", "collection": "authors", "collection_id": "3vv2c-e8p46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220322-742104000", "type": "article", "title": "A Neural Network-Assisted Euler Integrator for Stiff Kinetics in Atmospheric Chemistry", "author": [ { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric chemistry, characterized by highly coupled sets of ordinary differential equations (ODEs), is dynamically stiff owing to the fact that both fast and slow processes exist simultaneously. We develop here a neural network-assisted Euler integrator for the kinetics of atmospheric chemical reactions. We show that the integral kernel of the chemical reaction system can be represented by a neural network. The stiff kinetics of the atmospheric H\u2082O\u2082/OH/HO\u2082 system, involving 3 species and 4 reactions, and a simplified air pollution mechanism, involving 20 species and 25 reactions, are developed here in detail as illustrations of the neural network Euler integrator. The algorithm developed accelerates the numerical integration of large sets of coupled stiff ODEs by at least one order of magnitude by avoiding the intensive linear algebra that is required in traditional stiff ODE solvers; moreover, the mechanism-specific neural network-assisted algorithm can be readily coupled to other modules in a three-dimensional atmospheric chemical transport model.", "doi": "10.1021/acs.est.1c07648", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2022-04-05", "series_number": "7", "volume": "56", "issue": "7", "pages": "4676-4685" }, { "id": "authors:v13cc-e5q75", "collection": "authors", "collection_id": "v13cc-e5q75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220104-157888000", "type": "article", "title": "Rapid assessments of light-duty gasoline vehicle emissions using on-road remote sensing and machine learning", "author": [ { "family_name": "Xia", "given_name": "Yan", "clpid": "Xia-Yan" }, { "family_name": "Jiang", "given_name": "Linhui", "clpid": "Jiang-Linhui" }, { "family_name": "Wang", "given_name": "Lu", "clpid": "Wang-Lu" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Ye", "given_name": "Jianjie", "clpid": "Ye-Jianjie" }, { "family_name": "Hou", "given_name": "Tangyan", "clpid": "Hou-Tangyan" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Song", "given_name": "Zhe", "clpid": "Song-Zhe" }, { "family_name": "Jiang", "given_name": "Yaping", "clpid": "Jiang-Yaping" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" } ], "abstract": "In-time and accurate assessments of on-road vehicle emissions play a central role in urban air quality and health policymaking. However, official insight is hampered by the Inspection/Maintenance (I/M) procedure conducted in the laboratory annually. It not only has a large gap to real-world situations (e.g., meteorological conditions) but also is incapable of regular supervision. Here we build a unique dataset including 103,831 light-duty gasoline vehicles, in which on-road remote sensing (ORRS) measurements are linked to the I/M records based on the vehicle identification numbers and license plates. On this basis, we develop an ensemble model framework that integrates three machining learning algorithms, including neural network (NN), extreme gradient boosting (XGBoost), and random forest (RF). We demonstrate that this ensemble model could rapidly assess the vehicle-specific emissions (i.e., CO, HC, and NO). In particular, the model performs quite well for the passing vehicles under normal conditions (i.e., lower VSP (<18 kw/t), temperature (6\u201332 \u00b0C), relative humidity (<80%), and wind speed (<5 m/s)). Together with the current emission standard, we identify a large number of the 'dirty' (2.33%) or 'clean' (74.92%) vehicles in the real world. Our results show that the ORRS measurements, assisted by the machine-learning-based ensemble model developed here, can realize day-to-day supervision of on-road vehicle-specific emissions. This approach framework provides a valuable opportunity to reform the I/M procedures globally and mitigate urban air pollution deeply.", "doi": "10.1016/j.scitotenv.2021.152771", "issn": "0048-9697", "publisher": "Elsevier", "publication": "Science of the Total Environment", "publication_date": "2022-04-01", "volume": "815", "pages": "Art. No. 152771" }, { "id": "authors:76kw1-nf765", "collection": "authors", "collection_id": "76kw1-nf765", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220204-680248000", "type": "article", "title": "Secondary organic aerosol formation from the oxidation of decamethylcyclopentasiloxane at atmospherically relevant OH concentrations", "author": [ { "family_name": "Charan", "given_name": "Sophia M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-Sophia-M" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Buenconsejo", "given_name": "Reina S.", "orcid": "0000-0002-0162-905X", "clpid": "Buenconsejo-Reina-S" }, { "family_name": "Li", "given_name": "Qi", "clpid": "Li-Qi" }, { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-David-R-III" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Decamethylcyclopentasiloxane (D5, C\u2081\u2080H\u2083\u2080O\u2085Si\u2085) is measured at parts per trillion (ppt) levels outdoors and parts per billion (ppb) levels indoors. Primarily used in personal care products, its outdoor concentration is correlated to population density. Since understanding the aerosol formation potential of volatile chemical products is critical to understanding particulate matter in urban areas, the secondary organic aerosol yield of D5 was studied under a wide range of OH concentrations and, correspondingly, OH exposures using both batch-mode chamber and continuously run flow tube experiments. These results were comprehensively analyzed and compared to two other secondary organic aerosol (SOA) yield datasets from literature. It was found that the SOA yield from the oxidation of D5 is extremely dependent on either the OH concentration or exposure. For OH concentrations of \u2272\u200910\u2077\u2009molec. cm\u207b\u00b3 or OH exposures of \u2272\u20092\u2009\u00d7\u200910\u00b9\u00b9, molec. s cm\u207b\u00b3 the SOA yield is largely <\u20095\u2009% and usually \u223c\u20091\u2009%. This is significantly lower than SOA yields previously reported. Using a two-product absorptive partitioning model for the upper bound SOA yields, the stoichiometric mass fraction and absorptive partitioning coefficients are, for the first product, \u03b1\u2081\u2009=\u20090.056 and K_(OM,1)\u2009=\u20090.022\u2009m\u00b3\u2009\u00b5g\u207b\u00b9; for the second product, they are \u03b1\u2082\u2009=\u20097.7 and K_(OM,2)\u2009=\u20094.3\u2009\u00d7\u200910\u207b\u2075\u2009m\u00b3\u2009\u00b5g\u207b\u00b9. Generally, there are high SOA yields (>\u200990\u2009%) at OH mixing ratios of 5\u2009\u00d7\u200910\u2079\u2009 molec. cm\u207b\u00b3 or OH exposures above 10\u00b9\u00b2 molec. s cm\u207b\u00b3.", "doi": "10.5194/acp-22-917-2022", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2022-01-19", "series_number": "2", "volume": "22", "issue": "2", "pages": "917-928" }, { "id": "authors:p48d0-sbn20", "collection": "authors", "collection_id": "p48d0-sbn20", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220114-12791000", "type": "article", "title": "Modeling secondary organic aerosol formation from volatile chemical products", "author": [ { "family_name": "Pennington", "given_name": "Elyse A.", "orcid": "0000-0003-1736-2342", "clpid": "Pennington-Elyse-A" }, { "family_name": "Seltzer", "given_name": "Karl M.", "orcid": "0000-0002-2175-5678", "clpid": "Seltzer-Karl-M" }, { "family_name": "Murphy", "given_name": "Benjamin N.", "orcid": "0000-0003-3542-5378", "clpid": "Murphy-Benjamin-N" }, { "family_name": "Qin", "given_name": "Momei", "clpid": "Qin-Momei" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pye", "given_name": "Havala O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-Havala-O-T" } ], "abstract": "Volatile chemical products (VCPs) are commonly used consumer and industrial items that are an important source of anthropogenic emissions. Organic compounds from VCPs evaporate on atmospherically relevant timescales and include many species that are secondary organic aerosol (SOA) precursors. However, the chemistry leading to SOA, particularly that of intermediate-volatility organic compounds (IVOCs), has not been fully represented in regional-scale models such as the Community Multiscale Air Quality (CMAQ) model, which tend to underpredict SOA concentrations in urban areas. Here we develop a model to represent SOA formation from VCP emissions. The model incorporates a new VCP emissions inventory and employs three new classes of emissions: siloxanes, oxygenated IVOCs, and nonoxygenated IVOCs. VCPs are estimated to produce 1.67\u2009\u00b5g\u2009m\u22123 of noontime SOA, doubling the current model predictions and reducing the SOA mass concentration bias from \u221275\u2009% to \u221258\u2009% when compared to observations in Los Angeles in 2010. While oxygenated and nonoxygenated intermediate-volatility VCP species are emitted in similar quantities, SOA formation is dominated by the nonoxygenated IVOCs. Formaldehyde and SOA show similar relationships to temperature and bias signatures, indicating common sources and/or chemistry. This work suggests that VCPs contribute up to half of anthropogenic SOA in Los Angeles and models must better represent SOA precursors from VCPs to predict the urban enhancement of SOA.", "doi": "10.5194/acp-21-18247-2021", "pmcid": "PMC8788583", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2021-12-16", "series_number": "24", "volume": "21", "issue": "24", "pages": "18247-18261" }, { "id": "authors:3x646-k0k08", "collection": "authors", "collection_id": "3x646-k0k08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210817-221136253", "type": "article", "title": "Large scale control of surface ozone by relative humidity observed during warm seasons in China", "author": [ { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Lichtfouse", "given_name": "Eric", "orcid": "0000-0002-8535-8073", "clpid": "Lichtfouse-Eric" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Rising air pollution by surface ozone (O\u2083) in China has induced extensive efforts to control ozone generation in major urban and industrial areas, yet mechanisms ruling the ozone production and loss are not well understood. In particular, ozone levels are strongly influenced by meteorological factors such as relative humidity, but this has been explored only in local situations, and the effect of relative humidity on ozone levels in warm seasons on a large scale in China is still unknown. Here we studied surface ozone, relative humidity, temperature, and other meteorological variables in 74 major cities in China during 2017\u20132018, focusing on the warm seasons in seven regions. Results show that ozone levels decrease with increasing relative humidity in all cities, with an average correlation coefficient of\u2009\u2212\u20090.58, ranging from\u2009\u2212\u20090.17 in Zhangjiakou to\u2009\u2212\u20090.84 in Hengshui. At high relative humidity levels, above 75%, average ozone levels ranged from 44.6 to 122.5 \u03bcg m\u207b\u00b3, which is lower than Chinese quality threshold of hourly average ozone level of 200 \u03bcg m\u207b\u00b3. The decreases of ozone with relative humidity were more pronounced at high temperature, above 30 \u00b0C, than below 25 \u00b0C. The increases of ozone with temperature were more pronounced at low relative humidity, below 40%. Overall, our findings reveal that mechanisms ruling surface ozone levels are similar on a large scale. This is promising to design common methods of climate engineering to protect human health.", "doi": "10.1007/s10311-021-01265-0", "issn": "1610-3653", "publisher": "Springer", "publication": "Environmental Chemistry Letters", "publication_date": "2021-12", "series_number": "6", "volume": "19", "issue": "6", "pages": "3981-3989" }, { "id": "authors:adwmk-s5e59", "collection": "authors", "collection_id": "adwmk-s5e59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211207-6348000", "type": "article", "title": "Dominant Contributions of Secondary Aerosols and Vehicle Emissions to Water-Soluble Inorganic Ions of PM_(2.5) in an Urban Site in the Metropolitan Hangzhou, China", "author": [ { "family_name": "Xiong", "given_name": "Chun", "clpid": "Xiong-Chun" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Water soluble inorganic ions (WSIIs) are important components in PM_(2.5) and could strongly affect the acidity and hygroscopicity of PM_(2.5). In order to achieve the seasonal characteristics and determine the potential sources of WSIIs in PM_(2.5) in Hangzhou, online systems were used to measure hourly mass concentrations of WSIIs (SO\u2084\u00b2\u207b, NO\u2083\u207b, NH\u2084+, Cl\u207b, Na+, K+, Ca\u00b2+ and Mg\u00b2+) as well as PM_(2.5), NO\u2082 and SO\u2082 at an urban site for one month each season (May, August, October, December) in 2017. Results showed that the hourly mass concentrations of PM_(2.5) during the whole campaign varied from 1 to 292 \u03bcg\u00b7m\u207b\u00b3 with the mean of 56.03 \u03bcg\u00b7m\u207b\u00b3. The mean mass concentration of WSIIs was 26.49 \u00b1 20.78 \u03bcg\u00b7m\u207b\u00b3, which contributed 48.28% to averaged PM2.5 mass. SNA (SO\u2084\u00b2\u207b, NO\u2083\u207b and NH\u2084\u207a) were the most abundant ions in PM_(2.5) and on average, they comprised 41.57% of PM2.5 mass. PM_(2.5), NO\u2082, SO\u2082 and WSIIs showed higher mass concentrations in December, possibly due to higher energy consumption emissions, unfavorable meteorological factors (e.g., lower wind speed and temperature) and regional transport. Results from PCA models showed that secondary aerosols and vehicle emissions were the dominant sources of WSIIs in the observations. Our findings highlight the importance of stronger controls on precursor (e.g., SO\u2082 and NO\u2082) emissions in Hangzhou, and show that industrial areas should be controlled at local and regional scales in the future.", "doi": "10.3390/atmos12111529", "issn": "2073-4433", "publisher": "MDPI", "publication": "Atmosphere", "publication_date": "2021-11-22", "series_number": "11", "volume": "12", "issue": "11", "pages": "Art. No. 1529" }, { "id": "authors:5n0s7-76p22", "collection": "authors", "collection_id": "5n0s7-76p22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211118-233559021", "type": "article", "title": "Observations of Volatile Organic Compounds in the Los Angeles Basin during COVID-19", "author": [ { "family_name": "Van Rooy", "given_name": "Paul", "orcid": "0000-0003-1193-0994", "clpid": "Van-Rooy-Paul" }, { "family_name": "Tasnia", "given_name": "Afsara", "orcid": "0000-0002-3048-5083", "clpid": "Tasnia-Afsara" }, { "family_name": "Barletta", "given_name": "Barbara", "orcid": "0000-0003-3046-014X", "clpid": "Barletta-Barbara" }, { "family_name": "Buenconsejo", "given_name": "Reina", "orcid": "0000-0002-0162-905X", "clpid": "Buenconsejo-Reina-S" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-John-D" }, { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Meinardi", "given_name": "Simone", "orcid": "0000-0003-4828-9889", "clpid": "Meinardi-Simone" }, { "family_name": "Murphy", "given_name": "Sara", "clpid": "Murphy-Sara" }, { "family_name": "Parker", "given_name": "Harrison", "orcid": "0000-0002-0041-2764", "clpid": "Parker-Harrison" }, { "family_name": "Schulze", "given_name": "Benjamin", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Blake", "given_name": "Donald R.", "orcid": "0000-0002-8283-5014", "clpid": "Blake-Donald-R" }, { "family_name": "Barsanti", "given_name": "Kelley C.", "orcid": "0000-0002-6065-8643", "clpid": "Barsanti-Kelley-C" } ], "abstract": "Volatile organic compounds (VOCs) were measured in the Los Angeles (LA) Basin from mid-April to mid-July 2020 during the COVID-19 pandemic, as a part of the Los Angeles Air Quality Campaign (LAAQC). VOCs were quantified in over 450 samples using one- and two-dimensional gas chromatography with different detectors; mixing ratios were determined for 150 compounds associated with on- and off-road mobile, volatile chemical product, and biogenic sources. During the sampling period, traffic counts increased from \u223c55% to \u223c80% of pre-COVID levels. While the average afternoon combustion-derived VOCs and carbon monoxide (CO) mixing ratios did not change significantly between April\u2013May and June\u2013July, there was a shift in the distribution to higher mixing ratios in June\u2013July, particularly for VOCs associated with gasoline evaporation. Compared to observations made in the last major air quality campaign in the LA Basin (CalNex-2010), emission ratios for 40 compounds relative to acetylene (VOC/acetylene) have remained similar, while emission ratios relative to CO (VOC/CO) have dropped to \u223c60% of their 2010 values. This divergence in trends suggests that whereas mobile sources are still the dominant source of the combustion-derived VOCs measured in the LA Basin, there has been a shift in the mobile source sectors, with a growing contribution from sources that have lower CO/acetylene emission ratios, including off-road equipment and vehicles. In addition to the observed shift in source sector contributions, estimated OH exposure was 70\u2013120% higher than in 2010.", "doi": "10.1021/acsearthspacechem.1c00248", "issn": "2472-3452", "publisher": "American Chemical Society", "publication": "ACS Earth and Space Chemistry", "publication_date": "2021-11-18", "series_number": "11", "volume": "5", "issue": "11", "pages": "3045-3055" }, { "id": "authors:qx15n-yfh57", "collection": "authors", "collection_id": "qx15n-yfh57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210825-140510722", "type": "article", "title": "A computationally efficient model to represent the chemistry, thermodynamics, and microphysics of secondary organic aerosols (simpleSOM): model development and application to \u03b1-pinene SOA", "author": [ { "family_name": "Jathar", "given_name": "Shantanu H.", "orcid": "0000-0003-4106-2358", "clpid": "Jathar-Shantanu-H" }, { "family_name": "Cappa", "given_name": "Christopher D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-Christopher-D" }, { "family_name": "He", "given_name": "Yicong", "orcid": "0000-0001-8969-1167", "clpid": "He-Yicong" }, { "family_name": "Pierce", "given_name": "Jeffrey R.", "orcid": "0000-0002-4241-838X", "clpid": "Pierce-Jeffrey-R" }, { "family_name": "Chuang", "given_name": "Wayne", "clpid": "Chuang-Wayne" }, { "family_name": "Bilsback", "given_name": "Kelsey R.", "orcid": "0000-0002-5996-1522", "clpid": "Bilsback-Kelsey-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Zaveri", "given_name": "Rahul A.", "orcid": "0000-0001-9874-8807", "clpid": "Zaveri-Rahul-A" }, { "family_name": "Shrivastava", "given_name": "Manish", "orcid": "0000-0002-9053-2400", "clpid": "Shrivastava-Manish" } ], "abstract": "Secondary organic aerosols (SOA) constitute an important fraction of fine-mode atmospheric aerosol mass. Frameworks used to develop SOA parameters from laboratory experiments and subsequently used to simulate SOA formation in atmospheric models make many simplifying assumptions about the processes that lead to SOA formation in the interest of computational efficiency. These assumptions can limit the ability of the model to predict the mass, composition, and properties of SOA accurately. In this work, we developed a computationally efficient, process-level model named simpleSOM to represent the chemistry, thermodynamic properties, and microphysics of SOA. simpleSOM simulates multigenerational gas-phase chemistry, phase-state-influenced kinetic gas/particle partitioning, heterogeneous chemistry, oligomerization reactions, and vapor losses to the walls of Teflon chambers. As a case study, we used simpleSOM to simulate SOA formation from the photooxidation of \u03b1-pinene. This was done to demonstrate the ability of the model to develop parameters that can reproduce environmental chamber data, to highlight the chemical and microphysical processes within simpleSOM, and discuss implications for SOA formation in chambers and in the real atmosphere. SOA parameters developed from experiments performed in the chamber at the California Institute of Technology (Caltech) reproduced observations of SOA mass yield, O\u2006:\u2006C, and volatility distribution gathered from other experiments. Sensitivity simulations suggested that multigenerational gas-phase aging contributed to nearly half of all SOA and that in the absence of vapor wall losses, SOA production in the Caltech chamber could be nearly 50% higher. Heterogeneous chemistry did not seem to affect SOA formation over the short timescales for oxidation experienced in the chamber experiments. Simulations performed under atmospherically relevant conditions indicated that the SOA mass yields were sensitive to whether and how oligomerization reactions and the particle phase state were represented in the chamber experiment from which the parameters were developed. simpleSOM provides a comprehensive, process-based framework to consistently model the SOA formation and evolution in box and 3D models.", "doi": "10.1039/d1ea00014d", "issn": "2634-3606", "publisher": "Royal Society of Chemistry", "publication": "Environmental Science: Atmospheres", "publication_date": "2021-09-01", "series_number": "6", "volume": "1", "issue": "6", "pages": "372-394" }, { "id": "authors:psb8f-49x04", "collection": "authors", "collection_id": "psb8f-49x04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210930-191946415", "type": "article", "title": "The nano-scanning electrical mobility spectrometer (nSEMS) and its application to size distribution measurements of 1.5\u201325\u2009nm particles", "author": [ { "family_name": "Kong", "given_name": "Weimeng", "orcid": "0000-0002-9432-2857", "clpid": "Kong-Weimeng" }, { "family_name": "Amanatidis", "given_name": "Stavros", "orcid": "0000-0002-4924-8424", "clpid": "Amanatidis-Stavros" }, { "family_name": "Mai", "given_name": "Huajun", "orcid": "0000-0002-0616-1986", "clpid": "Mai-Huajun" }, { "family_name": "Kim", "given_name": "Changhyuk", "orcid": "0000-0002-8744-4880", "clpid": "Kim-Changhyuk" }, { "family_name": "Schulze", "given_name": "Benjamin C.", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Lewis", "given_name": "Gregory S.", "clpid": "Lewis-Gregory-S" }, { "family_name": "Hering", "given_name": "Susanne V.", "orcid": "0000-0001-6536-310X", "clpid": "Hering-Susanne-V" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "Particle size measurement in the low nanometer regime is of great importance to the study of cloud condensation nuclei formation and to better understand aerosol\u2013cloud interactions. Here we present the design, modeling, and experimental characterization of the nano-scanning electrical mobility spectrometer (nSEMS), a recently developed instrument that probes particle physical properties in the 1.5\u201325\u2009nm range. The nSEMS consists of a novel differential mobility analyzer and a two-stage condensation particle counter (CPC). The mobility analyzer, a radial opposed-migration ion and aerosol classifier (ROMIAC), can classify nanometer-sized particles with minimal degradation of its resolution and diffusional losses. The ROMIAC operates on a dual high-voltage supply with fast polarity-switching capability to minimize sensitivity to variations in the chemical nature of the ions used to charge the aerosol. Particles transmitted through the mobility analyzer are measured using a two-stage CPC. They are first activated in a fast-mixing diethylene glycol (DEG) stage before being counted by a second detection stage, an ADI MAGIC\u2122 water-based CPC. The transfer function of the integrated instrument is derived from both finite-element modeling and experimental characterization. The nSEMS performance has been evaluated during measurement of transient nucleation and growth events in the CLOUD atmospheric chamber at CERN. We show that the nSEMS can provide high-time- and size-resolution measurement of nanoparticles and can capture the critical aerosol dynamics of newly formed atmospheric particles. Using a soft x-ray bipolar ion source in a compact housing designed to optimize both nanoparticle charging and transmission efficiency as a charge conditioner, the nSEMS has enabled measurement of the contributions of both neutral and ion-mediated nucleation to new particle formation.", "doi": "10.5194/amt-14-5429-2021", "issn": "1867-8548", "publisher": "European Geosciences Union", "publication": "Atmospheric Measurement Techniques", "publication_date": "2021-08-09", "series_number": "8", "volume": "14", "issue": "8", "pages": "5429-5445" }, { "id": "authors:x2nbw-scs27", "collection": "authors", "collection_id": "x2nbw-scs27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211215-163227176", "type": "conference_item", "title": "Evidence for significant particulate organic nitrate formation in the Los Angeles Basin at night", "author": [ { "family_name": "Schulze", "given_name": "Benjamin", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Kenseth", "given_name": "Christopher", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Buenconsejo", "given_name": "Reina", "orcid": "0000-0002-0162-905X", "clpid": "Buenconsejo-Reina-S" }, { "family_name": "Van Rooy", "given_name": "Paul", "orcid": "0000-0003-1193-0994", "clpid": "Van-Rooy-Paul" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Parker", "given_name": "Harrison", "orcid": "0000-0002-0041-2764", "clpid": "Parker-Harrison-A" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Barletta", "given_name": "Barbara", "orcid": "0000-0003-3046-014X", "clpid": "Barletta-Barbara" }, { "family_name": "Meinardi", "given_name": "Simone", "orcid": "0000-0003-4828-9889", "clpid": "Meinardi-Simone" }, { "family_name": "Blake", "given_name": "Donald Ray", "clpid": "Blake-Donald-Ray" }, { "family_name": "Barsanti", "given_name": "Kelley", "orcid": "0000-0002-6065-8643", "clpid": "Barsanti-Kelley-C" }, { "family_name": "Wennberg", "given_name": "Paul", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Oxidn. of biogenic volatile org. compds. (BVOCs) by the nitrate radical (NO\u2083) represents a potentially efficient secondary org. aerosol (SOA) formation pathway. However, the contribution of nighttime NO\u2083-BVOC chem. to urban OA prodn. remains poorly constrained. Here, we present measurements of submicrometer aerosol compn. obtained at Caltech (Pasadena, CA) with an Aerodyne HR-ToF-AMS in May-June 2020. At night (19:00-6:00), a majority (>70%) of AMS-derived aerosol nitrate is org., and particulate org. nitrates (pONs) constitute up to 20-30% of total AMS-derived OA. Notably, clear increases in pON mass loadings are obsd. after sunset that correlate strongly with the prodn. rate of NO\u2083. The mass spectral signature of a pON-assocd. org. aerosol factor extd. using pos. matrix factorization (PMF) is compared to lab. SOA formed from NO\u2083 oxidn. of individual monoterpenes to aid source identification. Box model simulations reproduce obsd. overnight pON formation using reasonable SOA yields from NO\u2083 oxidn. of monoterpenes (~40%). Comparison to data collected in 2010 suggests that a major shift in the dominant nighttime nitrate aerosol formation pathway has occurred in the last decade. The observation of substantial NO\u2083-derived pON prodn. highlights the increasing importance of biogenic emissions to urban aerosol loadings and NO_x loss processes.", "publisher": "Caltech Library", "publication_date": "2021-08" }, { "id": "authors:0v15b-rxy97", "collection": "authors", "collection_id": "0v15b-rxy97", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210729-221138822", "type": "article", "title": "Switching to electric vehicles can lead to significant reductions of PM_(2.5) and NO\u2082 across China", "author": [ { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Jiang", "given_name": "Linhui", "clpid": "Jiang-Linhui" }, { "family_name": "Xia", "given_name": "Yan", "clpid": "Xia-Yan" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Li", "given_name": "Jiali", "clpid": "Li-Jiali" }, { "family_name": "Wang", "given_name": "Lu", "clpid": "Wang-Lu" }, { "family_name": "Hou", "given_name": "Tangyan", "clpid": "Hou-Tangyan" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Zhu", "given_name": "Tong", "clpid": "Zhu-Tong" }, { "family_name": "Zhang", "given_name": "Yuanhang", "clpid": "Zhang-Yuanhang" }, { "family_name": "Chen", "given_name": "Jianmin", "clpid": "Chen-Jianmin" }, { "family_name": "Wang", "given_name": "Shuxiao", "orcid": "0000-0001-9727-1963", "clpid": "Wang-Shuxiao" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" } ], "abstract": "Transportation contributes to around one-fifth of global greenhouse gas emissions, while also causing severe air pollution. The conversion to electric vehicles (EVs) represents a major path to decarbonize the transport sector, with potentially significant co-benefits for human health. However, the scale of such co-benefits largely remains an empirical question and lacks observational evidence. The full lockdown in China during the coronavirus disease 2019 (COVID-19) pandemic provides an unprecedented real-world experiment to evaluate emission reduction potentials of a large-scale transition to EVs. Here, we utilize ground and satellite observations of air quality during the full lockdown to constrain predictions of a comprehensive chemical transport model and find that the substantial traffic reductions are near-linearly linked to reductions of PM_(2.5) (particles with an aerodynamic diameter \u22642.5 \u03bcm) and NO\u2082. A further extrapolation of a full conversion to EVs shows a significant reduction of PM_(2.5) (30%\u201370%) and NO\u2082 (30%\u201380%) in most of China. Our findings provide fact-based evidence of potential environmental benefits generated by fully switching to EVs.", "doi": "10.1016/j.oneear.2021.06.008", "issn": "2590-3322", "publisher": "Elsevier", "publication": "One Earth", "publication_date": "2021-07-23", "series_number": "7", "volume": "4", "issue": "7", "pages": "1037-1048" }, { "id": "authors:fg8z5-x8a63", "collection": "authors", "collection_id": "fg8z5-x8a63", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210626-183437572", "type": "article", "title": "Multigeneration Production of Secondary Organic Aerosol from Toluene Photooxidation", "author": [ { "family_name": "Li", "given_name": "Yixin", "orcid": "0000-0001-7937-7385", "clpid": "Li-Yixin" }, { "family_name": "Zhao", "given_name": "Jiayun", "clpid": "Zhao-Jiayun" }, { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401", "clpid": "Wang-Yuan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Zhang", "given_name": "Renyi", "orcid": "0000-0001-8708-3862", "clpid": "Zhang-Renyi" } ], "abstract": "Photooxidation of volatile organic compounds (VOCs) produces secondary organic aerosol (SOA) and light-absorbing brown carbon (BrC) via multiple reaction steps/pathways, reflecting significant chemical complexity relevant to gaseous oxidation and subsequent gas-to-particle conversion. Toluene is an important VOC under urban conditions, but the fundamental chemical mechanism leading to SOA formation remains uncertain. Here, we elucidate multigeneration SOA production from toluene by simultaneously tracking the evolutions of gas-phase oxidation and aerosol formation in a reaction chamber. Large size increase and browning of monodisperse sub-micrometer seed particles occur shortly after initiating oxidation by hydroxyl radical (OH) at 10\u201390% relative humidity (RH). The evolution in gaseous products and aerosol properties (size/density/optical properties) and chemical speciation of aerosol-phase products indicate that the aerosol growth and browning result from earlier generation products consisting dominantly of dicarbonyl and carboxylic functional groups. While volatile dicarbonyls engage in aqueous reactions to yield nonvolatile oligomers and light-absorbing nitrogen heterocycles/heterochains (in the presence of NH\u2083) at high RH, organic acids contribute to aerosol carboxylates via ionic dissociation or acid\u2013base reaction in a wide RH range. We conclude that toluene contributes importantly to SOA/BrC formation from dicarbonyls and organic acids because of their prompt and high yields from photooxidation and unique functionalities for participation in aerosol-phase reactions.", "doi": "10.1021/acs.est.1c02026", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2021-07-06", "series_number": "13", "volume": "55", "issue": "13", "pages": "8592-8603" }, { "id": "authors:dxhed-gjf51", "collection": "authors", "collection_id": "dxhed-gjf51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210623-180037244", "type": "article", "title": "From COVID-19 to future electrification: Assessing traffic impacts on air quality by a machine-learning model", "author": [ { "family_name": "Yang", "given_name": "Jiani", "orcid": "0000-0003-0037-2413", "clpid": "Yang-Jiani" }, { "family_name": "Wen", "given_name": "Yifan", "orcid": "0000-0003-1876-7990", "clpid": "Wen-Yifan" }, { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401", "clpid": "Wang-Yuan" }, { "family_name": "Zhang", "given_name": "Shaojun", "orcid": "0000-0002-2176-6174", "clpid": "Zhang-Shaojun" }, { "family_name": "Pinto", "given_name": "Joseph P.", "orcid": "0000-0001-5639-8458", "clpid": "Pinto-Joseph-P" }, { "family_name": "Pennington", "given_name": "Elyse A.", "orcid": "0000-0003-1736-2342", "clpid": "Pennington-Elyse-A" }, { "family_name": "Wang", "given_name": "Zhou", "clpid": "Wang-Zhou" }, { "family_name": "Wu", "given_name": "Ye", "orcid": "0000-0002-9928-1177", "clpid": "Wu-Ye" }, { "family_name": "Sander", "given_name": "Stanley P.", "orcid": "0000-0003-1424-3620", "clpid": "Sander-Stanley-P" }, { "family_name": "Jiang", "given_name": "Jonathan H.", "orcid": "0000-0002-5929-8951", "clpid": "Jiang-Jonathan-H" }, { "family_name": "Hao", "given_name": "Jiming", "clpid": "Hao-Jiming" }, { "family_name": "Yung", "given_name": "Yuk L.", "orcid": "0000-0002-4263-2562", "clpid": "Yung-Y-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The large fluctuations in traffic during the COVID-19 pandemic provide an unparalleled opportunity to assess vehicle emission control efficacy. Here we develop a random-forest regression model, based on the large volume of real-time observational data during COVID-19, to predict surface-level NO\u2082, O\u2083, and fine particle concentration in the Los Angeles megacity. Our model exhibits high fidelity in reproducing pollutant concentrations in the Los Angeles Basin and identifies major factors controlling each species. During the strictest lockdown period, traffic reduction led to decreases in NO\u2082 and particulate matter with aerodynamic diameters <2.5 \u03bcm by \u201330.1% and \u201317.5%, respectively, but a 5.7% increase in O\u2083. Heavy-duty truck emissions contribute primarily to these variations. Future traffic-emission controls are estimated to impose similar effects as observed during the COVID-19 lockdown, but with smaller magnitude. Vehicular electrification will achieve further alleviation of NO\u2082 levels.", "doi": "10.1073/pnas.2102705118", "pmcid": "PMC8256029", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences", "publication_date": "2021-06-29", "series_number": "26", "volume": "118", "issue": "26", "pages": "Art. No. e2102705118" }, { "id": "authors:zz18s-1c181", "collection": "authors", "collection_id": "zz18s-1c181", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210727-171444056", "type": "article", "title": "Efficacy of a portable, moderate-resolution, fast-scanning differential mobility analyzer for ambient aerosol size distribution measurements", "author": [ { "family_name": "Amanatidis", "given_name": "Stavros", "orcid": "0000-0002-4924-8424", "clpid": "Amanatidis-Stavros" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Pushpawela", "given_name": "Buddhi", "clpid": "Pushpawela-Buddhi" }, { "family_name": "Schulze", "given_name": "Benjamin C.", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Ward", "given_name": "Ryan X.", "orcid": "0000-0003-2317-3310", "clpid": "Ward-Ryan-X" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Hering", "given_name": "Susanne V.", "orcid": "0000-0001-6536-310X", "clpid": "Hering-Susanne-V" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "Ambient aerosol size distributions obtained with a compact scanning mobility analyzer, the \"Spider\" differential mobility analyzer (DMA), are compared to those obtained with a conventional mobility analyzer, with specific attention to the effect of mobility resolution on the measured size distribution parameters. The Spider is a 12\u2009cm diameter radial differential mobility analyzer that spans the 10\u2013500\u2009nm size range with 30\u2009s mobility scans. It achieves its compact size by operating at a nominal mobility resolution R=3 (sheath flow\u2009=\u20090.9\u2009L\u2009min\u207b\u00b9; aerosol flow\u2009=\u20090.3\u2009L\u2009min\u207b\u00b9) in place of the higher ratio of sheath flow to aerosol flow commonly used. The question addressed here is whether the lower resolution is sufficient to capture key characteristics of ambient aerosol size distributions. The Spider, operated at R=3 with 30\u2009s up- and downscans, was co-located with a TSI 3081 long-column mobility analyzer, operated at R=10 with a 360\u2009s sampling duty cycle. Ambient aerosol data were collected over 26 consecutive days of continuous operation, in Pasadena, CA. Over the 17\u2013500\u2009nm size range, the two instruments exhibit excellent correlation in the total particle number concentrations and geometric mean diameters, with regression slopes of 1.13 and 1.00, respectively. Our results suggest that particle sizing at a lower resolution than typically employed may be sufficient to obtain key properties of ambient size distributions, at least for these two moments of the size distribution. Moreover, it enables better counting statistics, as the wider transfer function for a given aerosol flow rate results in a higher counting rate.", "doi": "10.5194/amt-14-4507-2021", "issn": "1867-8548", "publisher": "European Geosciences Union", "publication": "Atmospheric Measurement Techniques", "publication_date": "2021-06-18", "series_number": "6", "volume": "14", "issue": "6", "pages": "4507-4516" }, { "id": "authors:fn5x4-cq585", "collection": "authors", "collection_id": "fn5x4-cq585", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210316-073807806", "type": "article", "title": "Unexpected Oligomerization of Small \u03b1-Dicarbonyls for Secondary Organic Aerosol and Brown Carbon Formation", "author": [ { "family_name": "Li", "given_name": "Yixin", "clpid": "Li-Yixin" }, { "family_name": "Ji", "given_name": "Yuemeng", "orcid": "0000-0002-8641-4276", "clpid": "Ji-Yuemeng" }, { "family_name": "Zhao", "given_name": "Jiayun", "clpid": "Zhao-Jiayun" }, { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401", "clpid": "Wang-Yuan" }, { "family_name": "Shi", "given_name": "Qiuju", "clpid": "Shi-Qiuju" }, { "family_name": "Peng", "given_name": "Jianfei", "orcid": "0000-0003-4753-087X", "clpid": "Peng-Jianfei" }, { "family_name": "Wang", "given_name": "Yuying", "clpid": "Wang-Yuying" }, { "family_name": "Wang", "given_name": "Chunyu", "clpid": "Wang-Chunyu" }, { "family_name": "Zhang", "given_name": "Fang", "clpid": "Zhang-Fang" }, { "family_name": "Wang", "given_name": "Yuxuan", "clpid": "Wang-Yuxuan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Zhang", "given_name": "Renyi", "orcid": "0000-0001-8708-3862", "clpid": "Zhang-Renyi" } ], "abstract": "Large amounts of small \u03b1-dicarbonyls (glyoxal and methylglyoxal) are produced in the atmosphere from photochemical oxidation of biogenic isoprene and anthropogenic aromatics, but the fundamental mechanisms leading to secondary organic aerosol (SOA) and brown carbon (BrC) formation remain elusive. Methylglyoxal is commonly believed to be less reactive than glyoxal because of unreactive methyl substitution, and available laboratory measurements showed negligible aerosol growth from methylglyoxal. Herein, we present experimental results to demonstrate striking oligomerization of small \u03b1-dicarbonyls leading to SOA and BrC formation on sub-micrometer aerosols. Significantly more efficient growth and browning of aerosols occur upon exposure to methylglyoxal than glyoxal under atmospherically relevant concentrations and in the absence/presence of gas-phase ammonia and formaldehyde, and nonvolatile oligomers and light-absorbing nitrogen-heterocycles are identified as the dominant particle-phase products. The distinct aerosol growth and light absorption are attributed to carbenium ion-mediated nucleophilic addition, interfacial electric field-induced attraction, and synergetic oligomerization involving organic/inorganic species, leading to surface- or volume-limited reactions that are dependent on the reactivity and gaseous concentrations. Our findings resolve an outstanding discrepancy concerning the multiphase chemistry of small \u03b1-dicarbonyls and unravel a new avenue for SOA and BrC formation from atmospherically abundant, ubiquitous carbonyls and ammonia/ammonium sulfate.", "doi": "10.1021/acs.est.0c08066", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2021-04-20", "series_number": "8", "volume": "55", "issue": "8", "pages": "4430-4439" }, { "id": "authors:3081f-hq731", "collection": "authors", "collection_id": "3081f-hq731", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210119-143307488", "type": "article", "title": "City-level air quality improvement in the Beijing-Tianjin-Hebei region from 2016/17 to 2017/18 heating seasons: Attributions and process analysis", "author": [ { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "With the implementation of clean air strategies, PM_(2.5) pollution abatement has been observed in the \"2 + 26\" cities in the Beijing-Tianjin-Hebei (BTH) region (referred to as the BTH2+26) and their surrounding areas. To identify the drivers for PM_(2.5) concentration decreases in the BTH2+26 cites from the 2016/17 heating season (HS1617) to the 2017/18 heating season (HS1718), we investigated the contributions of meteorological conditions and emission-reduction measures by Community Multi-Scale Air Quality (CMAQ) model simulations. The source apportionments of five sector sources (i.e., agriculture, industry, power plants, traffic and residential), and regional sources (i.e., local, within-BTH: other cities within the BTH2+26 cities, outside-BTH, and boundary conditions (BCON)) to the PM_(2.5) decreases in the BTH2+26 cities were estimated with the Integrated Source Apportionment Method (ISAM). Mean PM_(2.5) concentrations in the BTH2+26 cities substantially decreased from 77.4 to 152.5 \u03bcg m\u207b\u00b3 in HS1617 to 52.9\u2013101.9 \u03bcg m\u207b\u00b3 in HS1718, with the numbers of heavy haze (daily PM_(2.5) \u2265150 \u03bcg m\u207b\u00b3) days decreasing from 17-77 to 5\u201330 days. The model simulation results indicated that the PM_(2.5) concentration decreases in most of the BTH2+26 cities were attributed to emission reductions (0.4\u201355.0 \u03bcg m\u207b\u00b3, 2.3\u201381.6% of total), but the favorable meteorological conditions also played important roles (1.9\u201325.4 \u03bcg m\u207b\u00b3, 18.4\u201397.7%). Residential sources dominated the PM_(2.5) reductions, leading to decreases in average PM_(2.5) concentrations by more than 30 \u03bcg m\u207b\u00b3 in severely polluted cities (i.e., Shijiazhuang, Baoding, Xingtai, and Beijing). Regional source analyses showed that both local and within-BTH sources were significant contributors to PM_(2.5) concentrations for most cities. Emission controls in local and within-BTH sources in HS1718 decreased the average PM_(2.5) concentrations by 0.1\u201347.2 \u03bcg m\u207b\u00b3 and 0.3\u201322.1 \u03bcg m\u207b\u00b3, respectively, relative to those in HS1617. Here we demonstrate that a combination of favorable meteorological conditions and anthropogenic emission reductions contributed to the improvement of air quality from HS1617 to HS1718 in the BTH2+26 cities.", "doi": "10.1016/j.envpol.2021.116523", "issn": "0269-7491", "publisher": "Elsevier", "publication": "Environmental Pollution", "publication_date": "2021-04-01", "volume": "274", "pages": "Art. No. 116523" }, { "id": "authors:hwae6-q5021", "collection": "authors", "collection_id": "hwae6-q5021", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210429-144554249", "type": "article", "title": "Anthropogenic aerosols prolong fog lifetime in China", "author": [ { "family_name": "Quan", "given_name": "Jiannong", "clpid": "Quan-Jiannong" }, { "family_name": "Liu", "given_name": "Yangang", "clpid": "Liu-Yangang" }, { "family_name": "Jia", "given_name": "Xingcan", "clpid": "Jia-Xingcan" }, { "family_name": "Liu", "given_name": "Lin", "clpid": "Liu-Lin" }, { "family_name": "Dou", "given_name": "Youjun", "clpid": "Dou-Youjun" }, { "family_name": "Xin", "given_name": "Jinyuan", "orcid": "0000-0003-4243-5072", "clpid": "Xin-Jinyuan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Investigation of aerosol effects on fog with long-term measurements has generally focused on fog occurrence frequency and intensity; here we examine the effects on fog lifetime, fog formation, and fog dissipation. From analysis of 52 years (1960\u20132011) of data collected at 404 stations in China, it is found that fog lifetime exhibits a clear increasing trend with time, and the increased lifetime is mainly attributable to delayed fog dissipation. Increased aerosol levels and global warming affect fog lifetime in opposite ways; increased aerosol levels serve to prolong fog lifetime by primarily delaying fog dissipation, whereas warming decreases fog lifetime by primarily delaying fog formation. The overall aerosol effect on fog lifetime in China is shown to predominate, especially in the highly polluted region of Eastern China. The observational findings are confirmed by a suite of WRF-Chem simulations that reveal the influences of both increased aerosol levels and temperatures through a complex chain of interactions among microphysical, dynamical, thermodynamic, and radiative processes.", "doi": "10.1088/1748-9326/abef32", "issn": "1748-9326", "publisher": "IOP", "publication": "Environmental Research Letters", "publication_date": "2021-04", "series_number": "4", "volume": "16", "issue": "4", "pages": "Art. No. 044048" }, { "id": "authors:1qp6z-6v547", "collection": "authors", "collection_id": "1qp6z-6v547", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210211-100851824", "type": "article", "title": "Emissions Measurements from Household Solid Fuel Use in Haryana, India: Implications for Climate and Health Co-benefits", "author": [ { "family_name": "Weltman", "given_name": "Robert M.", "clpid": "Weltman-Robert-M" }, { "family_name": "Edwards", "given_name": "Rufus D.", "orcid": "0000-0002-6051-6936", "clpid": "Edwards-Rufus-D" }, { "family_name": "Fleming", "given_name": "Lauren T.", "orcid": "0000-0001-6495-6261", "clpid": "Fleming-Lauren-T" }, { "family_name": "Yadav", "given_name": "Ankit", "clpid": "Yadav-Ankit" }, { "family_name": "Weyant", "given_name": "Cheryl L.", "orcid": "0000-0002-0654-6456", "clpid": "Weyant-Cheryl-L" }, { "family_name": "Rooney", "given_name": "Brigitte", "orcid": "0000-0002-9725-9080", "clpid": "Rooney-Brigitte" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Arora", "given_name": "Narendra K.", "orcid": "0000-0003-3008-8616", "clpid": "Arora-Narendra-K" }, { "family_name": "Bond", "given_name": "Tami C.", "orcid": "0000-0001-5968-8928", "clpid": "Bond-Tami-C" }, { "family_name": "Nizkorodov", "given_name": "Sergey A.", "orcid": "0000-0003-0891-0052", "clpid": "Nizkorodov-S-A" }, { "family_name": "Smith", "given_name": "Kirk R.", "orcid": "0000-0002-0439-1120", "clpid": "Smith-Kirk-R" } ], "abstract": "A large concern with estimates of climate and health co-benefits of \"clean\" cookstoves from controlled emissions testing is whether results represent what actually happens in real homes during normal use. A growing body of evidence indicates that in-field emissions during daily cooking activities differ substantially from values obtained in laboratories, with correspondingly different estimates of co-benefits. We report PM_(2.5) emission factors from uncontrolled cooking (n = 7) and minimally controlled cooking tests (n = 51) using traditional chulha and angithi stoves in village kitchens in Haryana, India. Minimally controlled cooking tests (n = 13) in a village kitchen with mixed dung and brushwood fuels were representative of uncontrolled field tests for fine particulate matter (PM_(2.5)), organic and elemental carbon (p > 0.5), but were substantially higher than previously published water boiling tests using dung or wood. When the fraction of nonrenewable biomass harvesting, elemental, and organic particulate emissions and modeled estimates of secondary organic aerosol (SOA) are included in 100 year global warming commitments (GWC\u2081\u2080\u2080), the chulha had a net cooling impact using mixed fuels typical of the region. Correlation between PM_(2.5) emission factors and GWC (R\u00b2 = 0.99) implies these stoves are climate neutral for primary PM_(2.5) emissions of 8.8 \u00b1 0.7 and 9.8 \u00b1 0.9 g PM_(2.5)/kg dry fuel for GWC\u2082\u2080 and GWC\u2081\u2080\u2080, respectively, which is close to the mean for biomass stoves in global emission inventories.", "doi": "10.1021/acs.est.0c05143", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2021-03-02", "series_number": "5", "volume": "55", "issue": "5", "pages": "3201-3209" }, { "id": "authors:tw82d-q8y37", "collection": "authors", "collection_id": "tw82d-q8y37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210114-143037999", "type": "article", "title": "Significant wintertime PM_(2.5) mitigation in the Yangtze River Delta, China, from 2016 to 2019: observational constraints on anthropogenic emission controls", "author": [ { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Mehmood", "given_name": "Khalid", "clpid": "Mehmood-Khalid" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Chai", "given_name": "Tianfeng", "orcid": "0000-0003-3520-2641", "clpid": "Chai-Tianfeng" }, { "family_name": "Zhu", "given_name": "Yannian", "orcid": "0000-0002-8371-1830", "clpid": "Zhu-Yannian" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Ambient fine particulate matter (PM_(2.5)) mitigation relies strongly on anthropogenic emission control measures, the actual effectiveness of which is challenging to pinpoint owing to the complex synergies between anthropogenic emissions and meteorology. Here, observational constraints on model simulations allow us to derive not only reliable PM_(2.5) evolution but also accurate meteorological fields. On this basis, we isolate meteorological factors to achieve reliable estimates of surface PM_(2.5) responses to both long-term and emergency emission control measures from 2016 to 2019 over the Yangtze River Delta (YRD), China. The results show that long-term emission control strategies play a crucial role in curbing PM_(2.5) levels, especially in the megacities and other areas with abundant anthropogenic emissions. The G20 summit hosted in Hangzhou in 2016 provides a unique and ideal opportunity involving the most stringent, even unsustainable, emergency emission control measures. These emergency measures lead to the largest decrease (\u223c\u200935\u2009\u00b5g\u2009m\u207b\u00b3, \u223c\u200959\u2009%) in PM_(2.5) concentrations in Hangzhou. The hotspots also emerge in megacities, especially in Shanghai (32\u2009\u00b5g\u2009m\u207b\u00b3, 51\u2009%), Nanjing (27\u2009\u00b5g\u2009m\u207b\u00b3, 55\u2009%), and Hefei (24\u2009\u00b5g\u2009m\u207b\u00b3, 44\u2009%) because of the emergency measures. Compared to the long-term policies from 2016 to 2019, the emergency emission control measures implemented during the G20 Summit achieve more significant decreases in PM_(2.5) concentrations (17\u2009\u00b5g\u2009m\u207b\u00b3 and 41\u2009%) over most of the whole domain, especially in Hangzhou (24\u2009\u00b5g\u2009m\u207b\u00b3, 48\u2009%) and Shanghai (21\u2009\u00b5g\u2009m\u207b\u00b3, 45\u2009%). By extrapolation, we derive insight into the magnitude and spatial distribution of PM_(2.5) mitigation potential across the YRD, revealing significantly additional room for curbing PM_(2.5) levels.", "doi": "10.5194/acp-20-14787-2020", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2020-12-02", "series_number": "23", "volume": "20", "issue": "23", "pages": "14787-14800" }, { "id": "authors:r9gea-8rx91", "collection": "authors", "collection_id": "r9gea-8rx91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210113-154200665", "type": "article", "title": "Air quality impact of the Northern California Camp Fire of November 2018", "author": [ { "family_name": "Rooney", "given_name": "Brigitte", "orcid": "0000-0002-9725-9080", "clpid": "Rooney-Brigitte" }, { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401", "clpid": "Wang-Yuan" }, { "family_name": "Jiang", "given_name": "Jonathan H.", "orcid": "0000-0002-5929-8951", "clpid": "Jiang-Jonathan-H" }, { "family_name": "Zhao", "given_name": "Bin", "orcid": "0000-0001-8438-9188", "clpid": "Zhao-Bin" }, { "family_name": "Zeng", "given_name": "Zhao-Cheng", "orcid": "0000-0002-0008-6508", "clpid": "Zeng-Zhao-Cheng" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The Northern California Camp Fire that took place in November 2018 was one of the most damaging environmental events in California history. Here, we analyze ground-based station observations of airborne particulate matter that has a diameter <2.5\u2009\u00b5m (PM_(2.5)) across Northern California and conduct numerical simulations of the Camp Fire using the Weather Research and Forecasting model online coupled with chemistry (WRF-Chem). Simulations are evaluated against ground-based observations of PM_(2.5), black carbon, and meteorology, as well as satellite measurements, such as Tropospheric Monitoring Instrument (TROPOMI) aerosol layer height and aerosol index. The Camp Fire led to an increase in Bay Area PM_(2.5) to over 50\u2009\u00b5g\u2009m\u207b\u00b3 for nearly 2 weeks, with localized peaks exceeding 300\u2009\u00b5g\u2009m\u207b\u00b3. Using the Visible Infrared Imaging Radiometer Suite (VIIRS) high-resolution fire detection products, the simulations reproduce the magnitude and evolution of surface PM_(2.5) concentrations, especially downwind of the wildfire. The overall spatial patterns of simulated aerosol plumes and their heights are comparable with the latest satellite products from TROPOMI. WRF-Chem sensitivity simulations are carried out to analyze uncertainties that arise from fire emissions, meteorological conditions, feedback of aerosol radiative effects on meteorology, and various physical parameterizations, including the planetary boundary layer model and the plume rise model. Downwind PM2.5 concentrations are sensitive to both flaming and smoldering emissions over the fire, so the uncertainty in the satellite-derived fire emission products can directly affect the air pollution simulations downwind. Our analysis also shows the importance of land surface and boundary layer parameterization in the fire simulation, which can result in large variations in magnitude and trend of surface PM_(2.5). Inclusion of aerosol radiative feedback moderately improves PM_(2.5) simulations, especially over the most polluted days. Results of this study can assist in the development of data assimilation systems as well as air quality forecasting of health exposures and economic impact studies.", "doi": "10.5194/acp-20-14597-2020", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2020-12-01", "series_number": "23", "volume": "20", "issue": "23", "pages": "14597-14616" }, { "id": "authors:8a5y8-cqe47", "collection": "authors", "collection_id": "8a5y8-cqe47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201201-072339842", "type": "article", "title": "Secondary organic aerosol yields from the oxidation of benzyl alcohol", "author": [ { "family_name": "Charan", "given_name": "Sophia M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-Sophia-M" }, { "family_name": "Buenconsejo", "given_name": "Reina S.", "orcid": "0000-0002-0162-905X", "clpid": "Buenconsejo-Reina-S" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recent inventory-based analysis suggests that emissions of volatile chemical products in urban areas are competitive with those from the transportation sector. Understanding the potential for secondary organic aerosol formation from these volatile chemical products is therefore critical to predicting levels of aerosol and for formulating policy to reduce aerosol exposure. Experimental and computationally simulated environmental chamber data provide an understanding of aerosol yield and chemistry under relevant urban conditions (5\u2013200\u2009ppb NO and 291\u2013312\u2009K) and give insight into the effect of volatile chemical products on the production of secondary organic aerosol. Benzyl alcohol, one of these volatile chemical products, is found to have a large secondary organic aerosol formation potential. At NO concentrations of \u223c\u200980\u2009ppb and 291\u2009K, secondary organic aerosol mass yields for benzyl alcohol can reach 1.", "doi": "10.5194/acp-20-13167-2020", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2020-11-10", "series_number": "21", "volume": "20", "issue": "21", "pages": "13167-13190" }, { "id": "authors:b40gb-e8v67", "collection": "authors", "collection_id": "b40gb-e8v67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200615-111229578", "type": "article", "title": "Coupling Filter-Based Thermal Desorption Chemical Ionization Mass Spectrometry with Liquid Chromatography/Electrospray Ionization Mass Spectrometry for Molecular Analysis of Secondary Organic Aerosol", "author": [ { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Filter-based thermal desorption (F-TD) techniques, such as the filter inlet for gases and aerosols, are widely employed to investigate the molecular composition and physicochemical properties of secondary organic aerosol (SOA). Here, we introduce an enhanced capability of F-TD through the combination of a customized F-TD inlet with chemical ionization mass spectrometry (CIMS) and ultraperformance liquid chromatography/electrospray ionization mass spectrometry (UPLC/ESI-MS). The utility of F-TD/CIMS + UPLC/ESI-MS is demonstrated by application to \u03b1-pinene ozonolysis SOA for which increased filter aerosol mass loading is shown to slow the evaporation rates of deposited compounds. Evidence for oligomer decomposition producing multimode F-TD/CIMS thermograms is provided by the measurement of the mass fraction remaining of monomeric and dimeric \u03b1-pinene oxidation products on the filter via UPLC/ESI-MS. In situ evaporation of aerosol particles suggests that \u03b1-pinene-derived hydroperoxides are thermally labile; thus, analysis of particle-phase (hydro)peroxides via F-TD may not be appropriate. A synthesized pinene-derived dimer ester (C\u2082\u2080H\u2083\u2082O\u2085) is found to be thermally stable up to 200 \u00b0C, whereas particle-phase dimers (C\u2081\u2089H\u2083\u2080O\u2085) are observed to form during F-TD analysis via thermally induced condensation of synthesized pinene-derived alcohols and diacids. The complementary F-TD/CIMS + UPLC/ESI-MS method offers previously inaccessible insight into the molecular composition and thermal desorption behavior of SOA that both clarifies and expands on analysis via traditional F-TD techniques.", "doi": "10.1021/acs.est.0c01779", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2020-10-20", "series_number": "20", "volume": "54", "issue": "20", "pages": "13238-13248" }, { "id": "authors:9wb0x-mgr33", "collection": "authors", "collection_id": "9wb0x-mgr33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200819-162804852", "type": "article", "title": "Synthesis of Carboxylic Acid and Dimer Ester Surrogates to Constrain the Abundance and Distribution of Molecular Products in \u03b1-Pinene and \u03b2-Pinene Secondary Organic Aerosol", "author": [ { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Hafeman", "given_name": "Nicholas J.", "orcid": "0000-0001-7525-7597", "clpid": "Hafeman-Nicholas-J" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Stoltz", "given_name": "Brian M.", "orcid": "0000-0001-9837-1528", "clpid": "Stoltz-B-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Liquid chromatography/negative electrospray ionization mass spectrometry [LC/(\u2212)ESI-MS] is routinely employed to characterize the identity and abundance of molecular products in secondary organic aerosol (SOA) derived from monoterpene oxidation. Due to a lack of authentic standards, however, commercial terpenoic acids (e.g., cis-pinonic acid) are typically used as surrogates to quantify both monomeric and dimeric SOA constituents. Here, we synthesize a series of enantiopure, pinene-derived carboxylic acid and dimer ester homologues. We find that the (\u2212)ESI efficiencies of the dimer esters are 19\u201336 times higher than that of cis-pinonic acid, demonstrating that the mass contribution of dimers to monoterpene SOA has been significantly overestimated in past studies. Using the measured (\u2212)ESI efficiencies of the carboxylic acids and dimer esters as more representative surrogates, we determine that molecular products measureable by LC/(\u2212)ESI-MS account for only 21.8 \u00b1 2.6% and 18.9 \u00b1 3.2% of the mass of SOA formed from ozonolysis of \u03b1-pinene and \u03b2-pinene, respectively. The 28\u201336 identified monomers (C\u2087\u208b\u2081\u2080H\u2081\u2080\u208b\u2081\u2088O\u2083\u208b\u2086) constitute 15.6\u201320.5% of total SOA mass, whereas only 1.3\u20133.3% of the SOA mass is attributable to the 46\u201362 identified dimers (C\u2081\u2085\u208b\u2081\u2089H\u2082\u2084\u208b\u2083\u2082O\u2084\u208b\u2081\u2081). The distribution of identified \u03b1-pinene and \u03b2-pinene SOA molecular products is examined as a function of carbon number (n_C), average carbon oxidation state (OS_C), and volatility (C*). The observed order-of-magnitude difference in (\u2212)ESI efficiency between monomers and dimers is expected to be broadly applicable to other biogenic and anthropogenic SOA systems analyzed via (\u2212) or (+) LC/ESI-MS under various LC conditions, and demonstrates that the use of unrepresentative surrogates can lead to substantial systematic errors in quantitative LC/ESI-MS analyses of SOA.", "doi": "10.1021/acs.est.0c01566", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2020-10-20", "series_number": "20", "volume": "54", "issue": "20", "pages": "12829-12839" }, { "id": "authors:sv55p-d9s19", "collection": "authors", "collection_id": "sv55p-d9s19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200615-082327667", "type": "article", "title": "Unexpected rise of ozone in urban and rural areas, and sulfur dioxide in rural areas during the coronavirus city lockdown in Hangzhou, China: implications for air quality", "author": [ { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Jiang", "given_name": "Linhui", "clpid": "Jiang-Linhui" }, { "family_name": "Xia", "given_name": "Yan", "clpid": "Xia-Yan" }, { "family_name": "Li", "given_name": "Jiali", "clpid": "Li-Jiali" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Liu", "given_name": "Pengfei", "orcid": "0000-0002-6714-7387", "clpid": "Liu-Pengfei" }, { "family_name": "Lichtfouse", "given_name": "Eric", "orcid": "0000-0002-8535-8073", "clpid": "Lichtfouse-Eric" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The outbreak of coronavirus named COVID-19, initially identified in Wuhan, China in December 2019, has spread rapidly at the global scale. Most countries have rapidly stopped almost all activities including industry, services and transportation of goods and people, thus decreasing air pollution in an unprecedented way, and providing a unique opportunity to study air pollutants. While satellite data have provided visual evidence for the global reduction in air pollution such as nitrogen dioxide (NO\u2082) worldwide, precise and quantitative information is missing at the local scale. Here we studied changes in particulate matter (PM_(2.5), PM\u2081\u2080), carbon monoxide (CO), NO\u2082, sulfur dioxide (SO\u2082) and ozone (O\u2083) at 10 urban sites in Hangzhou, a city of 7.03 million inhabitants, and at 1 rural site, before city lockdown, January 1\u201323, during city lockdown, January 24-February 15, and during resumption, February 16\u201328, in 2020. Results show that city lockdown induced a sharp decrease in PM_(2.5), PM\u2081\u2080, CO, and NO\u2082 concentrations at both urban and rural sites. The NO\u2082 decrease is explained by reduction in traffic emissions in the urban areas, and by lower regional transport in rural areas during lockdown, as expected. SO\u2082 concentrations decreased from 6.3 to 5.3 \u03bcg m\u207b\u00b3 in the city, but increased surprisingly from 4.7 to 5.8 \u03bcg m\u207b\u00b3 at the rural site: this increase is attributed both to higher coal consumption for heating and emissions from traditional fireworks of the Spring Eve and Lantern Festivals during lockdown. Unexpectedly, O\u2083 concentrations increased by 145% from 24.6 to 60.6 \u03bcg m\u207b\u00b3 in the urban area, and from 42.0 to 62.9 \u03bcg m\u207b\u00b3 in the rural area during the lockdown. This finding is explained by the weakening of chemical titration of O\u2083 by NO due to reductions of NO_x fresh emissions during the non-photochemical reaction period from 20:00 PM to 9:00 AM (local time). During the lockdown, compared to the same period in 2019, the daily average concentrations in the city decreased by 42.7% for PM_(2.5), 47.9% for PM\u2081\u2080, 28.6% for SO\u2082, 22.3% for CO and 58.4% for NO\u2082, which is obviously explained by the absence of city activities. Overall, we observed not only the expected reduction in some atmospheric pollutants (PM, SO\u2082, CO, NO\u2082), but also unexpected increases in SO\u2082 in the rural areas and of ozone (O\u2083) in both urban and rural areas, the latter being paradoxically due to the reduction in nitrogen oxide levels. In other words, the city lockdown has improved air quality by reducing PM_(2.5), PM\u2081\u2080, CO, and NO\u2082, but has also decreased air quality by augmenting O\u2083 and SO\u2082.", "doi": "10.1007/s10311-020-01028-3", "pmcid": "PMC7292245", "issn": "1610-3653", "publisher": "Springer", "publication": "Environmental Chemistry Letters", "publication_date": "2020-09", "series_number": "5", "volume": "18", "issue": "5", "pages": "1713-1723" }, { "id": "authors:6e46y-xz920", "collection": "authors", "collection_id": "6e46y-xz920", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200622-104138262", "type": "article", "title": "Unexpected air pollution with marked emission reductions during the COVID-19 outbreak in China", "author": [ { "family_name": "Le", "given_name": "Tianhao", "orcid": "0000-0002-6600-8270", "clpid": "Le-Tianhao" }, { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401", "clpid": "Wang-Yuan" }, { "family_name": "Liu", "given_name": "Lang", "orcid": "0000-0002-1092-0615", "clpid": "Liu-Lang" }, { "family_name": "Yang", "given_name": "Jiani", "clpid": "Yang-Jiani" }, { "family_name": "Yung", "given_name": "Yuk L.", "orcid": "0000-0002-4263-2562", "clpid": "Yung-Y-L" }, { "family_name": "Li", "given_name": "Guohui", "clpid": "Li-Guohui" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The absence of motor vehicle traffic and suspended manufacturing during the coronavirus disease 2019 (COVID-19) pandemic in China enabled assessment of the efficiency of air pollution mitigation. Up to 90% reduction of certain emissions during the city-lockdown period can be identified from satellite and ground-based observations. Unexpectedly, extreme particulate matter levels simultaneously occurred in northern China. Our synergistic observation analyses and model simulations show that anomalously high humidity promoted aerosol heterogeneous chemistry, along with stagnant airflow and uninterrupted emissions from power plants and petrochemical facilities, contributing to severe haze formation. Also, because of nonlinear production chemistry and titration of ozone in winter, reduced nitrogen oxides resulted in ozone enhancement in urban areas, further increasing the atmospheric oxidizing capacity and facilitating secondary aerosol formation.", "doi": "10.1126/science.abb7431", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2020-08-07", "series_number": "6504", "volume": "369", "issue": "6504", "pages": "702-706" }, { "id": "authors:8680x-shp96", "collection": "authors", "collection_id": "8680x-shp96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201221-084129753", "type": "conference_item", "title": "Synthesis of carboxylic acid and dimer ester surrogates to constrain the abundance and distribution of\n molecular products in \u03b1-pinene and \u03b2-pinene secondary organic aerosol", "author": [ { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Hafeman", "given_name": "Nicholas J.", "orcid": "0000-0001-7525-7597", "clpid": "Hafeman-Nicholas-J" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Stoltz", "given_name": "Brian Mark", "orcid": "0000-0001-9837-1528", "clpid": "Stoltz-B-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Liq. chromatog./neg. electrospray ionization mass spectrometry [LC/(-)ESI-MS] is routinely employed to characterize the\nidentity and abundance of mol. products in secondary org. aerosol (SOA) derived from monoterpene oxidn. Due to a\nlack of authentic stds., however, com. terpenoic acids (e.g., cis-pinonic acid) are typically used as surrogates to\nquantify both monomeric and dimeric SOA constituents. Here, we synthesize a series of enantiopure, pinene-derived\ncarboxylic acid and dimer ester homologues. We find that the (-)ESI efficiencies of the dimer esters are 19 to 36 times\nhigher than that of cis-pinonic acid, demonstrating that the mass contribution of dimers to monoterpene SOA has\nbeen significantly overestimated in past studies. Using the measured (-)ESI efficiencies of the carboxylic acids and\ndimer esters as more representative surrogates, we det. that mol. products measureable by LC/(-)ESI-MS account for\nonly 21.8 \u00b1 2.6% and 18.9 \u00b1 3.2% of the mass of SOA formed from ozonolysis of \u03b1-pinene and \u03b2-pinene, resp. The 28-\n36 identified monomers (C\u2087\u208b\u2081\u2080H\u2081\u2080\u208b\u2081\u2088O\u2083\u208b\u2086) constitute 15.6-20.5% of total SOA mass, whereas only 1.3-3.3% of the SOA\nmass is attributable to the 46-62 identified dimers (C\u2081\u2085\u208b\u2081\u2089H\u2082\u2084\u208b\u2083\u2082O\u2084\u208b\u2081\u2081). The distribution of identified \u03b1-pinene and \u03b2-pinene SOA mol. products is examd. as a function of carbon no. (n_C), av. carbon oxidn. state (OS_C), and volatility\n(C*). The obsd. order of magnitude difference in (-)ESI efficiency between monomers and dimers is expected to be\nbroadly applicable to other biogenic and anthropogenic SOA systems analyzed via (-) or (+) LC/ESI-MS, and\ndemonstrates that the use of unrepresentative surrogates can lead to substantial systematic errors in quant. LC/ESI-MS\nanalyses of SOA.", "publisher": "Caltech Library", "publication_date": "2020-08" }, { "id": "authors:4gffg-dja25", "collection": "authors", "collection_id": "4gffg-dja25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200622-104138439", "type": "article", "title": "Oxygenated Aromatic Compounds are Important Precursors of Secondary Organic Aerosol in Biomass Burning Emissions", "author": [ { "family_name": "Akherati", "given_name": "Ali", "clpid": "Akherati-Ali" }, { "family_name": "He", "given_name": "Yicong", "clpid": "He-Yicong" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Koss", "given_name": "Abigail R.", "clpid": "Koss-A-R" }, { "family_name": "Hodshire", "given_name": "Anna L.", "clpid": "Hodshire-Anna-L" }, { "family_name": "Sekimoto", "given_name": "Kanako", "clpid": "Sekimoto-Kanako" }, { "family_name": "Warneke", "given_name": "Carsten", "clpid": "Warneke-C" }, { "family_name": "de Gouw", "given_name": "Joost", "orcid": "0000-0002-0385-1826", "clpid": "de-Gouw-J-A" }, { "family_name": "Yee", "given_name": "Lindsay", "clpid": "Yee-Lindsay-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Onasch", "given_name": "Timothy B.", "clpid": "Onasch-T-B" }, { "family_name": "Herndon", "given_name": "Scott C.", "clpid": "Herndon-S-C" }, { "family_name": "Knighton", "given_name": "Walter B.", "clpid": "Knighton-W-B" }, { "family_name": "Cappa", "given_name": "Christopher D.", "clpid": "Cappa-C-D" }, { "family_name": "Kleeman", "given_name": "Michael J.", "clpid": "Kleeman-M-J" }, { "family_name": "Lim", "given_name": "Christopher Y.", "clpid": "Lim-Christopher-Y" }, { "family_name": "Kroll", "given_name": "Jesse H.", "clpid": "Kroll-J-H" }, { "family_name": "Pierce", "given_name": "Jeffrey R.", "clpid": "Pierce-J-R" }, { "family_name": "Jathar", "given_name": "Shantanu H.", "orcid": "0000-0003-4106-2358", "clpid": "Jathar-S-H" } ], "abstract": "Biomass burning is the largest combustion-related source of volatile organic compounds (VOCs) to the atmosphere. We describe the development of a state-of-the-science model to simulate the photochemical formation of secondary organic aerosol (SOA) from biomass-burning emissions observed in dry (RH <20%) environmental chamber experiments. The modeling is supported by (i) new oxidation chamber measurements, (ii) detailed concurrent measurements of SOA precursors in biomass-burning emissions, and (iii) development of SOA parameters for heterocyclic and oxygenated aromatic compounds based on historical chamber experiments. We find that oxygenated aromatic compounds, including phenols and methoxyphenols, account for slightly less than 60% of the SOA formed and help our model explain the variability in the organic aerosol mass (R\u00b2 = 0.68) and O/C (R\u00b2 = 0.69) enhancement ratios observed across 11 chamber experiments. Despite abundant emissions, heterocyclic compounds that included furans contribute to \u223c20% of the total SOA. The use of pyrolysis-temperature-based or averaged emission profiles to represent SOA precursors, rather than those specific to each fire, provide similar results to within 20%. Our findings demonstrate the necessity of accounting for oxygenated aromatics from biomass-burning emissions and their SOA formation in chemical mechanisms.", "doi": "10.1021/acs.est.0c01345", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2020-07-21", "series_number": "14", "volume": "54", "issue": "14", "pages": "8568-8579" }, { "id": "authors:e76fg-12919", "collection": "authors", "collection_id": "e76fg-12919", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200723-122440192", "type": "article", "title": "On the relationship between cloud water composition and cloud droplet number concentration", "author": [ { "family_name": "MacDonald", "given_name": "Alexander B.", "orcid": "0000-0002-7238-3341", "clpid": "MacDonald-A-B" }, { "family_name": "Hossein Mardi", "given_name": "Ali", "orcid": "0000-0002-8303-274X", "clpid": "Hossein-Mardi-A" }, { "family_name": "Dadashazar", "given_name": "Hossein", "orcid": "0000-0001-7054-4933", "clpid": "Dadashazar-H" }, { "family_name": "Azadi Aghdam", "given_name": "Mojtaba", "orcid": "0000-0002-1720-2894", "clpid": "Azadi-Aghdam-M" }, { "family_name": "Crosbie", "given_name": "Ewan", "orcid": "0000-0002-8895-8066", "clpid": "Crosbie-E" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" } ], "abstract": "Aerosol\u2013cloud interactions are the largest source of uncertainty in quantifying anthropogenic radiative forcing. The large uncertainty is, in part, due to the difficulty of predicting cloud microphysical parameters, such as the cloud droplet number concentration (N_d). Even though rigorous first-principle approaches exist to calculate Nd, the cloud and aerosol research community also relies on empirical approaches such as relating N_d to aerosol mass concentration. Here we analyze relationships between Nd and cloud water chemical composition, in addition to the effect of environmental factors on the degree of the relationships. Warm, marine, stratocumulus clouds off the California coast were sampled throughout four summer campaigns between 2011 and 2016. A total of 385 cloud water samples were collected and analyzed for 80 chemical species. Single- and multispecies log\u2013log linear regressions were performed to predict N_d using chemical composition. Single-species regressions reveal that the species that best predicts N_d is total sulfate (R\u00b2_(adj) = 0.40). Multispecies regressions reveal that adding more species does not necessarily produce a better model, as six or more species yield regressions that are statistically insignificant. A commonality among the multispecies regressions that produce the highest correlation with N_d was that most included sulfate (either total or non-sea-salt), an ocean emissions tracer (such as sodium), and an organic tracer (such as oxalate). Binning the data according to turbulence, smoke influence, and in-cloud height allowed for examination of the effect of these environmental factors on the composition\u2013Nd correlation. Accounting for turbulence, quantified as the standard deviation of vertical wind speed, showed that the correlation between N_d with both total sulfate and sodium increased at higher turbulence conditions, consistent with turbulence promoting the mixing between ocean surface and cloud base. Considering the influence of smoke significantly improved the correlation with N_d for two biomass burning tracer species in the study region, specifically oxalate and iron. When binning by in-cloud height, non-sea-salt sulfate and sodium correlated best with Nd at cloud top, whereas iron and oxalate correlated best with N_d at cloud base.", "doi": "10.5194/acp-20-7645-2020", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2020-07-02", "series_number": "13", "volume": "20", "issue": "13", "pages": "7645-7665" }, { "id": "authors:t030q-tn741", "collection": "authors", "collection_id": "t030q-tn741", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200608-101854097", "type": "article", "title": "Characterization of aerosol hygroscopicity over the Northeast Pacific Ocean: Impacts on prediction of CCN and stratocumulus cloud droplet number concentrations", "author": [ { "family_name": "Schulze", "given_name": "B. C.", "orcid": "0000-0002-6405-8872", "clpid": "Schulze-Benjamin-C" }, { "family_name": "Charan", "given_name": "S. M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-Sophia-M" }, { "family_name": "Kenseth", "given_name": "C. M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Kong", "given_name": "W.", "orcid": "0000-0002-9432-2857", "clpid": "Kong-Weimeng" }, { "family_name": "Bates", "given_name": "K. H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-Kelvin-H" }, { "family_name": "Williams", "given_name": "W.", "clpid": "Williams-W" }, { "family_name": "Metcalf", "given_name": "A. R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-Andrew-R" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Woods", "given_name": "R.", "clpid": "Woods-R" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "During the Marine Aerosol Cloud and Wildfire Study (MACAWS) in June and July of 2018, aerosol composition and cloud condensation nuclei (CCN) properties were measured over the N.E. Pacific to characterize the influence of aerosol hygroscopicity on predictions of ambient CCN and stratocumulus cloud droplet number concentrations (CDNC). Three vertical regions were characterized, corresponding to the marine boundary layer (MBL), an above\u2010cloud organic aerosol layer (AC\u2010OAL), and the free troposphere (FT) above the AC\u2010OAL. The aerosol hygroscopicity parameter (\u03ba) was calculated from CCN measurements (\u03ba_(CCN)) and bulk aerosol mass spectrometer (AMS) measurements (\u03ba_(AMS)). Within the MBL, measured hygroscopicities varied between values typical of both continental environments (~0.2) and remote marine locations (~0.7). For most flights, CCN closure was achieved within 20% in the MBL. For five of the seven flights, assuming a constant aerosol size distribution produced similar or better CCN closure than assuming a constant \"marine\" hygroscopicity (\u03ba = 0.72). An aerosol\u2010cloud parcel model was used to characterize the sensitivity of predicted stratocumulus CDNC to aerosol hygroscopicity, size distribution properties, and updraft velocity. Average CDNC sensitivity to accumulation mode aerosol hygroscopicity is 39% as large as the sensitivity to the geometric median diameter in this environment. Simulations suggest CDNC sensitivity to hygroscopicity is largest in marine stratocumulus with low updraft velocities (<0.2 m s\u207b\u00b9), where accumulation mode particles are most relevant to CDNC, and in marine stratocumulus or cumulus with large updraft velocities (>0.6 m s\u207b\u00b9), where hygroscopic properties of the Aitken mode dominate hygroscopicity sensitivity.", "doi": "10.1029/2020ea001098", "issn": "2333-5084", "publisher": "American Geophysical Union", "publication": "Earth and Space Science", "publication_date": "2020-07", "series_number": "7", "volume": "7", "issue": "7", "pages": "Art. No. e2020EA001098" }, { "id": "authors:7z1gv-rph48", "collection": "authors", "collection_id": "7z1gv-rph48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200625-112849901", "type": "article", "title": "Diffusional transfer function for the scanning electrical mobility spectrometer (SEMS)", "author": [ { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "The scanning electrical mobility spectrometer (SEMS), or scanning mobility particle sizer (SMPS), uses the differential mobility analyzer (DMA) operated in scanning mode to measure particle size distribution rapidly. To obtain the actual size distribution, the real-time transfer function (transmission efficiency of particles of different mobilities) is necessary, which has previously been investigated with numerical simulations or semi-analytical calculations. We present here a rigorous derivation of the diffusional DMA transfer function for an increasing-voltage scan based on analytically resolving particle trajectories between the instrument inlet and the outlet. This requires a 2D integration in the inlet and outlet space over the contour plot of the particle mobility distribution that can successfully transmit through the scanning DMA. For the first time, we show that the up-scan DMA transfer function for non-diffusive particles is trapezoidal (instead of triangular). The key parameter that determines the shape of the scanning DMA transfer function is the ratio of the characteristic scanning time to the average residence time, which yields the same transfer function as that for the static DMA when the ratio gets sufficiently large. The effect of particle diffusion is included via an extended outlet. The dimensionless equations for the trajectories and the method presented here can be generalized to the column DMA of any geometry.", "doi": "10.1080/02786826.2020.1760199", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2020-05-21", "series_number": "10", "volume": "54", "issue": "10", "pages": "1157-1168" }, { "id": "authors:w4f4k-p3t68", "collection": "authors", "collection_id": "w4f4k-p3t68", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200313-092203655", "type": "article", "title": "Rapid growth of new atmospheric particles by nitric acid and ammonia condensation", "author": [ { "family_name": "Wang", "given_name": "Mingyi", "orcid": "0000-0001-5782-2513", "clpid": "Wang-Mingyi" }, { "family_name": "Kong", "given_name": "Weimeng", "orcid": "0000-0002-9432-2857", "clpid": "Kong-Weimeng" }, { "family_name": "Marten", "given_name": "Ruby" }, { "family_name": "He", "given_name": "Xu-Cheng" }, { "family_name": "Chen", "given_name": "Dexian" }, { "family_name": "Pfeifer", "given_name": "Joschka" }, { "family_name": "Heitto", "given_name": "Arto" }, { "family_name": "Kontkanen", "given_name": "Jenni" }, { "family_name": "Dada", "given_name": "Lubna" }, { "family_name": "K\u00fcrten", "given_name": "Andreas" }, { "family_name": "Yli-Juuti", "given_name": "Taina" }, { "family_name": "Manninen", "given_name": "Hanna E." }, { "family_name": "Amanatidis", "given_name": "Stavros", "orcid": "0000-0002-4924-8424", "clpid": "Amanatidis-S" }, { "family_name": "Amorim", "given_name": "Antonio" }, { "family_name": "Baalbaki", "given_name": "Rima" }, { "family_name": "Baccarini", "given_name": "Andrea" }, { "family_name": "Bell", "given_name": "David M." }, { "family_name": "Bertozzi", "given_name": "Barbara" }, { "family_name": "Br\u00e4kling", "given_name": "Steffen" }, { "family_name": "Brilke", "given_name": "Sophia" }, { "family_name": "Murillo", "given_name": "Luc\u00eda Caudillo" }, { "family_name": "Chiu", "given_name": "Randall" }, { "family_name": "Chu", "given_name": "Biwu" }, { "family_name": "De Menezes", "given_name": "Louis-Philippe" }, { "family_name": "Duplissy", "given_name": "Jonathan" }, { "family_name": "Finkenzeller", "given_name": "Henning" }, { "family_name": "Carracedo", "given_name": "Loic Gonzalez" }, { "family_name": "Granzin", "given_name": "Manuel" }, { "family_name": "Guida", "given_name": "Roberto" }, { "family_name": "Hansel", "given_name": "Armin" }, { "family_name": "Hofbauer", "given_name": "Victoria" }, { "family_name": "Krechmer", "given_name": "Jordan" }, { "family_name": "Lehtipalo", "given_name": "Katrianne" }, { "family_name": "Lamkaddam", "given_name": "Houssni" }, { "family_name": "Lampim\u00e4ki", "given_name": "Markus" }, { "family_name": "Lee", "given_name": "Chuan Ping" }, { "family_name": "Makhmutov", "given_name": "Vladimir" }, { "family_name": "Marie", "given_name": "Guillaume" }, { "family_name": "Mathot", "given_name": "Serge" }, { "family_name": "Mauldin", "given_name": "Roy L." }, { "family_name": "Mentler", "given_name": "Bernhard" }, { "family_name": "M\u00fcller", "given_name": "Tatjana" }, { "family_name": "Onnela", "given_name": "Antti" }, { "family_name": "Partoll", "given_name": "Eva" }, { "family_name": "Pet\u00e4j\u00e4", "given_name": "Tuukka" }, { "family_name": "Philippov", "given_name": "Maxim" }, { "family_name": "Pospisilova", "given_name": "Veronika" }, { "family_name": "Ranjithkumar", "given_name": "Ananth" }, { "family_name": "Rissanen", "given_name": "Matti" }, { "family_name": "R\u00f6rup", "given_name": "Birte" }, { "family_name": "Scholz", "given_name": "Wiebke" }, { "family_name": "Shen", "given_name": "Jiali" }, { "family_name": "Simon", "given_name": "Mario" }, { "family_name": "Sipil\u00e4", "given_name": "Mikko" }, { "family_name": "Steiner", "given_name": "Gerhard" }, { "family_name": "Stolzenburg", "given_name": "Dominik" }, { "family_name": "Tham", "given_name": "Yee Jun" }, { "family_name": "Tom\u00e9", "given_name": "Ant\u00f3nio" }, { "family_name": "Wagner", "given_name": "Andrea C." }, { "family_name": "Wang", "given_name": "Dongyu S." }, { "family_name": "Wang", "given_name": "Yonghong" }, { "family_name": "Weber", "given_name": "Stefan K." }, { "family_name": "Winkler", "given_name": "Paul M." }, { "family_name": "Wlasits", "given_name": "Peter J." }, { "family_name": "Wu", "given_name": "Yusheng" }, { "family_name": "Xiao", "given_name": "Mao" }, { "family_name": "Ye", "given_name": "Qing" }, { "family_name": "Zauner-Wieczorek", "given_name": "Marcel" }, { "family_name": "Zhou", "given_name": "Xueqin" }, { "family_name": "Volkamer", "given_name": "Rainer" }, { "family_name": "Riipinen", "given_name": "Ilona" }, { "family_name": "Dommen", "given_name": "Josef" }, { "family_name": "Curtius", "given_name": "Joachim" }, { "family_name": "Baltensperger", "given_name": "Urs" }, { "family_name": "Kulmala", "given_name": "Markku" }, { "family_name": "Worsnop", "given_name": "Douglas R." }, { "family_name": "Kirkby", "given_name": "Jasper" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "El-Haddad", "given_name": "Imad" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Donahue", "given_name": "Neil M." } ], "abstract": "A list of authors and their affiliations appears at the end of the paper New-particle formation is a major contributor to urban smog, but how it occurs in cities is often puzzling. If the growth rates of urban particles are similar to those found in cleaner environments (1\u201310 nanometres per hour), then existing understanding suggests that new urban particles should be rapidly scavenged by the high concentration of pre-existing particles. Here we show, through experiments performed under atmospheric conditions in the CLOUD chamber at CERN, that below about +5 degrees Celsius, nitric acid and ammonia vapours can condense onto freshly nucleated particles as small as a few nanometres in diameter. Moreover, when it is cold enough (below \u221215 degrees Celsius), nitric acid and ammonia can nucleate directly through an acid\u2013base stabilization mechanism to form ammonium nitrate particles. Given that these vapours are often one thousand times more abundant than sulfuric acid, the resulting particle growth rates can be extremely high, reaching well above 100 nanometres per hour. However, these high growth rates require the gas-particle ammonium nitrate system to be out of equilibrium in order to sustain gas-phase supersaturations. In view of the strong temperature dependence that we measure for the gas-phase supersaturations, we expect such transient conditions to occur in inhomogeneous urban settings, especially in wintertime, driven by vertical mixing and by strong local sources such as traffic. Even though rapid growth from nitric acid and ammonia condensation may last for only a few minutes, it is nonetheless fast enough to shepherd freshly nucleated particles through the smallest size range where they are most vulnerable to scavenging loss, thus greatly increasing their survival probability. We also expect nitric acid and ammonia nucleation and rapid growth to be important in the relatively clean and cold upper free troposphere, where ammonia can be convected from the continental boundary layer and nitric acid is abundant from electrical storms.", "doi": "10.1038/s41586-020-2270-4", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2020-05-14", "series_number": "7807", "volume": "581", "issue": "7807", "pages": "184-189" }, { "id": "authors:pq6sk-jzs79", "collection": "authors", "collection_id": "pq6sk-jzs79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200420-133228103", "type": "article", "title": "Ammonia emission abatement does not fully control reduced forms of nitrogen deposition", "author": [ { "family_name": "Tan", "given_name": "Jiani", "orcid": "0000-0003-3296-6339", "clpid": "Tan-Jiani" }, { "family_name": "Fu", "given_name": "Joshua S.", "orcid": "0000-0001-5464-9225", "clpid": "Fu-Joshua-S" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Human activities and population growth have increased the natural burden of reactive nitrogen (N) in the environment. Excessive N deposition on Earth's surface leads to adverse feedbacks on ecosystems and humans. Similar to that of air pollution, emission control is recognized as an efficient means to control acid deposition. Control of nitrogen oxides (NO_x = NO + NO\u2082) emissions has led to reduction in deposition of oxidized nitrogen (NO_y, the sum of all oxidized nitrogen species, except nitrous oxide [N\u2082O]). Reduced forms of nitrogen (NH_x = ammonia [NH\u2083] + ammonium [NH\u2084\u207a]) deposition have, otherwise, increased, offsetting the benefit of reduction in NO_y deposition. Stringent control of NH\u2083 emissions is being considered. In this study, we assess the response of N deposition to N emission control on continental regions. We show that significant reduction of NHx deposition is unlikely to be achieved at the early stages of implementing NH\u2083 emission abatement. Per-unit NH\u2083 emission abatement is shown to result in only 60\u201380% reduction in NH_x deposition, which is significantly lower than the demonstrated 80\u2013120% benefit of controlling NO_x emissions on NO_y deposition. This 60\u201380% effectiveness of NH_x deposition reduction per unit NH\u2083 emission abatement reflects, in part, the effects of simultaneous reductions in NO_x and SO\u2082 emissions.", "doi": "10.1073/pnas.1920068117", "pmcid": "PMC7211968", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2020-05-05", "series_number": "18", "volume": "117", "issue": "18", "pages": "9771-9775" }, { "id": "authors:dxac7-vab77", "collection": "authors", "collection_id": "dxac7-vab77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200313-132837414", "type": "article", "title": "Common source areas of air pollution vary with haze intensity in the Yangtze River Delta, China", "author": [ { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Mehmood", "given_name": "Khalid", "clpid": "Mehmood-Khalid" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Lichtfouse", "given_name": "Eric", "orcid": "0000-0002-8535-8073", "clpid": "Lichtfouse-Eric" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Rapid development of China's industrialization and urbanization in the past decades has highly decreased air quality. For instance, the Yangtze River Delta, a major economic area in China, is incurring strong haze pollution, yet precise pollution sources are unknown. Here, we hypothesized that sources of haze pollution might be the same in nearby cities within the region. To test this hypothesis, we studied sources in four major cities, Hefei, Hangzhou, Nanjing, and Shanghai, during the strong haze period from November 28 to December 10, 2013. This period was divided into four periods according to air PM_(2.5) concentrations (PM: particulate matter): slight haze, moderate haze, heavy haze, and severe haze periods. Common pollution source areas were identified for the first time by backward trajectories and concentration weighted trajectory maps of PM_(2.5). Results show that all cities contain air masses transported from the northwestern and northeastern regions. Emissions came mainly from northern and central China during the moderate haze period and from adjacent provinces during the severe haze period. During the heavy haze period, common sources were mainly located in the Anhui province, while during the severe haze period, common sources were mainly located in the northeastern part of the Anhui province and the western part of the Jiangsu province. Overall, our findings show that areas of pollution sources vary with the intensity of haze pollution. Our mapping method should thus provide more precise information to control air pollution at the regional scale.", "doi": "10.1007/s10311-020-00976-0", "issn": "1610-3653", "publisher": "Springer", "publication": "Environmental Chemistry Letters", "publication_date": "2020-05", "series_number": "3", "volume": "18", "issue": "3", "pages": "957-965" }, { "id": "authors:7vyx7-sv944", "collection": "authors", "collection_id": "7vyx7-sv944", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191223-104532388", "type": "article", "title": "Reduced European aerosol emissions suppress winter extremes over northern Eurasia", "author": [ { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401", "clpid": "Wang-Yuan" }, { "family_name": "Le", "given_name": "Tianhao", "clpid": "Le-Tianhao" }, { "family_name": "Chen", "given_name": "Gang", "clpid": "Chen-Gang" }, { "family_name": "Yung", "given_name": "Yuk L.", "orcid": "0000-0002-4263-2562", "clpid": "Yung-Y-L" }, { "family_name": "Su", "given_name": "Hui", "orcid": "0000-0003-1265-9702", "clpid": "Su-Hui" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Jiang", "given_name": "Jonathan H.", "orcid": "0000-0002-5929-8951", "clpid": "Jiang-Jonathan-H" } ], "abstract": "Winter extreme weather events receive major public attention due to their serious impacts, but the dominant factors regulating their interdecadal trends have not been clearly established. Here, we show that the radiative forcing due to geospatially redistributed anthropogenic aerosols mainly determined the spatial variations of winter extreme weather in the Northern Hemisphere during 1970\u20132005, a unique transition period for global aerosol forcing. Over this period, the local Rossby wave activity and extreme events (top 10% in wave amplitude) exhibited marked declining trends at high latitudes, mainly in northern Eurasia. The combination of long-term observational data and a state-of-the-art climate model revealed the unambiguous signature of anthropogenic aerosols on the wintertime jet stream, planetary wave activity and surface temperature variability on interdecadal timescales. In particular, warming due to aerosol reductions in Europe enhanced the meridional temperature gradient on the jet's poleward flank and strengthened the zonal wind, resulting in significant suppression in extreme events over northern Eurasia. These results exemplify how aerosol forcing can impact large-scale extratropical atmospheric dynamics, and illustrate the importance of anthropogenic aerosols and their spatiotemporal variability in assessing the drivers of extreme weather in historical and future climate.", "doi": "10.1038/s41558-020-0693-4", "issn": "1758-678X", "publisher": "Nature Publishing Group", "publication": "Nature Climate Change", "publication_date": "2020-03", "series_number": "3", "volume": "10", "issue": "3", "pages": "225-230" }, { "id": "authors:8avmw-m7169", "collection": "authors", "collection_id": "8avmw-m7169", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200319-101522744", "type": "article", "title": "Relative effects of open biomass burning and open crop straw burning on haze formation over central and eastern China: modeling study driven by constrained emissions", "author": [ { "family_name": "Mehmood", "given_name": "Khalid", "clpid": "Mehmood-K" }, { "family_name": "Wu", "given_name": "Yujie", "clpid": "Wu-Yujie" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Liu", "given_name": "Pengfei", "orcid": "0000-0002-6714-7387", "clpid": "Liu-Pengfei" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Zhang", "given_name": "Yibo", "clpid": "Zhang-Yibo" }, { "family_name": "Li", "given_name": "Mengying", "clpid": "Li-Mengying" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Wang", "given_name": "Yuesi", "clpid": "Wang-Yuesi" }, { "family_name": "Liu", "given_name": "Zirui", "orcid": "0000-0002-1939-9715", "clpid": "Liu-Zirui" }, { "family_name": "Zhu", "given_name": "Yannian", "orcid": "0000-0002-8371-1830", "clpid": "Zhu-Yannian" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Open biomass burning (OBB) has a high potential to trigger local and regional severe haze with elevated fine particulate matter (PM_(2.5)) concentrations and could thus deteriorate ambient air quality and threaten human health. Open crop straw burning (OCSB), as a critical part of OBB, emits abundant gaseous and particulate pollutants, especially in fields with intensive agriculture, such as in central and eastern China (CEC). This region includes nine provinces, i.e., Hubei, Anhui, Henan, Hunan, Jiangxi, Shandong, Jiangsu, Shanghai, and Fujian. The first four ones are located inland, while the others are on the eastern coast. However, uncertainties in current OCSB and other types of OBB emissions in chemical transport models (CTMs) lead to inaccuracies in evaluating their impacts on haze formations. Satellite retrievals provide an alternative that can be used to simultaneously quantify emissions of OCSB and other types of OBB, such as the Fire INventory from NCAR version 1.5 (FINNv1.5), which, nevertheless, generally underestimates their magnitudes due to unresolved small fires. In this study, we selected June 2014 as our study period, which exhibited a complete evolution process of OBB (from 1 to 19 June) over CEC. During this period, OBB was dominated by OCSB in terms of the number of fire hotspots and associated emissions (74\u2009%\u201394\u2009%), most of which were located at Henan and Anhui (>\u200960\u2009%) with intensive enhancements from 5 to 14 June (>\u200980\u2009%). OCSB generally exhibits a spatiotemporal correlation with regional haze over the central part of CEC (Henan, Anhui, Hubei, and Hunan), while other types of OBB emissions had influences on Jiangxi, Zhejiang, and Fujian. Based on these analyses, we establish a constraining method that integrates ground-level PM_(2.5) measurements with a state-of-art fully coupled regional meteorological and chemical transport model (the two-way coupled WRF-CMAQ) in order to derive optimal OBB emissions based on FINNv1.5. It is demonstrated that these emissions allow the model to reproduce meteorological and chemical fields over CEC during the study period, whereas the original FINNv1.5 underestimated OBB emissions by 2\u20137 times, depending on specific spatiotemporal scales. The results show that OBB had substantial impacts on surface PM_(2.5) concentrations over CEC. Most of the OBB contributions were dominated by OCSB, especially in Henan, Anhui, Hubei, and Hunan, while other types of OBB emissions also exerted an influence in Jiangxi, Zhejiang, and Fujian. With the concentration-weighted trajectory (CWT) method, potential OCSB sources leading to severe haze in Henan, Anhui, Hubei, and Hunan were pinpointed. The results show that the OCSB emissions in Henan and Anhui can cause haze not only locally but also regionally through regional transport. Combining with meteorological analyses, we can find that surface weather patterns played a cardinal role in reshaping spatial and temporal characteristics of PM_(2.5) concentrations. Stationary high-pressure systems over CEC enhanced local PM_(2.5) concentrations in Henan and Anhui. Then, with the evolution of meteorological patterns, Hubei and Hunan in the low-pressure system were impacted by areas (i.e., Henan and Anhui) enveloped in the high-pressure system. These results suggest that policymakers should strictly undertake interprovincial joint enforcement actions to prohibit irregular OBB, especially OCSB over CEC. Constrained OBB emissions can, to a large extent, supplement estimations derived from satellite retrievals as well as reduce overestimates of bottom-up methods.", "doi": "10.5194/acp-20-2419-2020", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2020-02-28", "series_number": "4", "volume": "20", "issue": "4", "pages": "2419-2443" }, { "id": "authors:4zxs8-26y13", "collection": "authors", "collection_id": "4zxs8-26y13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191025-133026193", "type": "article", "title": "Computational Simulation of Secondary Organic Aerosol Formation in Laboratory Chambers", "author": [ { "family_name": "Charan", "given_name": "Sophia M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-Sophia-M" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In the atmosphere, certain volatile organic compounds (VOCs) undergo oxidation. Some of these oxidation products then condense into the particle phase. Oxidation products that transform into the particle phase by this route are termed secondary organic aerosol (SOA). Understanding the route by which particulate matter is formed from these reactions is a key challenge in atmospheric chemistry. The principal understanding of SOA formation is derived from studies in laboratory chambers, for which determination of the amount of SOA formed requires a rigorous, quantitative understanding of chamber phenomena. With computational simulation of the processes occurring within an environmental chamber, the extrapolation to atmospheric conditions can be assessed. Moreover, computational chamber modeling of secondary organic aerosol formation will become an integral part of experimental design and data analysis. Here, we present a comprehensive review of processes involved in laboratory chamber SOA formation with a focus on the coupling between different physicochemical processes and understanding that has recently emerged.", "doi": "10.1021/acs.chemrev.9b00358", "issn": "0009-2665", "publisher": "American Chemical Society", "publication": "Chemical Reviews", "publication_date": "2019-12-11", "series_number": "23", "volume": "119", "issue": "23", "pages": "11912-11944" }, { "id": "authors:wxfb1-vvb22", "collection": "authors", "collection_id": "wxfb1-vvb22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191118-100315290", "type": "article", "title": "Efficient control of atmospheric sulfate production based on three formation regimes", "author": [ { "family_name": "Xue", "given_name": "Jian", "clpid": "Xue-Jian" }, { "family_name": "Yu", "given_name": "Xin", "clpid": "Yu-Xin" }, { "family_name": "Yuan", "given_name": "Zibing", "clpid": "Yuan-Zibing" }, { "family_name": "Griffith", "given_name": "Stephen M.", "orcid": "0000-0002-0073-4456", "clpid": "Griffith-S-M" }, { "family_name": "Lau", "given_name": "Alexis K. H.", "orcid": "0000-0003-3802-828X", "clpid": "Lau-Alexis-Kai-Hon" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Yu", "given_name": "Jian Zhen", "orcid": "0000-0002-6165-6500", "clpid": "Yu-Jian-Zhen" } ], "abstract": "The formation of sulfate (SO\u2084\u00b2\u207b) in the atmosphere is linked chemically to its direct precursor, sulfur dioxide (SO\u2082), through several key oxidation paths for which nitrogen oxides or NO_x (NO and NO\u2082) play essential roles. Here we present a coherent description of the dependence of SO\u2084\u00b2\u207b formation on SO\u2082 and NO_x under haze-fog conditions, in which fog events are accompanied by high aerosol loadings and fog-water pH in the range of 4.7\u20136.9. Three SO\u2084\u00b2\u207b formation regimes emerge as defined by the role played by NO_x. In the low-NO_x regime, NO_x act as catalyst for HO_x, which is a major oxidant for SO\u2082, whereas in the high-NO_x regime, NO\u2082 is a sink for HO_x. Moreover, at highly elevated NO_x levels, a so-called NO\u2082-oxidant regime exists in which aqueous NO\u2082 serves as the dominant oxidant of SO\u2082. This regime also exists under clean fog conditions but is less prominent. Sensitivity calculations using an emission-driven box model show that the reduction of SO\u2084\u00b2\u207b is comparably sensitive to the reduction of SO\u2082 and NO_x emissions in the NO\u2082-oxidant regime, suggesting a co-reduction strategy. Formation of SO\u2084\u00b2\u207b is relatively insensitive to NO_x reduction in the low-NO_x regime, whereas reduction of NO_x actually leads to increased SO\u2084\u00b2\u207b production in the intermediate high-NO_x regime.", "doi": "10.1038/s41561-019-0485-5", "issn": "1752-0894", "publisher": "Nature Publishing Group", "publication": "Nature Geoscience", "publication_date": "2019-12", "series_number": "12", "volume": "12", "issue": "12", "pages": "977-982" }, { "id": "authors:ttp1m-35z69", "collection": "authors", "collection_id": "ttp1m-35z69", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191210-083307503", "type": "article", "title": "Effects of Biomass Burning on Stratocumulus Droplet Characteristics, Drizzle Rate, and Composition", "author": [ { "family_name": "Hossein Mardi", "given_name": "Ali", "orcid": "0000-0002-8303-274X", "clpid": "Hossein-Mardi-A" }, { "family_name": "Dadashazar", "given_name": "Hossein", "orcid": "0000-0001-7054-4933", "clpid": "Dadashazar-H" }, { "family_name": "MacDonald", "given_name": "Alexander B.", "orcid": "0000-0002-7238-3341", "clpid": "MacDonald-A-B" }, { "family_name": "Crosbie", "given_name": "Ewan", "orcid": "0000-0002-8895-8066", "clpid": "Crosbie-E" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Azadi Aghdam", "given_name": "Mojtaba", "orcid": "0000-0002-1720-2894", "clpid": "Azadi-Aghdam-M" }, { "family_name": "Woods", "given_name": "Roy K.", "orcid": "0000-0002-3632-6374", "clpid": "Woods-R-K" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" } ], "abstract": "This study reports on airborne measurements of stratocumulus cloud properties under varying degrees of influence from biomass burning (BB) plumes off the California coast. Data are reported from five total airborne campaigns based in Marina, California, with two of them including influence from wildfires in different areas along the coast of the western United States. The results indicate that subcloud cloud condensation nuclei number concentration and mass concentrations of important aerosol species (organics, sulfate, nitrate) were better correlated with cloud droplet number concentration (N_d) as compared to respective above\u2010cloud aerosol data. Given that the majority of BB particles resided above cloud tops, this is an important consideration for future work in the region as the data indicate that the subcloud BB particles likely were entrained from the free troposphere. Lower cloud condensation nuclei activation fractions were observed for BB\u2010impacted clouds as compared to non\u2010BB clouds due, at least partly, to less hygroscopic aerosols. Relationships between N_d and either droplet effective radius or drizzle rate are preserved regardless of BB influence, indicative of how parameterizations can exhibit consistent skill for varying degrees of BB influence as long as N_d is known. Lastly, the composition of both droplet residual particles and cloud water changed significantly when clouds were impacted by BB plumes, with differences observed for different fire sources stemming largely from effects of plume aging time and dust influence.", "doi": "10.1029/2019jd031159", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2019-11-27", "series_number": "22", "volume": "124", "issue": "22", "pages": "12301-12318" }, { "id": "authors:vhypm-kmp53", "collection": "authors", "collection_id": "vhypm-kmp53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190315-131932192", "type": "article", "title": "High-altitude and long-range transport of aerosols causing regional severe haze during extreme dust storms explains why afforestation does not prevent storms", "author": [ { "family_name": "Guo", "given_name": "Ping", "clpid": "Guo-Ping" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Mehmood", "given_name": "Khalid", "clpid": "Mehmood-K" }, { "family_name": "Chen", "given_name": "Xue", "clpid": "Chen-Xue" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Zhu", "given_name": "Yannian", "orcid": "0000-0002-8371-1830", "clpid": "Zhu-Yannian" }, { "family_name": "Yu", "given_name": "Xing", "clpid": "Yu-Xing" }, { "family_name": "Alapaty", "given_name": "Kiran", "clpid": "Alapaty-K" }, { "family_name": "Lichtfouse", "given_name": "Eric", "orcid": "0000-0002-8535-8073", "clpid": "Lichtfouse-E" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Climate change is predicted to induce more extreme events such as storms, heat waves, drought and floods. Dust storms are frequently occurring in northern China. Those storms degrade air quality by decreasing visibility and inducing cardiovascular and respiratory diseases. To control dust storms, the Chinese government has launched a large-scale afforestation program by planting trees in arid areas, but the effectiveness of this program is still uncertain because the trajectories and altitudes of dust transport are poorly known. In particular, afforestation would be effective only if dust transport occurs at low altitudes. To test this hypothesis, we analyzed the extreme dust storm from May 2 to 7, 2017, which resulted in record-breaking dust loads over northern China. For that, we used dust RGB-composite data from the Himawari-8 satellite and the cloud-aerosol lidar, moderate-resolution imaging spectroradiometer data, and surface monitoring data. The source regions of the dust storms were identified using the hybrid single-particle Lagrangian integrated trajectory model and infrared pathfinder satellite observation. Contrary to our hypothesis, results show that dust is transported at high altitude of 1.0\u20136.5 km over long distances from northwestern China. This finding explains why the afforestation has not been effective to prevent this storm. Results also disclose the highest particulate matter (PM) concentrations of 447.3 \u03bcg/m^3 for PM_(2.5) and 1842.0 \u03bcg/m^3 for PM_(10) during the dust storm. Those levels highly exceed Chinese ambient air quality standards of 75 \u03bcg/m^3 for PM_(2.5) and 150 \u03bcg/m^3 for PM_(10).", "doi": "10.1007/s10311-019-00858-0", "issn": "1610-3653", "publisher": "Springer", "publication": "Environmental Chemistry Letters", "publication_date": "2019-09", "series_number": "3", "volume": "17", "issue": "3", "pages": "1333-1340" }, { "id": "authors:mweyw-97w29", "collection": "authors", "collection_id": "mweyw-97w29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191003-113816634", "type": "article", "title": "Marine Boundary Layer Clouds Associated with Coastally Trapped Disturbances: Observations and Model Simulations", "author": [ { "family_name": "Juliano", "given_name": "Timothy W.", "clpid": "Juliano-T-W" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Thompson", "given_name": "Gregory", "orcid": "0000-0003-2519-932X", "clpid": "Thompson-G" }, { "family_name": "Rahn", "given_name": "David A.", "clpid": "Rahn-D-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Lebo", "given_name": "Zachary J.", "orcid": "0000-0002-1064-4833", "clpid": "Lebo-Z-J" } ], "abstract": "Modeling marine low clouds and fog in coastal environments remains an outstanding challenge due to the inherently complex ocean\u2013land\u2013atmosphere system. This is especially important in the context of global circulation models due to the profound radiative impact of these clouds. This study utilizes aircraft and satellite measurements, in addition to numerical simulations using the Weather Research and Forecasting (WRF) Model, to examine three well-observed coastally trapped disturbance (CTD) events from June 2006, July 2011, and July 2015. Cloud water-soluble ionic and elemental composition analyses conducted for two of the CTD cases indicate that anthropogenic aerosol sources may impact CTD cloud decks due to synoptic-scale patterns associated with CTD initiation. In general, the dynamics and thermodynamics of the CTD systems are well represented and are relatively insensitive to the choice of physics parameterizations; however, a set of WRF simulations suggests that the treatment of model physics strongly influences CTD cloud field evolution. Specifically, cloud liquid water path (LWP) is highly sensitive to the choice of the planetary boundary layer (PBL) scheme; in many instances, the PBL scheme affects cloud extent and LWP values as much as or more than the microphysics scheme. Results suggest that differences in the treatment of entrainment and vertical mixing in the Yonsei University (nonlocal) and Mellor\u2013Yamada\u2013Janji\u0107 (local) PBL schemes may play a significant role. The impact of using different driving models\u2014namely, the North American Mesoscale Forecast System (NAM) 12-km analysis and the NCEP North American Regional Reanalysis (NARR) 32-km products\u2014is also investigated.", "doi": "10.1175/jas-d-18-0317.1", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2019-09", "series_number": "9", "volume": "76", "issue": "9", "pages": "2963-2993" }, { "id": "authors:te21b-a1e49", "collection": "authors", "collection_id": "te21b-a1e49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190911-155430158", "type": "article", "title": "Aerosol\u2013Cloud\u2013Meteorology Interaction Airborne Field Investigations: Using Lessons Learned from the U.S. West Coast in the Design of ACTIVATE off the U.S. East Coast", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Anderson", "given_name": "Bruce" }, { "family_name": "Bauer", "given_name": "Susanne E." }, { "family_name": "Braun", "given_name": "Rachel A." }, { "family_name": "Cairns", "given_name": "Brian" }, { "family_name": "Crosbie", "given_name": "Ewan" }, { "family_name": "Dadashazar", "given_name": "Hossein" }, { "family_name": "Diskin", "given_name": "Glenn" }, { "family_name": "Ferrare", "given_name": "Richard" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Hair", "given_name": "Johnathan" }, { "family_name": "Hostetler", "given_name": "Chris" }, { "family_name": "Jonsson", "given_name": "Haflidi H." }, { "family_name": "Kleb", "given_name": "Mary M." }, { "family_name": "Liu", "given_name": "Hongyu" }, { "family_name": "MacDonald", "given_name": "Alexander B." }, { "family_name": "McComiskey", "given_name": "Allison" }, { "family_name": "Moore", "given_name": "Richard" }, { "family_name": "Painemal", "given_name": "David" }, { "family_name": "Russell", "given_name": "Lynn M." }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Shook", "given_name": "Michael" }, { "family_name": "Smith", "given_name": "William L." }, { "family_name": "Thornhill", "given_name": "Kenneth" }, { "family_name": "Tselioudis", "given_name": "George" }, { "family_name": "Wang", "given_name": "Hailong" }, { "family_name": "Zeng", "given_name": "Xubin" }, { "family_name": "Zhang", "given_name": "Bo" }, { "family_name": "Ziemba", "given_name": "Luke" }, { "family_name": "Zuidema", "given_name": "Paquita" } ], "abstract": "We report on a multiyear set of airborne field campaigns (2005\u201316) off the California coast to examine aerosols, clouds, and meteorology, and how lessons learned tie into the upcoming NASA Earth Venture Suborbital (EVS-3) campaign: Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE; 2019\u201323). The largest uncertainty in estimating global anthropogenic radiative forcing is associated with the interactions of aerosol particles with clouds, which stems from the variability of cloud systems and the multiple feedbacks that affect and hamper efforts to ascribe changes in cloud properties to aerosol perturbations. While past campaigns have been limited in flight hours and the ability to fly in and around clouds, efforts sponsored by the Office of Naval Research have resulted in 113 single aircraft flights (>500 flight hours) in a fixed region with warm marine boundary layer clouds. All flights used nearly the same payload of instruments on a Twin Otter to fly below, in, and above clouds, producing an unprecedented dataset. We provide here i) an overview of statistics of aerosol, cloud, and meteorological conditions encountered in those campaigns and ii) quantification of model-relevant metrics associated with aerosol\u2013cloud interactions leveraging the high data volume and statistics. Based on lessons learned from those flights, we describe the pragmatic innovation in sampling strategy (dual-aircraft approach with combined in situ and remote sensing) that will be used in ACTIVATE to generate a dataset that can advance scientific understanding and improve physical parameterizations for Earth system and weather forecasting models, and for assessing next-generation remote sensing retrieval algorithms.", "doi": "10.1175/bams-d-18-0100.1", "issn": "0003-0007", "publisher": "American Metereological Society", "publication": "Bulletin of the American Meteorological Society", "publication_date": "2019-08", "series_number": "8", "volume": "100", "issue": "8", "pages": "1511-1528" }, { "id": "authors:hcmwp-vbj29", "collection": "authors", "collection_id": "hcmwp-vbj29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190724-122707801", "type": "article", "title": "Satellite-Derived Correlation of SO_2, NO_2, and Aerosol Optical Depth with Meteorological Conditions over East Asia from 2005 to 2015", "author": [ { "family_name": "Lin", "given_name": "Chin-An", "clpid": "Lin-Chin-An" }, { "family_name": "Chen", "given_name": "Yi-Chun", "orcid": "0000-0001-7997-8578", "clpid": "Chen-Yi-Chun" }, { "family_name": "Liu", "given_name": "Chian-Yi", "orcid": "0000-0003-1725-4405", "clpid": "Liu-Chian-Yi" }, { "family_name": "Chen", "given_name": "Wei-Ting", "orcid": "0000-0002-9292-0933", "clpid": "Chen-Wei-Ting" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Chou", "given_name": "Charles C.-K.", "clpid": "Chou-Charles-C-K" } ], "abstract": "Intense economic and industrial development in China has been accompanied by severe local air pollution, as well as in other downwind countries in East Asia. This study analyzes satellite observational data of sulfur dioxide (SO_2), nitrogen dioxide (NO_2), and aerosol optical depth (AOD) to explore the spatial distribution, long-term temporal variation, and correlation to meteorological conditions over this region over the period 2005\u20132015. SO_2 and NO_2 data are retrieved from the ozone monitoring instrument (OMI) onboard the National Aeronautics and Space Administration (NASA) Aura satellite, while AOD data are from the moderate-resolution imaging spectroradiometer (MODIS) onboard the NASA Aqua satellite. Spatial distributions of SO_2, NO_2, and AOD show the highest levels in the North China Plain (NCP), with hotspots also in Southeastern China (SC) and the Sichuan Basin (SB). Biomass burning also contributes to a high level of AOD in Southeast Asia in spring and in Equatorial Asia in fall. Considering the correlation of pollutant levels to meteorological conditions, monitoring data show that higher temperature and higher relative humidity (RH) favor the conversion of SO_2 and NO_2 to sulfate and nitrate aerosol, respectively. The impact of stronger lower tropospheric stability facilitates the accumulation of SO_2 and NO_2 in NCP and SC. Transport of SO_2 and NO2 from intense source regions to relatively clean regions is highly influential over East Asia; such transport from the NCP leads to a considerable increase of pollutants in SC, SB, Taiwan Island (TW), and Taiwan Strait (TWS), particularly in winter. Aerosols generated by biomass burning in Southeast Asia and anthropogenic aerosol in SC are transported to TW and TWS and lead to the increase of AOD, with the highest levels of AOD in SC, TW, and TWS occurring in spring. Precipitation results in the removal of pollutants, especially in highly polluted regions, the effect of which is most significant in winter and spring.", "doi": "10.3390/rs11151738", "issn": "2072-4292", "publisher": "MDPI", "publication": "Remote Sensing", "publication_date": "2019-07-24", "series_number": "15", "volume": "11", "issue": "15", "pages": "Art. No. 1738" }, { "id": "authors:rvmsw-t6y50", "collection": "authors", "collection_id": "rvmsw-t6y50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200529-093434674", "type": "article", "title": "Impacts of household sources on air pollution at village and regional scales in India", "author": [ { "family_name": "Rooney", "given_name": "Brigitte", "orcid": "0000-0002-9725-9080", "clpid": "Rooney-Brigitte" }, { "family_name": "Zhao", "given_name": "Ran", "orcid": "0000-0002-1096-7632", "clpid": "Zhao-Ran" }, { "family_name": "Wang", "given_name": "Yuan", "orcid": "0000-0001-6657-8401", "clpid": "Wang-Yuan" }, { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-K-H" }, { "family_name": "Pillarisetti", "given_name": "Ajay", "clpid": "Pillarisetti-A" }, { "family_name": "Sharma", "given_name": "Sumit", "clpid": "Sharma-Sumit" }, { "family_name": "Kundu", "given_name": "Seema", "clpid": "Kundu-Seema" }, { "family_name": "Bond", "given_name": "Tami C.", "clpid": "Bond-T-C" }, { "family_name": "Lam", "given_name": "Nicholas L.", "clpid": "Lam-Nicholas-L" }, { "family_name": "Ozaltun", "given_name": "Bora", "orcid": "0000-0001-9491-6439", "clpid": "Ozaltun-B" }, { "family_name": "Xu", "given_name": "Li", "clpid": "Xu-Li" }, { "family_name": "Goel", "given_name": "Varun", "orcid": "0000-0002-2933-427X", "clpid": "Goel-Varun" }, { "family_name": "Fleming", "given_name": "Lauren T.", "orcid": "0000-0001-6495-6261", "clpid": "Fleming-L-T" }, { "family_name": "Weltman", "given_name": "Robert", "clpid": "Weltman-R" }, { "family_name": "Meinardi", "given_name": "Simone", "clpid": "Meinardi-S" }, { "family_name": "Blake", "given_name": "Donald R.", "clpid": "Blake-D-R" }, { "family_name": "Nizkorodov", "given_name": "Sergey A.", "orcid": "0000-0003-0891-0052", "clpid": "Nizkorodov-S-A" }, { "family_name": "Edwards", "given_name": "Rufus D.", "clpid": "Edwards-R-D" }, { "family_name": "Yadav", "given_name": "Ankit", "clpid": "Yadav-A" }, { "family_name": "Arora", "given_name": "Narendra K.", "orcid": "0000-0003-3008-8616", "clpid": "Arora-N-K" }, { "family_name": "Smith", "given_name": "Kirk R.", "orcid": "0000-0002-0439-1120", "clpid": "Smith-K-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Approximately 3 billion people worldwide cook with solid fuels, such as wood, charcoal, and agricultural residues. These fuels, also used for residential heating, are often combusted in inefficient devices, producing carbonaceous emissions. Between 2.6 and 3.8 million premature deaths occur as a result of exposure to fine particulate matter from the resulting household air pollution (Health Effects Institute, 2018a; World Health Organization, 2018). Household air pollution also contributes to ambient air pollution; the magnitude of this contribution is uncertain. Here, we simulate the distribution of the two major health-damaging outdoor air pollutants (PM_(2.5) and O\u2083) using state-of-the-science emissions databases and atmospheric chemical transport models to estimate the impact of household combustion on ambient air quality in India. The present study focuses on New Delhi and the SOMAARTH Demographic, Development, and Environmental Surveillance Site (DDESS) in the Palwal District of Haryana, located about 80\u2009km south of New Delhi. The DDESS covers an approximate population of 200\u2009000 within 52 villages. The emissions inventory used in the present study was prepared based on a national inventory in India (Sharma et al., 2015, 2016), an updated residential sector inventory prepared at the University of Illinois, updated cookstove emissions factors from Fleming et al. (2018b), and PM_(2.5) speciation from cooking fires from Jayarathne et al. (2018). Simulation of regional air quality was carried out using the US Environmental Protection Agency Community Multiscale Air Quality modeling system (CMAQ) in conjunction with the Weather Research and Forecasting modeling system (WRF) to simulate the meteorological inputs for CMAQ, and the global chemical transport model GEOS-Chem to generate concentrations on the boundary of the computational domain. Comparisons between observed and simulated O\u2083 and PM_(2.5) levels are carried out to assess overall airborne levels and to estimate the contribution of household cooking emissions. Observed and predicted ozone levels over New Delhi during September 2015, December 2015, and September 2016 routinely exceeded the 8\u2009h Indian standard of 100\u2009\u00b5g\u2009m\u207b\u00b3, and, on occasion, exceeded 180\u2009\u00b5g\u2009m\u207b\u00b3. PM_(2.5) levels are predicted over the SOMAARTH headquarters (September 2015 and September 2016), Bajada Pahari (a village in the surveillance site; September 2015, December 2015, and September 2016), and New Delhi (September 2015, December 2015, and September 2016). The predicted fractional impact of residential emissions on anthropogenic PM_(2.5) levels varies from about 0.27 in SOMAARTH HQ and Bajada Pahari to about 0.10 in New Delhi. The predicted secondary organic portion of PM_(2.5) produced by household emissions ranges from 16\u2009% to 80\u2009%. Predicted levels of secondary organic PM_(2.5) during the periods studied at the four locations averaged about 30\u2009\u00b5g\u2009m\u207b\u00b3, representing approximately 30\u2009% and 20\u2009% of total PM_(2.5) levels in the rural and urban stations, respectively.", "doi": "10.5194/acp-19-7719-2019", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2019-06-11", "series_number": "11", "volume": "19", "issue": "11", "pages": "7719-7742" }, { "id": "authors:v4xhc-b2396", "collection": "authors", "collection_id": "v4xhc-b2396", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190620-093004504", "type": "article", "title": "Low-volatility compounds contribute significantly to isoprene secondary organic aerosol (SOA) under high-NO_x conditions", "author": [ { "family_name": "Schwantes", "given_name": "Rebecca H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-Rebecca-H" }, { "family_name": "Charan", "given_name": "Sophia M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-Sophia-M" }, { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-Kelvin-H" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Nguyen", "given_name": "Tran B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Mai", "given_name": "Huajun", "orcid": "0000-0002-0616-1986", "clpid": "Mai-Huajun" }, { "family_name": "Kong", "given_name": "Weimeng", "orcid": "0000-0002-9432-2857", "clpid": "Kong-Weimeng" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recent advances in our knowledge of the gas-phase oxidation of isoprene, the impact of chamber walls on secondary organic aerosol (SOA) mass yields, and aerosol measurement analysis techniques warrant reevaluating SOA yields from isoprene. In particular, SOA from isoprene oxidation under high-NOx conditions forms via two major pathways: (1) low-volatility nitrates and dinitrates (LV pathway) and (2) hydroxymethyl-methyl-\u03b1-lactone (HMML) reaction on a surface or the condensed phase of particles to form 2-methyl glyceric acid and its oligomers (2MGA pathway). These SOA production pathways respond differently to reaction conditions. Past chamber experiments generated SOA with varying contributions from these two unique pathways, leading to results that are difficult to interpret. This study examines the SOA yields from these two pathways independently, which improves the interpretation of previous results and provides further understanding of the relevance of chamber SOA yields to the atmosphere and regional or global modeling. Results suggest that low-volatility nitrates and dinitrates produce significantly more aerosol than previously thought; the experimentally measured SOA mass yield from the LV pathway is \u223c0.15. Sufficient seed surface area at the start of the reaction is needed to limit the effects of vapor wall losses of low-volatility compounds and accurately measure the complete SOA mass yield. Under dry conditions, substantial amounts of SOA are formed from HMML ring-opening reactions with inorganic ions and HMML organic oligomerization processes. However, the lactone organic oligomerization reactions are suppressed under more atmospherically relevant humidity levels, where hydration of the lactone is more competitive. This limits the SOA formation potential from the 2MGA pathway to HMML ring-opening reactions with water or inorganic ions under typical atmospheric conditions. The isoprene SOA mass yield from the LV pathway measured in this work is significantly higher than previous studies have reported, suggesting that low-volatility compounds such as organic nitrates and dinitrates may contribute to isoprene SOA under high-NOx conditions significantly more than previously thought and thus deserve continued study.", "doi": "10.5194/acp-19-7255-2019", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2019-06-03", "series_number": "11", "volume": "19", "issue": "11", "pages": "7255-7278" }, { "id": "authors:cg03d-6st85", "collection": "authors", "collection_id": "cg03d-6st85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190124-103511314", "type": "article", "title": "A Note on Flow Behavior in Axially-Dispersed Plug Flow Reactors with Step Input of Tracer", "author": [ { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric chemistry studies are frequently conducted in flow reactors, such as the potential aerosol mass (PAM) reactor. To characterize the flow condition in such a reactor, an axially-dispersed plug flow reactor (AD-PFR) model has been applied to explain the observed residence time distribution (RTD). Compared with the traditional RTD analysis that directly fits the observed data from a pulse input or differentiates the data points from a step input, we introduce here a direct method to retrieve the axial diffusivity in an AD-PFR model by fitting an analytical formula to the rising profile of the tracer at the beginning of the experiment (the transition data before the reactor reaches steady state). This method can be readily used to determine the flow conditions inside an AD-PFR.", "doi": "10.1016/j.aeaoa.2019.100006", "issn": "2590-1621", "publisher": "Elsevier", "publication": "Atmospheric Environment: X", "publication_date": "2019-01", "volume": "1", "pages": "Art. No. 100006" }, { "id": "authors:6e7ke-55k56", "collection": "authors", "collection_id": "6e7ke-55k56", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190429-072814298", "type": "article", "title": "Cloud Adiabaticity and Its Relationship to Marine Stratocumulus Characteristics Over the Northeast Pacific Ocean", "author": [ { "family_name": "Braun", "given_name": "Rachel A.", "orcid": "0000-0002-9353-9923", "clpid": "Braun-R-A" }, { "family_name": "Dadashazar", "given_name": "Hossein", "orcid": "0000-0001-7054-4933", "clpid": "Dadashazar-H" }, { "family_name": "MacDonald", "given_name": "Alexander B.", "orcid": "0000-0002-7238-3341", "clpid": "MacDonald-A-B" }, { "family_name": "Crosbie", "given_name": "Ewan", "orcid": "0000-0002-8895-8066", "clpid": "Crosbie-E" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Woods", "given_name": "Roy K.", "orcid": "0000-0002-3632-6374", "clpid": "Woods-R-K" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" } ], "abstract": "Cloud adiabaticity (\u03b1) is defined as the ratio of the actual liquid water path (LWP_(measured)) in a cloud to its corresponding adiabatic value (LWP_(ad)). Processes such as drizzle and entrainment can lead to subadiabatic LWP_(measured). This study examines \u03b1 and its relationship to microphysical properties for 86 cloud events over the Northeast Pacific Ocean based on data collected during four separate summertime airborne campaigns. For the study region, \u03b1 was found to be 0.766 \u00b1 0.134. For most cases, clouds with a low value of \u03b1 were found to have lower droplet number concentration (N_d), higher droplet effective radius (r_e), higher relative dispersion (d), and higher rain rate (R). The subcloud aerosol concentration (N_a) was often less for the low\u2010\u03b1 cases. The relationship between \u03b1 and the vertical profiles and cloud\u2010top characteristics for both the cloud droplet\u2010only spectrum and full spectrum (cloud and rain droplets) is also examined. Inclusion of rain droplets produced a larger change in d for the low\u2010\u03b1 clouds as compared to the high\u2010\u03b1 clouds. On average, R increased at cloud top for high\u2010\u03b1 clouds but decreased at cloud top for low\u2010\u03b1 clouds. Accounting for \u03b1 when estimating N_d from Moderate Resolution Imaging Spectroradiometer retrievals results in better agreement with in situ N_d values. Results of this work motivate the need for additional focus on the factors governing \u03b1, such as cloud type, and implications of its value, especially for remote\u2010sensing retrievals.", "doi": "10.1029/2018jd029287", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2018-12-27", "series_number": "24", "volume": "123", "issue": "24", "pages": "13790-13806" }, { "id": "authors:p7fr7-d9t29", "collection": "authors", "collection_id": "p7fr7-d9t29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190201-111654431", "type": "article", "title": "Biomass Burning Plumes in the Vicinity of the California Coast: Airborne Characterization of Physicochemical Properties, Heating Rates, and Spatiotemporal Features", "author": [ { "family_name": "Hossein Mardi", "given_name": "Ali", "orcid": "0000-0002-8303-274X", "clpid": "Hossein-Mardi-A" }, { "family_name": "Dadashazar", "given_name": "Hossein", "orcid": "0000-0001-7054-4933", "clpid": "Dadashazar-H" }, { "family_name": "MacDonald", "given_name": "Alexander B.", "orcid": "0000-0002-7238-3341", "clpid": "MacDonald-A-B" }, { "family_name": "Braun", "given_name": "Rachel A.", "orcid": "0000-0002-9353-9923", "clpid": "Braun-R-A" }, { "family_name": "Crosbie", "given_name": "Ewan", "orcid": "0000-0002-8895-8066", "clpid": "Crosbie-E" }, { "family_name": "Xian", "given_name": "Peng", "orcid": "0000-0001-7602-0524", "clpid": "Xian-Peng" }, { "family_name": "Thorsen", "given_name": "Tyler J.", "orcid": "0000-0002-4405-3572", "clpid": "Thorsen-T-J" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Fenn", "given_name": "Marta A.", "orcid": "0000-0001-6088-6200", "clpid": "Fenn-M-A" }, { "family_name": "Ferrare", "given_name": "Richard A.", "orcid": "0000-0002-1005-9730", "clpid": "Ferrare-R-A" }, { "family_name": "Hair", "given_name": "Johnathan W.", "orcid": "0000-0002-9672-1237", "clpid": "Hair-J-W" }, { "family_name": "Woods", "given_name": "Roy K.", "orcid": "0000-0002-3632-6374", "clpid": "Woods-R-K" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" } ], "abstract": "This study characterizes in situ airborne properties associated with biomass burning (BB) plumes in the vicinity of the California coast. Out of 231 total aircraft soundings in July\u2013August 2013 and 2016, 81 were impacted by BB layers. A number of vertical characteristics of BB layers are summarized in this work (altitude, location relative to cloud top height, thickness, number of vertically adjacent layers, interlayer distances) in addition to differences in vertical aerosol concentration profiles due to either surface type (e.g., land or ocean) or time of day. Significant BB layer stratification occurred, especially over ocean versus land, with the majority of layers in the free troposphere and within 100 m of the boundary layer top. Heating rate profiles demonstrated the combined effect of cloud and BB layers and their mutual interactions, with enhanced heating in BB layers with clouds present underneath. Aerosol size distribution data are summarized below and above the boundary layer, with a notable finding being enhanced concentrations of supermicrometer particles in BB conditions. A plume aging case study revealed the dominance of organics in the free troposphere, with secondary production of inorganic and organic species and coagulation as a function of distance from fire source up to 450 km. Rather than higher horizontal and vertical resolution, a new smoke injection height method was the source of improved agreement for the vertical distribution of BB aerosol in the Navy Aerosol Analysis and Prediction System model when compared to airborne data.", "doi": "10.1029/2018jd029134", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2018-12-16", "series_number": "23", "volume": "123", "issue": "23", "pages": "13560-13582" }, { "id": "authors:m71fb-5gt08", "collection": "authors", "collection_id": "m71fb-5gt08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181204-084757460", "type": "article", "title": "Scanning DMA data analysis II. Integrated DMA-CPC instrument response and data inversion", "author": [ { "family_name": "Mai", "given_name": "Huajun", "orcid": "0000-0002-0616-1986", "clpid": "Mai-Huajun" }, { "family_name": "Kong", "given_name": "Weimeng", "orcid": "0000-0002-9432-2857", "clpid": "Kong-Weimeng" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "Analysis of scanning electrical mobility spectrometer (SEMS) or SMPS data requires coupling the scanning differential mobility analyzer (DMA) transfer function with the response functions for the instrument plumbing and the detector. In the limit of plug flow (uniform velocity) within the DMA, the scanning DMA transfer function has the same form as that for constant voltage. Most SEMS/SMPS data analysis uses this model, though previous studies have shown that boundary layers distort the transfer function during scanning DMA measurements. Part I determined the instantaneous transfer function during scanning of the TSI Model 3081 A long column DMA by modeling the flows, fields, and particle trajectories within the actual DMA geometry. This study (Part II) combines that transfer function with empirical data on the efficiencies and delay time distributions of the plumbing and detector of the SEMS/SMPS to determine the instantaneous rate at which particles are counted, and integrates the count rate over the finite counting time interval to obtain the integrated SEMS/SMPS response function. Simulations using this geometrical model are compared with those obtained using traditional, idealized DMA models for scan rates ranging from slow (240\u2009s) to very fast (10\u2009s), and with measurements of monodisperse calibration aerosols. Data inversion studies show that both increasing and decreasing voltage scans can be used to determine the particle size distribution, even with fast scans.", "doi": "10.1080/02786826.2018.1528006", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2018-12", "series_number": "12", "volume": "52", "issue": "12", "pages": "1400-1414" }, { "id": "authors:vx6sz-h0p50", "collection": "authors", "collection_id": "vx6sz-h0p50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180404-104535608", "type": "article", "title": "Residential emissions predicted as a major source of fine particulate matter in winter over the Yangtze River Delta, China", "author": [ { "family_name": "Wu", "given_name": "Yujie", "clpid": "Wu-Yujie" }, { "family_name": "Wang", "given_name": "Peng", "clpid": "Wang-Peng" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Liu", "given_name": "Pengfei", "orcid": "0000-0002-6714-7387", "clpid": "Liu-Pengfei" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Mehmood", "given_name": "Khalid", "clpid": "Mehmood-K" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Wu", "given_name": "Jian", "clpid": "Wu-Jian" }, { "family_name": "Lichtfouse", "given_name": "Eric", "orcid": "0000-0002-8535-8073", "clpid": "Lichtfouse-E" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Air pollution is an increasingly critical health issue responsible for numerous diseases and deaths worldwide. In China, to address severe air pollution in the Yangtze River Delta region, the local government has formulated Five-Year Plans to set the road map for air pollution control by phased targets in 2020, but the effectiveness of these policies is still uncertain. There is therefore a need for accurate prediction of control strategies. Here we present a computational evaluation of the predicted effectiveness of four emission control strategies: normal or enhanced emission reduction for industry and power plants, and normal or enhanced emission reduction for industry, power plants and transportation, designed on the basis of policies of the 13th Five-Year Plans. Effectiveness was tested on concentrations of PM_(2.5), e.g., particulate matter with aerodynamic diameter less than 2.5 \u03bcm, using the two-way coupled Weather Research and Forecasting\u2014Community Multiscale Air Quality (WRF-CMAQ) model. Results show that by implementing the four emission control strategies, only Hangzhou with the strictest emission controls in four main cities (Hangzhou, Hefei, Nanjing and Shanghai) can meet the 20% reduction goals of PM_(2.5) concentrations in the 13th Five-Year Plan, indicating that current policies are not sufficient to control the severe air pollution in the Yangtze River Delta region. Sensitivity tests show that residential emissions have the highest contributions to the PM_(2.5) concentrations in January in the four main cities of Hangzhou, Hefei, Nanjing and Shanghai, followed by agriculture, industry, transportation and power plants. Predicted annual mean reduction percentages for PM2.5 are the highest in Hangzhou, from \u2212 9.7 to \u2212 20.1%, followed by Nanjing, from \u2212 8.2 to \u2212 18.7%, Shanghai, from \u2212 7.4 to \u2212 15.8%, and Hefei, from \u2212 6.1 to \u2212 13.8%. This finding highlights the predominance of residential emissions, which should be better controlled, notably coal burning. By comparison, predicted annual contributions of regional transport and natural sources to mean PM_(2.5) concentrations in four cities range from 29.2 to 36.6%. Overall, a major finding is that residential sources are of comparable importance to industrial, power plant and transportation sources to PM_(2.5) concentrations, especially for winter. This information will help governments of other regions of China, as well as other developing countries, to formulate more appropriate emission control strategies where coal is used for heating and cooking purposes in the developing countries.", "doi": "10.1007/s10311-018-0735-6", "issn": "1610-3653", "publisher": "Springer", "publication": "Environmental Chemistry Letters", "publication_date": "2018-09", "series_number": "3", "volume": "16", "issue": "3", "pages": "1117-1127" }, { "id": "authors:vvy23-j9468", "collection": "authors", "collection_id": "vvy23-j9468", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180803-132305205", "type": "article", "title": "Synergistic O\u2083 + OH oxidation pathway to extremely low-volatility dimers revealed in \u03b2-pinene secondary organic aerosol", "author": [ { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Zhao", "given_name": "Ran", "orcid": "0000-0002-1096-7632", "clpid": "Zhao-Ran" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Hethcox", "given_name": "J. Caleb", "orcid": "0000-0002-7712-308X", "clpid": "Hethcox-J-Caleb" }, { "family_name": "Stoltz", "given_name": "Brian M.", "orcid": "0000-0001-9837-1528", "clpid": "Stoltz-B-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Dimeric compounds contribute significantly to the formation and growth of atmospheric secondary organic aerosol (SOA) derived from monoterpene oxidation. However, the mechanisms of dimer production, in particular the relevance of gas- vs. particle-phase chemistry, remain unclear. Here, through a combination of mass spectrometric, chromatographic, and synthetic techniques, we identify a suite of dimeric compounds (C_(15\u201319)H_(24\u201332)O_(5\u201311)) formed from concerted O\u2083 and OH oxidation of \u03b2-pinene (i.e., accretion of O\u2083- and OH-derived products/intermediates). These dimers account for an appreciable fraction (5.9\u201325.4%) of the \u03b2-pinene SOA mass and are designated as extremely low-volatility organic compounds. Certain dimers, characterized as covalent dimer esters, are conclusively shown to form through heterogeneous chemistry, while evidence of dimer production via gas-phase reactions is also presented. The formation of dimers through synergistic O\u2083 + OH oxidation represents a potentially significant, heretofore-unidentified source of low-volatility monoterpene SOA. This reactivity also suggests that the current treatment of SOA formation as a sum of products originating from the isolated oxidation of individual precursors fails to accurately reflect the complexity of oxidation pathways at play in the real atmosphere. Accounting for the role of synergistic oxidation in ambient SOA formation could help to resolve the discrepancy between the measured atmospheric burden of SOA and that predicted by regional air quality and global climate models.", "doi": "10.1073/pnas.1804671115", "pmcid": "PMC6099901", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2018-08-14", "series_number": "33", "volume": "115", "issue": "33", "pages": "8301-8306" }, { "id": "authors:atnrd-1e527", "collection": "authors", "collection_id": "atnrd-1e527", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180716-151443186", "type": "article", "title": "Probing the OH Oxidation of Pinonic Acid at the Air-Water Interface Using Field-Induced Droplet Ionization Mass Spectrometry (FIDI-MS)", "author": [ { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Barraza", "given_name": "Kevin M.", "orcid": "0000-0003-1849-5219", "clpid": "Barraza-Kevin-M" }, { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Zhao", "given_name": "Ran", "orcid": "0000-0002-1096-7632", "clpid": "Zhao-Ran" }, { "family_name": "Wang", "given_name": "Chen", "orcid": "0000-0001-9565-8777", "clpid": "Wang-Chen" }, { "family_name": "Beauchamp", "given_name": "Jesse L.", "orcid": "0000-0001-8839-4822", "clpid": "Beauchamp-J-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Gas and aqueous phases are essential media for atmospheric chemistry and aerosol formation. Numerous studies have focused on aqueous-phase reactions as well as coupled gas/aqueous-phase mass transport and reaction. Few studies have directly addressed processes occurring at the air\u2013water interface, especially involving surface-active compounds. We report here the application of field-induced droplet ionization mass spectrometry (FIDI-MS) to chemical reactions occurring at the atmospheric air\u2013water interface. We determine the air\u2013water interfacial OH radical reaction rate constants for sodium dodecyl sulfate (SDS), a common surfactant, and pinonic acid (PA), a surface-active species and proxy for biogenic atmospheric oxidation products, as 2.87 \u00d7 10^(\u20138) and 9.38 \u00d7 10^(\u20138) cm^2 molec^(\u20131) s^(\u20131), respectively. In support of the experimental data, a comprehensive gas-surface-aqueous multiphase transport and reaction model of general applicability to atmospheric interfacial processes is developed. Through application of the model, PA is shown to be oxidized exclusively at the air\u2013water interface of droplets with a diameter of 5 \u03bcm under typical ambient OH levels. In the absence of interfacial reaction, aqueous- rather than gas-phase oxidation is the major PA sink. We demonstrate the critical importance of air\u2013water interfacial chemistry in determining the fate of surface-active species.", "doi": "10.1021/acs.jpca.8b05353", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2018-08-09", "series_number": "31", "volume": "122", "issue": "31", "pages": "6445-6456" }, { "id": "authors:aqf1v-rwh38", "collection": "authors", "collection_id": "aqf1v-rwh38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180813-075456363", "type": "article", "title": "Effect of particle charge on aerosol dynamics in Teflon environmental chambers", "author": [ { "family_name": "Charan", "given_name": "Sophia M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-S-M" }, { "family_name": "Kong", "given_name": "Weimeng", "orcid": "0000-0002-9432-2857", "clpid": "Kong-Weimeng" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The contribution of particle charge to the rate of particle wall deposition has been a persistent source of uncertainty for experiments performed in environmental chambers. By tracking the preferential deposition of positively charged particles; by comparing experiments carried out under standard, humid, and highly statically charged conditions; and by performing two-parameter optimizations for the chamber eddy-diffusion coefficient (k_e) and the average magnitude of the electric field (E), the effect of charge on the rate of particle-wall deposition is isolated. A combined experimental and computational method is also developed for determining values for k_e and E within a FEP Teflon chamber. To fully account for the effects of charge on particle dynamics in environmental chambers, studies of the effect of air ion concentration on the rate of particle coagulation over a typical 20\u2009h experiment are performed and demonstrated, in general, that particle charge is negligible for characteristic chamber ion concentrations. While the effect of particle charge on aerosol dynamics in an environmental chamber must be addressed for each specific chamber, we demonstrate experimentally that for the Caltech 19 m^3 Environmental Chamber, charge effects on the rate of particle-wall deposition are negligible.", "doi": "10.1080/02786826.2018.1474167", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2018-07-30", "series_number": "8", "volume": "52", "issue": "8", "pages": "854-871" }, { "id": "authors:kx6nd-yan91", "collection": "authors", "collection_id": "kx6nd-yan91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180521-153616529", "type": "article", "title": "Rapid Aqueous-Phase Hydrolysis of Ester Hydroperoxides Arising from Criegee Intermediates and Organic Acids", "author": [ { "family_name": "Zhao", "given_name": "Ran", "orcid": "0000-0002-1096-7632", "clpid": "Zhao-Ran" }, { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Kuang", "given_name": "Xiaobi M.", "clpid": "Kuang-Xiaobi-M" }, { "family_name": "Chen", "given_name": "Jierou", "clpid": "Chen-Jierou" }, { "family_name": "Paulson", "given_name": "Suzanne E.", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-Suzanne-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Stabilized Criegee intermediates react with organic acids in the gas phase and at the air\u2013water interface to form a class of ester hydroperoxides, \u03b1-acyloxyalkyl hydroperoxides (\u03b1AAHPs). A number of recent studies have proposed the importance of \u03b1AAHPs to the formation and growth of secondary organic aerosol (SOA). The chemistry of \u03b1AAHPs has not been investigated due to a lack of commercially available chemical standards. In this work, the behavior of \u03b1AAHPs in condensed phases is investigated for the first time. Experiments were performed with two synthesized \u03b1AAHP species. \u03b1AAHPs decomposed rapidly in the aqueous phase, with the rate highly dependent on the solvent, temperature, solution pH, and other compounds present in the solution. The measured 1st-order decomposition rate coefficient varied between 10^(\u20133) and 10^(\u20135) s^(\u20131) under the conditions examined in this work. Elucidation of the reaction mechanism is complicated by byproducts arising from the synthetic procedure, but observations are consistent with a base-catalyzed hydrolysis of \u03b1AAHPs. The rapid hydrolysis of \u03b1AAHPs observed in this work implies their short lifetimes in ambient cloud and fog waters. Decomposition of \u03b1AAHPs likely gives rise to smaller peroxides, such as H_2O_2. The loss of \u03b1AAHPs is also relevant to filter extraction, which is commonly practiced in laboratory experiments, potentially explaining contradictory results reported in the existing literature regarding the importance of \u03b1AAHPs in SOA.", "doi": "10.1021/acs.jpca.8b02195", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2018-06-14", "series_number": "23", "volume": "122", "issue": "23", "pages": "5190-5201" }, { "id": "authors:9b1yy-cr897", "collection": "authors", "collection_id": "9b1yy-cr897", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180420-134803479", "type": "article", "title": "Photopolarimetric sensitivity to black carbon content of wildfire smoke: Results from the 2016 IMPACT-PM field campaign", "author": [ { "family_name": "Kalashnikova", "given_name": "O. V.", "orcid": "0000-0002-1330-1529", "clpid": "Kalashnikova-Olga-V" }, { "family_name": "Garay", "given_name": "M. J.", "orcid": "0000-0002-1374-5074", "clpid": "Garay-Michael-J" }, { "family_name": "Bates", "given_name": "K. H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-Kelvin-H" }, { "family_name": "Kenseth", "given_name": "C. M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Kong", "given_name": "W.", "orcid": "0000-0002-9432-2857", "clpid": "Kong-Weimeng" }, { "family_name": "Cappa", "given_name": "C. D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-Christopher-D" }, { "family_name": "Lyapustin", "given_name": "A.", "orcid": "0000-0003-1105-5739", "clpid": "Lyapustin-Alexei" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Seidel", "given_name": "F. C.", "orcid": "0000-0002-4282-2198", "clpid": "Seidel-Felix-C" }, { "family_name": "Xu", "given_name": "F.", "orcid": "0000-0001-5155-9478", "clpid": "Xu-Feng" }, { "family_name": "Diner", "given_name": "D. J.", "orcid": "0000-0001-8102-7616", "clpid": "Diner-David-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Detailed characterization of the aerosol content of wildfire smoke plumes is typically performed through in situ aircraft observations, which have limited temporal and spatial coverage. Extending such observations to regional or global scales requires new remote sensing approaches, such as retrievals that make use of spectropolarimetric, multiangle imaging. In this work measurements made during the Imaging Polarimetric Assessment and Characterization of Tropospheric Particulate Matter (ImPACT\u2010PM) field campaign in a smoke plume near the town of Lebec in Southern California by the Navy Center for Interdisciplinary Remotely Piloted Aircraft Studies Twin Otter aircraft on 8 July 2016 are used in conjunction with near\u2010coincident measurements from the Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) on the National Aeronautics and Space Administration ER\u20102 high\u2010altitude research aircraft to assess the sensitivity of spectropolarimetric measurements to the black carbon content of the plume. Tracking visible features in the smoke through the sequence of AirMSPI observations allowed the height of the plume to be estimated through geometric techniques. Then, by constraining the fractional amounts of the aerosol constituents with the in situ data, radiative closure was obtained through simulations performed with a polarimetric radiative transfer code, demonstrating the ability to constrain the black carbon mass fraction to approximately 5%, given the uncertainties in the AirMSPI measurements and the assumption of external mixing of aerosol components. The AirMSPI retrieval, made using a limited set of observations from the 470 nm polarimetric spectral band alone, was also generally consistent with operational retrievals of aerosol optical depth and surface reflectance made by the Multi\u2010Angle Implementation of Atmospheric Correction algorithm at 1 km resolution.", "doi": "10.1029/2017JD028032", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2018-05-27", "series_number": "10", "volume": "123", "issue": "10", "pages": "5376-5396" }, { "id": "authors:74hf6-g3d80", "collection": "authors", "collection_id": "74hf6-g3d80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180525-101017448", "type": "article", "title": "Mitigation of severe urban haze pollution by a precision air pollution control approach", "author": [ { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Liu", "given_name": "Pengfei", "orcid": "0000-0002-6714-7387", "clpid": "Liu-Pengfei" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Wu", "given_name": "Yujie", "clpid": "Wu-Yujie" }, { "family_name": "Wang", "given_name": "Si", "clpid": "Wang-Si" }, { "family_name": "Liu", "given_name": "Kai", "orcid": "0000-0002-2109-8196", "clpid": "Liu-Kai" }, { "family_name": "Zhu", "given_name": "Tong", "orcid": "0000-0002-2752-7924", "clpid": "Zhu-Tong" }, { "family_name": "Zhang", "given_name": "Yuanhang", "clpid": "Zhang-Yuanhang" }, { "family_name": "Hu", "given_name": "Min", "clpid": "Hu-Min" }, { "family_name": "Zeng", "given_name": "Liming", "clpid": "Zeng-Liming" }, { "family_name": "Zhang", "given_name": "Xiaoye", "clpid": "Zhang-Xiaoye" }, { "family_name": "Cao", "given_name": "Junji", "orcid": "0000-0003-1000-7241", "clpid": "Cao-Junji" }, { "family_name": "Alapaty", "given_name": "Kiran", "clpid": "Alapaty-Kiran" }, { "family_name": "Wong", "given_name": "David C.", "orcid": "0000-0002-1712-9527", "clpid": "Wong-David-C-S" }, { "family_name": "Pleim", "given_name": "Jon", "clpid": "Pleim-Jon" }, { "family_name": "Mathur", "given_name": "Rohit", "clpid": "Mathur-Rohit" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Severe and persistent haze pollution involving fine particulate matter (PM_(2.5)) concentrations reaching unprecedentedly high levels across many cities in China poses a serious threat to human health. Although mandatory temporary cessation of most urban and surrounding emission sources is an effective, but costly, short-term measure to abate air pollution, development of long-term crisis response measures remains a challenge, especially for curbing severe urban haze events on a regular basis. Here we introduce and evaluate a novel precision air pollution control approach (PAPCA) to mitigate severe urban haze events. The approach involves combining predictions of high PM_(2.5) concentrations, with a hybrid trajectory-receptor model and a comprehensive 3-D atmospheric model, to pinpoint the origins of emissions leading to such events and to optimize emission controls. Results of the PAPCA application to five severe haze episodes in major urban areas in China suggest that this strategy has the potential to significantly mitigate severe urban haze by decreasing PM_(2.5) peak concentrations by more than 60% from above 300\u2009\u03bcg m^(\u22123) to below 100\u2009\u03bcg m^(\u22123), while requiring ~30% to 70% less emission controls as compared to complete emission reductions. The PAPCA strategy has the potential to tackle effectively severe urban haze pollution events with economic efficiency.", "doi": "10.1038/s41598-018-26344-1", "pmcid": "PMC5970218", "issn": "2045-2322", "publisher": "Nature Publishing Group", "publication": "Scientific Reports", "publication_date": "2018-05-25", "volume": "8", "pages": "Art. No. 8151" }, { "id": "authors:v6e1r-zsk98", "collection": "authors", "collection_id": "v6e1r-zsk98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180516-141614487", "type": "article", "title": "Characteristic Vertical Profiles of Cloud Water Composition in Marine Stratocumulus Clouds and Relationships With Precipitation", "author": [ { "family_name": "MacDonald", "given_name": "Alexander B.", "orcid": "0000-0002-7238-3341", "clpid": "MacDonald-A-B" }, { "family_name": "Dadashazar", "given_name": "Hossein", "orcid": "0000-0001-7054-4933", "clpid": "Dadashazar-H" }, { "family_name": "Chuang", "given_name": "Patrick Y.", "orcid": "0000-0003-2290-8346", "clpid": "Chuang-Patrick-Y" }, { "family_name": "Crosbie", "given_name": "Ewan", "orcid": "0000-0002-8895-8066", "clpid": "Crosbie-E" }, { "family_name": "Wang", "given_name": "Hailong", "orcid": "0000-0002-1994-4402", "clpid": "Wang-Hailong" }, { "family_name": "Wang", "given_name": "Zhen", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" } ], "abstract": "This study uses airborne cloud water composition measurements to characterize the vertical structure of air\u2010equivalent mass concentrations of water\u2010soluble species in marine stratocumulus clouds off the California coast. A total of 385 cloud water samples were collected in the months of July and August between 2011 and 2016 and analyzed for water\u2010soluble ionic and elemental composition. Three characteristic profiles emerge: (i) a reduction of concentration with in\u2010cloud altitude for particulate species directly emitted from sources below cloud without in\u2010cloud sources (e.g., Cl^\u2212 and Na^+), (ii) an increase of concentration with in\u2010cloud altitude (e.g., NO_2\u2212 and formate), and (iii) species exhibiting a peak in concentration in the middle of cloud (e.g., non\u2013sea\u2010salt SO_4^2\u2212, NO_3\u2212, and organic acids). Vertical profiles of rainout parameters such as loss frequency, lifetime, and change in concentration with respect to time show that the scavenging efficiency throughout the cloud depth depends strongly on the thickness of the cloud. Thin clouds exhibit a greater scavenging loss frequency at cloud top, while thick clouds have a greater scavenging loss frequency at cloud base. The implications of these results for treatment of wet scavenging in models are discussed.", "doi": "10.1002/2017JD027900", "pmcid": "PMC7002026", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2018-04-16", "series_number": "7", "volume": "123", "issue": "7", "pages": "3704-3723" }, { "id": "authors:86xwq-5jt04", "collection": "authors", "collection_id": "86xwq-5jt04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180314-102355395", "type": "article", "title": "Gas-Phase Reactions of Isoprene and Its Major Oxidation Products", "author": [ { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-K-H" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Dodson", "given_name": "Leah G.", "orcid": "0000-0001-5960-056X", "clpid": "Dodson-L-G" }, { "family_name": "McVay", "given_name": "Renee C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-R-C" }, { "family_name": "Mertens", "given_name": "Laura A.", "clpid": "Mertens-L-A" }, { "family_name": "Nguyen", "given_name": "Tran B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Praske", "given_name": "Eric", "orcid": "0000-0001-7169-4423", "clpid": "Praske-E" }, { "family_name": "Schwantes", "given_name": "Rebecca H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Smarte", "given_name": "Matthew D.", "clpid": "Smarte-M-D" }, { "family_name": "St. Clair", "given_name": "Jason M.", "orcid": "0000-0002-9367-5749", "clpid": "St-Clair-J-M" }, { "family_name": "Teng", "given_name": "Alexander P.", "orcid": "0000-0002-6434-0501", "clpid": "Teng-Alexander-P" }, { "family_name": "Zhang", "given_name": "Xuan", "orcid": "0000-0003-1548-8021", "clpid": "Zhang-Xuan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Isoprene carries approximately half of the flux of non-methane volatile organic carbon emitted to the atmosphere by the biosphere. Accurate representation of its oxidation rate and products is essential for quantifying its influence on the abundance of the hydroxyl radical (OH), nitrogen oxide free radicals (NO_x), ozone (O_3), and, via the formation of highly oxygenated compounds, aerosol. We present a review of recent laboratory and theoretical studies of the oxidation pathways of isoprene initiated by addition of OH, O_3, the nitrate radical (NO_3), and the chlorine atom. From this review, a recommendation for a nearly complete gas-phase oxidation mechanism of isoprene and its major products is developed. The mechanism is compiled with the aims of providing an accurate representation of the flow of carbon while allowing quantification of the impact of isoprene emissions on HO_x and NO_x free radical concentrations and of the yields of products known to be involved in condensed-phase processes. Finally, a simplified (reduced) mechanism is developed for use in chemical transport models that retains the essential chemistry required to accurately simulate isoprene oxidation under conditions where it occurs in the atmosphere\u2014above forested regions remote from large NO_x emissions.", "doi": "10.1021/acs.chemrev.7b00439", "issn": "0009-2665", "publisher": "American Chemical Society", "publication": "Chemical Reviews", "publication_date": "2018-04-11", "series_number": "7", "volume": "118", "issue": "7", "pages": "3337-3390" }, { "id": "authors:1fwpw-dwm23", "collection": "authors", "collection_id": "1fwpw-dwm23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171201-154316219", "type": "article", "title": "Spatial and temporal distributions of air pollutant emissions from open crop straw and biomass burnings in China from 2002 to 2016", "author": [ { "family_name": "Mehmood", "given_name": "Khalid", "clpid": "Mehmood-K" }, { "family_name": "Chang", "given_name": "Shucheng", "clpid": "Chang-Shucheng" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Li", "given_name": "Pengfei", "clpid": "Li-Pengfei" }, { "family_name": "Li", "given_name": "Zhen", "clpid": "Li-Zhen" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Open biomass burning (OBB) with a main contribution from open crop straw burning (OCSB) plays a key role in the formation of heavy haze episodes during harvest seasons in China through release of particulate matter (PM) and gaseous pollutants. Here we analyze spatial and temporal distributions of air pollutant emissions from OCSB and OBB in China from 2002 to 2016 on the basis of daily and highly resolved (1 km) emissions from the latest FINNv1.5 inventory. Estimated annual emissions of black carbon, organic carbon, PM_(2.5), PM_(10), CH_4, CO, CO_2, NH_3, NO_x, SO_2 and NMVOCS from OBB in China from 2002 to 2016 have increased by 192, 180, 191, 196, 212, 199, 173, 208, 185, 184 and 225%, respectively, whereas emissions from OCSB have increased consistently by ~ 200% for each species. Estimated PM_(2.5) annual emissions from OCSB increased significantly by 245.7% from 14.9 Gg/year in 2012 to 51.5 Gg/year in 2016 in Northeast China, whereas decreasing by 76.1% from 76.3 Gg/year in 2012 to 18.2 Gg/year in 2016 in East China. Contributions of OCSB in OBB emissions increased from 25.4% in 2002 to 56.4% in 2016 in North China and from 31.0% in 2002 to 66.4% in 2016 in Northeast China. Spatial distributions for the period of 2002-2016 indicate that the largest PM_(2.5) annual mean emissions from OCSB (37.0 Gg/year) occur in East China, followed by Northeast China (20.0 Gg/year) and Central China (13.5 Gg/year), whereas Southwest China has the largest PM_(2.5) annual mean emissions from OBB (286.5 Gg/year), following by East China (273.7 Gg/year), South China (237.3 Gg/year) and Central China (126.1 Gg/year). Contributions of OCSB in OBB emissions for PM_(2.5) have increased significantly to 56.4\u201366.4% in North and Northeast China in 2016.", "doi": "10.1007/s10311-017-0675-6", "issn": "1610-3653", "publisher": "Springer", "publication": "Environmental Chemistry Letters", "publication_date": "2018-03", "series_number": "1", "volume": "16", "issue": "1", "pages": "301-309" }, { "id": "authors:7dk5f-qzb28", "collection": "authors", "collection_id": "7dk5f-qzb28", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180306-085251940", "type": "article", "title": "A multi-year data set on aerosol-cloud-precipitation-meteorology interactions for marine stratocumulus clouds", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-Kelvin-H" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-Jill-S" }, { "family_name": "Hodas", "given_name": "Natasha", "clpid": "Hodas-Natasha" }, { "family_name": "Rissman", "given_name": "Tracey A.", "clpid": "Rissman-Tracey-A" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-Varuntida" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Airborne measurements of meteorological, aerosol, and stratocumulus cloud properties have been harmonized from six field campaigns during July-August months between 2005 and 2016 off the California coast. A consistent set of core instruments was deployed on the Center for Interdisciplinary Remotely-Piloted Aircraft Studies Twin Otter for 113 flight days, amounting to 514 flight hours. A unique aspect of the compiled data set is detailed measurements of aerosol microphysical properties (size distribution, composition, bioaerosol detection, hygroscopicity, optical), cloud water composition, and different sampling inlets to distinguish between clear air aerosol, interstitial in-cloud aerosol, and droplet residual particles in cloud. Measurements and data analysis follow documented methods for quality assurance. The data set is suitable for studies associated with aerosol-cloud-precipitation-meteorology-radiation interactions, especially owing to sharp aerosol perturbations from ship traffic and biomass burning. The data set can be used for model initialization and synergistic application with meteorological models and remote sensing data to improve understanding of the very interactions that comprise the largest uncertainty in the effect of anthropogenic emissions on radiative forcing.", "doi": "10.1038/sdata.2018.26", "pmcid": "PMC5827690", "issn": "2052-4463", "publisher": "Nature Publishing Group", "publication": "Scientific Data", "publication_date": "2018-02-27", "volume": "5", "pages": "Art. No. 180026" }, { "id": "authors:nqtze-tq111", "collection": "authors", "collection_id": "nqtze-tq111", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180129-090016392", "type": "article", "title": "Iodometry-Assisted Liquid Chromatography Electrospray Ionization Mass Spectrometry for Analysis of Organic Peroxides - an Application to Atmospheric Secondary Organic Aerosol", "author": [ { "family_name": "Zhao", "given_name": "Ran", "orcid": "0000-0002-1096-7632", "clpid": "Zhao-Ran" }, { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Organic peroxides comprise a significant fraction of atmospheric secondary organic aerosol (SOA). Detection and quantification of particle-phase organic peroxides are highly challenging, and current efforts rely significantly on filter extraction and offline mass spectrometry (MS). Here, a novel technique, iodometry-assisted liquid chromatography electrospray ionization mass spectrometry (iodometry-assisted LC-ESI-MS), is developed and evaluated with a class of atmospherically relevant organic peroxides, \u03b1-acyloxyalkyl hydroperoxides, synthesized via liquid ozonolysis. Iodometry-assisted LC-ESI-MS unambiguously distinguishes organic peroxides, compensating for the lack of functional group information that can be obtained with MS. This technique can be versatile for a wide spectrum of environmental analytical applications for which a molecular-level identification of organic peroxide is required. Here, iodometry-assisted LC-ESI-MS is applied to the water-soluble organic carbon (WSOC) of \u03b1-pinene SOA. Unexpectedly, a limited number of detectable compounds in WSOC appear to be organic peroxides, despite the fact that spectroscopy-based iodometry indicates 15% of WSOC mass is associated with organic peroxides. This observation would be consistent with decomposition of multifunctional organic peroxides to small peroxides that can be quantified by spectroscopy-based iodometry but not by LC-ESI-MS. Overall, this study raises concerns regarding filter extraction-based studies, showing that assignment of organic peroxides solely on the basis of MS signatures can be misleading.", "doi": "10.1021/acs.est.7b04863", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2018-02-20", "series_number": "4", "volume": "52", "issue": "4", "pages": "2108-2117" }, { "id": "authors:zjfza-qb934", "collection": "authors", "collection_id": "zjfza-qb934", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180130-144207182", "type": "article", "title": "Unified Theory of Vapor-Wall Mass Transport in Teflon-Walled Environmental Chambers", "author": [ { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Zhao", "given_name": "Ran", "orcid": "0000-0002-1096-7632", "clpid": "Zhao-Ran" }, { "family_name": "Charan", "given_name": "Sophia M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-Sophia-M" }, { "family_name": "Kenseth", "given_name": "Christopher M.", "orcid": "0000-0003-3188-2336", "clpid": "Kenseth-Christopher-M" }, { "family_name": "Zhang", "given_name": "Xuan", "orcid": "0000-0003-1548-8021", "clpid": "Zhang-Xuan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) formation is studied in laboratory chambers, in which volatile organic compounds (VOCs) are oxidized to produce low-volatility compounds that condense into the aerosol phase. It has been established that such oxidized low-volatility compounds can partition into the chamber walls, which traditionally consist of Teflon film. Several studies exist in which the rates of uptake of individual vapor compounds to the chamber walls have been measured, but a unified theory capable of describing the range of experimental measurements has been lacking. Here, a two-layer model of observed short and long vapor\u2013wall interaction time scales in Teflon-walled environmental chambers is presented and shown to be consistent with experimental data on the rate of wall deposition of more than 90 compounds. Semiempirical relationships between key parameters in the model and vapor molecular properties are derived, which can be used to predict the fate of gas-phase vapor in the chamber under dry conditions.", "doi": "10.1021/acs.est.7b05575", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2018-02-20", "series_number": "4", "volume": "52", "issue": "4", "pages": "2134-2142" }, { "id": "authors:x6fvc-x9098", "collection": "authors", "collection_id": "x6fvc-x9098", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171219-095249096", "type": "article", "title": "Growth kinetics and size distribution dynamics of viscous secondary organic aerosol", "author": [ { "family_name": "Zaveri", "given_name": "Rahul A.", "orcid": "0000-0001-9874-8807", "clpid": "Zaveri-R-A" }, { "family_name": "Shilling", "given_name": "John E.", "orcid": "0000-0002-3728-0195", "clpid": "Shilling-J-E" }, { "family_name": "Zelenyuk", "given_name": "Alla", "orcid": "0000-0002-0674-0910", "clpid": "Zelenyuk-A" }, { "family_name": "Liu", "given_name": "Jiumeng", "clpid": "Liu-Jiumeng" }, { "family_name": "Bell", "given_name": "David M.", "clpid": "Bell-D-M" }, { "family_name": "D'Ambro", "given_name": "Emma L.", "clpid": "D'Ambro-E-L" }, { "family_name": "Gaston", "given_name": "Cassandra J.", "clpid": "Gaston-C-J" }, { "family_name": "Thornton", "given_name": "Joel A.", "orcid": "0000-0002-5098-4867", "clpid": "Thornton-J-A" }, { "family_name": "Laskin", "given_name": "Alexander", "orcid": "0000-0002-7836-8417", "clpid": "Laskin-A" }, { "family_name": "Lin", "given_name": "Peng", "clpid": "Lin-Peng" }, { "family_name": "Wilson", "given_name": "Jacqueline M.", "clpid": "Wilson-J-M" }, { "family_name": "Easter", "given_name": "Richard C.", "orcid": "0000-0002-8602-1464", "clpid": "Easter-R-C" }, { "family_name": "Wang", "given_name": "Jian", "clpid": "Wang-Jian" }, { "family_name": "Bertram", "given_name": "Allan K.", "clpid": "Bertram-A-K" }, { "family_name": "Martin", "given_name": "Scot T.", "clpid": "Martin-S-T" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Worsnop", "given_name": "Douglas R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-D-R" } ], "abstract": "Low bulk diffusivity inside viscous semisolid atmospheric secondary organic aerosol (SOA) can prolong equilibration time scale, but its broader impacts on aerosol growth and size distribution dynamics are poorly understood. Here, we present quantitative insights into the effects of bulk diffusivity on the growth and evaporation kinetics of SOA formed under dry conditions from photooxidation of isoprene in the presence of a bimodal aerosol consisting of Aitken (ammonium sulfate) and accumulation (isoprene or \u03b1-pinene SOA) mode particles. Aerosol composition measurements and evaporation kinetics indicate that isoprene SOA is composed of several semivolatile organic compounds (SVOCs), with some reversibly reacting to form oligomers. Model analysis shows that liquid-like bulk diffusivities can be used to fit the observed evaporation kinetics of accumulation mode particles but fail to explain the growth kinetics of bimodal aerosol by significantly under-predicting the evolution of the Aitken mode. In contrast, the semisolid scenario successfully reproduces both evaporation and growth kinetics, with the interpretation that hindered partitioning of SVOCs into large viscous particles effectively promotes the growth of smaller particles that have shorter diffusion time scales. This effect has important implications for the growth of atmospheric ultrafine particles to climatically active sizes.", "doi": "10.1021/acs.est.7b04623", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2018-02-06", "series_number": "3", "volume": "52", "issue": "3", "pages": "1191-1199" }, { "id": "authors:kjfzm-btk70", "collection": "authors", "collection_id": "kjfzm-btk70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180212-081231529", "type": "article", "title": "Computational simulation of the dynamics of secondary organic aerosol formation in an environmental chamber", "author": [ { "family_name": "Sunol", "given_name": "A. M.", "clpid": "Sunol-A-M" }, { "family_name": "Charan", "given_name": "S. M.", "orcid": "0000-0002-2023-6403", "clpid": "Charan-S-M" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A key atmospheric process that is studied in laboratory chambers is the oxidation of volatile organic compounds to form low volatility products that condense on existing atmospheric particles (or nucleate) to form organic aerosol, so-called secondary organic aerosol. The laboratory chamber operates as a chemical reactor, in which a number of chemical and physical processes take place: gas-phase chemistry, transport of vapor oxidation products to suspended particles followed by uptake into the particles, deposition of vapors on the walls of the chamber, deposition of particles on the walls of the chamber, and coagulation of suspended particles. Understanding the complex interplay among these simultaneous physicochemical processes is necessary in order to interpret the results of chamber experiments. Here we develop and utilize a comprehensive computational model for dynamics of vapors and particles in a laboratory chamber and analyze chamber behavior over a range of physicochemical conditions.", "doi": "10.1080/02786826.2018.1427209", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2018-01-29", "series_number": "4", "volume": "52", "issue": "4", "pages": "470-482" }, { "id": "authors:zngx5-kee48", "collection": "authors", "collection_id": "zngx5-kee48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180118-111915790", "type": "article", "title": "Predicted impact of thermal power generation emission control measures in the Beijing-Tianjin-Hebei region on air pollution over Beijing, China", "author": [ { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Liu", "given_name": "Pengfei", "orcid": "0000-0002-6714-7387", "clpid": "Liu-Pengfei" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Mehmood", "given_name": "Khalid", "clpid": "Mehmood-Khalid" }, { "family_name": "Liu", "given_name": "Zhen", "orcid": "0000-0002-6313-823X", "clpid": "Liu-Zhen" }, { "family_name": "Chang", "given_name": "Shucheng", "clpid": "Chang-Shucheng" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Widespread economic growth in China has led to increasing episodes of severe air pollution, especially in major urban areas. Thermal power plants represent a particularly important class of emissions. Here we present an evaluation of the predicted effectiveness of a series of recently proposed thermal power plant emission controls in the Beijing-Tianjin-Hebei (BTH) region on air quality over Beijing using the Community Multiscale Air Quality(CMAQ) atmospheric chemical transport model to predict CO, SO_2, NO_2, PM_(2.5), and PM_(10) levels. A baseline simulation of the hypothetical removal of all thermal power plants in the BTH region is predicted to lead to 38%, 23%, 23%, 24%, and 24% reductions in current annual mean levels of CO, SO_2, NO_2, PM_(2.5), and PM_(10) in Beijing, respectively. Similar percentage reductions are predicted in the major cities in the BTH region. Simulations of the air quality impact of six proposed thermal power plant emission reduction strategies over the BTH region provide an estimate of the potential improvement in air quality in the Beijing metropolitan area, as a function of the time of year.", "doi": "10.1038/s41598-018-19481-0", "pmcid": "PMC5772530", "issn": "2045-2322", "publisher": "Nature Publishing Group", "publication": "Scientific Reports", "publication_date": "2018-01-17", "volume": "8", "pages": "Art. No. 934" }, { "id": "authors:5sxzd-m9s38", "collection": "authors", "collection_id": "5sxzd-m9s38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170628-110648347", "type": "article", "title": "High reduction of ozone and particulate matter during the 2016 G-20 summit in Hangzhou by forced emission controls of industry and traffic", "author": [ { "family_name": "Liu", "given_name": "Pengfei", "orcid": "0000-0002-6714-7387", "clpid": "Liu-Pengfei" }, { "family_name": "Wang", "given_name": "Liqiang", "clpid": "Wang-Liqiang" }, { "family_name": "Guo", "given_name": "Ping", "clpid": "Guo-Ping" }, { "family_name": "Yu", "given_name": "Shaocai", "orcid": "0000-0001-9718-8246", "clpid": "Yu-Shaocai" }, { "family_name": "Mehmood", "given_name": "Khalid", "clpid": "Mehmood-Khalid" }, { "family_name": "Wang", "given_name": "Si", "clpid": "Wang-Si" }, { "family_name": "Liu", "given_name": "Weiping", "orcid": "0000-0002-1173-892X", "clpid": "Liu-Weiping" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Zhang", "given_name": "Yang", "orcid": "0000-0002-4168-9225", "clpid": "Zhang-Yang" }, { "family_name": "Wong", "given_name": "David C.", "clpid": "Wong-David-C" }, { "family_name": "Alapaty", "given_name": "Kiran", "clpid": "Alapaty-Kiran" }, { "family_name": "Pleim", "given_name": "Jon", "clpid": "Pleim-Jon" }, { "family_name": "Mathur", "given_name": "Rohit", "clpid": "Mathur-Rohit" } ], "abstract": "Many regions in China experience air pollution episodes because of the rapid urbanization and industrialization over the past decades. Here we analyzed the effect of emission controls implemented during the G-20 2016 Hangzhou summit on air quality. Emission controls included a forced closure of highly polluting industries, and limiting traffic and construction emissions in the cities and surroundings. Particles with aerodynamic diameter lower than 2.5 \u03bcm (PM_(2.5)) and ozone (O_3) were measured. We also simulated air quality using a forecast system consisting of the two-way coupled Weather Research and Forecast and Community Multi-scale Air Quality (WRF-CMAQ) model. Results show PM_(2.5) and ozone levels in Hangzhou during the G-20 Summit were considerably lower than previous to the G-20 Summit. The predicted concentrations of ozone were reduced by 25.4%, whereas the predicted concentrations of PM_(2.5) were reduced by 56%.", "doi": "10.1007/s10311-017-0642-2", "pmcid": "PMC5920520", "issn": "1610-3653", "publisher": "Springer", "publication": "Environmental Chemistry Letters", "publication_date": "2017-12", "series_number": "4", "volume": "15", "issue": "4", "pages": "709-715" }, { "id": "authors:r3qrg-35197", "collection": "authors", "collection_id": "r3qrg-35197", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171116-112429011", "type": "article", "title": "SAM-CAAM: A Concept for Acquiring Systematic Aircraft Measurements to Characterize Aerosol Air Masses", "author": [ { "family_name": "Kahn", "given_name": "Ralph A.", "clpid": "Kahn-Ralph-A" }, { "family_name": "Berkoff", "given_name": "Tim A.", "clpid": "Berkoff-Tim-A" }, { "family_name": "Brock", "given_name": "Charles", "clpid": "Brock-Charles" }, { "family_name": "Chen", "given_name": "Gao", "clpid": "Chen-Gao" }, { "family_name": "Ferrare", "given_name": "Richard A.", "orcid": "0000-0002-1005-9730", "clpid": "Ferrare-Richard-A" }, { "family_name": "Ghan", "given_name": "Steven", "clpid": "Ghan-Steven-J" }, { "family_name": "Hansico", "given_name": "Thomas F.", "clpid": "Hansico-Thomas-F" }, { "family_name": "Hegg", "given_name": "Dean A.", "clpid": "Hegg-Dean-A" }, { "family_name": "Martins", "given_name": "J. Vanderlei", "clpid": "Martins-J-Vanderlei" }, { "family_name": "McNaughton", "given_name": "Cameron S.", "clpid": "McNaughton-Cameron-S" }, { "family_name": "Murphy", "given_name": "Daniel M.", "clpid": "Murphy-Daniel-M" }, { "family_name": "Ogren", "given_name": "John A.", "clpid": "Ogren-John-A" }, { "family_name": "Penner", "given_name": "Joyce E.", "clpid": "Penner-Joyce-E" }, { "family_name": "Pilewskie", "given_name": "Peter", "clpid": "Pilewskie-Peter" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Worsnop", "given_name": "Douglas R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-Douglas-R" } ], "abstract": "A modest operational program of systematic aircraft measurements can resolve key satellite aerosol data record limitations. Satellite observations provide frequent global aerosol amount maps but offer only loose aerosol property constraints needed for climate and air quality applications. We define and illustrate the feasibility of flying an aircraft payload to measure key aerosol optical, microphysical, and chemical properties in situ. The flight program could characterize major aerosol airmass types statistically, at a level of detail unobtainable from space. It would 1) enhance satellite aerosol retrieval products with better climatology assumptions and 2) improve translation between satellite-retrieved optical properties and species-specific aerosol mass and size simulated in climate models to assess aerosol forcing, its anthropogenic components, and other environmental impacts. As such, Systematic Aircraft Measurements to Characterize Aerosol Air Masses (SAM-CAAM) could add value to data records representing several decades of aerosol observations from space; improve aerosol constraints on climate modeling; help interrelate remote sensing, in situ, and modeling aerosol-type definitions; and contribute to future satellite aerosol missions. Fifteen required variables are identified and four payload options of increasing ambition are defined to constrain these quantities. \"Option C\" could meet all the SAM-CAAM objectives with about 20 instruments, most of which have flown before, but never routinely several times per week, and never as a group. Aircraft integration and approaches to data handling, payload support, and logistical considerations for a long-term, operational mission are discussed. SAM-CAAM is feasible because, for most aerosol sources and specified seasons, particle properties tend to be repeatable, even if aerosol loading varies.", "doi": "10.1175/BAMS-D-16-0003.1", "pmcid": "PMC5745363", "issn": "0003-0007", "publisher": "American Meteorological Society", "publication": "Bulletin of the American Meteorological Society", "publication_date": "2017-10", "series_number": "10", "volume": "98", "issue": "10", "pages": "2215-2228" }, { "id": "authors:3xej0-f1s14", "collection": "authors", "collection_id": "3xej0-f1s14", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170627-090237623", "type": "article", "title": "Surface tension prevails over solute effect in organic-influenced cloud droplet activation", "author": [ { "family_name": "Ovadnevaite", "given_name": "Jurgita", "clpid": "Ovadnevaite-Jurgita" }, { "family_name": "Zuend", "given_name": "Andreas", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-Andreas" }, { "family_name": "Laaksonen", "given_name": "Ari", "clpid": "Laaksonen-Ari" }, { "family_name": "Sanchez", "given_name": "Kevin J.", "clpid": "Sanchez-Kevin-J" }, { "family_name": "Roberts", "given_name": "Greg", "orcid": "0000-0002-3636-8590", "clpid": "Roberts-G-C" }, { "family_name": "Ceburnis", "given_name": "Darius", "clpid": "Ceburnis-Dariius" }, { "family_name": "Decesari", "given_name": "Stefano", "clpid": "Decesari-Stefano" }, { "family_name": "Rinaldi", "given_name": "Matteo", "clpid": "Rinaldi-Matteo" }, { "family_name": "Hodas", "given_name": "Natasha", "clpid": "Hodas-Natasha" }, { "family_name": "Facchini", "given_name": "Maria Cristina", "clpid": "Facchini-Maria-Cristina" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "O' Dowd", "given_name": "Colin", "clpid": "O'Dowd-Colin" } ], "abstract": "The spontaneous growth of cloud condensation nuclei (CCN) into cloud droplets under supersaturated water vapour conditions is described by classic K\u00f6hler theory. This spontaneous activation of CCN depends on the interplay between the Raoult effect, whereby activation potential increases with decreasing water activity or increasing solute concentration, and the Kelvin effect, whereby activation potential decreases with decreasing droplet size or increases with decreasing surface tension, which is sensitive to surfactants. Surface tension lowering caused by organic surfactants, which diminishes the Kelvin effect, is expected to be negated by a concomitant reduction in the Raoult effect, driven by the displacement of surfactant molecules from the droplet bulk to the droplet\u2013vapour interface. Here we present observational and theoretical evidence illustrating that, in ambient air, surface tension lowering can prevail over the reduction in the Raoult effect, leading to substantial increases in cloud droplet concentrations. We suggest that consideration of liquid\u2013liquid phase separation, leading to complete or partial engulfing of a hygroscopic particle core by a hydrophobic organic-rich phase, can explain the lack of concomitant reduction of the Raoult effect, while maintaining substantial lowering of surface tension, even for partial surface coverage. Apart from the importance of particle size and composition in droplet activation, we show by observation and modelling that incorporation of phase-separation effects into activation thermodynamics can lead to a CCN number concentration that is up to ten times what is predicted by climate models, changing the properties of clouds. An adequate representation of the CCN activation process is essential to the prediction of clouds in climate models, and given the effect of clouds on the Earth's energy balance, improved prediction of aerosol\u2013cloud\u2013climate interactions is likely to result in improved assessments of future climate change.", "doi": "10.1038/nature22806", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2017-06-29", "series_number": "7660", "volume": "546", "issue": "7660", "pages": "637-641" }, { "id": "authors:0kyf5-qx229", "collection": "authors", "collection_id": "0kyf5-qx229", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170728-093929313", "type": "article", "title": "Recent advances in understanding secondary organic aerosol: Implications for global climate forcing", "author": [ { "family_name": "Shrivastava", "given_name": "Manish", "orcid": "0000-0002-9053-2400", "clpid": "Shrivastava-M" }, { "family_name": "Cappa", "given_name": "Christopher D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-C-D" }, { "family_name": "Fan", "given_name": "Jiwen", "orcid": "0000-0001-5280-4391", "clpid": "Fan-Jiwen" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" }, { "family_name": "Guenther", "given_name": "Alex B.", "orcid": "0000-0001-6283-8288", "clpid": "Guenther-A-B" }, { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Kuang", "given_name": "Chongai", "clpid": "Kuang-Chongai" }, { "family_name": "Laskin", "given_name": "Alexander", "orcid": "0000-0002-7836-8417", "clpid": "Laskin-A" }, { "family_name": "Martin", "given_name": "Scot T.", "clpid": "Martin-S-T" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Pet\u00e4j\u00e4", "given_name": "Tuukka", "clpid": "Pet\u00e4j\u00e4-T" }, { "family_name": "Pierce", "given_name": "Jeffrey R.", "clpid": "Pierce-J-R" }, { "family_name": "Rasch", "given_name": "Philip J.", "orcid": "0000-0002-5125-2174", "clpid": "Rasch-P-J" }, { "family_name": "Roldin", "given_name": "Pontus", "clpid": "Roldin-P" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Shilling", "given_name": "John", "orcid": "0000-0002-3728-0195", "clpid": "Shilling-J" }, { "family_name": "Smith", "given_name": "James N.", "orcid": "0000-0003-4677-8224", "clpid": "Smith-J-N" }, { "family_name": "Thornton", "given_name": "Joel A.", "orcid": "0000-0002-5098-4867", "clpid": "Thornton-J-A" }, { "family_name": "Volkamer", "given_name": "Rainer", "orcid": "0000-0002-0899-1369", "clpid": "Volkamer-R" }, { "family_name": "Wang", "given_name": "Jian", "clpid": "Wang-Jian" }, { "family_name": "Worsnop", "given_name": "Douglas R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-D-R" }, { "family_name": "Zaveri", "given_name": "Rahul A.", "orcid": "0000-0001-9874-8807", "clpid": "Zaveri-R-A" }, { "family_name": "Zelenyuk", "given_name": "Alla", "orcid": "0000-0002-0674-0910", "clpid": "Zelenyuk-A" }, { "family_name": "Zhang", "given_name": "Qi", "orcid": "0000-0002-5203-8778", "clpid": "Zhang-Qi" } ], "abstract": "Anthropogenic emissions and land use changes have modified atmospheric aerosol concentrations and size distributions over time. Understanding preindustrial conditions and changes in organic aerosol due to anthropogenic activities is important because these features (1) influence estimates of aerosol radiative forcing and (2) can confound estimates of the historical response of climate to increases in greenhouse gases. Secondary organic aerosol (SOA), formed in the atmosphere by oxidation of organic gases, represents a major fraction of global submicron-sized atmospheric organic aerosol. Over the past decade, significant advances in understanding SOA properties and formation mechanisms have occurred through measurements, yet current climate models typically do not comprehensively include all important processes. This review summarizes some of the important developments during the past decade in understanding SOA formation. We highlight the importance of some processes that influence the growth of SOA particles to sizes relevant for clouds and radiative forcing, including formation of extremely low volatility organics in the gas phase, acid-catalyzed multiphase chemistry of isoprene epoxydiols, particle-phase oligomerization, and physical properties such as volatility and viscosity. Several SOA processes highlighted in this review are complex and interdependent and have nonlinear effects on the properties, formation, and evolution of SOA. Current global models neglect this complexity and nonlinearity and thus are less likely to accurately predict the climate forcing of SOA and project future climate sensitivity to greenhouse gases. Efforts are also needed to rank the most influential processes and nonlinear process-related interactions, so that these processes can be accurately represented in atmospheric chemistry-climate models.", "doi": "10.1002/2016RG000540", "issn": "8755-1209", "publisher": "American Geophysical Union", "publication": "Reviews of Geophysics", "publication_date": "2017-06", "series_number": "2", "volume": "55", "issue": "2", "pages": "509-559" }, { "id": "authors:xxk6d-tj712", "collection": "authors", "collection_id": "xxk6d-tj712", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170515-102340363", "type": "article", "title": "Design, simulation, and characterization of a radial opposed migration ion and aerosol classifier (ROMIAC)", "author": [ { "family_name": "Mui", "given_name": "Wilton", "orcid": "0000-0003-3065-1296", "clpid": "Mui-Wilton" }, { "family_name": "Mai", "given_name": "Huajun", "orcid": "0000-0002-0616-1986", "clpid": "Mai-Huajun" }, { "family_name": "Downard", "given_name": "Andrew J.", "clpid": "Downard-A-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "We present the design, simulation, and characterization of the radial opposed migration ion and aerosol classifier (ROMIAC), a compact differential electrical mobility classifier. We evaluate the performance of the ROMIAC using a combination of finite element modeling and experimental validation of two nearly identical instruments using tetra-alkyl ammonium halide mass standards and sodium chloride particles. Mobility and efficiency calibrations were performed over a wide range of particle diameters and flow rates to characterize ROMIAC performance under the range of anticipated operating conditions. The ROMIAC performs as designed, though performance deviates from that predicted using simplistic models of the instrument. The underlying causes of this non-ideal behavior are found through finite element simulations that predict the performance of the ROMIAC with greater accuracy than the simplistic models. It is concluded that analytical performance models based on idealized geometries, flows, and fields should not be relied on to make accurate a priori predictions about instrumental behavior if the actual geometry or fields deviate from the ideal assumptions. However, if such deviations are accurately captured, finite element simulations have the potential to predict instrumental performance. The present prototype of the ROMIAC maintains its resolution over nearly three orders of magnitude in particle mobility, obtaining sub-20 nm particle size distributions in a compact package with relatively low flow rate operation requirements.", "doi": "10.1080/02786826.2017.1315046", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2017-04-04", "series_number": "7", "volume": "51", "issue": "7", "pages": "801-823" }, { "id": "authors:3am17-02x87", "collection": "authors", "collection_id": "3am17-02x87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170313-154649613", "type": "article", "title": "Relationships Between Giant Sea Salt Particles and Clouds Inferred from Aircraft Physicochemical Data", "author": [ { "family_name": "Dadashazar", "given_name": "Hossein", "orcid": "0000-0001-7054-4933", "clpid": "Dadashazar-H" }, { "family_name": "Wang", "given_name": "Zhen", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Crosbie", "given_name": "Ewan", "orcid": "0000-0002-8895-8066", "clpid": "Crosbie-E" }, { "family_name": "Brunke", "given_name": "Michael", "clpid": "Brunke-M" }, { "family_name": "Zeng", "given_name": "Xubin", "orcid": "0000-0001-7352-2764", "clpid": "Zeng-Xubin" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Woods", "given_name": "Roy K.", "orcid": "0000-0002-3632-6374", "clpid": "Woods-R-K" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" } ], "abstract": "This study uses airborne data from multiple field campaigns off the California coast to determine the extent to which a size distribution parameter and a cloud water chemical measurement can capture the effect of giant cloud condensation nuclei (GCCN), specifically sea salt, on marine stratocumulus cloud properties. The two GCCN proxy variables, near-surface particle number concentration for diameters\u2009>\u20095\u2009\u00b5m and cloud water chloride concentration, are significantly correlated (95% confidence) with each other, and both exhibit expected relationships with other parameters (e.g., surface wind) that typically coincide with sea salt emissions. Factors influencing the relationship between these two GCCN proxy measurements include precipitation rate (R) and the standard deviation of the sub-cloud vertical velocity owing likely to scavenging effects and improved mixing/transport of sea salt to cloud base, respectively. When comparing twelve pairs of high and low chloride cloud cases (at fixed liquid water path and cloud drop number concentration), the average drop spectra for high chloride cases exhibit enhanced drop number at diameters exceeding 20\u2009\u00b5m, especially above 30\u2009\u00b5m. In addition, high chloride cases coincide with enhanced mean columnar R and negative values of precipitation susceptibility. The difference in drop effective radius between high and low chloride conditions decreases with height in cloud, suggesting that some GCCN-produced rain drops precipitate before reaching cloud tops. The sign of cloud responses (i.e., R) to perturbations in giant sea salt particle concentration, as evaluated from MERRA-2 reanalysis data, is consistent with the aircraft data.", "doi": "10.1002/2016JD026019", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2017-03-27", "series_number": "6", "volume": "122", "issue": "6", "pages": "3421-3434" }, { "id": "authors:4kya4-sc541", "collection": "authors", "collection_id": "4kya4-sc541", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170407-102119598", "type": "article", "title": "Formation of highly oxygenated low-volatility products from cresol oxidation", "author": [ { "family_name": "Schwantes", "given_name": "Rebecca H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Schilling", "given_name": "Katherine A.", "clpid": "Schilling-K-A" }, { "family_name": "McVay", "given_name": "Renee C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-R-C" }, { "family_name": "Lignell", "given_name": "Hanna", "orcid": "0000-0001-7049-1659", "clpid": "Lignell-H" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Hydroxyl radical (OH) oxidation of toluene produces ring-retaining products: cresol and benzaldehyde, and ring-opening products: bicyclic intermediate compounds and epoxides. Here, first- and later-generation OH oxidation products from cresol and benzaldehyde are identified in laboratory chamber experiments. For benzaldehyde, first-generation ring-retaining products are identified, but later-generation products are not detected. For cresol, low-volatility (saturation mass concentration, C*\u2009\u223c\u20093.5\u202f\u2009\u00d7\u2009\u202f10^4\u202f\u2212\u202f7.7\u202f\u2009\u00d7\u2009\u202f10^(\u22123)\u202f\u00b5g\u202fm^(\u22123)), first- and later-generation ring-retaining products are identified. Subsequent OH addition to the aromatic ring of o-cresol leads to compounds such as hydroxy, dihydroxy, and trihydroxy methyl benzoquinones and dihydroxy, trihydroxy, tetrahydroxy, and pentahydroxy toluenes. These products are detected in the gas phase by chemical ionization mass spectrometry (CIMS) and in the particle phase using offline direct analysis in real-time mass spectrometry (DART-MS). Our data suggest that the yield of trihydroxy toluene from dihydroxy toluene is substantial. While an exact yield cannot be reported as authentic standards are unavailable, we find that a yield for trihydroxy toluene from dihydroxy toluene of \u223c\u20090.7 (equal to the reported yield of dihydroxy toluene from o-cresol; Olariu et al., 2002) is consistent with experimental results for o-cresol oxidation under low-NO conditions. These results suggest that even though the cresol pathway accounts for only \u223c\u200920\u202f% of the oxidation products of toluene, it is the source of a significant fraction (\u223c\u200920\u201340\u202f%) of toluene secondary organic aerosol (SOA) due to the formation of low-volatility products.", "doi": "10.5194/acp-17-3453-2017", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2017-03-10", "series_number": "5", "volume": "17", "issue": "5", "pages": "3453-3474" }, { "id": "authors:cn83t-tz967", "collection": "authors", "collection_id": "cn83t-tz967", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170417-111141889", "type": "article", "title": "The Caltech Photooxidation Flow Tube reactor: design, fluid dynamics and characterization", "author": [ { "family_name": "Huang", "given_name": "Yuanlong", "orcid": "0000-0002-6726-8904", "clpid": "Huang-Yuanlong" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-Matthew-M" }, { "family_name": "Zhao", "given_name": "Ran", "orcid": "0000-0002-1096-7632", "clpid": "Zhao-Ran" }, { "family_name": "Lignell", "given_name": "Hanna", "orcid": "0000-0001-7049-1659", "clpid": "Lignell-Hanna" }, { "family_name": "Bauer", "given_name": "Michael U.", "clpid": "Bauer-Michael-U" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Flow tube reactors are widely employed to study gas-phase atmospheric chemistry and secondary organic aerosol (SOA) formation. The development of a new laminar-flow tube reactor, the Caltech Photooxidation Flow Tube (CPOT), intended for the study of gas-phase atmospheric chemistry and SOA formation, is reported here. The present work addresses the reactor design based on fluid dynamical characterization and the fundamental behavior of vapor molecules and particles in the reactor. The design of the inlet to the reactor, based on computational fluid dynamics (CFD) simulations, comprises a static mixer and a conical diffuser to facilitate development of a characteristic laminar flow profile. To assess the extent to which the actual performance adheres to the theoretical CFD model, residence time distribution (RTD) experiments are reported with vapor molecules (O_3) and submicrometer ammonium sulfate particles. As confirmed by the CFD prediction, the presence of a slight deviation from strictly isothermal conditions leads to secondary flows in the reactor that produce deviations from the ideal parabolic laminar flow. The characterization experiments, in conjunction with theory, provide a basis for interpretation of atmospheric chemistry and SOA studies to follow. A 1-D photochemical model within an axially dispersed plug flow reactor (AD-PFR) framework is formulated to evaluate the oxidation level in the reactor. The simulation indicates that the OH concentration is uniform along the reactor, and an OH exposure (OH_(exp)) ranging from \u223c\u200910^9 to \u223c 10^(12) molecules\u202fcm^(\u22123)\u202fs can be achieved from photolysis of H_2O_2. A method to calculate OH_(exp) with a consideration for the axial dispersion in the present photochemical system is developed.", "doi": "10.5194/amt-10-839-2017", "issn": "1867-8548", "publisher": "European Geosciences Union", "publication": "Atmospheric Measurement Techniques", "publication_date": "2017-03-09", "series_number": "3", "volume": "10", "issue": "3", "pages": "839-867" }, { "id": "authors:sysws-naq47", "collection": "authors", "collection_id": "sysws-naq47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170407-094115855", "type": "article", "title": "Constraining uncertainties in particle-wall deposition correction during SOA formation in chamber experiments", "author": [ { "family_name": "Nah", "given_name": "Theodora", "orcid": "0000-0002-8755-6153", "clpid": "Nah-Theodora" }, { "family_name": "McVay", "given_name": "Renee C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-R-C" }, { "family_name": "Pierce", "given_name": "Jeffrey R.", "clpid": "Pierce-J-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" } ], "abstract": "The effect of vapor-wall deposition on secondary organic aerosol (SOA) formation has gained significant attention; however, uncertainties in experimentally derived SOA mass yields due to uncertainties in particle-wall deposition remain. Different approaches have been used to correct for particle-wall deposition in SOA formation studies, each having its own set of assumptions in determining the particle-wall loss rate. In volatile and intermediate-volatility organic compound (VOC and IVOC) systems in which SOA formation is governed by kinetically limited growth, the effect of vapor-wall deposition on SOA mass yields can be constrained by using high surface area concentrations of seed aerosol to promote the condensation of SOA-forming vapors onto seed aerosol instead of the chamber walls. However, under such high seed aerosol levels, the presence of significant coagulation may complicate the particle-wall deposition correction. Here, we present a model framework that accounts for coagulation in chamber studies in which high seed aerosol surface area concentrations are used. For the \u03b1-pinene ozonolysis system, we find that after accounting for coagulation, SOA mass yields remain approximately constant when high seed aerosol surface area concentrations (\u2009\u2265\u2009\u202f8000\u202f\u00b5m^2\u202fcm^(\u22123)) are used, consistent with our prior study (Nah et al., 2016) showing that \u03b1-pinene ozonolysis SOA formation is governed by quasi-equilibrium growth. In addition, we systematically assess the uncertainties in the calculated SOA mass concentrations and yields between four different particle-wall loss correction methods over the series of \u03b1-pinene ozonolysis experiments. At low seed aerosol surface area concentrations (<\u202f3000\u202f\u00b5m^2\u202fcm^(\u22123)), the SOA mass yields at peak SOA growth obtained from the particle-wall loss correction methods agree within 14\u202f%. However, at high seed aerosol surface area concentrations (\u2009\u2265\u2009\u202f8000\u202f\u00b5m^2\u202fcm^(\u22123)), the SOA mass yields at peak SOA growth obtained from different particle-wall loss correction methods can differ by as much as 58\u202f%. These differences arise from assumptions made in the particle-wall loss correction regarding the first-order particle-wall loss rate. This study highlights the importance of accounting for particle-wall deposition accurately during SOA formation chamber experiments and assessing the uncertainties associated with the application of the particle-wall deposition correction method when comparing and using SOA mass yields measured in different studies.", "doi": "10.5194/acp-17-2297-2017", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2017-02-14", "series_number": "3", "volume": "17", "issue": "3", "pages": "2297-2310" }, { "id": "authors:5eghr-5w830", "collection": "authors", "collection_id": "5eghr-5w830", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170411-074904432", "type": "book_section", "title": "Science of the Environmental Chamber", "book_title": "Advances in Atmospheric Chemistry", "author": [ { "family_name": "Schwantes", "given_name": "Rebecca H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "McVay", "given_name": "Renee C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-R-C" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Lignell", "given_name": "Hanna", "orcid": "0000-0001-7049-1659", "clpid": "Lignell-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Barker", "given_name": "John R.", "clpid": "Barker-J-R" }, { "family_name": "Steiner", "given_name": "Allison L.", "clpid": "Steiner-A-L" }, { "family_name": "Wallington", "given_name": "Timothy J.", "clpid": "Wallington-T-J" } ], "abstract": "Atmospheric chemistry is simulated in the laboratory using several types of environmental chambers; these include the batch chamber, the continuously mixed flow reactor, and the flow tube reactor. These reactors are used to study gas-phase oxidation of volatile organic compounds (VOCs) as well as the formation of secondary organic aerosol (SOA), the process by which VOCs undergo oxidation to form low-volatility products that condense onto particles. This chapter focuses on the design and characterization of environmental chambers, including: (1) radiation conditions; (2) chamber mixing state; (3) chemical blank experiments; (4) free radical generation (principally the hydroxyl (OH) radical); (5) high-versus-low-NO conditions that govern the nature of VOC oxidation chemistry; (6) deposition of particles onto chamber walls; (7) deposition of organic vapors onto chamber walls; and (8) determination of the yield of SOA. Comparison of the design and behavior of the different types of reactor is addressed in detail. The performance of the differential mobility analyzer (DMA), the prime instrument for measuring aerosol size distributions in chambers, is addressed.", "doi": "10.1142/9789813147355_0001", "isbn": "9789813147355", "publisher": "World Scientific", "publication_date": "2017", "pages": "1-93" }, { "id": "authors:vz6wt-7b740", "collection": "authors", "collection_id": "vz6wt-7b740", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161021-115049301", "type": "article", "title": "Real-Time Studies of Iron Oxalate-Mediated Oxidation of Glycolaldehyde as a Model for Photochemical Aging of Aqueous Tropospheric Aerosols", "author": [ { "family_name": "Thomas", "given_name": "Daniel A.", "orcid": "0000-0001-9415-5991", "clpid": "Thomas-D-A" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Lignell", "given_name": "Hanna", "orcid": "0000-0001-7049-1659", "clpid": "Lignell-H" }, { "family_name": "Schilling", "given_name": "Katherine Ann", "clpid": "Schilling-K-A" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Schwantes", "given_name": "Rebecca H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Beauchamp", "given_name": "Jesse Lee", "orcid": "0000-0001-8839-4822", "clpid": "Beauchamp-J-L" } ], "abstract": "The complexation of iron (III) with oxalic acid in aqueous solution yields a strongly absorbing chromophore that undergoes efficient photodissociation to give iron (II) and the carbon dioxide anion radical. Importantly, iron (III) oxalate complexes absorb near-UV radiation (\u03bb > 350 nm), providing a potentially powerful source of oxidants in aqueous tropospheric chemistry. Although this photochemical system has been studied extensively, the mechanistic details associated with its role in the oxidation of dissolved organic matter within aqueous aerosol remain largely unknown. This study utilizes glycolaldehyde as a model organic species to examine the oxidation pathways and evolution of organic aerosol initiated by the photodissociation of aqueous iron (III) oxalate complexes. Hanging droplets (radius 1 mm) containing iron (III), oxalic acid, glycolaldehyde, and ammonium sulfate (pH ~ 3) are exposed to irradiation at 365 nm and sampled at discrete time points utilizing field-induced droplet ionization mass spectrometry (FIDI-MS). Glycolaldehyde is found to undergo rapid oxidation to form glyoxal, glycolic acid, and glyoxylic acid, but the formation of high molecular weight oligomers is not observed. For comparison, particle-phase experiments conducted in a laboratory chamber explore the reactive uptake of gas-phase glycolaldehyde onto aqueous seed aerosol containing iron and oxalic acid. The presence of iron oxalate in seed aerosol is found to inhibit aerosol growth. These results suggest that photodissociation of iron (III) oxalate can lead to the formation of volatile oxidation products in tropospheric aqueous aerosols.", "doi": "10.1021/acs.est.6b03588", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2016-11-15", "series_number": "22", "volume": "50", "issue": "22", "pages": "12241-12249" }, { "id": "authors:wbmqj-5ne71", "collection": "authors", "collection_id": "wbmqj-5ne71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170106-155452341", "type": "article", "title": "A note on the effects of inorganic seed aerosol on the oxidation state of secondary organic aerosol-\u03b1-Pinene ozonolysis", "author": [ { "family_name": "Huang", "given_name": "Dan Dan", "clpid": "Huang-Dan-Dan" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-N-F" }, { "family_name": "Lignell", "given_name": "Hanna", "orcid": "0000-0001-7049-1659", "clpid": "Lignell-H" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Chan", "given_name": "Chi-Ming", "clpid": "Chan-Chi-Ming" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Chan", "given_name": "Chak K.", "orcid": "0000-0001-9687-8771", "clpid": "Chan-Chak-Keung" } ], "abstract": "We compare the oxidation state and molecular composition of \u03b1-pinene-derived secondary organic aerosol (SOA) by varying the types and surface areas of inorganic seed aerosol that are used to promote the condensation of SOA-forming vapors. The oxidation state of \u03b1-pinene SOA is found to increase with inorganic seed surface area, likely a result of enhanced condensation of low-volatility organic compounds on particles versus deposition on the chamber wall. \u03b1-Pinene SOA is more highly oxygenated in the presence of sodium nitrate (SN) seed than ammonium sulfate seed. The relative abundance of semivolatile monomers and low-volatility dimer components that account for more than half of \u03b1-pinene SOA mass is not significantly affected by the composition of seed aerosol. Enhanced uptake of highly oxidized small carboxylic acids onto SN seed particles is observed, which could potentially explain the observed higher SOA oxidation state in the presence of SN seed aerosol. Overall, our results demonstrate that a combined effect of seed aerosol composition and surface area leads to an increase in the O:C atomic ratio of \u03b1-pinene SOA by as much as a factor of 2.", "doi": "10.1002/2016JD025999", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2016-10-27", "series_number": "20", "volume": "121", "issue": "20", "pages": "12476-12483" }, { "id": "authors:af7xc-5p651", "collection": "authors", "collection_id": "af7xc-5p651", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161013-104431240", "type": "article", "title": "Reduced anthropogenic aerosol radiative forcing caused by biogenic new particle formation", "author": [ { "family_name": "Gordon", "given_name": "Hamish", "orcid": "0000-0002-1822-3224", "clpid": "Gordon-Hamish" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-Jill-S" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Zhang", "given_name": "Xuan", "orcid": "0000-0003-1548-8021", "clpid": "Zhang-Xuan" } ], "abstract": "The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud condensation nuclei (CCN) concentrations and aerosol\u2013cloud radiative forcing over the industrial period. Model simulations show that the pure biogenic particle formation mechanism has a much larger relative effect on CCN concentrations in the preindustrial atmosphere than in the present atmosphere because of the lower aerosol concentrations. Consequently, preindustrial cloud albedo is increased more than under present day conditions, and therefore the cooling forcing of anthropogenic aerosols is reduced. The mechanism increases CCN concentrations by 20\u2013100% over a large fraction of the preindustrial lower atmosphere, and the magnitude of annual global mean radiative forcing caused by changes of cloud albedo since 1750 is reduced by 0.22 W m^(\u22122) (27%) to \u22120.60 W m^(\u22122). Model uncertainties, relatively slow formation rates, and limited available ambient measurements make it difficult to establish the significance of a mechanism that has its dominant effect under preindustrial conditions. Our simulations predict more particle formation in the Amazon than is observed. However, the first observation of pure organic nucleation has now been reported for the free troposphere. Given the potentially significant effect on anthropogenic forcing, effort should be made to better understand such naturally driven aerosol processes.", "doi": "10.1073/pnas.1602360113", "pmcid": "PMC5087035", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2016-10-25", "series_number": "43", "volume": "113", "issue": "43", "pages": "12053-12058" }, { "id": "authors:0a73g-f6w71", "collection": "authors", "collection_id": "0a73g-f6w71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161202-131843652", "type": "article", "title": "Contrasting cloud composition between coupled and decoupled marine boundary layer clouds", "author": [ { "family_name": "Wang", "given_name": "Zhen", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Ramirez", "given_name": "Marco Mora", "clpid": "Ramirez-M-M" }, { "family_name": "Dadashazar", "given_name": "Hossein", "orcid": "0000-0001-7054-4933", "clpid": "Dadashazar-H" }, { "family_name": "MacDonald", "given_name": "Alex B.", "orcid": "0000-0002-7238-3341", "clpid": "MacDonald-A-B" }, { "family_name": "Crosbie", "given_name": "Ewan", "orcid": "0000-0002-8895-8066", "clpid": "Crosbie-E" }, { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-K-H" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-J-S" }, { "family_name": "Lynch", "given_name": "Peng", "orcid": "0000-0002-9661-8045", "clpid": "Lynch-P" }, { "family_name": "Campbell", "given_name": "James R.", "clpid": "Campbell-J-R" }, { "family_name": "Azadi Aghdam", "given_name": "Mojtaba", "orcid": "0000-0002-1720-2894", "clpid": "Azadi-Aghdam-M" }, { "family_name": "Woods", "given_name": "Roy K.", "orcid": "0000-0002-3632-6374", "clpid": "Woods-R-K" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" } ], "abstract": "Marine stratocumulus clouds often become decoupled from the vertical layer immediately above the ocean surface. This study contrasts cloud chemical composition between coupled and decoupled marine stratocumulus clouds for dissolved nonwater substances. Cloud water and droplet residual particle composition were measured in clouds off the California coast during three airborne experiments in July\u2013August of separate years (Eastern Pacific Emitted Aerosol Cloud Experiment 2011, Nucleation in California Experiment 2013, and Biological and Oceanic Atmospheric Study 2015). Decoupled clouds exhibited significantly lower air-equivalent mass concentrations in both cloud water and droplet residual particles, consistent with reduced cloud droplet number concentration and subcloud aerosol (D_p\u2009>\u2009100\u2009nm) number concentration, owing to detachment from surface sources. Nonrefractory submicrometer aerosol measurements show that coupled clouds exhibit higher sulfate mass fractions in droplet residual particles, owing to more abundant precursor emissions from the ocean and ships. Consequently, decoupled clouds exhibited higher mass fractions of organics, nitrate, and ammonium in droplet residual particles, owing to effects of long-range transport from more distant sources. Sodium and chloride dominated in terms of air-equivalent concentration in cloud water for coupled clouds, and their mass fractions and concentrations exceeded those in decoupled clouds. Conversely, with the exception of sea-salt constituents (e.g., Cl, Na, Mg, and K), cloud water mass fractions of all species examined were higher in decoupled clouds relative to coupled clouds. Satellite and Navy Aerosol Analysis and Prediction System-based reanalysis data are compared with each other, and the airborne data to conclude that limitations in resolving boundary layer processes in a global model prevent it from accurately quantifying observed differences between coupled and decoupled cloud composition.", "doi": "10.1002/2016JD025695", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2016-10-16", "series_number": "19", "volume": "121", "issue": "19", "pages": "11679-11691" }, { "id": "authors:ecg33-a1d52", "collection": "authors", "collection_id": "ecg33-a1d52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161107-145058887", "type": "article", "title": "Discontinuities in hygroscopic growth below and above water saturation for laboratory surrogates of oligomers in organic atmospheric aerosols", "author": [ { "family_name": "Hodas", "given_name": "Natasha", "clpid": "Hodas-N" }, { "family_name": "Zuend", "given_name": "Andreas", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Schilling", "given_name": "Katherine", "clpid": "Schilling-K-A" }, { "family_name": "Berkemeier", "given_name": "Thomas", "clpid": "Berkemeier-T" }, { "family_name": "Shiraiwa", "given_name": "Manabu", "orcid": "0000-0003-2532-5373", "clpid": "Shiraiwa-Manabu" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Discontinuities in apparent hygroscopicity below and above water saturation have been observed for organic and mixed organic\u2013inorganic aerosol particles in both laboratory studies and in the ambient atmosphere. However, uncertainty remains regarding the factors that contribute to observations of low hygroscopic growth below water saturation but enhanced cloud condensation nuclei (CCN) activity for a given aerosol population. Utilizing laboratory surrogates for oligomers in atmospheric aerosols, we explore the extent to which such discontinuities are influenced by organic component molecular mass and viscosity, non-ideal thermodynamic interactions between aerosol components, and the combination of these factors. Measurements of hygroscopic growth under subsaturated conditions and the CCN activity of aerosols comprised of polyethylene glycol (PEG) with average molecular masses ranging from 200 to 10\u202f000\u202fg\u202fmol\u207b\u00b9 and mixtures of PEG with ammonium sulfate (AS) were conducted. Experimental results are compared to calculations of hygroscopic growth at thermodynamic equilibrium conducted with the Aerosol Inorganic Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model, and the potential influence of kinetic limitations on observed water uptake was further explored through estimations of water diffusivity in the PEG oligomers. Particle-phase behavior, including the prevalence of liquid\u2013liquid phase separation (LLPS), was also modeled with AIOMFAC. Under subsaturated relative humidity (RH) conditions, we observed little variability in hygroscopic growth across PEG systems with different molecular masses; however, an increase in CCN activity with increasing PEG molecular mass was observed. This effect is most pronounced for PEG\u2013AS mixtures, and, in fact, an enhancement in CCN activity was observed for the PEG10000\u2013AS mixture as compared to pure AS, as evidenced by a 15\u202f% reduction in critical activation diameter at a supersaturation of 0.8\u202f%. We also observed a marked increase in apparent hygroscopicity for mixtures of higher molecular mass PEG and AS under supersaturated conditions as compared to subsaturated hygroscopic growth. AIOMFAC-based predictions and estimations of water diffusivity in PEG suggest that such discontinuities in apparent hygroscopicity above and below water saturation can be attributed, at least in part, to differences in the sensitivity of water uptake behavior to surface tension effects. There is no evidence that kinetic limitations to water uptake due to the presence of viscous aerosol components influenced hygroscopic growth. For the systems that display an enhancement in apparent hygroscopicity above water saturation, LLPS is predicted to persist to high RH. This indicates a miscibility gap and is likely to influence bulk-to-surface partitioning of PEG at high RH, impacting droplet surface tension and CCN activity. This work provides insight into the factors likely to be contributing to discontinuities in aerosol water-uptake behavior below and above water saturation that have been observed previously in the ambient atmosphere.", "doi": "10.5194/acp-16-12767-2016", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2016-10-13", "series_number": "19", "volume": "16", "issue": "19", "pages": "12767-12792" }, { "id": "authors:v2ew8-jka10", "collection": "authors", "collection_id": "v2ew8-jka10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161007-150253060", "type": "article", "title": "Influence of seed aerosol surface area and oxidation rate on vapor wall deposition and SOA mass yields: a case study with \u03b1-pinene ozonolysis", "author": [ { "family_name": "Nah", "given_name": "Theodora", "orcid": "0000-0002-8755-6153", "clpid": "Nah-Theodora" }, { "family_name": "McVay", "given_name": "Renee C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-R-C" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Boyd", "given_name": "Christopher M.", "clpid": "Boyd-C-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" } ], "abstract": "Laboratory chambers, invaluable in atmospheric chemistry and aerosol formation studies, are subject to particle and vapor wall deposition, processes that need to be accounted for in order to accurately determine secondary organic aerosol (SOA) mass yields. Although particle wall deposition is reasonably well understood and usually accounted for, vapor wall deposition is less so. The effects of vapor wall deposition on SOA mass yields in chamber experiments can be constrained experimentally by increasing the seed aerosol surface area to promote the preferential condensation of SOA-forming vapors onto seed aerosol. Here, we study the influence of seed aerosol surface area and oxidation rate on SOA formation in \u03b1-pinene ozonolysis. The observations are analyzed using a coupled vapor\u2013particle dynamics model to interpret the roles of gas\u2013particle partitioning (quasi-equilibrium vs. kinetically limited SOA growth) and \u03b1-pinene oxidation rate in influencing vapor wall deposition. We find that the SOA growth rate and mass yields are independent of seed surface area within the range of seed surface area concentrations used in this study. This behavior arises when the condensation of SOA-forming vapors is dominated by quasi-equilibrium growth. Faster \u03b1-pinene oxidation rates and higher SOA mass yields are observed at increasing O3 concentrations for the same initial \u03b1-pinene concentration. When the \u03b1-pinene oxidation rate increases relative to vapor wall deposition, rapidly produced SOA-forming oxidation products condense more readily onto seed aerosol particles, resulting in higher SOA mass yields. Our results indicate that the extent to which vapor wall deposition affects SOA mass yields depends on the particular volatility organic compound system and can be mitigated through the use of excess oxidant concentrations.", "doi": "10.5194/acp-16-9361-2016", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2016-07-28", "series_number": "14", "volume": "16", "issue": "14", "pages": "9361-9379" }, { "id": "authors:n7v89-41537", "collection": "authors", "collection_id": "n7v89-41537", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160601-132221963", "type": "article", "title": "Ion-induced nucleation of pure biogenic particles", "author": [ { "family_name": "Kirkby", "given_name": "Jasper", "orcid": "0000-0003-2341-9069", "clpid": "Kirkby-Jasper" }, { "family_name": "Craven", "given_name": "Jill", "clpid": "Craven-Jill-S" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Zhang", "given_name": "Xuan", "orcid": "0000-0002-7203-2293", "clpid": "Zhang-Xuan" } ], "abstract": "Atmospheric aerosols and their effect on clouds are thought to be important for anthropogenic radiative forcing of the climate, yet remain poorly understood. Globally, around half of cloud condensation nuclei originate from nucleation of atmospheric vapours. It is thought that sulfuric acid is essential to initiate most particle formation in the atmosphere, and that ions have a relatively minor role. Some laboratory studies, however, have reported organic particle formation without the intentional addition of sulfuric acid, although contamination could not be excluded. Here we present evidence for the formation of aerosol particles from highly oxidized biogenic vapours in the absence of sulfuric acid in a large chamber under atmospheric conditions. The highly oxygenated molecules (HOMs) are produced by ozonolysis of \u03b1-pinene. We find that ions from Galactic cosmic rays increase the nucleation rate by one to two orders of magnitude compared with neutral nucleation. Our experimental findings are supported by quantum chemical calculations of the cluster binding energies of representative HOMs. Ion-induced nucleation of pure organic particles constitutes a potentially widespread source of aerosol particles in terrestrial environments with low sulfuric acid pollution.", "doi": "10.1038/nature17953", "pmcid": "PMC8384037", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2016-05-26", "series_number": "7604", "volume": "533", "issue": "7604", "pages": "521-526" }, { "id": "authors:4nske-80g87", "collection": "authors", "collection_id": "4nske-80g87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160525-075839327", "type": "article", "title": "Improving our fundamental understanding of the role of aerosol\u2212cloud interactions in the climate system", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Bretherton", "given_name": "Christopher S.", "orcid": "0000-0002-6712-8856", "clpid": "Bretherton-Christopher-S" }, { "family_name": "Carslaw", "given_name": "Kenneth S.", "orcid": "0000-0002-6800-154X", "clpid": "Carslaw-Kenneth-S" }, { "family_name": "Coe", "given_name": "Hugh", "orcid": "0000-0002-3264-1713", "clpid": "Coe-Hugh" }, { "family_name": "DeMott", "given_name": "Paul J.", "orcid": "0000-0002-3719-1889", "clpid": "DeMott-Paul-J" }, { "family_name": "Dunlea", "given_name": "Edward J.", "clpid": "Dunlea-Edward-J" }, { "family_name": "Feingold", "given_name": "Graham", "orcid": "0000-0002-0774-2926", "clpid": "Feingold-Graham" }, { "family_name": "Ghan", "given_name": "Steven", "orcid": "0000-0001-8355-8699", "clpid": "Ghan-Steven-J" }, { "family_name": "Guenther", "given_name": "Alex B.", "orcid": "0000-0001-6283-8288", "clpid": "Guenther-Alex-B" }, { "family_name": "Kahn", "given_name": "Ralph", "orcid": "0000-0002-5234-6359", "clpid": "Kahn-Ralph-A" }, { "family_name": "Kraucunas", "given_name": "Ian", "orcid": "0000-0002-2549-6837", "clpid": "Kraucunas-Ian" }, { "family_name": "Kreidenweis", "given_name": "Sonia M.", "orcid": "0000-0002-2561-2914", "clpid": "Kreidenweis-Sonia-M" }, { "family_name": "Molina", "given_name": "Mario J.", "orcid": "0000-0003-2339-3225", "clpid": "Molina-Mario-J" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Penner", "given_name": "Joyce E.", "orcid": "0000-0001-5577-452X", "clpid": "Penner-Joyce-E" }, { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" }, { "family_name": "Ramanathan", "given_name": "V.", "clpid": "Ramanathan-V" }, { "family_name": "Ramaswamy", "given_name": "Venkatachalam", "clpid": "Ramaswamy-Venkatachalam" }, { "family_name": "Rasch", "given_name": "Philip J.", "orcid": "0000-0002-5125-2174", "clpid": "Rasch-Philip-J" }, { "family_name": "Ravishankara", "given_name": "A. R.", "clpid": "Ravishankara-A-R" }, { "family_name": "Rosenfeld", "given_name": "Daniel", "orcid": "0000-0002-0784-7656", "clpid": "Rosenfeld-Daniel" }, { "family_name": "Stephens", "given_name": "Graeme", "orcid": "0000-0002-9860-0287", "clpid": "Stephens-Graeme-L" }, { "family_name": "Wood", "given_name": "Robert", "clpid": "Wood-Robert-J" } ], "abstract": "The effect of an increase in atmospheric aerosol concentrations on the distribution and radiative properties of Earth's clouds is the most uncertain component of the overall global radiative forcing from preindustrial time. General circulation models (GCMs) are the tool for predicting future climate, but the treatment of aerosols, clouds, and aerosol\u2212cloud radiative effects carries large uncertainties that directly affect GCM predictions, such as climate sensitivity. Predictions are hampered by the large range of scales of interaction between various components that need to be captured. Observation systems (remote sensing, in situ) are increasingly being used to constrain predictions, but significant challenges exist, to some extent because of the large range of scales and the fact that the various measuring systems tend to address different scales. Fine-scale models represent clouds, aerosols, and aerosol\u2212cloud interactions with high fidelity but do not include interactions with the larger scale and are therefore limited from a climatic point of view. We suggest strategies for improving estimates of aerosol\u2212cloud relationships in climate models, for new remote sensing and in situ measurements, and for quantifying and reducing model uncertainty.", "doi": "10.1073/pnas.1514043113", "pmcid": "PMC4889348", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2016-05-24", "series_number": "21", "volume": "113", "issue": "21", "pages": "5781-5790" }, { "id": "authors:hjrs5-85c36", "collection": "authors", "collection_id": "hjrs5-85c36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160718-133339102", "type": "article", "title": "Meteorological and aerosol effects on marine cloud microphysical properties", "author": [ { "family_name": "Sanchez", "given_name": "K. J.", "clpid": "Sanchez-Kevin-J" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Modini", "given_name": "R. L.", "orcid": "0000-0002-2982-1369", "clpid": "Modini-Robin-L" }, { "family_name": "Frossard", "given_name": "A. A.", "orcid": "0000-0002-5728-0854", "clpid": "Frossard-Amanda-A" }, { "family_name": "Ahlm", "given_name": "L.", "clpid": "Ahlm-Lars" }, { "family_name": "Corrigan", "given_name": "C. E.", "clpid": "Corrigan-C-E" }, { "family_name": "Roberts", "given_name": "G. C.", "orcid": "0000-0002-3636-8590", "clpid": "Roberts-Greg-C" }, { "family_name": "Hawkins", "given_name": "L. N.", "clpid": "Hawkins-L-N" }, { "family_name": "Schroder", "given_name": "J. C.", "orcid": "0000-0001-9749-151X", "clpid": "Schroder-Jason-C" }, { "family_name": "Bertram", "given_name": "A. K.", "orcid": "0000-0002-5621-2323", "clpid": "Bertram-Allan-K" }, { "family_name": "Zhao", "given_name": "R.", "clpid": "Zhao-R" }, { "family_name": "Lee", "given_name": "A. K. Y.", "clpid": "Lee-Alex-K-Y" }, { "family_name": "Lin", "given_name": "J. J.", "orcid": "0000-0002-4453-1263", "clpid": "Lin-Jack-J" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Wang", "given_name": "Z.", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Wonasch\u00fctz", "given_name": "A.", "clpid": "Wonasch\u00fctz-Anna" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Noone", "given_name": "K. J.", "orcid": "0000-0001-7095-7412", "clpid": "Noone-Kevin-J" }, { "family_name": "Jonsson", "given_name": "H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Toom", "given_name": "D.", "clpid": "Toom-D" }, { "family_name": "Macdonald", "given_name": "A. M.", "clpid": "Macdonald-A-M" }, { "family_name": "Leaitch", "given_name": "W. R.", "clpid": "Leaitch-W-R" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Meteorology and microphysics affect cloud formation, cloud droplet distributions, and shortwave reflectance. The Eastern Pacific Emitted Aerosol Cloud Experiment and the Stratocumulus Observations of Los-Angeles Emissions Derived Aerosol-Droplets studies provided measurements in six case studies of cloud thermodynamic properties, initial particle number distribution and composition, and cloud drop distribution. In this study, we use simulations from a chemical and microphysical aerosol-cloud parcel (ACP) model with explicit kinetic drop activation to reproduce observed cloud droplet distributions of the case studies. Four cases had subadiabatic lapse rates, resulting in fewer activated droplets, lower liquid water content, and higher cloud base height than an adiabatic lapse rate. A weighted ensemble of simulations that reflect measured variation in updraft velocity and cloud base height was used to reproduce observed droplet distributions. Simulations show that organic hygroscopicity in internally mixed cases causes small effects on cloud reflectivity (CR) (<0.01), except for cargo ship and smoke plumes, which increased CR by 0.02 and 0.07, respectively, owing to their high organic mass fraction. Organic hygroscopicity had larger effects on droplet concentrations for cases with higher aerosol concentrations near the critical diameter (namely, polluted cases with a modal peak near 0.1\u2009\u00b5m). Differences in simulated droplet spectral widths (k) caused larger differences in CR than organic hygroscopicity in cases with organic mass fractions of 60% or less for the cases shown. Finally, simulations from a numerical parameterization of cloud droplet activation suitable for general circulation models compared well with the ACP model, except under high organic mass fraction.", "doi": "10.1002/2015JD024595", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2016-04-27", "series_number": "8", "volume": "121", "issue": "8", "pages": "4142-4161" }, { "id": "authors:vzxzy-xky13", "collection": "authors", "collection_id": "vzxzy-xky13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160404-151740437", "type": "article", "title": "Atmospheric fates of Criegee intermediates in the ozonolysis of isoprene", "author": [ { "family_name": "Nguyen", "given_name": "Tran B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Tyndall", "given_name": "Geoffrey S.", "clpid": "Tyndall-G-S" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Teng", "given_name": "Alexander P.", "orcid": "0000-0002-6434-0501", "clpid": "Teng-Alexander-P" }, { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-K-H" }, { "family_name": "Schwantes", "given_name": "Rebecca H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Zhang", "given_name": "Li", "clpid": "Zhang-Li" }, { "family_name": "Feiner", "given_name": "Philip", "clpid": "Feiner-P" }, { "family_name": "Milller", "given_name": "David O.", "clpid": "Milller-D-O" }, { "family_name": "Skog", "given_name": "Kate M.", "clpid": "Skog-K-M" }, { "family_name": "Rivera-Rios", "given_name": "Jean C.", "clpid": "Rivera-Rios-J-C" }, { "family_name": "Dorris", "given_name": "Matthew", "clpid": "Dorris-M" }, { "family_name": "Olson", "given_name": "Kevin F.", "clpid": "Olson-K-F" }, { "family_name": "Koss", "given_name": "Abigail", "clpid": "Koss-A" }, { "family_name": "Wild", "given_name": "Robert J.", "clpid": "Wild-R-J" }, { "family_name": "Brown", "given_name": "Steven S.", "clpid": "Brown-S-S" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" }, { "family_name": "de Gouw", "given_name": "Joost A.", "orcid": "0000-0002-0385-1826", "clpid": "de-Gouw-J-A" }, { "family_name": "Brune", "given_name": "William H.", "orcid": "0000-0002-1609-4051", "clpid": "Brune-W-H" }, { "family_name": "Keutsch", "given_name": "Frank N.", "clpid": "Keutsch-F-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "We use a large laboratory, modeling, and field dataset to investigate the isoprene + O_3 reaction, with the goal of better understanding the fates of the C_1 and C_4 Criegee intermediates in the atmosphere. Although ozonolysis can produce several distinct Criegee intermediates, the C_1 stabilized Criegee (CH_2OO, 61 \u00b1 9%) is the only one observed to react bimolecularly. We suggest that the C_4 Criegees have a low stabilization fraction and propose pathways for their decomposition. Both prompt and non-prompt reactions are important in the production of OH (28% \u00b1 5%) and formaldehyde (81% \u00b1 16%). The yields of unimolecular products (OH, formaldehyde, methacrolein (42 \u00b1 6%) and methyl vinyl ketone (18 \u00b1 6%)) are fairly insensitive to water, i.e., changes in yields in response to water vapor (\u22644% absolute) are within the error of the analysis. We propose a comprehensive reaction mechanism that can be incorporated into atmospheric models, which reproduces laboratory data over a wide range of relative humidities. The mechanism proposes that CH_2OO + H_2O (k_((H_2O)) \u223c 1 \u00d7 10^(\u221215) cm^3 molec^(\u22121) s^(\u22121)) yields 73% hydroxymethyl hydroperoxide (HMHP), 6% formaldehyde + H_2O_2, and 21% formic acid + H_2O; and CH_2OO + (H_2O)_2 (k_((H_2O)_2) \u223c 1 \u00d7 10^(\u221212) cm^3 molec^(\u22121) s^(\u22121)) yields 40% HMHP, 6% formaldehyde + H_2O_2, and 54% formic acid + H_2O. Competitive rate determinations (k_(SO_2/k(H_2O)n=1,2) \u223c 2.2 (\u00b10.3) \u00d7 10^4) and field observations suggest that water vapor is a sink for greater than 98% of CH2OO in a Southeastern US forest, even during pollution episodes ([SO_2] \u223c 10 ppb). The importance of the CH_2OO + (H_2O)n reaction is demonstrated by high HMHP mixing ratios observed over the forest canopy. We find that CH_2OO does not substantially affect the lifetime of SO_2 or HCOOH in the Southeast US, e.g., CH_2OO + SO_2 reaction is a minor contribution (<6%) to sulfate formation. Extrapolating, these results imply that sulfate production by stabilized Criegees is likely unimportant in regions dominated by the reactivity of ozone with isoprene. In contrast, hydroperoxide, organic acid, and formaldehyde formation from isoprene ozonolysis in those areas may be significant.", "doi": "10.1039/C6CP00053C", "issn": "1463-9076", "publisher": "Royal Society of Chemistry", "publication": "Physical Chemistry Chemical Physics", "publication_date": "2016-04-21", "series_number": "15", "volume": "18", "issue": "15", "pages": "10241-10254" }, { "id": "authors:n6z1t-ftk84", "collection": "authors", "collection_id": "n6z1t-ftk84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160610-124411535", "type": "article", "title": "Simulating secondary organic aerosol in a regional air quality model using the statistical oxidation model \u2013 Part 2: Assessing the influence of vapor wall losses", "author": [ { "family_name": "Cappa", "given_name": "Christopher D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-C-D" }, { "family_name": "Jathar", "given_name": "Shantanu H.", "orcid": "0000-0003-4106-2358", "clpid": "Jathar-S-H" }, { "family_name": "Kleeman", "given_name": "Michael J.", "clpid": "Kleeman-M-J" }, { "family_name": "Docherty", "given_name": "Kenneth S.", "clpid": "Docherty-K-S" }, { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wexler", "given_name": "Anthony S.", "clpid": "Wexler-A-S" } ], "abstract": "The influence of losses of organic vapors to chamber walls during secondary organic aerosol (SOA) formation experiments has recently been established. Here, the influence of such losses on simulated ambient SOA concentrations and properties is assessed in the University of California at Davis / California Institute of Technology (UCD/CIT) regional air quality model using the statistical oxidation model (SOM) for SOA. The SOM was fit to laboratory chamber data both with and without accounting for vapor wall losses following the approach of Zhang et al. (2014). Two vapor wall-loss scenarios are considered when fitting of SOM to chamber data to determine best-fit SOM parameters, one with \"low\" and one with \"high\" vapor wall-loss rates to approximately account for the current range of uncertainty in this process. Simulations were run using these different parameterizations (scenarios) for both the southern California/South Coast Air Basin (SoCAB) and the eastern United States (US). Accounting for vapor wall losses leads to substantial increases in the simulated SOA concentrations from volatile organic compounds (VOCs) in both domains, by factors of \u2009\u223c\u2009\u202f2\u20135 for the low and \u2009\u223c\u2009\u202f5\u201310 for the high scenarios. The magnitude of the increase scales approximately inversely with the absolute SOA concentration of the no loss scenario. In SoCAB, the predicted SOA fraction of total organic aerosol (OA) increases from \u2009\u223c\u2009\u202f0.2 (no) to \u2009\u223c\u2009\u202f0.5 (low) and to \u2009\u223c\u2009\u202f0.7 (high), with the high vapor wall-loss simulations providing best general agreement with observations. In the eastern US, the SOA fraction is large in all cases but increases further when vapor wall losses are accounted for. The total OA\u202f\u2215\u202f\u0394CO ratio captures the influence of dilution on SOA concentrations. The simulated OA\u202f\u2215\u202f\u0394CO in SoCAB (specifically, at Riverside, CA) is found to increase substantially during the day only for the high vapor wall-loss scenario, which is consistent with observations and indicative of photochemical production of SOA. Simulated O\u202f:\u202fC atomic ratios for both SOA and for total OA increase when vapor wall losses are accounted for, while simulated H\u202f:\u202fC atomic ratios decrease. The agreement between simulations and observations of both the absolute values and the diurnal profile of the O\u202f:\u202fC and H\u202f:\u202fC atomic ratios for total OA was greatly improved when vapor wall-losses were accounted for. These results overall demonstrate that vapor wall losses in chambers have the potential to exert a large influence on simulated ambient SOA concentrations, and further suggest that accounting for such effects in models can explain a number of different observations and model\u2013measurement discrepancies.", "doi": "10.5194/acp-16-3041-2016", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2016-03-09", "series_number": "5", "volume": "16", "issue": "5", "pages": "3041-3059" }, { "id": "authors:f0g3b-f1643", "collection": "authors", "collection_id": "f0g3b-f1643", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160610-123722476", "type": "article", "title": "SOA formation from the photooxidation of \u03b1-pinene: systematic exploration of the simulation of chamber data", "author": [ { "family_name": "McVay", "given_name": "Renee C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-R-C" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Aumont", "given_name": "Bernard", "clpid": "Aumont-B" }, { "family_name": "Valorso", "given_name": "Richard", "clpid": "Valorso-R" }, { "family_name": "Camredon", "given_name": "Marie", "clpid": "Camredon-M" }, { "family_name": "La", "given_name": "Yuyi S.", "clpid": "La-Yuyi-S" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Chemical mechanisms play an important role in simulating the atmospheric chemistry of volatile organic compound oxidation. Comparison of mechanism simulations with laboratory chamber data tests our level of understanding of the prevailing chemistry as well as the dynamic processes occurring in the chamber itself. \u03b1-Pinene photooxidation is a well-studied system experimentally, for which detailed chemical mechanisms have been formulated. Here, we present the results of simulating low-NO \u03b1-pinene photooxidation experiments conducted in the Caltech chamber with the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) under varying concentrations of seed particles and OH levels. Unexpectedly, experiments conducted at low and high OH levels yield the same secondary organic aerosol (SOA) growth, whereas GECKO-A predicts greater SOA growth under high OH levels. SOA formation in the chamber is a result of a competition among the rates of gas-phase oxidation to low-volatility products, wall deposition of these products, and condensation into the aerosol phase. Various processes \u2013 such as photolysis of condensed-phase products, particle-phase dimerization, and peroxy radical autoxidation \u2013 are explored to rationalize the observations. In order to explain the observed similar SOA growth at different OH levels, we conclude that vapor wall loss in the Caltech chamber is likely of order 10^(\u22125)\u202fs^(\u22121), consistent with previous experimental measurements in that chamber. We find that GECKO-A tends to overpredict the contribution to SOA of later-generation oxidation products under high-OH conditions. Moreover, we propose that autoxidation may alternatively resolve some or all of the measurement\u2013model discrepancy, but this hypothesis cannot be confirmed until more explicit mechanisms are established for \u03b1-pinene autoxidation. The key role of the interplay among oxidation rate, product volatility, and vapor\u2013wall deposition in chamber experiments is illustrated.", "doi": "10.5194/acp-16-2785-2016", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2016-03-04", "series_number": "5", "volume": "16", "issue": "5", "pages": "2785-2802" }, { "id": "authors:dnh0v-n1778", "collection": "authors", "collection_id": "dnh0v-n1778", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160314-082627109", "type": "article", "title": "Stratocumulus Cloud Clearings and Notable Thermodynamic and Aerosol Contrasts across the Clear\u2013Cloudy Interface", "author": [ { "family_name": "Crosbie", "given_name": "Ewan", "orcid": "0000-0002-8895-8066", "clpid": "Crosbie-E" }, { "family_name": "Wang", "given_name": "Zhen", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Chuang", "given_name": "Patrick Y.", "orcid": "0000-0003-2290-8346", "clpid": "Chuang-Patrick-Y" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-J-S" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Brunke", "given_name": "Michael", "clpid": "Brunke-M" }, { "family_name": "Zeng", "given_name": "Xubin", "orcid": "0000-0001-7352-2764", "clpid": "Zeng-Xubin" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Woods", "given_name": "Roy K.", "orcid": "0000-0002-3632-6374", "clpid": "Woods-R-K" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Data from three research flights, conducted over water near the California coast, are used to investigate the boundary between stratocumulus cloud decks and clearings of different sizes. Large clearings exhibit a diurnal cycle with growth during the day and contraction overnight and a multiday life cycle that can include oscillations between growth and decay, whereas a small coastal clearing was observed to be locally confined with a subdiurnal lifetime. Subcloud aerosol characteristics are similar on both sides of the clear\u2013cloudy boundary in the three cases, while meteorological properties exhibit subtle, yet important, gradients, implying that dynamics, and not microphysics, is the primary driver for the clearing characteristics. Transects, made at multiple levels across the cloud boundary during one flight, highlight the importance of microscale (~1 km) structure in thermodynamic properties near the cloud edge, suggesting that dynamic forcing at length scales comparable to the convective eddy scale may be influential to the larger-scale characteristics of the clearing. These results have implications for modeling and observational studies of marine boundary layer clouds, especially in relation to aerosol\u2013cloud interactions and scales of variability responsible for the evolution of stratocumulus clearings.", "doi": "10.1175/JAS-D-15-0137.1", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2016-03", "series_number": "3", "volume": "73", "issue": "3", "pages": "1083-1099" }, { "id": "authors:ydges-6fy45", "collection": "authors", "collection_id": "ydges-6fy45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160426-093403913", "type": "article", "title": "Simulating secondary organic aerosol in a regional air quality model using the statistical oxidation model \u2013 Part 1: Assessing the influence of constrained multi-generational ageing", "author": [ { "family_name": "Jathar", "given_name": "S. H.", "orcid": "0000-0003-4106-2358", "clpid": "Jathar-S-H" }, { "family_name": "Cappa", "given_name": "C. D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-C-D" }, { "family_name": "Wexler", "given_name": "A. S.", "clpid": "Wexler-A-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Kleeman", "given_name": "M. J.", "clpid": "Kleeman-M-J" } ], "abstract": "Multi-generational oxidation of volatile organic compound (VOC) oxidation products can significantly alter the mass, chemical composition and properties of secondary organic aerosol (SOA) compared to calculations that consider only the first few generations of oxidation reactions. However, the most commonly used state-of-the-science schemes in 3-D regional or global models that account for multi-generational oxidation (1) consider only functionalization reactions but do not consider fragmentation reactions, (2) have not been constrained to experimental data and (3) are added on top of existing parameterizations. The incomplete description of multi-generational oxidation in these models has the potential to bias source apportionment and control calculations for SOA. In this work, we used the statistical oxidation model (SOM) of Cappa and Wilson (2012), constrained by experimental laboratory chamber data, to evaluate the regional implications of multi-generational oxidation considering both functionalization and fragmentation reactions. SOM was implemented into the regional University of California at Davis / California Institute of Technology (UCD/CIT) air quality model and applied to air quality episodes in California and the eastern USA. The mass, composition and properties of SOA predicted using SOM were compared to SOA predictions generated by a traditional two-product model to fully investigate the impact of explicit and self-consistent accounting of multi-generational oxidation.\n\nResults show that SOA mass concentrations predicted by the UCD/CIT-SOM model are very similar to those predicted by a two-product model when both models use parameters that are derived from the same chamber data. Since the two-product model does not explicitly resolve multi-generational oxidation reactions, this finding suggests that the chamber data used to parameterize the models captures the majority of the SOA mass formation from multi-generational oxidation under the conditions tested. Consequently, the use of low and high NOx yields perturbs SOA concentrations by a factor of two and are probably a much stronger determinant in 3-D models than multi-generational oxidation. While total predicted SOA mass is similar for the SOM and two-product models, the SOM model predicts increased SOA contributions from anthropogenic (alkane, aromatic) and sesquiterpenes and decreased SOA contributions from isoprene and monoterpene relative to the two-product model calculations. The SOA predicted by SOM has a much lower volatility than that predicted by the traditional model, resulting in better qualitative agreement with volatility measurements of ambient OA. On account of its lower-volatility, the SOA mass produced by SOM does not appear to be as strongly influenced by the inclusion of oligomerization reactions, whereas the two-product model relies heavily on oligomerization to form low-volatility SOA products. Finally, an unconstrained contemporary hybrid scheme to model multi-generational oxidation within the framework of a two-product model in which ageing reactions are added on top of the existing two-product parameterization is considered. This hybrid scheme formed at least 3 times more SOA than the SOM during regional simulations as a result of excessive transformation of semi-volatile vapors into lower volatility material that strongly partitions to the particle phase. This finding suggests that these hybrid multi-generational schemes should be used with great caution in regional models.", "doi": "10.5194/acp-16-2309-2016", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2016-02-26", "series_number": "4", "volume": "16", "issue": "4", "pages": "2309-2322" }, { "id": "authors:j66fk-evs29", "collection": "authors", "collection_id": "j66fk-evs29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160112-074404722", "type": "article", "title": "Production and Fate of C_4 Dihydroxycarbonyl Compounds from Isoprene Oxidation", "author": [ { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-K-H" }, { "family_name": "Nguyen", "given_name": "Tran B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Teng", "given_name": "Alex P.", "clpid": "Teng-Alex-P" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Kjaergaard", "given_name": "Henrik G.", "orcid": "0000-0002-7275-8297", "clpid": "Kjaergaard-H-G" }, { "family_name": "Stoltz", "given_name": "Brian M.", "orcid": "0000-0001-9837-1528", "clpid": "Stoltz-B-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "Isoprene epoxydiols (IEPOX) are formed in high yield as second-generation products of atmospheric isoprene oxidation in pristine (low-NO) environments. IEPOX has received significant attention for its ability to form secondary organic aerosol, but the fate of IEPOX in the gas phase, and those of its oxidation products, remains largely unexplored. In this study, three dihydroxycarbonyl compounds with molecular formula of C_4H_8O_3, putative products of IEPOX oxidation, are synthesized to determine their isomer-specific yields from IEPOX. We find that 3,4-dihydroxy-2-butanone (DHBO) comprises 43% and 36% of the products from cis- and trans-\u03b2-IEPOX, respectively, and is by far the most abundant C_4H_8O_3 dihydroxycarbonyl compound produced by this mechanism. OH is found to react with DHBO with a rate coefficient of 1.10 \u00d7 10^(\u201311) cm^3 molecule^(\u20131) s^(\u20131) at 297 K, forming two hydroxydicarbonyl compounds that share the molecular formula C_4H_6O_3 with unitary yield. The results of this study are compared with field observations and used to propose a multigenerational mechanism of IEPOX oxidation. Finally, global simulations using GEOS-Chem, a chemical transport model, show that the C_4H_8O_3 dihydroxycarbonyl compounds and their oxidation products are widespread in the atmosphere and estimate annual global production of C_4H_8O_3 dihydroxycarbonyls to be 54 Tg\u202fy^(\u20131), primarily as DHBO.", "doi": "10.1021/acs.jpca.5b10335", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2016-01-14", "series_number": "1", "volume": "120", "issue": "1", "pages": "106-117" }, { "id": "authors:v35fm-56n83", "collection": "authors", "collection_id": "v35fm-56n83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151109-082447673", "type": "article", "title": "Formation and evolution of molecular products in \u03b1-pinene secondary organic aerosol", "author": [ { "family_name": "Zhang", "given_name": "Xuan", "orcid": "0000-0002-7203-2293", "clpid": "Zhang-Xuan" }, { "family_name": "McVay", "given_name": "Renee C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-Renee-C" }, { "family_name": "Huang", "given_name": "Dan D.", "clpid": "Huang-Dan-D" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Aumont", "given_name": "Bernard", "orcid": "0000-0002-2781-0877", "clpid": "Aumont-Berrnard" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Much of our understanding of atmospheric secondary organic aerosol (SOA) formation from volatile organic compounds derives from laboratory chamber measurements, including mass yield and elemental composition. These measurements alone are insufficient to identify the chemical mechanisms of SOA production. We present here a comprehensive dataset on the molecular identity, abundance, and kinetics of \u03b1-pinene SOA, a canonical system that has received much attention owing to its importance as an organic aerosol source in the pristine atmosphere. Identified organic species account for \u223c58\u201372% of the \u03b1-pinene SOA mass, and are characterized as semivolatile/low-volatility monomers and extremely low volatility dimers, which exhibit comparable oxidation states yet different functionalities. Features of the \u03b1-pinene SOA formation process are revealed for the first time, to our knowledge, from the dynamics of individual particle-phase components. Although monomeric products dominate the overall aerosol mass, rapid production of dimers plays a key role in initiating particle growth. Continuous production of monomers is observed after the parent \u03b1-pinene is consumed, which cannot be explained solely by gas-phase photochemical production. Additionally, distinct responses of monomers and dimers to \u03b1-pinene oxidation by ozone vs. hydroxyl radicals, temperature, and relative humidity are observed. Gas-phase radical combination reactions together with condensed phase rearrangement of labile molecules potentially explain the newly characterized SOA features, thereby opening up further avenues for understanding formation and evolution mechanisms of \u03b1-pinene SOA.", "doi": "10.1073/pnas.1517742112", "pmcid": "PMC4655512", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2015-11-17", "series_number": "46", "volume": "112", "issue": "46", "pages": "14168-14173" }, { "id": "authors:33btd-6c986", "collection": "authors", "collection_id": "33btd-6c986", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160104-153602008", "type": "article", "title": "CCN Properties of Organic Aerosol Collected Below and within Marine Stratocumulus Clouds near Monterey, California", "author": [ { "family_name": "Asa-Awuku", "given_name": "Akua", "orcid": "0000-0002-0354-8368", "clpid": "Asa-Awuku-Akua" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" } ], "abstract": "The composition of aerosol from cloud droplets differs from that below cloud. Its implications for the Cloud Condensation Nuclei (CCN) activity are the focus of this study. Water-soluble organic matter from below cloud, and cloud droplet residuals off the coast of Monterey, California were collected; offline chemical composition, CCN activity and surface tension measurements coupled with K\u00f6hler Theory Analysis are used to infer the molar volume and surfactant characteristics of organics in both samples. Based on the surface tension depression of the samples, it is unlikely that the aerosol contains strong surfactants. The activation kinetics for all samples examined are consistent with rapid (NH4)2SO4 calibration aerosol. This is consistent with our current understanding of droplet kinetics for ambient CCN. However, the carbonaceous material in cloud drop residuals is far more hygroscopic than in sub-cloud aerosol, suggestive of the impact of cloud chemistry on the hygroscopic properties of organic matter.", "doi": "10.3390/atmos6111590", "issn": "2073-4433", "publisher": "MDPI", "publication": "Atmosphere", "publication_date": "2015-11", "series_number": "11", "volume": "6", "issue": "11", "pages": "1590-1607" }, { "id": "authors:vg2kz-a8k50", "collection": "authors", "collection_id": "vg2kz-a8k50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150928-082640803", "type": "article", "title": "Isoprene NO_3 Oxidation Products from the RO_2 + HO_2 Pathway", "author": [ { "family_name": "Schwantes", "given_name": "Rebecca H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Teng", "given_name": "Alexander P.", "orcid": "0000-0002-6434-0501", "clpid": "Teng-Alexander-P" }, { "family_name": "Nguyen", "given_name": "Tran B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "St. Clair", "given_name": "Jason M.", "orcid": "0000-0002-9367-5749", "clpid": "St-Clair-J-M" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Schilling", "given_name": "Katherine A.", "clpid": "Schilling-K-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "We describe the products of the reaction of the hydroperoxy radical (HO_2) with the alkylperoxy radical formed following addition of the nitrate radical (NO_3) and O_2 to isoprene. NO_3 adds preferentially to the C_1 position of isoprene (>6 times more favorably than addition to C_4), followed by the addition of O_2 to produce a suite of nitrooxy alkylperoxy radicals (RO_2). At an RO_2 lifetime of \u223c30 s, \u03b4-nitrooxy and \u03b2-nitrooxy alkylperoxy radicals are present in similar amounts. Gas-phase product yields from the RO_2 + HO_2 pathway are identified as 0.75\u20130.78 isoprene nitrooxy hydroperoxide (INP), 0.22 methyl vinyl ketone (MVK) + formaldehyde (CH_2O) + hydroxyl radical (OH) + nitrogen dioxide (NO_2), and 0\u20130.03 methacrolein (MACR) + CH_2O + OH + NO_2. We further examined the photochemistry of INP and identified propanone nitrate (PROPNN) and isoprene nitrooxy hydroxyepoxide (INHE) as the main products. INHE undergoes similar heterogeneous chemistry as isoprene dihydroxy epoxide (IEPOX), likely contributing to atmospheric secondary organic aerosol formation.", "doi": "10.1021/acs.jpca.5b06355", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2015-10-08", "series_number": "40", "volume": "119", "issue": "40", "pages": "10158-10171" }, { "id": "authors:zd12w-30345", "collection": "authors", "collection_id": "zd12w-30345", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150921-111503736", "type": "article", "title": "Under What Conditions Can Equilibrium Gas\u2013Particle Partitioning Be Expected to Hold in the Atmosphere?", "author": [ { "family_name": "Mai", "given_name": "Huajun", "orcid": "0000-0002-0616-1986", "clpid": "Mai-Huajun" }, { "family_name": "Shiraiwa", "given_name": "Manabu", "orcid": "0000-0003-2532-5373", "clpid": "Shiraiwa-Manabu" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The prevailing treatment of secondary organic aerosol formation in atmospheric models is based on the assumption of instantaneous gas\u2013particle equilibrium for the condensing species, yet compelling experimental evidence indicates that organic aerosols can exhibit the properties of highly viscous, semisolid particles, for which gas\u2013particle equilibrium may be achieved slowly. The approach to gas\u2013particle equilibrium partitioning is controlled by gas-phase diffusion, interfacial transport, and particle-phase diffusion. Here we evaluate the controlling processes and the time scale to achieve gas\u2013particle equilibrium as a function of the volatility of the condensing species, its surface accommodation coefficient, and its particle-phase diffusivity. For particles in the size range of typical atmospheric organic aerosols (\u223c50\u2013500 nm), the time scale to establish gas\u2013particle equilibrium is generally governed either by interfacial accommodation or particle-phase diffusion. The rate of approach to equilibrium varies, depending on whether the bulk vapor concentration is constant, typical of an open system, or decreasing as a result of condensation into the particles, typical of a closed system.", "doi": "10.1021/acs.est.5b02587", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2015-10-06", "series_number": "19", "volume": "49", "issue": "19", "pages": "11485-11491" }, { "id": "authors:ntp8d-nzm35", "collection": "authors", "collection_id": "ntp8d-nzm35", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150909-091738012", "type": "article", "title": "Time-resolved molecular characterization of organic aerosols by PILS + UPLC/ESI-Q-TOFMS", "author": [ { "family_name": "Zhang", "given_name": "X.", "clpid": "Zhang-X" }, { "family_name": "Dalleska", "given_name": "N. F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-N-F" }, { "family_name": "Huang", "given_name": "D. D.", "clpid": "Huang-D-D" }, { "family_name": "Bates", "given_name": "K. H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-K-H" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Real-time and quantitative measurement of particulate matter chemical composition represents one of the most challenging problems in the field of atmospheric chemistry. In the present study, we integrate the Particle-into-Liquid Sampler (PILS) with Ultra Performance Liquid Chromatography/Electrospray ionization Quadrupole Time-of-Flight High-Resolution/Mass Spectrometry (UPLC/ESI-Q-TOFMS) for the time-resolved molecular speciation of chamber-derived secondary organic aerosol (SOA). The unique aspect of the combination of these two well-proven techniques is to provide quantifiable molecular-level information of particle-phase organic compounds on timescales of minutes. We demonstrate that the application of the PILS + UPLC/ESI-Q-TOFMS method is not limited to water-soluble inorganic ions and organic carbon, but is extended to slightly water-soluble species through collection efficiency calibration together with sensitivity and linearity tests. By correlating the water solubility of individual species with their O:C ratio, a parameter that is available for aerosol ensembles as well, we define an average aerosol O:C ratio threshold of 0.3, above which the PILS overall particulate mass collection efficiency approaches \u223c0.7. The PILS + UPLC/ESI-Q-TOFMS method can be potentially applied to probe the formation and evolution mechanism of a variety of biogenic and anthropogenic SOA systems in laboratory chamber experiments. We illustrate the application of this method to the reactive uptake of isoprene epoxydiols (IEPOX) on hydrated and acidic ammonium sulfate aerosols.", "doi": "10.1016/j.atmosenv.2015.08.049", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2015-09-09", "volume": "130", "pages": "180-189" }, { "id": "authors:1nq85-xtp77", "collection": "authors", "collection_id": "1nq85-xtp77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150911-144046678", "type": "article", "title": "Formation of Low Volatility Organic Compounds and Secondary Organic Aerosol from Isoprene Hydroxyhydroperoxide Low-NO Oxidation", "author": [ { "family_name": "Krechmer", "given_name": "Jordan E.", "orcid": "0000-0003-3642-0659", "clpid": "Krechmer-J-E" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Nguyen", "given_name": "Tran B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "St. Clair", "given_name": "Jason M.", "orcid": "0000-0002-9367-5749", "clpid": "St-Clair-J-M" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Gas-phase low volatility organic compounds (LVOC), produced from oxidation of isoprene 4-hydroxy-3-hydroperoxide (4,3-ISOPOOH) under low-NO conditions, were observed during the FIXCIT chamber study. Decreases in LVOC directly correspond to appearance and growth in secondary organic aerosol (SOA) of consistent elemental composition, indicating that LVOC condense (at OA below 1 \u03bcg m^(\u20133)). This represents the first simultaneous measurement of condensing low volatility species from isoprene oxidation in both the gas and particle phases. The SOA formation in this study is separate from previously described isoprene epoxydiol (IEPOX) uptake. Assigning all condensing LVOC signals to 4,3-ISOPOOH oxidation in the chamber study implies a wall-loss corrected non-IEPOX SOA mass yield of \u223c4%. By contrast to monoterpene oxidation, in which extremely low volatility VOC (ELVOC) constitute the organic aerosol, in the isoprene system LVOC with saturation concentrations from 10^(\u20132) to 10 \u03bcg m^(\u20133) are the main constituents. These LVOC may be important for the growth of nanoparticles in environments with low OA concentrations. LVOC observed in the chamber were also observed in the atmosphere during SOAS-2013 in the Southeastern United States, with the expected diurnal cycle. This previously uncharacterized aerosol formation pathway could account for \u223c5.0 Tg yr^(\u20131) of SOA production, or 3.3% of global SOA.", "doi": "10.1021/acs.est.5b02031", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2015-09-01", "series_number": "17", "volume": "49", "issue": "17", "pages": "10330-10339" }, { "id": "authors:9ym54-sq143", "collection": "authors", "collection_id": "9ym54-sq143", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150924-104904357", "type": "article", "title": "Multi-generational oxidation model to simulate secondary organic aerosol in a 3-D air quality model", "author": [ { "family_name": "Jathar", "given_name": "S. H.", "orcid": "0000-0003-4106-2358", "clpid": "Jathar-S-H" }, { "family_name": "Cappa", "given_name": "C. D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-C-D" }, { "family_name": "Wexler", "given_name": "A. S.", "clpid": "Wexler-A-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Kleeman", "given_name": "M. J.", "clpid": "Kleeman-M-J" } ], "abstract": "Multi-generational gas-phase oxidation of organic vapors can influence the abundance, composition and properties of secondary organic aerosol (SOA). Only recently have SOA models been developed that explicitly represent multi-generational SOA formation. In this work, we integrated the statistical oxidation model (SOM) into SAPRC-11 to simulate the multi-generational oxidation and gas/particle partitioning of SOA in the regional UCD/CIT (University of California, Davis/California Institute of Technology) air quality model. In the SOM, evolution of organic vapors by reaction with the hydroxyl radical is defined by (1) the number of oxygen atoms added per reaction, (2) the decrease in volatility upon addition of an oxygen atom and (3) the probability that a given reaction leads to fragmentation of the organic molecule. These SOM parameter values were fit to laboratory smog chamber data for each precursor/compound class. SOM was installed in the UCD/CIT model, which simulated air quality over 2-week periods in the South Coast Air Basin of California and the eastern United States. For the regions and episodes tested, the two-product SOA model and SOM produce similar SOA concentrations but a modestly different SOA chemical composition. Predictions of the oxygen-to-carbon ratio qualitatively agree with those measured globally using aerosol mass spectrometers. Overall, the implementation of the SOM in a 3-D model provides a comprehensive framework to simulate the atmospheric evolution of organic aerosol.", "doi": "10.5194/gmd-8-2553-2015", "issn": "1991-959X", "publisher": "European Geosciences Union", "publication": "Geoscientific Model Development", "publication_date": "2015-08-13", "series_number": "8", "volume": "8", "issue": "8", "pages": "2553-2567" }, { "id": "authors:q26qh-hbs30", "collection": "authors", "collection_id": "q26qh-hbs30", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150701-104453949", "type": "article", "title": "Mechanism of the hydroxyl radical oxidation of methacryloyl peroxynitrate (MPAN) and its pathway toward secondary organic aerosol formation in the atmosphere", "author": [ { "family_name": "Nguyen", "given_name": "Tran B.", "orcid": "0000-0001-9206-4359", "clpid": "Nguyen-Tran-B" }, { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-Kelvin-H" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-John-D" }, { "family_name": "Schwantes", "given_name": "Rebecca H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-Rebecca-H" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Kjaergaard", "given_name": "Henrik G.", "orcid": "0000-0002-7275-8297", "clpid": "Kjaergaard-Henrik-G" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Lin", "given_name": "Peng", "clpid": "Lin-Peng" }, { "family_name": "Laskin", "given_name": "Alexander", "orcid": "0000-0002-7836-8417", "clpid": "Laskin-Alexander" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "Methacryloyl peroxynitrate (MPAN), the acyl peroxynitrate of methacrolein, has been suggested to be an important secondary organic aerosol (SOA) precursor from isoprene oxidation. Yet, the mechanism by which MPAN produces SOA through reaction with the hydroxyl radical (OH) is unclear. We systematically evaluate three proposed mechanisms in controlled chamber experiments and provide the first experimental support for the theoretically-predicted lactone formation pathway from the MPAN + OH reaction, producing hydroxymethyl-methyl-\u03b1-lactone (HMML). The decomposition of the MPAN\u2013OH adduct yields HMML + NO_3 ( 75%) and hydroxyacetone + CO + NO_3 ( 25%), out-competing its reaction with atmospheric oxygen. The production of other proposed SOA precursors, e.g., methacrylic acid epoxide (MAE), from MPAN and methacrolein are negligible (<2%). Furthermore, we show that the beta-alkenyl moiety of MPAN is critical for lactone formation. Alkyl radicals formed cold via H-abstraction by OH do not decompose to HMML, even if they are structurally identical to the MPAN\u2013OH adduct. The SOA formation from HMML, from polyaddition of the lactone to organic compounds at the particle interface or in the condensed phase, is close to unity under dry conditions. However, the SOA yield is sensitive to particle liquid water and solvated ions. In hydrated inorganic particles, HMML reacts primarily with H\u00ac_2O to produce the monomeric 2-methylglyceric acid (2MGA) or with aqueous sulfate and nitrate to produce the associated organosulfate and organonitrate, respectively. 2MGA, a tracer for isoprene SOA, is semivolatile and its accommodation in aerosol water decreases with decreasing pH. Conditions that enhance the production of neutral 2MGA suppress SOA mass from the HMML channel. Considering the liquid water content and pH ranges of ambient particles, 2MGA will exist largely as a gaseous compound in some parts of the atmosphere.", "doi": "10.1039/c5cp02001h", "issn": "1463-9076", "publisher": "Royal Society of Chemistry", "publication": "Physical Chemistry Chemical Physics", "publication_date": "2015-07-21", "series_number": "27", "volume": "17", "issue": "27", "pages": "17914-17926" }, { "id": "authors:r428k-2pm56", "collection": "authors", "collection_id": "r428k-2pm56", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150731-142648614", "type": "article", "title": "Investigating the links between ozone and organic aerosol chemistry in a biomass burning plume from a prescribed fire in California chaparral", "author": [ { "family_name": "Alvarado", "given_name": "M. J.", "clpid": "Alvarado-M-J" }, { "family_name": "Lonsdale", "given_name": "C. R.", "clpid": "Lonsdale-C-R" }, { "family_name": "Yokelson", "given_name": "R. J.", "orcid": "0000-0002-8415-6808", "clpid": "Yokelson-R-J" }, { "family_name": "Akagi", "given_name": "S. K.", "clpid": "Akagi-S-K" }, { "family_name": "Coe", "given_name": "H.", "clpid": "Coe-H" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Fischer", "given_name": "E. V.", "clpid": "Fischer-E-V" }, { "family_name": "McMeeking", "given_name": "G. R.", "clpid": "McMeeking-G-R" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Soni", "given_name": "T.", "clpid": "Soni-T" }, { "family_name": "Taylor", "given_name": "J. W.", "clpid": "Taylor-J-W" }, { "family_name": "Weise", "given_name": "D. R.", "clpid": "Weise-D-R" }, { "family_name": "Wold", "given_name": "C. E.", "clpid": "Wold-C-E" } ], "abstract": "Within minutes after emission, complex photochemistry in biomass burning smoke plumes can cause large changes in the concentrations of ozone (O_3) and organic aerosol (OA). Being able to understand and simulate this rapid chemical evolution under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use version 2.1 of the Aerosol Simulation Program (ASP) to simulate the evolution of O_3 and secondary organic aerosol (SOA) within a young biomass burning smoke plume from the Williams prescribed fire in chaparral, which was sampled over California in November 2009. We demonstrate the use of a method for simultaneously accounting for the impact of the unidentified intermediate volatility, semi-volatile, and extremely low volatility organic compounds (here collectively called \"SVOCs\") on the formation of OA (using the Volatility Basis Set \u2013 VBS) and O_3 (using the concept of mechanistic reactivity). We show that this method can successfully simulate the observations of O_3, OA, NO_x, ethylene (C_2H_4), and OH to within measurement uncertainty using reasonable assumptions about the average chemistry of the unidentified SVOCs. These assumptions were (1) a reaction rate constant with OH of ~ 10^(-11) cm^3 s^(\u22121); (2) a significant fraction (up to ~ 50 %) of the RO_2 + NO reaction resulted in fragmentation, rather than functionalization, of the parent SVOC; (3) ~ 1.1 molecules of O_3 were formed for every molecule of SVOC that reacted; (4) ~ 60 % of the OH that reacted with the unidentified non-methane organic compounds (NMOC) was regenerated as HO_2; and (5) that ~ 50 % of the NO that reacted with the SVOC peroxy radicals was lost, presumably to organic nitrate formation. Additional evidence for the fragmentation pathway is provided by the observed rate of formation of acetic acid (CH_3COOH), which is consistent with our assumed fragmentation rate. However, the model overestimates peroxyacetyl nitrate (PAN) formation downwind by about 50 %, suggesting the need for further refinements to the chemistry. This method could provide a way for classifying different smoke plume observations in terms of the average chemistry of their SVOCs, and could be used to study how the chemistry of these compounds (and the O_3 and OA they form) varies between plumes.", "doi": "10.5194/acp-15-6667-2015", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2015-06-17", "series_number": "12", "volume": "15", "issue": "12", "pages": "6667-6688" }, { "id": "authors:91mvg-bbx03", "collection": "authors", "collection_id": "91mvg-bbx03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190501-161717861", "type": "article", "title": "Precipitation effects of giant cloud condensation nuclei artificially introduced into stratocumulus clouds", "author": [ { "family_name": "Jung", "given_name": "E.", "orcid": "0000-0003-0970-2730", "clpid": "Jung-Eunsil" }, { "family_name": "Albrecht", "given_name": "B. A.", "clpid": "Albrecht-B-A" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Chen", "given_name": "Y.-C.", "orcid": "0000-0001-7997-8578", "clpid": "Chen-Yi-Chun" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Metcalf", "given_name": "A. R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" }, { "family_name": "Song", "given_name": "S.", "clpid": "Song-S" }, { "family_name": "Fang", "given_name": "M.", "clpid": "Fang-M" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" } ], "abstract": "To study the effect of giant cloud condensation nuclei (GCCN) on precipitation processes in stratocumulus clouds, 1\u201310 \u03bcm diameter salt particles (salt powder) were released from an aircraft while flying near the cloud top on 3 August 2011 off the central coast of California. The seeded area was subsequently sampled from the aircraft that was equipped with aerosol, cloud, and precipitation probes and an upward-facing cloud radar. During post-seeding sampling, made 30\u201360 min after seeding, the mean cloud droplet size increased, the droplet number concentration decreased, and large drop (e.g., diameter larger than 10 \u03bcm) concentration increased. Average drizzle rates increased from about 0.05 to 0.20 mm h^(\u22121), and the liquid water path decreased from about 52 to 43 g m^(\u22122). Strong radar returns associated with drizzle were observed on the post-seeding cloud-base level-leg flights and were accompanied by a substantial depletion of the cloud liquid water content. The changes were large enough to suggest that the salt particles with concentrations estimated to be 10^(\u22122) to 10^(-4) cm^(\u22123) resulted in a four-fold increase in the cloud-base rainfall rate and depletion of the cloud water due to rainout. In contrast, a case is shown where the cloud was already precipitating (on 10 August) and the effect of adding GCCN to the cloud was insignificant.", "doi": "10.5194/acp-15-5645-2015", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2015-05-22", "series_number": "10", "volume": "15", "issue": "10", "pages": "5645-5658" }, { "id": "authors:p03pz-11d77", "collection": "authors", "collection_id": "p03pz-11d77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150702-131234390", "type": "article", "title": "Primary marine aerosol-cloud interactions off the coast of California", "author": [ { "family_name": "Modini", "given_name": "R. L.", "orcid": "0000-0002-2982-1369", "clpid": "Modini-Robin-L" }, { "family_name": "Frossard", "given_name": "A. A.", "orcid": "0000-0002-5728-0854", "clpid": "Frossard-Amanda-A" }, { "family_name": "Ahlm", "given_name": "L.", "clpid": "Ahlm-Lars" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Corrigan", "given_name": "C. E.", "clpid": "Corrigan-C-E" }, { "family_name": "Roberts", "given_name": "G. C.", "orcid": "0000-0002-3636-8590", "clpid": "Roberts-Greg-C" }, { "family_name": "Hawkins", "given_name": "L. N.", "clpid": "Hawkins-L-N" }, { "family_name": "Schroder", "given_name": "J. C.", "clpid": "Schroder-J-C" }, { "family_name": "Bertram", "given_name": "A. K.", "orcid": "0000-0002-5621-2323", "clpid": "Bertram-Allan-K" }, { "family_name": "Zhao", "given_name": "R.", "clpid": "Zhao-R" }, { "family_name": "Lee", "given_name": "A. K. Y.", "clpid": "Lee-Alex-K-Y" }, { "family_name": "Abbatt", "given_name": "J. P. D.", "clpid": "Abbatt-J-P-D" }, { "family_name": "Lin", "given_name": "J.", "orcid": "0000-0002-4453-1263", "clpid": "Lin-Jack-J" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Wang", "given_name": "Z.", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Wonasch\u00fctz", "given_name": "A.", "clpid": "Wonasch\u00fctz-A" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Noone", "given_name": "K. J.", "orcid": "0000-0001-7095-7412", "clpid": "Noone-Kevin-J" }, { "family_name": "Jonsson", "given_name": "H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Toom-Sauntry", "given_name": "D.", "clpid": "Toom-Sauntry-D" }, { "family_name": "Macdonald", "given_name": "A. M.", "clpid": "Macdonald-A-M" }, { "family_name": "Leaitch", "given_name": "W. R.", "clpid": "Leaitch-W-R" } ], "abstract": "Primary marine aerosol (PMA)-cloud interactions off the coast of California were investigated using observations of marine aerosol, cloud condensation nuclei (CCN), and stratocumulus clouds during the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) and the Stratocumulus Observations of Los-Angeles Emissions Derived Aerosol-Droplets (SOLEDAD) studies. Based on recently reported measurements of PMA size distributions, a constrained lognormal-mode-fitting procedure was devised to isolate PMA number size distributions from total aerosol size distributions and applied to E-PEACE measurements. During the 12 day E-PEACE cruise on the R/V Point Sur, PMA typically contributed less than 15% of total particle concentrations. PMA number concentrations averaged 12 cm^(\u22123) during a relatively calmer period (average wind speed 12\u2009m/s^1) lasting 8 days, and 71\u2009cm^(\u22123) during a period of higher wind speeds (average 16\u2009m/s^1) lasting 5 days. On average, PMA contributed less than 10% of total CCN at supersaturations up to 0.9% during the calmer period; however, during the higher wind speed period, PMA comprised 5\u201363% of CCN (average 16\u201328%) at supersaturations less than 0.3%. Sea salt was measured directly in the dried residuals of cloud droplets during the SOLEDAD study. The mass fractions of sea salt in the residuals averaged 12 to 24% during three cloud events. Comparing the marine stratocumulus clouds sampled in the two campaigns, measured peak supersaturations were 0.2\u2009\u00b1\u20090.04% during E-PEACE and 0.05\u20130.1% during SOLEDAD. The available measurements show that cloud droplet number concentrations increased with >100 nm particles in E-PEACE but decreased in the three SOLEDAD cloud events.", "doi": "10.1002/2014JD022963", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2015-05-16", "series_number": "9", "volume": "120", "issue": "9", "pages": "4282-4303" }, { "id": "authors:hsvny-72v24", "collection": "authors", "collection_id": "hsvny-72v24", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140604-095405433", "type": "article", "title": "Secondary Organic Aerosol Composition from C\u2081\u2082 Alkanes", "author": [ { "family_name": "Schilling Fahnestock", "given_name": "Katherine A.", "clpid": "Schilling-K-A" }, { "family_name": "Yee", "given_name": "Lindsay D.", "clpid": "Yee-Lindsay-D" }, { "family_name": "Loza", "given_name": "Christine L.", "clpid": "Loza-C-L" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Schwantes", "given_name": "Rebecca", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Dalleska", "given_name": "Nathan F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-N-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The effects of structure, NO_x conditions, relative humidity, and aerosol acidity on the chemical composition of secondary organic aerosol (SOA) are reported for the photooxidation of three C_(12) alkanes: n-dodecane, cyclododecane, and hexylcyclohexane. Acidity was modified through seed particle composition: NaCl, (NH_4)_2SO_4, and (NH_4)_2SO_4 + H_2SO_4. Off-line analysis of SOA was carried out by solvent extraction and gas chromatography\u2013mass spectrometry (GC/MS) and direct analysis in real-time mass spectrometry. We report here 750 individual masses of SOA products identified from these three alkane systems and 324 isomers resolved by GC/MS analysis. The chemical compositions for each alkane system provide compelling evidence of particle-phase chemistry, including reactions leading to oligomer formation. Major oligomeric species for alkane SOA are peroxyhemiacetals, hemiacetals, esters, and aldol condensation products. Furans, dihydrofurans, hydroxycarbonyls, and their corresponding imine analogues are important participants in these oligomer-producing reactions. Imines are formed in the particle phase from the reaction of the ammonium sulfate seed aerosol with carbonyl-bearing compounds present in all the SOA systems. Under high-NO conditions, organonitrate products can lead to an increase of aerosol volume concentration by up to a factor of 5 over that in low-NO conditions. Structure was found to play a key role in determining the degree of functionalization and fragmentation of the parent alkane, influencing the mean molecular weight of the SOA produced and the mean atomic O:C ratio.", "doi": "10.1021/jp501779w", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2015-05-14", "series_number": "19", "volume": "119", "issue": "19", "pages": "4281-4297" }, { "id": "authors:dsgq8-6t712", "collection": "authors", "collection_id": "dsgq8-6t712", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150619-084717049", "type": "article", "title": "Influence of particle-phase state on the hygroscopic behavior of mixed organic-inorganic aerosols", "author": [ { "family_name": "Hodas", "given_name": "N.", "clpid": "Hodas-N" }, { "family_name": "Zuend", "given_name": "A.", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Mui", "given_name": "W.", "orcid": "0000-0003-3065-1296", "clpid": "Mui-Wilton" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recent work has demonstrated that organic and mixed organic\u2013inorganic particles can exhibit multiple phase states depending on their chemical composition and on ambient conditions such as relative humidity (RH). To explore the extent to which water uptake varies with particle-phase behavior, hygroscopic growth factors (HGFs) of nine laboratory-generated, organic and organic\u2013inorganic aerosol systems with physical states ranging from well-mixed liquids to phase-separated particles to viscous liquids or semi-solids were measured with the Differential Aerosol Sizing and Hygroscopicity Spectrometer Probe at RH values ranging from 40 to 90%. Water-uptake measurements were accompanied by HGF and RH-dependent thermodynamic equilibrium calculations using the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model. In addition, AIOMFAC-predicted growth curves are compared to several simplified HGF modeling approaches: (1) representing particles as ideal, well-mixed liquids; (2) forcing a single phase but accounting for non-ideal interactions through activity coefficient calculations; and (3) a Zdanovskii\u2013Stokes\u2013Robinson-like calculation in which complete separation of the inorganic and organic components is assumed at all RH values, with water uptake treated separately in each of the individual phases. We observed variability in the characteristics of measured hygroscopic growth curves across aerosol systems with differing phase behaviors, with growth curves approaching smoother, more continuous water uptake with decreasing prevalence of liquid\u2013liquid phase separation and increasing oxygen : carbon ratios of the organic aerosol components. We also observed indirect evidence for the dehydration-induced formation of highly viscous semi-solid phases and for kinetic limitations to the crystallization of ammonium sulfate at low RH for sucrose-containing particles. AIOMFAC-predicted growth curves are generally in good agreement with the HGF measurements. The performances of the simplified modeling approaches, however, differ for particles with differing phase states. This suggests that no single simplified modeling approach can be used to capture the water-uptake behavior for the diversity of particle-phase behavior expected in the atmosphere. Errors in HGFs calculated with the simplified models are of sufficient magnitude to produce substantial errors in estimates of particle optical and radiative properties, particularly for the assumption that water uptake is driven by absorptive equilibrium partitioning with ideal particle-phase mixing.", "doi": "10.5194/acp-15-5027-2015", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2015-05-05", "series_number": "9", "volume": "15", "issue": "9", "pages": "5027-5045" }, { "id": "authors:bjckz-t0c06", "collection": "authors", "collection_id": "bjckz-t0c06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150603-080918173", "type": "article", "title": "Vapor wall deposition in Teflon chambers", "author": [ { "family_name": "Zhang", "given_name": "X.", "clpid": "Zhang-Xuan" }, { "family_name": "Schwantes", "given_name": "R. H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "McVay", "given_name": "R. C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-R-C" }, { "family_name": "Lignell", "given_name": "H.", "orcid": "0000-0001-7049-1659", "clpid": "Lignell-H" }, { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Teflon chambers are ubiquitous in studies of atmospheric chemistry. Secondary organic aerosol (SOA) formation can be underestimated, owing to deposition of SOA-forming vapors to the chamber wall. We present here an experimental protocol and a model framework to constrain the vapor\u2013wall interactions in Teflon chambers. We measured the wall deposition rates of 25 oxidized organic compounds generated from the photooxidation of isoprene, toluene, \u03b1-pinene, and dodecane in two chambers that had been extensively used and in two new unused chambers. We found that the extent of prior use of the chamber did not significantly affect the sorption behavior of the Teflon films. Among the 25 compounds studied, the maximum wall deposition rate is exhibited by the most highly oxygenated and least volatile compounds. By optimizing the model output to the observed vapor decay profiles, we identified that the dominant parameter governing the extent of wall deposition of a compound is its wall accommodation coefficient (\u03b1_(wi)), which can be correlated through its volatility with the number of carbons and oxygens in the molecule. By doing so, the wall-induced deposition rate of intermediate/semi-volatile organic vapors can be reasonably predicted based on their molecular constituency. The extent to which vapor wall deposition impacts measured SOA yields depends on the competition between uptake of organic vapors by suspended particles and the chamber wall. The timescale associated with vapor wall deposition can vary from minutes to hours depending on the value of \u03b1_(w,i). For volatile and intermediate volatility organic compounds (small \u03b1_(w,i)), gas-particle partitioning will dominate wall deposition for typical particle number concentrations in chamber experiments. For compounds characterized by relatively large \u03b1_(w,i), vapor transport to particles is suppressed by competition with the chamber wall even with perfect particle accommodation.", "doi": "10.5194/acp-15-4197-2015", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2015-04-23", "series_number": "8", "volume": "15", "issue": "8", "pages": "4197-4214" }, { "id": "authors:dcvqx-m3p66", "collection": "authors", "collection_id": "dcvqx-m3p66", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150515-110243412", "type": "article", "title": "On the presence of giant particles downwind of ships in the marine boundary layer", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Prabhakar", "given_name": "Gouri", "clpid": "Prabhakar-G" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Woods", "given_name": "Roy K.", "orcid": "0000-0002-3632-6374", "clpid": "Woods-R-K" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This study examines large oceangoing ships as a source of giant cloud condensation nuclei (D_p\u2009>\u20092\u2009\u00b5m) due to wake and stack emissions off the California coast. Observed particle number concentrations behind 10 ships exceeded those in \"control\" areas, exhibiting number concentration enhancement ratios (ERs) for minimum threshold diameters of ~2, ~10, and ~20\u2009\u00b5m as high as 2.7, 5.5, and 7.5, respectively. ER decreases with increasing downwind distance and altitude. ER becomes better correlated with ship size variables (gross tonnage, length, and beam) as the minimum size threshold increases from 2 to 20\u2009\u00b5m, whereas ship speed has a less distinct relationship with ER. One case study of a container ship shows that there are higher concentrations of sea-salt tracer species behind it relative to adjacent control areas. These results have implications for cloud properties and precipitation in marine boundary layers exposed to ship traffic.", "doi": "10.1002/2015GL063179", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2015-03-28", "series_number": "6", "volume": "42", "issue": "6", "pages": "2024-2030" }, { "id": "authors:y5gsn-ac250", "collection": "authors", "collection_id": "y5gsn-ac250", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150220-105538803", "type": "article", "title": "Methane Emissions from Process Equipment at Natural Gas Production Sites in the United States: Pneumatic Controllers", "author": [ { "family_name": "Allen", "given_name": "David T.", "clpid": "Allen-D-T" }, { "family_name": "Pacsi", "given_name": "Adam P.", "clpid": "Pacsi-A-P" }, { "family_name": "Sullivan", "given_name": "David W.", "clpid": "Sullivan-D-W" }, { "family_name": "Zavala-Araiza", "given_name": "Daniel", "clpid": "Zavala-Araiza-D" }, { "family_name": "Harrison", "given_name": "Matthew", "clpid": "Harrison-M" }, { "family_name": "Keen", "given_name": "Kindal", "clpid": "Keen-K" }, { "family_name": "Fraser", "given_name": "Matthew P.", "clpid": "Fraser-M-P" }, { "family_name": "Hill", "given_name": "A. Daniel", "clpid": "Hill-A-D" }, { "family_name": "Sawyer", "given_name": "Robert F.", "clpid": "Sawyer-R-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Emissions from 377 gas actuated (pneumatic) controllers were measured at natural gas production sites and a small number of oil production sites, throughout the United States. A small subset of the devices (19%), with whole gas emission rates in excess of 6 standard cubic feet per hour (scf/h), accounted for 95% of emissions. More than half of the controllers recorded emissions of 0.001 scf/h or less during 15 min of measurement. Pneumatic controllers in level control applications on separators and in compressor applications had higher emission rates than controllers in other types of applications. Regional differences in emissions were observed, with the lowest emissions measured in the Rocky Mountains and the highest emissions in the Gulf Coast. Average methane emissions per controller reported in this work are 17% higher than the average emissions per controller in the 2012 EPA greenhouse gas national emission inventory (2012 GHG NEI, released in 2014); the average of 2.7 controllers per well observed in this work is higher than the 1.0 controllers per well reported in the 2012 GHG NEI.", "doi": "10.1021/es5040156", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2015-01-06", "series_number": "1", "volume": "49", "issue": "1", "pages": "633-640" }, { "id": "authors:3fqn0-pch10", "collection": "authors", "collection_id": "3fqn0-pch10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150223-111044023", "type": "article", "title": "Methane Emissions from Process Equipment at Natural Gas Production Sites in the United States: Liquid Unloadings", "author": [ { "family_name": "Allen", "given_name": "David T.", "clpid": "Allen-D-T" }, { "family_name": "Sullivan", "given_name": "David W.", "clpid": "Sullivan-D-W" }, { "family_name": "Zavala-Araiza", "given_name": "Daniel", "clpid": "Zavala-Araiza-D" }, { "family_name": "Pacsi", "given_name": "Adam P.", "clpid": "Pacsi-A-P" }, { "family_name": "Harrison", "given_name": "Matthew", "clpid": "Harrison-M" }, { "family_name": "Keen", "given_name": "Kindal", "clpid": "Keen-K" }, { "family_name": "Fraser", "given_name": "Matthew P.", "clpid": "Fraser-M-P" }, { "family_name": "Hill", "given_name": "A. Daniel", "clpid": "Hill-A-D" }, { "family_name": "Lamb", "given_name": "Brian K.", "clpid": "Lamb-B-K" }, { "family_name": "Sawyer", "given_name": "Robert F.", "clpid": "Sawyer-R-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Methane emissions from liquid unloadings were measured at 107 wells in natural gas production regions throughout the United States. Liquid unloadings clear wells of accumulated liquids to increase production, employing a variety of liquid lifting mechanisms. In this work, wells with and without plunger lifts were sampled. Most wells without plunger lifts unload less than 10 times per year with emissions averaging 21\u2009000\u201335\u2009000 scf methane (0.4\u20130.7 Mg) per event (95% confidence limits of 10\u2009000\u201350\u2009000 scf/event). For wells with plunger lifts, emissions averaged 1000\u201310\u2009000 scf methane (0.02\u20130.2 Mg) per event (95% confidence limits of 500\u201312\u2009000 scf/event). Some wells with plunger lifts are automatically triggered and unload thousands of times per year and these wells account for the majority of the emissions from all wells with liquid unloadings. If the data collected in this work are assumed to be representative of national populations, the data suggest that the central estimate of emissions from unloadings (270 Gg/yr, 95% confidence range of 190\u2013400 Gg) are within a few percent of the emissions estimated in the EPA 2012 Greenhouse Gas National Emission Inventory (released in 2014), with emissions dominated by wells with high frequencies of unloadings.", "doi": "10.1021/es504016r", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2015-01-06", "series_number": "1", "volume": "49", "issue": "1", "pages": "641-648" }, { "id": "authors:j26c7-awn07", "collection": "authors", "collection_id": "j26c7-awn07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150220-132616278", "type": "article", "title": "Overview of the Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT): mechanistic chamber studies on the oxidation of biogenic compounds", "author": [ { "family_name": "Nguyen", "given_name": "T. B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Crounse", "given_name": "J. D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Schwantes", "given_name": "R. H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Teng", "given_name": "A. P.", "clpid": "Teng-Alex-P" }, { "family_name": "Bates", "given_name": "K. H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-K-H" }, { "family_name": "Zhang", "given_name": "X.", "clpid": "Zhang-Xuan" }, { "family_name": "St. Clair", "given_name": "J. M.", "orcid": "0000-0002-9367-5749", "clpid": "St-Clair-J-M" }, { "family_name": "Brune", "given_name": "W. H.", "orcid": "0000-0002-1609-4051", "clpid": "Brune-W-H" }, { "family_name": "Tyndall", "given_name": "G. S.", "clpid": "Tyndall-G-S" }, { "family_name": "Keutsch", "given_name": "F. N.", "clpid": "Keutsch-F-N" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "The Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT) was a collaborative atmospheric chamber campaign that occurred during January 2014. FIXCIT is the laboratory component of a synergistic field and laboratory effort aimed toward (1) better understanding the chemical details behind ambient observations relevant to the southeastern United States, (2) advancing the knowledge of atmospheric oxidation mechanisms of important biogenic hydrocarbons, and (3) characterizing the behavior of field instrumentation using authentic standards. Approximately 20 principal scientists from 14 academic and government institutions performed parallel measurements at a forested site in Alabama and at the atmospheric chambers at Caltech. During the 4 week campaign period, a series of chamber experiments was conducted to investigate the dark- and photo-induced oxidation of isoprene, \u03b1-pinene, methacrolein, pinonaldehyde, acylperoxy nitrates, isoprene hydroxy nitrates (ISOPN), isoprene hydroxy hydroperoxides (ISOPOOH), and isoprene epoxydiols (IEPOX) in a highly controlled and atmospherically relevant manner. Pinonaldehyde and isomer-specific standards of ISOPN, ISOPOOH, and IEPOX were synthesized and contributed by campaign participants, which enabled explicit exploration into the oxidation mechanisms and instrument responses for these important atmospheric compounds. The present overview describes the goals, experimental design, instrumental techniques, and preliminary observations from the campaign. This work provides context for forthcoming publications affiliated with the FIXCIT campaign. Insights from FIXCIT are anticipated to aid significantly in interpretation of field data and the revision of mechanisms currently implemented in regional and global atmospheric models.", "doi": "10.5194/acp-14-13531-2014", "issn": "1680-7367", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2014-12-19", "series_number": "24", "volume": "14", "issue": "24", "pages": "13531-13549" }, { "id": "authors:zqqhe-6ss59", "collection": "authors", "collection_id": "zqqhe-6ss59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150220-091742441", "type": "article", "title": "Conversion of hydroperoxides to carbonyls in field and laboratory instrumentation: Observational bias in diagnosing pristine versus anthropogenically controlled atmospheric chemistry", "author": [ { "family_name": "Rivera-Rios", "given_name": "J. C.", "clpid": "Rivera-Rios-J-C" }, { "family_name": "Nguyen", "given_name": "T. B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Crounse", "given_name": "J. D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Jud", "given_name": "W.", "clpid": "Jud-W" }, { "family_name": "St. Clair", "given_name": "J. M.", "orcid": "0000-0002-9367-5749", "clpid": "St-Clair-J-M" }, { "family_name": "Mikoviny", "given_name": "T.", "clpid": "Mikoviny-T" }, { "family_name": "Gilman", "given_name": "J. B.", "clpid": "Gilman-J-B" }, { "family_name": "Lerner", "given_name": "B. M.", "clpid": "Lerner-B-M" }, { "family_name": "Kaiser", "given_name": "J. B.", "clpid": "Kaiser-J-B" }, { "family_name": "de Gouw", "given_name": "J.", "orcid": "0000-0002-0385-1826", "clpid": "de-Gouw-J-A" }, { "family_name": "Wisthaler", "given_name": "A.", "clpid": "Wisthaler-A" }, { "family_name": "Hansel", "given_name": "A.", "clpid": "Hansel-A" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Keutsch", "given_name": "F. N.", "clpid": "Keutsch-F-N" } ], "abstract": "Atmospheric volatile organic compound (VOC) oxidation mechanisms under pristine (rural/remote) and urban (anthropogenically-influenced) conditions follow distinct pathways due to large differences in nitrogen oxide (NO_x) concentrations. These two pathways lead to products that have different chemical and physical properties and reactivity. Under pristine conditions, isoprene hydroxy hydroperoxides (ISOPOOHs) are the dominant first-generation isoprene oxidation products. Utilizing authentic ISOPOOH standards, we demonstrate that two of the most commonly used methods of measuring VOC oxidation products (i.e., gas chromatography and proton transfer reaction mass spectrometry) observe these hydroperoxides as their equivalent high-NO isoprene oxidation products \u2013 methyl vinyl ketone (MVK) and methacrolein (MACR). This interference has led to an observational bias affecting our understanding of global atmospheric processes. Considering these artifacts will help close the gap on discrepancies regarding the identity and fate of reactive organic carbon, revise our understanding of surface-atmosphere exchange of reactive carbon and SOA formation, and improve our understanding of atmospheric oxidative capacity.", "doi": "10.1002/2014GL061919", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2014-12-16", "series_number": "23", "volume": "41", "issue": "23", "pages": "8645-8651" }, { "id": "authors:t1nnw-cc961", "collection": "authors", "collection_id": "t1nnw-cc961", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141118-070255543", "type": "article", "title": "Sources of nitrate in stratocumulus cloud water: Airborne measurements during the 2011 E-PEACE and 2013 NiCE studies", "author": [ { "family_name": "Prabhakar", "given_name": "Gouri", "clpid": "Prabhakar-G" }, { "family_name": "Ervens", "given_name": "B.", "clpid": "Ervens-B" }, { "family_name": "Wang", "given_name": "Z.", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Maudlin", "given_name": "L. C.", "clpid": "Maudlin-L-C" }, { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" } ], "abstract": "This study examines the sources of NO_3^\u2212 in stratocumulus clouds over the eastern Pacific Ocean off the California coast using airborne and surface measurement data from the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE; 2011) and Nucleation in California Experiment (NiCE; 2013). Average NO_3^\u2212 air-equivalent concentrations in cloud water samples categorized as having been influenced by ship exhaust (2.5 \u03bcg m^(\u22123)), strong marine emissions (2.5 \u03bcg m^(\u22123)) and fires (2.0 \u03bcg m^(\u22123)) were more than twice that in the background cloud water (0.9 \u03bcg m^(\u22123)). During periods when biomass burning plumes resided above cloud top, 16 of 29 cloud water samples were impacted due to instability in the entrainment interface layer with NO_3^\u2212 levels reaching as high as 9.0 \u03bcg m^(\u22123). Nucleation scavenging of chloride depleted sea-salt is a source of cloud water NO^3^\u2212, with the lowest Cl^\u2212:Na^+ ratio (1.5) observed in ship-influenced samples. Surface aerosol measurements show that NO_3^\u2212 concentrations peak in the particle diameter range of 1.0\u20135.6 \u03bcm, similar to Na, Cl^\u2212 and Si, suggesting that drop activation of crustal particles and sea salt could be an important source of NO_3^\u2212 in cloud water. The contrasting behavior of NO_3^\u2212 and SO_4^(2\u2212) is emphasized by the NO_3^\u2212:SO_4^(2\u2212) mass concentration ratio which is highest in cloud water (by more than a factor of two) followed by above cloud aerosol, droplet residual particles, and below cloud aerosol. Trends of a decreasing NO_3^\u2212:SO_4^(2\u2212) ratio with altitude in clouds are confirmed by parcel model studies due to the higher rate of in-cloud sulfate formation as compared to HNO_3 uptake by droplets.", "doi": "10.1016/j.atmosenv.2014.08.019", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2014-11", "volume": "97", "pages": "166-173" }, { "id": "authors:8p23f-6sv58", "collection": "authors", "collection_id": "8p23f-6sv58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-090854847", "type": "article", "title": "Aerosol emissions from prescribed fires in the United States: A synthesis of laboratory and aircraft measurements", "author": [ { "family_name": "May", "given_name": "A. A.", "clpid": "May-A-A" }, { "family_name": "McMeeking", "given_name": "G. R.", "clpid": "McMeeking-G-R" }, { "family_name": "Lee", "given_name": "T.", "clpid": "Lee-T" }, { "family_name": "Taylor", "given_name": "J. W.", "clpid": "Taylor-J-W" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Burling", "given_name": "I. R.", "clpid": "Burling-I-R" }, { "family_name": "Sullivan", "given_name": "A. P.", "clpid": "Sullivan-A-P" }, { "family_name": "Akagi", "given_name": "S. K.", "clpid": "Akagi-S-K" }, { "family_name": "Collett", "given_name": "J. L., Jr.", "clpid": "Collett-J-R-Jr" }, { "family_name": "Flynn", "given_name": "M.", "clpid": "Flynn-M" }, { "family_name": "Coe", "given_name": "H.", "clpid": "Coe-H" }, { "family_name": "Urbanski", "given_name": "S. P.", "clpid": "Urbanski-S-P" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Yokelson", "given_name": "R. J.", "orcid": "0000-0002-8415-6808", "clpid": "Yokelson-R-J" }, { "family_name": "Kreidenweis", "given_name": "S. M.", "clpid": "Kreidenweis-S-M" } ], "abstract": "Aerosol emissions from prescribed fires can affect air quality on regional scales. Accurate representation of these emissions in models requires information regarding the amount and composition of the emitted species. We measured a suite of submicron particulate matter species in young plumes emitted from prescribed fires (chaparral and montane ecosystems in California; coastal plain ecosystem in South Carolina) and from open burning of over 15 individual plant species in the laboratory. We report emission ratios and emission factors for refractory black carbon (rBC) and submicron nonrefractory aerosol and compare field and laboratory measurements to assess the representativeness of our laboratory-measured emissions. Laboratory measurements of organic aerosol (OA) emission factors for some fires were an order of magnitude higher than those derived from any of our aircraft observations; these are likely due to higher-fuel moisture contents, lower modified combustion efficiencies, and less dilution compared to field studies. Nonrefractory inorganic aerosol emissions depended more strongly on fuel type and fuel composition than on combustion conditions. Laboratory and field measurements for rBC were in good agreement when differences in modified combustion efficiency were considered; however, rBC emission factors measured both from aircraft and in the laboratory during the present study using the Single Particle Soot Photometer were generally higher than values previously reported in the literature, which have been based largely on filter measurements. Although natural variability may account for some of these differences, an increase in the BC emission factors incorporated within emission inventories may be required, pending additional field measurements for a wider variety of fires.", "doi": "10.1002/2014JD021848", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2014-10-27", "series_number": "20", "volume": "119", "issue": "20", "pages": "11826-11849" }, { "id": "authors:8pykm-4f506", "collection": "authors", "collection_id": "8pykm-4f506", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141015-092611684", "type": "article", "title": "Neutral molecular cluster formation of sulfuric acid\u2013dimethylamine observed in real time under atmospheric conditions", "author": [ { "family_name": "K\u00fcrten", "given_name": "Andreas", "orcid": "0000-0002-8955-4450", "clpid": "K\u00fcrten-A" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "For atmospheric sulfuric acid (SA) concentrations the presence of dimethylamine (DMA) at mixing ratios of several parts per trillion by volume can explain observed boundary layer new particle formation rates. However, the concentration and molecular composition of the neutral (uncharged) clusters have not been reported so far due to the lack of suitable instrumentation. Here we report on experiments from the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research revealing the formation of neutral particles containing up to 14 SA and 16 DMA molecules, corresponding to a mobility diameter of about 2 nm, under atmospherically relevant conditions. These measurements bridge the gap between the molecular and particle perspectives of nucleation, revealing the fundamental processes involved in particle formation and growth. The neutral clusters are found to form at or close to the kinetic limit where particle formation is limited only by the collision rate of SA molecules. Even though the neutral particles are stable against evaporation from the SA dimer onward, the formation rates of particles at 1.7-nm size, which contain about 10 SA molecules, are up to 4 orders of magnitude smaller compared with those of the dimer due to coagulation and wall loss of particles before they reach 1.7 nm in diameter. This demonstrates that neither the atmospheric particle formation rate nor its dependence on SA can simply be interpreted in terms of cluster evaporation or the molecular composition of a critical nucleus.", "doi": "10.1073/pnas.1404853111", "pmcid": "PMC4210346", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2014-10-21", "series_number": "42", "volume": "111", "issue": "42", "pages": "15019-15024" }, { "id": "authors:ax1th-35p85", "collection": "authors", "collection_id": "ax1th-35p85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141023-142740037", "type": "article", "title": "Insight into the numerical challenges of implementing 2-dimensional SOA models in atmospheric chemical transport models", "author": [ { "family_name": "Napier", "given_name": "W. J.", "clpid": "Napier-W-J" }, { "family_name": "Ensberg", "given_name": "J. J.", "clpid": "Ensberg-J-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The new generation of secondary organic aerosol (SOA) models that represent gas- and particle-phase chemistry and thermodynamic partitioning using discrete two-dimensional grids (e.g. SOM, 2D-VBS) cannot be efficiently implemented into three-dimensional atmospheric chemical transport models (CTMs) due to the large number of bins (tracers) required. In this study, we introduce a novel mathematical framework, termed the Oxidation State/Volatility Moment Method, that is designed to address these computational burdens so as to allow the new generation of SOA models to be implemented into CTMs. This is accomplished by mapping the two-dimensional grids onto probability distributions that conserve carbon and oxygen mass. Assessment of the Moment Method strengths (speed, carbon and oxygen conservation) and weaknesses (numerical drift) provide valuable insight that can guide future development of SOA modules for atmospheric CTMs.", "doi": "10.1016/j.atmosenv.2014.07.048", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2014-10", "volume": "96", "pages": "331-344" }, { "id": "authors:v1khc-dfa98", "collection": "authors", "collection_id": "v1khc-dfa98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141017-101125407", "type": "article", "title": "Modeling regional aerosol and aerosol precursor variability over California and its sensitivity to emissions and long-range transport during the 2010 CalNex and CARES campaigns", "author": [ { "family_name": "Fast", "given_name": "J. D.", "clpid": "Fast-J-D" }, { "family_name": "Craven", "given_name": "J.", "clpid": "Craven-J-S" }, { "family_name": "Metcalf", "given_name": "A.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The performance of the Weather Research and Forecasting regional model with chemistry (WRF-Chem) in simulating the spatial and temporal variations in aerosol mass, composition, and size over California is quantified using the extensive meteorological, trace gas, and aerosol measurements collected during the California Nexus of Air Quality and Climate Experiment (CalNex) and the Carbonaceous Aerosol and Radiative Effects Study (CARES) conducted during May and June of 2010. The overall objective of the field campaigns was to obtain data needed to better understand processes that affect both climate and air quality, including emission assessments, transport and chemical aging of aerosols, aerosol radiative effects. Simulations were performed that examined the sensitivity of aerosol concentrations to anthropogenic emissions and to long-range transport of aerosols into the domain obtained from a global model. The configuration of WRF-Chem used in this study is shown to reproduce the overall synoptic conditions, thermally driven circulations, and boundary layer structure observed in region that controls the transport and mixing of trace gases and aerosols. Reducing the default emissions inventory by 50% led to an overall improvement in many simulated trace gases and black carbon aerosol at most sites and along most aircraft flight paths; however, simulated organic aerosol was closer to observed when there were no adjustments to the primary organic aerosol emissions. We found that sulfate was better simulated over northern California whereas nitrate was better simulated over southern California. While the overall spatial and temporal variability of aerosols and their precursors were simulated reasonably well, we show cases where the local transport of some aerosol plumes were either too slow or too fast, which adversely affects the statistics quantifying the differences between observed and simulated quantities. Comparisons with lidar and in situ measurements indicate that long-range transport of aerosols from the global model was likely too high in the free troposphere even though their concentrations were relatively low. This bias led to an over-prediction in aerosol optical depth by as much as a factor of 2 that offset the under-predictions of boundary-layer extinction resulting primarily from local emissions. Lowering the boundary conditions of aerosol concentrations by 50% greatly reduced the bias in simulated aerosol optical depth for all regions of California. This study shows that quantifying regional-scale variations in aerosol radiative forcing and determining the relative role of emissions from local and distant sources is challenging during 'clean' conditions and that a wide array of measurements are needed to ensure model predictions are correct for the right reasons. In this regard, the combined CalNex and CARES data sets are an ideal test bed that can be used to evaluate aerosol models in great detail and develop improved treatments for aerosol processes.", "doi": "10.5194/acp-14-10013-2014", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2014-09-22", "series_number": "18", "volume": "14", "issue": "18", "pages": "10013-10060" }, { "id": "authors:v56zy-h7q37", "collection": "authors", "collection_id": "v56zy-h7q37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190503-143316299", "type": "book_section", "title": "Tropospheric Chemistry and Composition - Aerosols/Particles", "book_title": "Encyclopedia of Atmospheric Sciences", "author": [ { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "North", "given_name": "Gerald R.", "clpid": "North-G-R" }, { "family_name": "Pyle", "given_name": "John A.", "clpid": "Pyle-J-A" }, { "family_name": "Zhang", "given_name": "Fuqing", "clpid": "Zhang-Fuqing" } ], "abstract": "Particles are ubiquitous in the atmosphere. The tropospheric aerosol is remarkably diverse in its composition, reflecting the wide range of particle sources in the atmosphere. Chemical components of tropospheric particles include inorganic materials such as sulfate, ammonium, nitrate, trace metals, and a wide array of carbonaceous compounds. Concentrations of airborne particles vary greatly over the globe, from the lowest concentrations in pristine areas to the highest levels in polluted urban centers. Atmospheric aerosols carry the chemical signature of the sources of direct particle emissions into the atmosphere as well as that of the conversion of gaseous molecules into particulate-phase species.", "doi": "10.1016/b978-0-12-382225-3.00438-2", "isbn": "978-0-12-382225-3", "publisher": "Elsevier", "place_of_publication": "Amsterdam", "publication_date": "2014-09-18", "pages": "182-187" }, { "id": "authors:patte-6yz19", "collection": "authors", "collection_id": "patte-6yz19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140820-083412204", "type": "article", "title": "Vapor\u2212Wall Deposition in Chambers: Theoretical Considerations", "author": [ { "family_name": "McVay", "given_name": "Renee C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-R-C" }, { "family_name": "Cappa", "given_name": "Christopher D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-C-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In order to constrain the effects of vapor\u2013wall deposition on measured secondary organic aerosol (SOA) yields in laboratory chambers, researchers recently varied the seed aerosol surface area in toluene oxidation and observed a clear increase in the SOA yield with increasing seed surface area (Zhang, X.; et al. Proc. Natl. Acad. Sci. U.S.A. 2014, 111, 5802). Using a coupled vapor\u2013particle dynamics model, we examine the extent to which this increase is the result of vapor\u2013wall deposition versus kinetic limitations arising from imperfect accommodation of organic species into the particle phase. We show that a seed surface area dependence of the SOA yield is present only when condensation of vapors onto particles is kinetically limited. The existence of kinetic limitation can be predicted by comparing the characteristic time scales of gas-phase reaction, vapor\u2013wall deposition, and gas\u2013particle equilibration. The gas\u2013particle equilibration time scale depends on the gas\u2013particle accommodation coefficient \u03b1_p. Regardless of the extent of kinetic limitation, vapor\u2013wall deposition depresses the SOA yield from that in its absence since vapor molecules that might otherwise condense on particles deposit on the walls. To accurately extrapolate chamber-derived yields to atmospheric conditions, both vapor\u2013wall deposition and kinetic limitations must be taken into account.", "doi": "10.1021/es502170j", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2014-09-02", "series_number": "17", "volume": "48", "issue": "17", "pages": "10251-10258" }, { "id": "authors:c7gmd-mh993", "collection": "authors", "collection_id": "c7gmd-mh993", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140701-132233552", "type": "article", "title": "Satellite-based estimate of global aerosol\u2013cloud radiative forcing by marine warm clouds", "author": [ { "family_name": "Chen", "given_name": "Yi-Chun", "orcid": "0000-0001-7997-8578", "clpid": "Chen-Yi-Chun" }, { "family_name": "Christensen", "given_name": "Matthew W.", "clpid": "Christensen-M-W" }, { "family_name": "Stephens", "given_name": "Graeme L.", "clpid": "Stephens-G-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Changes in aerosol concentrations affect cloud albedo and Earth's radiative balance. Aerosol radiative forcing from pre-industrial time to the present due to the effect of atmospheric aerosol levels on the micro- and macrophysics of clouds bears the largest uncertainty among external influences on climate change. Of all cloud forms, low-level marine clouds exert the largest impact on the planet's albedo. For example, a 6% increase in the albedo of global marine stratiform clouds could offset the warming that would result from a doubling of atmospheric CO_2 concentrations. Marine warm cloud properties are thought to depend on aerosol levels and large-scale dynamic or thermodynamic states. Here we present a comprehensive analysis of multiple measurements from the A-Train constellation of Earth-observing satellites, to quantify the radiative forcing exerted by aerosols interacting with marine clouds. Specifically, we analyse observations of co-located aerosols and clouds over the world's oceans for the period August 2006\u2013April 2011, comprising over 7.3 million CloudSat single-layer marine warm cloud pixels. We find that thermodynamic conditions\u2014that is, tropospheric stability and humidity in the free troposphere\u2014and the state of precipitation act together to govern the cloud liquid water responses to the presence of aerosols and the strength of aerosol\u2013cloud radiative forcing.", "doi": "10.1038/ngeo2214", "issn": "1752-0894", "publisher": "Nature Publishing Group", "publication": "Nature Geoscience", "publication_date": "2014-09", "series_number": "9", "volume": "7", "issue": "9", "pages": "643-646" }, { "id": "authors:4fxez-d4b49", "collection": "authors", "collection_id": "4fxez-d4b49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141016-135244641", "type": "article", "title": "Molecular corridors and kinetic regimes in the multiphase chemical evolution of secondary organic aerosol", "author": [ { "family_name": "Shiraiwa", "given_name": "M.", "orcid": "0000-0003-2532-5373", "clpid": "Shiraiwa-Manabu" }, { "family_name": "Berkemeier", "given_name": "T.", "clpid": "Berkemeier-T" }, { "family_name": "Schilling-Fahnestock", "given_name": "K. A.", "clpid": "Schilling-K-A" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "P\u00f6schl", "given_name": "U.", "clpid": "P\u00f6schl-U" } ], "abstract": "The dominant component of atmospheric, organic aerosol is that derived from the oxidation of volatile organic compounds (VOCs), so-called secondary organic aerosol (SOA). SOA consists of a multitude of organic compounds, only a small fraction of which has historically been identified. Formation and evolution of SOA is a complex process involving coupled chemical reaction and mass transport in the gas and particle phases. Current SOA models do not embody the full spectrum of reaction and transport processes, nor do they identify the dominant rate-limiting steps in SOA formation. Based on molecular identification of SOA oxidation products, we show here that the chemical evolution of SOA from a variety of VOC precursors adheres to characteristic \"molecular corridors\" with a tight inverse correlation between volatility and molar mass. The slope of these corridors corresponds to the increase in molar mass required to decrease volatility by one order of magnitude (-dM / dlogC_0). It varies in the range of 10\u201330 g mol^(\u22121), depending on the molecular size of the SOA precursor and the O : C ratio of the reaction products. Sequential and parallel reaction pathways of oxidation and dimerization or oligomerization progressing along these corridors pass through characteristic regimes of reaction-, diffusion-, or accommodation-limited multiphase chemical kinetics that can be classified according to reaction location, degree of saturation, and extent of heterogeneity of gas and particle phases. The molecular corridors and kinetic regimes help to constrain and describe the properties of the products, pathways, and rates of SOA evolution, thereby facilitating the further development of aerosol models for air quality and climate.", "doi": "10.5194/acp-14-8323-2014", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2014-08-20", "series_number": "16", "volume": "14", "issue": "16", "pages": "8323-8341" }, { "id": "authors:mmg7c-gv420", "collection": "authors", "collection_id": "mmg7c-gv420", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140729-082417829", "type": "article", "title": "Observations of continental biogenic impacts on marine aerosol and clouds off the coast of California", "author": [ { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-Matthew-M" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Wang", "given_name": "Z.", "clpid": "Wang-Z" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-Jill-S" }, { "family_name": "Metcalf", "given_name": "A. R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-Andrew-R" }, { "family_name": "Lin", "given_name": "J. J.", "orcid": "0000-0002-4453-1263", "clpid": "Lin-Jack-J" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "During the 2011 Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) and 2013 Nucleation in California Experiment (NiCE) field campaigns, a predominantly organic aerosol (> 85% by mass) was observed in the free troposphere over marine stratocumulus off the coast of California. These particles originated from a densely forested region in the Northwestern United States. The organic mass spectrum resolved by positive matrix factorization is consistent with the mass spectra of previously measured biogenic organic aerosol. Particulate organic mass exhibits a latitudinal gradient that corresponds to the geographical distribution of vegetation density and composition, with the highest concentration over regions impacted by densely populated monoterpene sources. Due to meteorological conditions during summer months, cloud-clearing events transport aerosol from the Northwestern United States into the free troposphere above marine stratocumulus. Based on the variation of meteorological variables with altitude, dry air containing enhanced biogenic organic aerosol is shown to entrain into the marine boundary layer. Fresh impacts on cloud water composition are observed north of San Francisco, CA which is consistent with fresh continental impacts on the marine atmosphere at higher latitudes. Continental aerosol size distributions are bimodal. Particles in the 100\u2009nm mode are impacted by biogenic sources, while particles in the \u223c 30\u2009nm mode may originate from fresh biogenic emissions. Continental aerosol in the 100\u2009nm mode is cloud condensation nuclei active and may play a role in modulating marine stratocumulus microphysics.", "doi": "10.1002/2013JD021228", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2014-06-16", "series_number": "11", "volume": "119", "issue": "11", "pages": "6724-6748" }, { "id": "authors:favfa-yte09", "collection": "authors", "collection_id": "favfa-yte09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140605-084912235", "type": "article", "title": "Analytical solution for transient partitioning and reaction of a condensing vapor species in a droplet", "author": [ { "family_name": "Liu", "given_name": "Albert Tianxiang", "clpid": "Liu-Albert-Tianxiang" }, { "family_name": "Zaveri", "given_name": "Rahul A.", "orcid": "0000-0001-9874-8807", "clpid": "Zaveri-R-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We present the exact analytical solution of the transient equation of gas-phase diffusion of a condensing vapor to, and diffusion and reaction in, an aqueous droplet. Droplet-phase reaction is represented by first-order chemistry. The solution facilitates study of the dynamic nature of the vapor uptake process as a function of droplet size, Henry's law coefficient, and first-order reaction rate constant for conversion in the droplet phase.", "doi": "10.1016/j.atmosenv.2014.02.065", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2014-06", "volume": "89", "pages": "651-654" }, { "id": "authors:6wpfs-b4741", "collection": "authors", "collection_id": "6wpfs-b4741", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140627-151937621", "type": "article", "title": "Modeling kinetic partitioning of secondary organic aerosol and size distribution dynamics: representing effects of volatility, phase state, and particle-phase reaction", "author": [ { "family_name": "Zaveri", "given_name": "R. A.", "orcid": "0000-0001-9874-8807", "clpid": "Zaveri-R-A" }, { "family_name": "Easter", "given_name": "R. C.", "orcid": "0000-0002-8602-1464", "clpid": "Easter-R-C" }, { "family_name": "Shilling", "given_name": "J. E.", "orcid": "0000-0002-3728-0195", "clpid": "Shilling-J-E" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This paper describes and evaluates a new framework for modeling kinetic gas-particle partitioning of secondary organic aerosol (SOA) that takes into account diffusion and chemical reaction within the particle phase. The framework uses a combination of (a) an analytical quasi-steady-state treatment for the diffusion\u2013reaction process within the particle phase for fast-reacting organic solutes, and (b) a two-film theory approach for slow- and nonreacting solutes. The framework is amenable for use in regional and global atmospheric models, although it currently awaits specification of the various gas- and particle-phase chemistries and the related physicochemical properties that are important for SOA formation. Here, the new framework is implemented in the computationally efficient Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) to investigate the competitive growth dynamics of the Aitken and accumulation mode particles. Results show that the timescale of SOA partitioning and the associated size distribution dynamics depend on the complex interplay between organic solute volatility, particle-phase bulk diffusivity, and particle-phase reactivity (as exemplified by a pseudo-first-order reaction rate constant), each of which can vary over several orders of magnitude. In general, the timescale of SOA partitioning increases with increase in volatility and decrease in bulk diffusivity and rate constant. At the same time, the shape of the aerosol size distribution displays appreciable narrowing with decrease in volatility and bulk diffusivity and increase in rate constant. A proper representation of these physicochemical processes and parameters is needed in the next generation models to reliably predict not only the total SOA mass, but also its composition- and number-diameter distributions, all of which together determine the overall optical and cloud-nucleating properties.", "doi": "10.5194/acp-14-5153-2014", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2014-05-27", "series_number": "10", "volume": "14", "issue": "10", "pages": "5153-5181" }, { "id": "authors:q24sg-ttd73", "collection": "authors", "collection_id": "q24sg-ttd73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140606-095223059", "type": "article", "title": "Oxidation Products of Biogenic Emissions Contribute to Nucleation of Atmospheric Particles", "author": [ { "family_name": "Riccobono", "given_name": "Francesco", "clpid": "Riccobono-F" }, { "family_name": "Downard", "given_name": "Andrew", "clpid": "Downard-A-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations.", "doi": "10.1126/science.1243527", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2014-05-16", "series_number": "6185", "volume": "344", "issue": "6185", "pages": "717-721" }, { "id": "authors:xve2s-92p04", "collection": "authors", "collection_id": "xve2s-92p04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140414-094346479", "type": "article", "title": "Influence of vapor wall loss in laboratory chambers on yields of secondary organic aerosol", "author": [ { "family_name": "Zhang", "given_name": "Xuan", "clpid": "Zhang-Xuan" }, { "family_name": "Cappa", "given_name": "Christopher D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-C-D" }, { "family_name": "Jathar", "given_name": "Shantanu H.", "orcid": "0000-0003-4106-2358", "clpid": "Jathar-S-H" }, { "family_name": "McVay", "given_name": "Renee C.", "orcid": "0000-0001-7766-5009", "clpid": "McVay-R-C" }, { "family_name": "Ensberg", "given_name": "Jospeh J.", "clpid": "Ensberg-J-J" }, { "family_name": "Kleeman", "given_name": "Michael J.", "clpid": "Kleeman-M-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric secondary organic aerosol (SOA) has important impacts on climate and air quality, yet models continue to have difficulty in accurately simulating SOA concentrations. Nearly all SOA models are tied to observations of SOA formation in laboratory chamber experiments. Here, a comprehensive analysis of new experimental results demonstrates that the formation of SOA in laboratory chambers may be substantially suppressed due to losses of SOA-forming vapors to chamber walls, which leads to underestimates of SOA in air-quality and climate models, especially in urban areas where anthropogenic SOA precursors dominate. This analysis provides a time-dependent framework for the interpretation of laboratory chamber experiments that will allow for development of parameterized models of SOA formation that are appropriate for use in atmospheric models.", "doi": "10.1073/pnas.1404727111", "pmcid": "PMC4000817", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2014-04-22", "series_number": "16", "volume": "111", "issue": "16", "pages": "5802-5807" }, { "id": "authors:f87qe-bng25", "collection": "authors", "collection_id": "f87qe-bng25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140529-084758310", "type": "article", "title": "Organic aerosol formation from the reactive uptake of isoprene epoxydiols (IEPOX) onto non-acidified inorganic seeds", "author": [ { "family_name": "Nguyen", "given_name": "T. B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Bates", "given_name": "K. H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-K-H" }, { "family_name": "Zhang", "given_name": "X.", "clpid": "Zhang-Xuan" }, { "family_name": "Schwantes", "given_name": "R. H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Schilling", "given_name": "K. A.", "clpid": "Schilling-K-A" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-C-L" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The reactive partitioning of cis and trans \u03b2-IEPOX was investigated on hydrated inorganic seed particles, without the addition of acids. No organic aerosol (OA) formation was observed on dry ammonium sulfate (AS); however, prompt and efficient OA growth was observed for the cis and trans \u03b2-IEPOX on AS seeds at liquid water contents of 40\u201375% of the total particle mass. OA formation from IEPOX is a kinetically limited process, thus the OA growth continues if there is a reservoir of gas-phase IEPOX. There appears to be no differences, within error, in the OA growth or composition attributable to the cis / trans isomeric structures. Reactive uptake of IEPOX onto hydrated AS seeds with added base (NaOH) also produced high OA loadings, suggesting the pH dependence for OA formation from IEPOX is weak for AS particles. No OA formation, after particle drying, was observed on seed particles where Na^+ was substituted for NH^(+)_(4). The Henry's Law partitioning of IEPOX was measured on NaCl particles (ionic strength ~9 M) to be 3 \u00d7 10^7 M atm^\u22121 (\u221250 / +100%). A small quantity of OA was produced when NH4+ was present in the particles, but the chloride (Cl-) anion was substituted for sulfate (SO^(2-)_(4)), possibly suggesting differences in nucleophilic strength of the anions. Online time-of-flight aerosol mass spectrometry and offline filter analysis provide evidence of oxygenated hydrocarbons, organosulfates, and amines in the particle organic composition. The results are consistent with weak correlations between IEPOX-derived OA and particle acidity or liquid water observed in field studies, as the chemical system is nucleophile-limited and not limited in water or catalyst activity.", "doi": "10.5194/acp-14-3497-2014", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2014-04-08", "series_number": "7", "volume": "14", "issue": "7", "pages": "3497-3510" }, { "id": "authors:554yf-3ec39", "collection": "authors", "collection_id": "554yf-3ec39", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140521-072422141", "type": "article", "title": "Emission factor ratios, SOA mass yields, and the impact of vehicular emissions on SOA formation", "author": [ { "family_name": "Ensberg", "given_name": "J. J.", "clpid": "Ensberg-J-J" }, { "family_name": "Hayes", "given_name": "P. L.", "clpid": "Hayes-P-L" }, { "family_name": "Jimenez", "given_name": "J. L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Gilman", "given_name": "J. B.", "clpid": "Gilman-J-B" }, { "family_name": "Kuster", "given_name": "W. C.", "clpid": "Kuster-W-C" }, { "family_name": "de Gouw", "given_name": "J. A.", "orcid": "0000-0002-0385-1826", "clpid": "de-Gouw-J-A" }, { "family_name": "Holloway", "given_name": "J. S.", "clpid": "Holloway-J-S" }, { "family_name": "Gordon", "given_name": "T. D.", "clpid": "Gordon-T-D" }, { "family_name": "Jathar", "given_name": "S.", "orcid": "0000-0003-4106-2358", "clpid": "Jathar-S-H" }, { "family_name": "Robinson", "given_name": "A. L.", "clpid": "Robinson-A-L" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The underprediction of ambient secondary organic aerosol (SOA) levels by current atmospheric models in urban areas is well established, yet the cause of this underprediction remains elusive. Likewise, the relative contribution of emissions from gasoline- and diesel-fueled vehicles to the formation of SOA is generally unresolved. We investigate the source of these two discrepancies using data from the 2010 CalNex experiment carried out in the Los Angeles Basin (Ryerson et al., 2013). Specifically, we use gas-phase organic mass (GPOM) and CO emission factors in conjunction with measured enhancements in oxygenated organic aerosol (OOA) relative to CO to quantify the significant lack of closure between expected and observed organic aerosol concentrations attributable to fossil-fuel emissions. Two possible conclusions emerge from the analysis to yield consistency with the ambient data: (1) vehicular emissions are not a dominant source of anthropogenic fossil SOA in the Los Angeles Basin, or (2) the ambient SOA mass yields used to determine the SOA formation potential of vehicular emissions are substantially higher than those derived from laboratory chamber studies.", "doi": "10.5194/acp-14-2383-2014", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2014-03-07", "series_number": "5", "volume": "14", "issue": "5", "pages": "2383-2387" }, { "id": "authors:4qs8k-tjn63", "collection": "authors", "collection_id": "4qs8k-tjn63", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140210-145231305", "type": "article", "title": "Gas Phase Production and Loss of Isoprene Epoxydiols", "author": [ { "family_name": "Bates", "given_name": "Kelvin H.", "orcid": "0000-0001-7544-9580", "clpid": "Bates-K-H" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "St. Clair", "given_name": "Jason M.", "orcid": "0000-0002-9367-5749", "clpid": "St-Clair-J-M" }, { "family_name": "Bennett", "given_name": "Nathan B.", "clpid": "Bennett-N-B" }, { "family_name": "Nguyen", "given_name": "Tran B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Stoltz", "given_name": "Brian M.", "orcid": "0000-0001-9837-1528", "clpid": "Stoltz-B-M" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "Isoprene epoxydiols (IEPOX) form in high yields from the OH-initiated oxidation of isoprene under low-NO conditions. These compounds contribute significantly to secondary organic aerosol formation. Their gas-phase chemistry has, however, remained largely unexplored. In this study, we characterize the formation of IEPOX isomers from the oxidation of isoprene by OH. We find that cis-\u03b2- and trans-\u03b2-IEPOX are the dominant isomers produced, and that they are created in an approximate ratio of 1:2 from the low-NO oxidation of isoprene. Three isomers of IEPOX, including cis-\u03b2- and trans-\u03b2, were synthesized and oxidized by OH in environmental chambers under high- and low-NO conditions. We find that IEPOX reacts with OH at 299 K with rate coefficients of (0.84 \u00b1 0.07) \u00d7 10^(\u201311), (1.52 \u00b1 0.07) \u00d7 10^(\u201311), and (0.98 \u00b1 0.05) \u00d7 10^(\u201311) cm^3 molecule^(\u20131) s^(\u20131) for the \u03b41, cis-\u03b2, and trans-\u03b2 isomers. Finally, yields of the first-generation products of IEPOX + OH oxidation were measured, and a new mechanism of IEPOX oxidation is proposed here to account for the observed products. The substantial yield of glyoxal and methylglyoxal from IEPOX oxidation may help explain elevated levels of those compounds observed in low-NO environments with high isoprene emissions.", "doi": "10.1021/jp4107958", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2014-02-20", "series_number": "7", "volume": "118", "issue": "7", "pages": "1237-1246" }, { "id": "authors:v5bhs-13766", "collection": "authors", "collection_id": "v5bhs-13766", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140407-135255247", "type": "article", "title": "Role of ozone in SOA formation from alkane photooxidation", "author": [ { "family_name": "Zhang", "given_name": "X.", "clpid": "Zhang-Xuan" }, { "family_name": "Schwantes", "given_name": "R. H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-C-L" }, { "family_name": "Schilling", "given_name": "K. A.", "clpid": "Schilling-K-A" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Long-chain alkanes, which can be categorized as intermediate volatility organic compounds, are an important source of secondary organic aerosol (SOA). Mechanisms for the gas-phase OH-initiated oxidation of long-chain alkanes have been well documented; particle-phase chemistry, however, has received less attention. The \u03b4-hydroxycarbonyl, which is generated from the isomerization of alkoxy radicals, can undergo heterogeneous cyclization and dehydration to form substituted dihydrofuran. Due to the presence of C=C bonds, the substituted dihydrofuran is predicted to be highly reactive with OH, and even more so with O_3 and NO_3, thereby opening a reaction pathway that is not usually accessible to alkanes. This work focuses on the role of substituted dihydrofuran formation and its subsequent reaction with OH, and more importantly ozone, in SOA formation from the photooxidation of long-chain alkanes. Experiments were carried out in the Caltech Environmental Chamber using dodecane as a representative alkane to investigate the difference in aerosol composition generated from \"OH-oxidation-dominating\" vs. \"ozonolysis-dominating\" environments. A detailed mechanism incorporating the specific gas-phase photochemistry, together with the heterogeneous formation of substituted dihydrofuran and its subsequent gas-phase OH/O_3 oxidation, is used to evaluate the importance of this reaction channel in dodecane SOA formation. We conclude that (1) the formation of \u03b4-hydroxycarbonyl and its subsequent heterogeneous conversion to substituted dihydrofuran is significant in the presence of NO_x; (2) the ozonolysis of substituted dihydrofuran dominates over the OH-initiated oxidation under conditions prevalent in urban and rural air; and (3) a spectrum of highly oxygenated products with carboxylic acid, ester, and ether functional groups are produced from the substituted dihydrofuran chemistry, thereby affecting the average oxidation state of the SOA.", "doi": "10.5194/acp-14-1733-2014", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2014-02-14", "series_number": "3", "volume": "14", "issue": "3", "pages": "1733-1753" }, { "id": "authors:s1mc2-t0r44", "collection": "authors", "collection_id": "s1mc2-t0r44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140407-104929017", "type": "article", "title": "Secondary organic aerosol yields of 12-carbon alkanes", "author": [ { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-C-L" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Yee", "given_name": "L. D.", "clpid": "Yee-Lindsay-D" }, { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Schwantes", "given_name": "R. H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Shiraiwa", "given_name": "M.", "orcid": "0000-0003-2532-5373", "clpid": "Shiraiwa-Manabu" }, { "family_name": "Zhang", "given_name": "X.", "clpid": "Zhang-Xuan" }, { "family_name": "Schilling", "given_name": "K. A.", "clpid": "Schilling-K-A" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Canagaratna", "given_name": "M. R.", "clpid": "Canagaratna-M-R" }, { "family_name": "Ziemann", "given_name": "P. J.", "clpid": "Ziemann-P-J" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) yields were measured for cyclododecane, hexylcyclohexane, n-dodecane, and 2-methylundecane under high-NOx conditions, in which alkyl proxy radicals (RO_2) react primarily with NO, and under low-NO_x conditions, in which RO2 reacts primarily with HO2. Experiments were run until 95\u2013100% of the initial alkane had reacted. Particle wall loss was evaluated as two limiting cases using a new approach that requires only suspended particle number-size distribution data and accounts for size-dependent particle wall losses and condensation. SOA yield differed by a factor of 2 between the two limiting cases, but the same trends among alkane precursors were observed for both limiting cases. Vapor-phase wall losses were addressed through a modeling study and increased SOA yield uncertainty by approximately 30%. SOA yields were highest from cyclododecane under both NOx conditions. SOA yields ranged from 3.3% (dodecane, low-NO_x conditions) to 160% (cyclododecane, high-NO_x conditions). Under high-NO_x conditions, SOA yields increased from 2-methylundecane < dodecane ~ hexylcyclohexane < cyclododecane, consistent with previous studies. Under low-NO_x conditions, SOA yields increased from 2-methylundecane ~ dodecane < hexylcyclohexane < cyclododecane. The presence of cyclization in the parent alkane structure increased SOA yields, whereas the presence of branch points decreased SOA yields due to increased vapor-phase fragmentation. Vapor-phase fragmentation was found to be more prevalent under high-NO_x conditions than under low-NO_x conditions. For different initial mixing ratios of the same alkane and same NO_x conditions, SOA yield did not correlate with SOA mass throughout SOA growth, suggesting kinetically limited SOA growth for these systems.", "doi": "10.5194/acp-14-1423-2014", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2014-02-07", "series_number": "3", "volume": "14", "issue": "3", "pages": "1423-1439" }, { "id": "authors:d3qc9-4c487", "collection": "authors", "collection_id": "d3qc9-4c487", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140213-094604820", "type": "article", "title": "Biogenic and biomass burning organic aerosol in a boreal forest at Hyyti\u00e4l\u00e4, Finland, during HUMPPA-COPEC 2010", "author": [ { "family_name": "Corrigan", "given_name": "A. L.", "clpid": "Corrigan-A-L" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Takahama", "given_name": "S.", "orcid": "0000-0002-3335-8741", "clpid": "Takahama-Satoshi" }, { "family_name": "\u00c4ij\u00e4l\u00e4", "given_name": "M.", "clpid": "\u00c4ij\u00e4l\u00e4-M" }, { "family_name": "Ehn", "given_name": "M.", "orcid": "0000-0002-0215-4893", "clpid": "Ehn-Mikael" }, { "family_name": "Junninen", "given_name": "H.", "orcid": "0000-0001-7178-9430", "clpid": "Junninen-Heikki" }, { "family_name": "Rinne", "given_name": "J.", "orcid": "0000-0003-1168-7138", "clpid": "Rinne-Janne" }, { "family_name": "Pet\u00e4j\u00e4", "given_name": "T.", "orcid": "0000-0002-1881-9044", "clpid": "Pet\u00e4j\u00e4-Tuukka" }, { "family_name": "Kulmala", "given_name": "M.", "orcid": "0000-0003-3464-7825", "clpid": "Kulmala-Markku" }, { "family_name": "Vogel", "given_name": "A. L.", "clpid": "Vogel-A-L" }, { "family_name": "Hoffmann", "given_name": "T.", "orcid": "0000-0003-0939-271X", "clpid": "Hoffmann-Thorsten" }, { "family_name": "Ebben", "given_name": "C. J.", "clpid": "Ebben-C-J" }, { "family_name": "Geiger", "given_name": "F. M.", "orcid": "0000-0001-8569-4045", "clpid": "Geiger-Franz-M" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Worsnop", "given_name": "D. R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-Douglas-R" }, { "family_name": "Song", "given_name": "W.", "clpid": "Song-W" }, { "family_name": "Auld", "given_name": "J.", "clpid": "Auld-J" }, { "family_name": "Williams", "given_name": "J.", "clpid": "Williams-J" } ], "abstract": "Submicron aerosol particles were collected during July and August 2010 in Hyyti\u00e4l\u00e4, Finland, to determine the composition and sources of aerosol at that boreal forest site. Submicron particles were collected on Teflon filters and analyzed by Fourier transform infrared (FTIR) spectroscopy for organic functional groups (OFGs). Positive matrix factorization (PMF) was applied to aerosol mass spectrometry (AMS) measurements and FTIR spectra to identify summertime sources of submicron aerosol mass at the sampling site. The two largest sources of organic mass (OM) in particles identified at Hyyti\u00e4l\u00e4 were (1) biogenic aerosol from surrounding local forest and (2) biomass burning aerosol, transported 4\u20135 days from large wildfires burning near Moscow, Russia, and northern Ukraine. The robustness of this apportionment is supported by the agreement of two independent analytical methods for organic measurements with three statistical techniques. FTIR factor analysis was more sensitive to the chemical differences between biogenic and biomass burning organic components, while AMS factor analysis had a higher time resolution that more clearly linked the temporal behavior of separate OM factors to that of different source tracers even though their fragment mass spectrum were similar. The greater chemical sensitivity of the FTIR is attributed to the nondestructive preparation and the functional group specificity of spectroscopy. The FTIR spectra show strong similarities among biogenic and biomass burning factors from different regions as well as with reference OM (namely olive tree burning organic aerosol and \u03b1-pinene chamber secondary organic aerosol (SOA)). The biogenic factor correlated strongly with temperature and oxidation products of biogenic volatile organic compounds (BVOCs), included more than half of the oxygenated OFGs (carbonyl groups at 29% and carboxylic acid groups at 22%), and represented 35% of the submicron OM. Compared to previous studies at Hyyti\u00e4l\u00e4, the summertime biogenic OM is 1.5 to 3 times larger than springtime biogenic OM (0.64 \u03bcg m^\u22123 and 0.4 \u03bcg m^\u22123, measured in 2005 and 2007, respectively), even though it contributed only 35% of OM. The biomass burning factor contributed 25% of OM on average and up to 62% of OM during three periods of transported biomass burning emissions: 26\u201328 July, 29\u201330 July, and 8\u20139 August, with OFG consisting mostly of carbonyl (41%) and alcohol (25%) groups. The high summertime terrestrial biogenic OM (1.7 \u03bcg m^\u22123) and the high biomass burning contributions (1.2 \u03bcg m^\u22123) were likely due to the abnormally high temperatures that resulted in both stressed boreal forest conditions with high regional BVOC emissions and numerous wildfires in upwind regions.", "doi": "10.5194/acp-13-12233-2013", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2013-12-17", "series_number": "24", "volume": "13", "issue": "24", "pages": "12233-12256" }, { "id": "authors:1wf8g-xca49", "collection": "authors", "collection_id": "1wf8g-xca49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140109-074510558", "type": "article", "title": "Effect of chemical structure on secondary organic aerosol formation from C_(12) alkanes", "author": [ { "family_name": "Yee", "given_name": "L. D.", "clpid": "Yee-Lindsay-D" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-C-L" }, { "family_name": "Schilling", "given_name": "K. A.", "clpid": "Schilling-K-A" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Canagaratna", "given_name": "M. R.", "clpid": "Canagaratna-M-R" }, { "family_name": "Ziemann", "given_name": "P. J.", "clpid": "Ziemann-P-J" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The secondary organic aerosol (SOA) formation from four C_(12) alkanes (n-dodecane, 2-methylundecane, hexylcyclohexane, and cyclododecane) is studied in the Caltech Environmental Chamber under low-NO_x conditions, in which the principal fate of the peroxy radical formed in the initial OH reaction is reaction with HO_2. Simultaneous gas- and particle-phase measurements elucidate the effect of alkane structure on the chemical mechanisms underlying SOA growth. Reaction of branched structures leads to fragmentation and more volatile products, while cyclic structures are subject to faster oxidation and lead to less volatile products. Product identifications reveal that particle-phase reactions involving peroxyhemiacetal formation from several multifunctional hydroperoxide species are key components of initial SOA growth in all four systems. The continued chemical evolution of the particle-phase is structure-dependent, with 2-methylundecane SOA formation exhibiting the least extent of chemical processing and cyclododecane SOA achieving sustained growth with the greatest variety of chemical pathways. The extent of chemical development is not necessarily reflected in the oxygen to carbon (O : C) ratio of the aerosol as cyclododecane achieves the lowest O : C, just above 0.2, by the end of the experiment and hexylcyclohexane the highest, approaching 0.35.", "doi": "10.5194/acp-13-11121-2013", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2013-11-15", "series_number": "21", "volume": "13", "issue": "21", "pages": "11121-11140" }, { "id": "authors:7rdgj-g2k45", "collection": "authors", "collection_id": "7rdgj-g2k45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131210-101910500", "type": "article", "title": "Measurements of methane emissions at natural gas production sites in the United States", "author": [ { "family_name": "Allen", "given_name": "David T.", "clpid": "Allen-D-T" }, { "family_name": "Torres", "given_name": "Vincent M.", "clpid": "Torres-V-M" }, { "family_name": "Thomas", "given_name": "James", "clpid": "Thomas-J" }, { "family_name": "Sullivan", "given_name": "David W.", "clpid": "Sullivan-D-W" }, { "family_name": "Harrison", "given_name": "Matthew", "clpid": "Harrison-M" }, { "family_name": "Hendler", "given_name": "Al", "clpid": "Hendler-A" }, { "family_name": "Herndon", "given_name": "Scott C.", "clpid": "Herndon-S-C" }, { "family_name": "Kolb", "given_name": "Charles E.", "clpid": "Kolb-C-E" }, { "family_name": "Fraser", "given_name": "Matthew P.", "clpid": "Fraser-M-P" }, { "family_name": "Hill", "given_name": "A. Daniel", "clpid": "Hill-A-D" }, { "family_name": "Lamb", "given_name": "Brian K.", "clpid": "Lamb-B-K" }, { "family_name": "Miskimins", "given_name": "Jennifer", "clpid": "Miskimins-J" }, { "family_name": "Sawyer", "given_name": "Robert F.", "clpid": "Sawyer-R-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Engineering estimates of methane emissions from natural gas production have led to varied projections of national emissions. This work reports direct measurements of methane emissions at 190 onshore natural gas sites in the United States (150 production sites, 27 well completion flowbacks, 9 well unloadings, and 4 workovers). For well completion flowbacks, which clear fractured wells of liquid to allow gas production, methane emissions ranged from 0.01 Mg to 17 Mg (mean = 1.7 Mg; 95% confidence bounds of 0.67\u20133.3 Mg), compared with an average of 81 Mg per event in the 2011 EPA national emission inventory from April 2013. Emission factors for pneumatic pumps and controllers as well as equipment leaks were both comparable to and higher than estimates in the national inventory. Overall, if emission factors from this work for completion flowbacks, equipment leaks, and pneumatic pumps and controllers are assumed to be representative of national populations and are used to estimate national emissions, total annual emissions from these source categories are calculated to be 957 Gg of methane (with sampling and measurement uncertainties estimated at \u00b1200 Gg). The estimate for comparable source categories in the EPA national inventory is \u223c1,200 Gg. Additional measurements of unloadings and workovers are needed to produce national emission estimates for these source categories. The 957 Gg in emissions for completion flowbacks, pneumatics, and equipment leaks, coupled with EPA national inventory estimates for other categories, leads to an estimated 2,300 Gg of methane emissions from natural gas production (0.42% of gross gas production).", "doi": "10.1073/pnas.1304880110", "pmcid": "PMC3816463", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2013-10-29", "series_number": "44", "volume": "110", "issue": "44", "pages": "17768-17773" }, { "id": "authors:8tf9h-00283", "collection": "authors", "collection_id": "8tf9h-00283", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131115-115842493", "type": "article", "title": "Molecular understanding of sulphuric acid\u2013amine particle nucleation in the atmosphere", "author": [ { "family_name": "Almeida", "given_name": "Jo\u00e3o", "clpid": "Almeida-Jo\u00e3o" }, { "family_name": "Downard", "given_name": "Andrew J.", "clpid": "Downard-Andrew-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases. However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere3. It is thought that amines may enhance nucleation, but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid\u2013amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid\u2013dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.", "doi": "10.1038/nature12663", "pmcid": "PMC7449521", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2013-10-17", "series_number": "7471", "volume": "502", "issue": "7471", "pages": "359-363" }, { "id": "authors:qeh25-7tk97", "collection": "authors", "collection_id": "qeh25-7tk97", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131204-104912735", "type": "article", "title": "Observational Insights into Aerosol Formation from Isoprene", "author": [ { "family_name": "Worton", "given_name": "David R.", "clpid": "Worton-D-R" }, { "family_name": "Beaver", "given_name": "Melinda", "clpid": "Beaver-M-R" }, { "family_name": "St. Clair", "given_name": "Jason M.", "orcid": "0000-0002-9367-5749", "clpid": "St-Clair-J-M" }, { "family_name": "Crounse", "given_name": "John", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Wennberg", "given_name": "Paul", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric photooxidation of isoprene is an important source of secondary organic aerosol (SOA) and there is increasing evidence that anthropogenic oxidant emissions can enhance this SOA formation. In this work, we use ambient observations of organosulfates formed from isoprene epoxydiols (IEPOX) and methacrylic acid epoxide (MAE) and a broad suite of chemical measurements to investigate the relative importance of nitrogen oxide (NO/NO_2) and hydroperoxyl (HO_2) SOA formation pathways from isoprene at a forested site in California. In contrast to IEPOX, the calculated production rate of MAE was observed to be independent of temperature. This is the result of the very fast thermolysis of MPAN at high temperatures that affects the distribution of the MPAN reservoir (MPAN / MPA radical) reducing the fraction that can react with OH to form MAE and subsequently SOA (F_(MAE formation)). The strong temperature dependence of F_(MAE formation) helps to explain our observations of similar concentrations of IEPOX-derived organosulfates (IEPOX-OS;~1 ng m^(\u20133)) and MAE-derived organosulfates (MAE-OS;~1 ng m^(\u20133)) under cooler conditions (lower isoprene concentrations) and much higher IEPOX-OS (~20 ng m^(\u20133)) relative to MAE-OS (<0.0005 ng m^(\u20133)) at higher temperatures (higher isoprene concentrations). A kinetic model of IEPOX and MAE loss showed that MAE forms 10\u2212100 times more ring-opening products than IEPOX and that both are strongly dependent on aerosol water content when aerosol pH is constant. However, the higher fraction of MAE ring opening products does not compensate for the lower MAE production under warmer conditions (higher isoprene concentrations) resulting in lower formation of MAE-derived products relative to IEPOX at the surface. In regions of high NO_x, high isoprene emissions and strong vertical mixing the slower MPAN thermolysis rate aloft could increase the fraction of MPAN that forms MAE resulting in a vertically varying isoprene SOA source.", "doi": "10.1021/es4011064", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2013-10-15", "series_number": "20", "volume": "47", "issue": "20", "pages": "11403-11413" }, { "id": "authors:dq59h-xzh41", "collection": "authors", "collection_id": "dq59h-xzh41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140319-075647979", "type": "article", "title": "Los Angeles Basin airborne organic aerosol characterization during CalNex", "author": [ { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Metcalf", "given_name": "A. R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" }, { "family_name": "Bahreini", "given_name": "R.", "clpid": "Bahreini-R" }, { "family_name": "Middlebrook", "given_name": "A.", "clpid": "Middlebrook-A" }, { "family_name": "Hayes", "given_name": "P. L.", "clpid": "Hayes-P-L" }, { "family_name": "Duong", "given_name": "H. T.", "clpid": "Duong-Hanh-T" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Jimenez", "given_name": "J. L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We report airborne organic aerosol (OA) measurements over Los Angeles carried out in May 2010 as part of the CalNex field campaign. The principal platform for the airborne data reported here was the CIRPAS Twin Otter (TO); airborne data from NOAA WP-3D aircraft and Pasadena CalNex ground-site data acquired during simultaneous TO flybys are also presented. Aerodyne aerosol mass spectrometer measurements constitute the main source of data analyzed. The increase in organic aerosol oxidation from west to east in the basin was sensitive to OA mass loading, with a greater spatial trend in O:C associated with lower mass concentration. Three positive matrix factorization (PMF) components (hydrocarbon-like organic aerosol (HOA), semi-volatile oxidized organic aerosol (SVOOA), and low volatility oxidized organic aerosol (LVOOA)) were resolved for the one flight that exhibited the largest variability in estimated O:C ratio. Comparison of the PMF factors with two optical modes of refractory black carbon (rBC)-containing aerosol revealed that the coating of thinly coated rBC-containing aerosol, dominant in the downtown region, is likely composed of HOA, whereas more thickly coated rBC-containing aerosol, dominant in the Banning pass outflow, is composed of SVOOA and LVOOA. The correlation of water-soluble organic mass to oxidized organic aerosol (OOA) is higher in the outflows than in the basin due to the higher mass fraction of OOA/OA in the outflows. By comparison, the average OA concentration over Mexico City MILAGRO (Megacity Initiative: Local and Global Research Observations) campaign was \u223c7 times higher than the airborne average during CalNex.", "doi": "10.1002/jgrd.50853", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2013-10-14", "series_number": "19", "volume": "118", "issue": "19", "pages": "11453-11467" }, { "id": "authors:29wnx-am387", "collection": "authors", "collection_id": "29wnx-am387", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131118-100634113", "type": "article", "title": "Hygroscopic properties of smoke-generated organic aerosol particles emitted in the marine atmosphere", "author": [ { "family_name": "Wonasch\u00fctz", "given_name": "A.", "clpid": "Wonasch\u00fctz-A" }, { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Modini", "given_name": "R.", "orcid": "0000-0002-2982-1369", "clpid": "Modini-R-L" }, { "family_name": "Frossard", "given_name": "A. A.", "orcid": "0000-0002-5728-0854", "clpid": "Frossard-A-A" }, { "family_name": "Ahlm", "given_name": "L.", "clpid": "Ahlm-L" }, { "family_name": "M\u00fclmenst\u00e4dt", "given_name": "J.", "orcid": "0000-0003-1105-6678", "clpid": "M\u00fclmenst\u00e4dt-J" }, { "family_name": "Roberts", "given_name": "G. C.", "orcid": "0000-0002-3636-8590", "clpid": "Roberts-G-C" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Dey", "given_name": "S.", "clpid": "Dey-S" }, { "family_name": "Brechtel", "given_name": "F. J.", "clpid": "Brechtel-F-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "During the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE), a plume of organic aerosol was produced by a smoke generator and emitted into the marine atmosphere from aboard the R/V Point Sur. In this study, the hygroscopic properties and the chemical composition of the plume were studied at plume ages between 0 and 4 h in different meteorological conditions. In sunny conditions, the plume particles had very low hygroscopic growth factors (GFs): between 1.05 and 1.09 for 30 nm and between 1.02 and 1.1 for 150 nm dry size at a relative humidity (RH) of 92%, contrasted by an average marine background GF of 1.6. New particles were produced in large quantities (several 10 000 cm^\u22123), which lead to substantially increased cloud condensation nuclei (CCN) concentrations at supersaturations between 0.07 and 0.88%. Ratios of oxygen to carbon (O : C) and water-soluble organic mass (WSOM) increased with plume age: from < 0.001 to 0.2, and from 2.42 to 4.96 \u03bcg m^\u22123, respectively, while organic mass fractions decreased slightly (~ 0.97 to ~ 0.94). High-resolution aerosol mass spectrometer (AMS) spectra show that the organic fragment m/z 43 was dominated by C_(2)H_(3)O^+ in the small, new particle mode and by C_(3)H_(7)^+ in the large particle mode. In the marine background aerosol, GFs for 150 nm particles at 40% RH were found to be enhanced at higher organic mass fractions: an average GF of 1.06 was observed for aerosols with an organic mass fraction of 0.53, and a GF of 1.04 for an organic mass fraction of 0.35.", "doi": "10.5194/acp-13-9819-2013", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2013-10-07", "series_number": "19", "volume": "13", "issue": "19", "pages": "9819-9835" }, { "id": "authors:tsv99-sn952", "collection": "authors", "collection_id": "tsv99-sn952", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130923-142910735", "type": "article", "title": "Secondary organic aerosol formation from biomass burning intermediates: phenol and methoxyphenols", "author": [ { "family_name": "Yee", "given_name": "L. D.", "orcid": "0000-0001-8965-9319", "clpid": "Yee-Lindsay-D" }, { "family_name": "Kautzman", "given_name": "K. E.", "clpid": "Kautzman-K-E" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-Christine-L" }, { "family_name": "Schilling", "given_name": "K. A.", "clpid": "Schilling-Katherine-A" }, { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-Matthew-M" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Chan", "given_name": "M. N.", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Hersey", "given_name": "S. P.", "clpid": "Hersey-Scott-P" }, { "family_name": "Crounse", "given_name": "J. D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-John-D" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The formation of secondary organic aerosol from oxidation of phenol, guaiacol (2-methoxyphenol), and syringol (2,6-dimethoxyphenol), major components of biomass burning, is described. Photooxidation experiments were conducted in the Caltech laboratory chambers under low-NO\u2093 (< 10 ppb) conditions using H\u2082O\u2082 as the OH source. Secondary organic aerosol (SOA) yields (ratio of mass of SOA formed to mass of primary organic reacted) greater than 25% are observed. Aerosol growth is rapid and linear with the primary organic conversion, consistent with the formation of essentially non-volatile products. Gas- and aerosol-phase oxidation products from the guaiacol system provide insight into the chemical mechanisms responsible for SOA formation. Syringol SOA yields are lower than those of phenol and guaiacol, likely due to novel methoxy group chemistry that leads to early fragmentation in the gas-phase photooxidation. Atomic oxygen to carbon (O : C) ratios calculated from high-resolution-time-of-flight Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS) measurements of the SOA in all three systems are ~ 0.9, which represent among the highest such ratios achieved in laboratory chamber experiments and are similar to that of aged atmospheric organic aerosol. The global contribution of SOA from intermediate volatility and semivolatile organic compounds has been shown to be substantial (Pye and Seinfeld, 2010). An approach to representing SOA formation from biomass burning emissions in atmospheric models could involve one or more surrogate species for which aerosol formation under well-controlled conditions has been quantified. The present work provides data for such an approach.", "doi": "10.5194/acp-13-8019-2013", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2013-08-21", "series_number": "16", "volume": "13", "issue": "16", "pages": "8019-8043" }, { "id": "authors:1jgej-13m13", "collection": "authors", "collection_id": "1jgej-13m13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130924-145659455", "type": "article", "title": "Projected effect of 2000-2050 changes in climate and emissions on aerosol levels in China and associated transboundary transport", "author": [ { "family_name": "Jiang", "given_name": "H.", "clpid": "Jiang-H" }, { "family_name": "Liao", "given_name": "H.", "clpid": "Liao-H" }, { "family_name": "Pye", "given_name": "H. O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-H-O-T" }, { "family_name": "Wu", "given_name": "S.", "clpid": "Wu-S" }, { "family_name": "Mickley", "given_name": "L. J.", "orcid": "0000-0002-7859-3470", "clpid": "Mickley-L-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Zhang", "given_name": "X. Y.", "clpid": "Zhang-X-Y" } ], "abstract": "We investigate projected 2000\u20132050 changes in concentrations of aerosols in China and the associated transboundary aerosol transport by using the chemical transport model GEOS-Chem driven by the Goddard Institute for Space Studies (GISS) general circulation model (GCM) 3 at 4\u00b0 \u00d7 5\u00b0 resolution. Future changes in climate and emissions projected by the IPCC A1B scenario are imposed separately and together through sensitivity simulations. Accounting for sulfate, nitrate, ammonium, black carbon (BC), and organic carbon (OC) aerosols, concentrations of individual aerosol species change by \u22121.5 to +0.8 \u03bcg m^(\u22123), and PM_(2.5) levels are projected to change by about 10\u201320% in eastern China as a result of 2000\u20132050 change in climate alone. With future changes in anthropogenic emissions alone, concentrations of sulfate, BC, and OC are simulated to decrease because of assumed reductions in emissions, and those of nitrate are predicted to increase because of higher NO_x emissions combined with decreases in sulfate. The net result is a predicted reduction of seasonal mean PM_(2.5) concentrations in eastern China by 1\u20138 \u03bcg m^(\u22123) (or 10\u201340%) over 2000\u20132050. It is noted that current emission inventories for BC and OC over China are judged to be inadequate at present. Transboundary fluxes of different aerosol species show different sensitivities to future changes in climate and emissions. The annual outflow of PM_(2.5) from eastern China to the western Pacific is estimated to change by \u22127.0%, \u22120.7%, and \u22129.0% over 2000\u20132050 owing to climate change alone, changes in emissions alone, and changes in both climate and emissions, respectively. The fluxes of nitrate and ammonium aerosols from Europe and Central Asia into western China increase over 2000\u20132050 in response to projected changes in emissions, leading to a 10.5% increase in annual inflow of PM_(2.5) to western China with future changes in both emissions and climate. Fluxes of BC and OC from South Asia to China in spring contribute a large fraction of the annual inflow of PM_(2.5). The annual inflow of PM_(2.5) from South Asia and Southeast Asia to China is estimated to change by \u22128%, +281%, and +227% over 2000\u20132050 owing to climate change alone, changes in emissions alone, and changes in both climate and emissions, respectively. While the 4\u00b0 \u00d7 5\u00b0 spatial resolution is a limitation of the present study, the direction of predicted changes in aerosol levels and transboundary fluxes still provides valuable insight into future air quality.", "doi": "10.5194/acp-13-7937-2013", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2013-08-16", "series_number": "16", "volume": "13", "issue": "16", "pages": "7937-7960" }, { "id": "authors:naawh-e6s72", "collection": "authors", "collection_id": "naawh-e6s72", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130613-081545477", "type": "article", "title": "Gas-particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology", "author": [ { "family_name": "Shiraiwa", "given_name": "Manabu", "orcid": "0000-0003-2532-5373", "clpid": "Shiraiwa-Manabu" }, { "family_name": "Zuend", "given_name": "Andreas", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Bertram", "given_name": "Allan K.", "clpid": "Bertram-A-K" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric aerosols, comprising organic compounds and inorganic salts, play a key role in air quality and climate. Mounting evidence exists that these particles frequently exhibit phase separation into predominantly organic and aqueous electrolyte-rich phases. As well, the presence of amorphous semi-solid or glassy particle phases has been established. Using the canonical system of ammonium sulfate mixed with organics from the ozone oxidation of \u03b1-pinene, we illustrate theoretically the interplay of physical state, non-ideality, and particle morphology affecting aerosol mass concentration and the characteristic timescale of gas\u2013particle mass transfer. Phase separation can significantly affect overall particle mass and chemical composition. Semi-solid or glassy phases can kinetically inhibit the partitioning of semivolatile components and hygroscopic growth, in contrast to the traditional assumption that organic compounds exist in quasi-instantaneous gas\u2013particle equilibrium. These effects have significant implications for the interpretation of laboratory data and the development of improved atmospheric air quality and climate models.", "doi": "10.1039/c3cp51595h", "issn": "1463-9076", "publisher": "Royal Society of Chemistry", "publication": "Physical Chemistry Chemical Physics", "publication_date": "2013-07-21", "series_number": "27", "volume": "15", "issue": "27", "pages": "11441-11453" }, { "id": "authors:c3gev-v7q70", "collection": "authors", "collection_id": "c3gev-v7q70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130903-105605191", "type": "article", "title": "Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation", "author": [ { "family_name": "Shiraiwa", "given_name": "Manabu", "orcid": "0000-0003-2532-5373", "clpid": "Shiraiwa-Manabu" }, { "family_name": "Yee", "given_name": "Lindsay D.", "clpid": "Yee-Lindsay-D" }, { "family_name": "Schilling", "given_name": "Katherine A.", "clpid": "Schilling-K-A" }, { "family_name": "Loza", "given_name": "Christine L.", "clpid": "Loza-C-L" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-J-S" }, { "family_name": "Zuend", "given_name": "Andreas", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Ziemann", "given_name": "Paul J.", "clpid": "Ziemann-P-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process.", "doi": "10.1073/pnas.1307501110", "pmcid": "PMC3718153", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2013-07-16", "series_number": "29", "volume": "110", "issue": "29", "pages": "11746-11750" }, { "id": "authors:ch32z-sta02", "collection": "authors", "collection_id": "ch32z-sta02", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130830-103839195", "type": "article", "title": "Ion Mobility-Mass Spectrometry with a Radial Opposed Migration Ion and Aerosol Classifier (ROMIAC)", "author": [ { "family_name": "Mui", "given_name": "Wilton", "orcid": "0000-0003-3065-1296", "clpid": "Mui-Wilton" }, { "family_name": "Thomas", "given_name": "Daniel A.", "orcid": "0000-0001-9415-5991", "clpid": "Thomas-D-A" }, { "family_name": "Downard", "given_name": "Andrew J.", "clpid": "Downard-A-J" }, { "family_name": "Beauchamp", "given_name": "Jesse L.", "orcid": "0000-0001-8839-4822", "clpid": "Beauchamp-J-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "The first application of a novel differential mobility analyzer, the radial opposed migration ion and aerosol classifier (ROMIAC), is demonstrated. The ROMIAC uses antiparallel forces from an electric field and a cross-flow gas to both scan ion mobilities and continuously transmit target mobility ions with 100% duty cycle. In the ROMIAC, diffusive losses are minimized, and resolution of ions, with collisional cross-sections of 200\u20132000 \u00c5^2, is achieved near the nondispersive resolution of ~20. Higher resolution is theoretically possible with greater cross-flow rates. The ROMIAC was coupled to a linear trap quadrupole mass spectrometer and used to classify electrosprayed C2\u2013C12 tetra-alkyl ammonium ions, bradykinin, angiotensin I, angiotensin II, bovine ubiquitin, and two pairs of model peptide isomers. Instrument and mobility calibrations of the ROMIAC show that it exhibits linear responses to changes in electrode potential, making the ROMIAC suitable for mobility and cross-section measurements. The high resolution of the ROMIAC facilitates separation of isobaric isomeric peptides. Monitoring distinct dissociation pathways associated with peptide isomers fully resolves overlapping peaks in the ion mobility data. The ability of the ROMIAC to operate at atmospheric pressure and serve as a front-end analyzer to continuously transmit ions with a particular mobility facilitates extensive studies of target molecules using a variety of mass spectrometric methods.", "doi": "10.1021/ac400580u", "issn": "0003-2700", "publisher": "American Chemical Society", "publication": "Analytical Chemistry", "publication_date": "2013-07-02", "series_number": "13", "volume": "85", "issue": "13", "pages": "6319-6326" }, { "id": "authors:9che7-mt295", "collection": "authors", "collection_id": "9che7-mt295", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130815-104759279", "type": "article", "title": "A functional group oxidation model (FGOM) for SOA formation and aging", "author": [ { "family_name": "Zhang", "given_name": "X.", "clpid": "Zhang-X" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) formation from a volatile organic compound (VOC) involves multiple generations of oxidation that include functionalization and fragmentation of the parent carbon backbone and likely particle-phase oxidation and/or accretion reactions. Despite the typical complexity of the detailed molecular mechanism of SOA formation and aging, a relatively small number of functional groups characterize the oxidized molecules that constitute SOA. Given the carbon number and set of functional groups, the volatility of the molecule can be estimated. We present here a functional group oxidation model (FGOM) that represents the process of SOA formation and aging. The FGOM contains a set of parameters that are to be determined by fitting of the model to laboratory chamber data: total organic aerosol concentration, and O : C and H : C atomic ratios. The sensitivity of the model prediction to variation of the adjustable parameters allows one to assess the relative importance of various pathways involved in SOA formation. An analysis of SOA formation from the high- and low-NOx photooxidation of four C12 alkanes (n-dodecane, 2-methylundecane, hexylcyclohexane, and cyclododecane) using the FGOM is presented, and comparison with the statistical oxidation model (SOM) of Cappa et al. (2013) is discussed.", "doi": "10.5194/acp-13-5907-2013", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2013-06-18", "series_number": "12", "volume": "13", "issue": "12", "pages": "5907-5926" }, { "id": "authors:pe0cv-8ge37", "collection": "authors", "collection_id": "pe0cv-8ge37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130816-104202754", "type": "article", "title": "On the Mixing and Evaporation of Secondary Organic Aerosol Components", "author": [ { "family_name": "Loza", "given_name": "Christine L.", "clpid": "Loza-C-L" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Nguyen", "given_name": "Tran B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Zuend", "given_name": "Andreas", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The physical state and chemical composition of an organic aerosol affect its degree of mixing and its interactions with condensing species. We present here a laboratory chamber procedure for studying the effect of the mixing of organic aerosol components on particle evaporation. The procedure is applied to the formation of secondary organic aerosol (SOA) from \u03b1-pinene and toluene photooxidation. SOA evaporation is induced by heating the chamber aerosol from room temperature (25 \u00b0C) to 42 \u00b0C over 7 h and detected by a shift in the peak diameter of the SOA size distribution. With this protocol, \u03b1-pinene SOA is found to be more volatile than toluene SOA. When SOA is formed from the two precursors sequentially, the evaporation behavior of the SOA most closely resembles that of SOA from the second parent hydrocarbon, suggesting that the structure of the mixed SOA resembles a core of SOA from the initial precursor coated by a layer of SOA from the second precursor. Such a core-and-shell configuration of the organic aerosol phases implies limited mixing of the SOA from the two precursors on the time scale of the experiments, consistent with a high viscosity of at least one of the phases.", "doi": "10.1021/es400979k", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2013-06-18", "series_number": "12", "volume": "47", "issue": "12", "pages": "6173-6180" }, { "id": "authors:qfttn-1cw57", "collection": "authors", "collection_id": "qfttn-1cw57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131106-095002310", "type": "article", "title": "The 2010 California Research at the Nexus of Air Quality\n and Climate Change (CalNex) field study", "author": [ { "family_name": "Ryerson", "given_name": "T. B.", "orcid": "0000-0003-2800-7581", "clpid": "Ryerson-T-B" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The California Research at the Nexus of Air Quality and Climate Change (CalNex) field study was conducted throughout California in May, June, and July of 2010. The study was organized to address issues simultaneously relevant to atmospheric pollution and climate change, including (1) emission inventory assessment, (2) atmospheric transport and dispersion, (3) atmospheric chemical processing, and (4) cloud-aerosol interactions and aerosol radiative effects. Measurements from networks of ground sites, a research ship, tall towers, balloon-borne ozonesondes, multiple aircraft, and satellites provided in situ and remotely sensed data on trace pollutant and greenhouse gas concentrations, aerosol chemical composition and microphysical properties, cloud microphysics, and meteorological parameters. This overview report provides operational information for the variety of sites, platforms, and measurements, their joint deployment strategy, and summarizes findings that have resulted from the collaborative analyses of the CalNex field study. Climate-relevant findings from CalNex include that leakage from natural gas infrastructure may account for the excess of observed methane over emission estimates in Los Angeles. Air-quality relevant findings include the following: mobile fleet VOC significantly declines, and NO_x emissions continue to have an impact on ozone in the Los Angeles basin; the relative contributions of diesel and gasoline emission to secondary organic aerosol are not fully understood; and nighttime NO_3 chemistry contributes significantly to secondary organic aerosol mass in the San Joaquin Valley. Findings simultaneously relevant to climate and air quality include the following: marine vessel emissions changes due to fuel sulfur and speed controls result in a net warming effect but have substantial positive impacts on local air quality.", "doi": "10.1002/jgrd.50331", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2013-06-16", "series_number": "11", "volume": "118", "issue": "11", "pages": "5830-5866" }, { "id": "authors:pcvfz-3c825", "collection": "authors", "collection_id": "pcvfz-3c825", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140310-102849450", "type": "book_section", "title": "Observed aerosol effects on marine cloud nucleation and supersaturation", "book_title": "Nucleation and Atmospheric Aerosols", "author": [ { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Chen", "given_name": "Yi-Chun", "orcid": "0000-0001-7997-8578", "clpid": "Chen-Yi-Chun" }, { "family_name": "Coggon", "given_name": "Matthew", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-J-S" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Metcalf", "given_name": "Andrew R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" } ], "contributor": [ { "family_name": "DeMott", "given_name": "Paul J.", "clpid": "DeMott-P-J" }, { "family_name": "O'Dowd", "given_name": "Colin D.", "clpid": "O'Dowd-C-D" } ], "abstract": "Aerosol particles in the marine boundary layer include primary organic and salt particles from sea spray and combustion-derived particles from ships and coastal cities. These particle types serve as nuclei for marine cloud droplet activation, although the particles that activate depend on the particle size and composition as well as the supersaturation that results from cloud updraft velocities. The Eastern Pacific Emitted Aerosol Cloud Experiment (EPEACE) 2011 was a targeted aircraft campaign to assess how different particle types nucleate cloud droplets. As part of E-PEACE 2011, we studied the role of marine particles as cloud droplet nuclei and used emitted particle sources to separate particle-induced feedbacks from dynamical variability. The emitted particle sources included shipboard smoke-generated particles with 0.05-1 \u03bcm diameters (which produced tracks measured by satellite and had drop composition characteristic of organic smoke) and combustion particles from container ships with 0.05-0.2 \u03bcm diameters (which were measured in a variety of conditions with droplets containing both organic and sulfate components) [1]. Three central aspects of the collaborative E-PEACE results are: (1) the size and chemical composition of the emitted smoke particles compared to ship-track-forming cargo ship emissions as well as background marine particles, with particular attention to the role of organic particles, (2) the characteristics of cloud track formation for smoke and cargo ships, as well as the role of multi-layered low clouds, and (3) the implications of these findings for quantifying aerosol indirect effects. For comparison with the E-PEACE results, the preliminary results of the Stratocumulus Observations of Los-Angeles Emissions Derived Aerosol-Droplets (SOLEDAD) 2012 provided evidence of the cloud-nucleating roles of both marine organic particles and coastal urban pollution, with simultaneous measurements of the effective supersaturations of the clouds in the California coastal region.", "doi": "10.1063/1.4803366", "isbn": "978-0-7354-1152-4", "publisher": "Melville, NY", "place_of_publication": "American Institute of Physics", "publication_date": "2013-06", "pages": "696-701" }, { "id": "authors:sw6pe-dy351", "collection": "authors", "collection_id": "sw6pe-dy351", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130703-095608075", "type": "article", "title": "Reactive Uptake and Photo-Fenton Oxidation of Glycolaldehyde in Aerosol Liquid Water", "author": [ { "family_name": "Nguyen", "given_name": "T. B.", "clpid": "Nguyen-Tran-B" }, { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The reactive uptake and aqueous oxidation of glycolaldehyde were examined in a photochemical flow reactor using hydrated ammonium sulfate (AS) seed aerosols at RH = 80%. The glycolaldehyde that partitioned into the aerosol liquid water was oxidized via two mechanisms that may produce aqueous OH: hydrogen peroxide photolysis (H_(2)O_(2) + h\u03bd) and the photo-Fenton reaction (Fe_(II) + H_(2)O_(2) + h\u03bd). The uptake of 80 (\u00b110) ppb glycolaldehyde produced 2\u20134 wt % organic aerosol mass in the dark (k_(H)* = (2.09\u20134.17) \u00d7 10^6 M atm^(\u20131)), and the presence of an OH source increased the aqueous uptake by a factor of 4. Although the uptake was similar in both OH-aging mechanisms, photo-Fenton significantly increased the degree of oxidation (O/C = 0.9) of the aerosols compared to H_(2)O_(2) photolysis (O/C = 0.5). Aerosol organics oxidized by photo-Fenton and H_(2)O_(2) photolysis resemble ambient \"aged\" and \"fresh\" OA, respectively, after the equivalent of 2 h atmospheric aging. No uptake or changes in particle composition occurred on dry seed aerosol. This work illustrates that photo-Fenton chemistry efficiently forms highly oxidized organic mass in aerosol liquid water, providing a possible mechanism to bridge the gap between bulk-phase experiments and ambient particles.", "doi": "10.1021/es400538j", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2013-05-07", "series_number": "9", "volume": "47", "issue": "9", "pages": "4307-4316" }, { "id": "authors:3sv8h-6xd04", "collection": "authors", "collection_id": "3sv8h-6xd04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130628-084224102", "type": "article", "title": "Bringing the ocean into the laboratory to probe the chemical complexity of sea spray aerosol", "author": [ { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Hersey", "given_name": "Scott P.", "clpid": "Hersey-Scott-P" }, { "family_name": "Mui", "given_name": "Wilton", "orcid": "0000-0003-3065-1296", "clpid": "Mui-Wilton" } ], "abstract": "The production, size, and chemical composition of sea spray aerosol (SSA) particles strongly depend on seawater chemistry, which is controlled by physical, chemical, and biological processes. Despite decades of studies in marine environments, a direct relationship has yet to be established between ocean biology and the physicochemical properties of SSA. The ability to establish such relationships is hindered by the fact that SSA measurements are typically dominated by overwhelming background aerosol concentrations even in remote marine environments. Herein, we describe a newly developed approach for reproducing the chemical complexity of SSA in a laboratory setting, comprising a unique ocean-atmosphere facility equipped with actual breaking waves. A mesocosm experiment was performed in natural seawater, using controlled phytoplankton and heterotrophic bacteria concentrations, which showed SSA size and chemical mixing state are acutely sensitive to the aerosol production mechanism, as well as to the type of biological species present. The largest reduction in the hygroscopicity of SSA occurred as heterotrophic bacteria concentrations increased, whereas phytoplankton and chlorophyll-a concentrations decreased, directly corresponding to a change in mixing state in the smallest (60\u2013180 nm) size range. Using this newly developed approach to generate realistic SSA, systematic studies can now be performed to advance our fundamental understanding of the impact of ocean biology on SSA chemical mixing state, heterogeneous reactivity, and the resulting climate-relevant properties.", "doi": "10.1073/pnas.1300262110", "pmcid": "PMC3651460", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2013-05-07", "series_number": "19", "volume": "110", "issue": "19", "pages": "7550-7555" }, { "id": "authors:11zfb-8ny50", "collection": "authors", "collection_id": "11zfb-8ny50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130717-111104322", "type": "article", "title": "The effects of \u03b1-pinene versus toluene-derived secondary organic aerosol exposure on the expression of markers associated with vascular disease", "author": [ { "family_name": "Lund", "given_name": "Amie K.", "clpid": "Lund-Amie-K" }, { "family_name": "Doyle-Eisele", "given_name": "Melanie", "clpid": "Doyle-Eisele-Melanie" }, { "family_name": "Lin", "given_name": "Ying-Hsuan", "orcid": "0000-0001-8904-1287", "clpid": "Lin-Ying-Hsuan" }, { "family_name": "Arashiro", "given_name": "Maiko", "clpid": "Arashiro-Maiko" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Holmes", "given_name": "Tom", "orcid": "0000-0003-2116-8147", "clpid": "Holmes-Tom" }, { "family_name": "Schilling", "given_name": "Katherine A.", "clpid": "Schilling-Katherine-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Rohr", "given_name": "Annette C.", "clpid": "Rohr-Annette-C" }, { "family_name": "Knipping", "given_name": "Eladio M.", "orcid": "0000-0002-9654-9019", "clpid": "Knipping-Eladio-M" }, { "family_name": "McDonald", "given_name": "Jacob D.", "clpid": "McDonald-Jacob-D" } ], "abstract": "To investigate the toxicological effects of biogenic- versus anthropogenic-source secondary organic aerosol (SOA) on the cardiovascular system, the Secondary Particulate Health Effects Research program irradiation chamber was used to expose atherosclerotic apolipoprotein E null (Apo E\u2212/\u2212) mice to SOA from the oxidation of either \u03b1-pinene or toluene for 7 days. SOA atmospheres were produced to yield 250\u2013300\u2009\u03bcg/m3 of particulate matter and ratios of 10:1:1 \u03b1-pinene:nitrogen oxide (NO_x):ammonia (NH_3); 10:1:1:1 \u03b1-pinene:NO_x:NH_3:sulfur dioxide (SO2) or 10:1:1 toluene:NO_x:NH_3; and 10:1:1:1 toluene:NO_x:NH_3:SO_2. Resulting effects on the cardiovascular system were assessed by measurement of vascular lipid peroxidation (thiobarbituric acid reactive substance (TBARS)), as well as quantification of heme-oxygenase (HO)-1, endothelin (ET)-1, and matrix metalloproteinase (MMP)-9 mRNA expression for comparison to previous program exposure results. Consistent with similar previous studies, vascular TBARS were not increased significantly with any acute SOA exposure. However, vascular HO-1, MMP-9, and ET-1 observed in Apo E\u2212/\u2212 mice exposed to \u03b1-pinene\u2009+\u2009NOx\u2009+\u2009NH_3\u2009+\u2009SO_2 increased statistically, while \u03b1-pinene\u2009+\u2009NO_x\u2009+\u2009NH3 exposure to either toluene\u2009+\u2009NO_x\u2009+\u2009NH_3 or toluene\u2009+NO_x\u2009+\u2009NH_3\u2009+\u2009SO_2 resulted in a decreased expression of these vascular factors. Such findings suggest that the specific chemistry created by the presence or absence of acidic components may be important in SOA-mediated toxicity in the cardiovascular system and/or progression of cardiovascular disease.", "doi": "10.3109/08958378.2013.782080", "issn": "0895-8378", "publisher": "Taylor & Francis", "publication": "Inhalation Toxicology", "publication_date": "2013-05", "series_number": "6", "volume": "25", "issue": "6", "pages": "309-324" }, { "id": "authors:082gf-bdv27", "collection": "authors", "collection_id": "082gf-bdv27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130708-131056964", "type": "article", "title": "Eastern Pacific Emitted Aerosol Cloud Experiment", "author": [ { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Albrecht", "given_name": "Bruce A.", "orcid": "0000-0001-5085-4272", "clpid": "Albrecht-Bruce-A" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Ahlm", "given_name": "Lars", "clpid": "Ahlm-Lars" }, { "family_name": "Chen", "given_name": "Yi-Chun", "orcid": "0000-0001-7997-8578", "clpid": "Chen-Yi-Chun" }, { "family_name": "Coggon", "given_name": "Matthew", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-Matthew-M" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-Jill-S" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Frossard", "given_name": "Amanda A.", "orcid": "0000-0002-5728-0854", "clpid": "Frossard-Amanda-A" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Jung", "given_name": "Eunsil", "orcid": "0000-0003-0970-2730", "clpid": "Jung-Eunsil" }, { "family_name": "Lin", "given_name": "Jack J.", "orcid": "0000-0002-4453-1263", "clpid": "Lin-Jack-J" }, { "family_name": "Metcalfe", "given_name": "Andrew R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-Andrew-R" }, { "family_name": "Modini", "given_name": "Robin", "orcid": "0000-0002-2982-1369", "clpid": "Modini-Robin-L" }, { "family_name": "M\u00fclmenst\u00e4dt", "given_name": "Johannes", "orcid": "0000-0003-1105-6678", "clpid": "M\u00fclmenst\u00e4dt-Johannes" }, { "family_name": "Roberts", "given_name": "Greg C.", "orcid": "0000-0002-3636-8590", "clpid": "Roberts-Greg-C" }, { "family_name": "Shingler", "given_name": "Taylor", "orcid": "0000-0003-4596-1027", "clpid": "Shingler-Taylor" }, { "family_name": "Song", "given_name": "Siwon", "orcid": "0000-0002-2001-4106", "clpid": "Song-Siwon" }, { "family_name": "Wang", "given_name": "Zhen", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Wonasch\u00fctz", "given_name": "Anna", "clpid": "Wonasch\u00fctz-Anna" } ], "abstract": "Aerosol\u2013cloud\u2013radiation interactions are widely held to be the largest single source of uncertainty in climate model projections of future radiative forcing due to increasing anthropogenic emissions. The underlying causes of this uncertainty among modeled predictions of climate are the gaps in our fundamental understanding of cloud processes. There has been significant progress with both observations and models in addressing these important questions but quantifying them correctly is nontrivial, thus limiting our ability to represent them in global climate models. The Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) 2011 was a targeted aircraft campaign with embedded modeling studies, using the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft and the research vessel Point Sur in July and August 2011 off the central coast of California, with a full payload of instruments to measure particle and cloud number, mass, composition, and water uptake distributions. EPEACE used three emitted particle sources to separate particle-induced feedbacks from dynamical variability, namely 1) shipboard smoke-generated particles with 0.05\u20131-\u03bcm diameters (which produced tracks measured by satellite and had drop composition characteristic of organic smoke), 2) combustion particles from container ships with 0.05\u20130.2-\u03bcm diameters (which were measured in a variety of conditions with droplets containing both organic and sulfate components), and 3) aircraft-based milled salt particles with 3\u20135-\u03bcm diameters (which showed enhanced drizzle rates in some clouds). The aircraft observations were consistent with past large-eddy simulations of deeper clouds in ship tracks and aerosol\u2013 cloud parcel modeling of cloud drop number and composition, providing quantitative constraints on aerosol effects on warm-cloud microphysics.", "doi": "10.1175/BAMS-D-12-00015.1", "issn": "0003-0007", "publisher": "American Meteorological Society", "publication": "Bulletin of the American Meteorological Society", "publication_date": "2013-05", "series_number": "5", "volume": "94", "issue": "5", "pages": "709-729" }, { "id": "authors:qd3wf-ap042", "collection": "authors", "collection_id": "qd3wf-ap042", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130712-102252597", "type": "article", "title": "Composition and hygroscopicity of the Los Angeles Aerosol: CalNex", "author": [ { "family_name": "Hersey", "given_name": "Scott P.", "clpid": "Hersey-Scott-P" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-Jill-S" }, { "family_name": "Metcalfe", "given_name": "Andrew R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-Andrew-R" }, { "family_name": "Lin", "given_name": "Jack", "orcid": "0000-0002-4453-1263", "clpid": "Lin-Jack-J" }, { "family_name": "Lathem", "given_name": "Terry", "clpid": "Lathem-Terry-L" }, { "family_name": "Suski", "given_name": "Kaitlyn J.", "orcid": "0000-0001-5183-7335", "clpid": "Suski-Kaitlyn-J" }, { "family_name": "Cahill", "given_name": "John F.", "clpid": "Cahill-John-F" }, { "family_name": "Duong", "given_name": "Hanh T.", "clpid": "Duong-Hanh-T" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Shiraiwa", "given_name": "Manabu", "orcid": "0000-0003-2532-5373", "clpid": "Shiraiwa-Manabu" }, { "family_name": "Zuend", "given_name": "Andreas", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-Andreas" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aircraft-based measurements of aerosol composition, either bulk or single-particle, and both subsaturated and supersaturated hygroscopicity were made in the Los Angeles Basin and its outflows during May 2010 during the CalNex field study. Aerosol composition evolves from source-rich areas in the western Basin to downwind sites in the eastern Basin, evidenced by transition from an external to internal mixture, as well as enhancements in organic O\u2009:\u2009C ratio, the amount of organics and nitrate internally mixed on almost all particle types, and coating thickness on refractory black carbon (rBC). Transport into hot, dilute outflow regions leads to significant volatilization of semivolatile material, resulting in a unimodal aerosol comprising primarily oxygenated, low-volatility, water-soluble organics and sulfate. The fraction of particles with rBC or soot cores is between 27 and 51% based on data from a Single Particle Soot Photometer (SP2) and Aerosol Time of Flight Mass Spectrometer (ATOFMS). Secondary organics appear to inhibit subsaturated water uptake in aged particles, while CCN activity is enhanced with photochemical age. A biomass-burning event resulted in suppression of subsaturated hygroscopicity but enhancement in CCN activity, suggesting that BB particles may be nonhygroscopic at subsaturated RH but are important sources of CCN. Aerosol aging and biomass burning can lead to discrepancies between subsaturated and supersaturated hygroscopicity that may be related to mixing state. In the cases of biomass burning aerosol and aged particles coated with secondary material, more than a single parameter representation of subsaturated hygroscopicity and CCN activity is needed.", "doi": "10.1002/jgrd.50307", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2013-04-16", "series_number": "7", "volume": "118", "issue": "7", "pages": "3016-3036" }, { "id": "authors:wtvvy-p7t86", "collection": "authors", "collection_id": "wtvvy-p7t86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130423-105257604", "type": "article", "title": "Worldwide data sets constrain the water vapor uptake coefficient in cloud formation", "author": [ { "family_name": "Raatikainen", "given_name": "Tomi", "orcid": "0000-0002-2603-516X", "clpid": "Raatikainen-Tomi" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Morales", "given_name": "Ricardo", "clpid": "Morales-Ricardo" }, { "family_name": "Moore", "given_name": "Richard H.", "orcid": "0000-0003-2911-4469", "clpid": "Moore-Richard-H" }, { "family_name": "Lathem", "given_name": "Terry L.", "clpid": "Lathem-Terry-L" }, { "family_name": "Lance", "given_name": "Sara", "orcid": "0000-0002-2396-2582", "clpid": "Lance-Sara" }, { "family_name": "Padr\u00f3", "given_name": "Luz T.", "clpid": "Padr\u00f3-Luz-T" }, { "family_name": "Lin", "given_name": "Jack L.", "clpid": "Lin-Jack-L" }, { "family_name": "Cerully", "given_name": "Kate M.", "clpid": "Cerully-Kate-M" }, { "family_name": "Bougiatioti", "given_name": "Aikaterini", "clpid": "Bougiatiot-Aikaterini" }, { "family_name": "Cozic", "given_name": "Julie", "clpid": "Cozic-Julie" }, { "family_name": "Ruehl", "given_name": "Christopher R.", "clpid": "Ruehl-Christopher-R" }, { "family_name": "Chuang", "given_name": "Patrick Y.", "orcid": "0000-0003-2290-8346", "clpid": "Chuang-Patrick-Y" }, { "family_name": "Anderson", "given_name": "Bruce E.", "orcid": "0000-0002-7821-7299", "clpid": "Anderson-Bruce-E" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Mihalopoulos", "given_name": "Nikos", "clpid": "Mihalopoulos-Nikos" }, { "family_name": "Smith", "given_name": "James N.", "orcid": "0000-0003-4677-8224", "clpid": "Smith-James-N" } ], "abstract": "Cloud droplet formation depends on the condensation of water vapor on ambient aerosols, the rate of which is strongly affected by the kinetics of water uptake as expressed by the condensation (or mass accommodation) coefficient, \u03b1_c. Estimates of \u03b1_c for droplet growth from activation of ambient particles vary considerably and represent a critical source of uncertainty in estimates of global cloud droplet distributions and the aerosol indirect forcing of climate. We present an analysis of 10 globally relevant data sets of cloud condensation nuclei to constrain the value of \u03b1c for ambient aerosol. We find that rapid activation kinetics (\u03b1_c > 0.1) is uniformly prevalent. This finding resolves a long-standing issue in cloud physics, as the uncertainty in water vapor accommodation on droplets is considerably less than previously thought.", "doi": "10.1073/pnas.1219591110", "pmcid": "PMC3593859", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2013-03-05", "series_number": "10", "volume": "110", "issue": "10", "pages": "3760-3764" }, { "id": "authors:g40cm-0pp80", "collection": "authors", "collection_id": "g40cm-0pp80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130802-153334814", "type": "article", "title": "Secondary Organic Aerosol Coating Formation and Evaporation: Chamber Studies Using Black Carbon Seed Aerosol and the Single-Particle Soot Photometer", "author": [ { "family_name": "Metcalf", "given_name": "Andrew R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" }, { "family_name": "Loza", "given_name": "Christine L.", "clpid": "Loza-C-L" }, { "family_name": "Coggon", "given_name": "Matthew M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-J-S" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We report a protocol for using black carbon (BC) aerosol as the seed for secondary organic aerosol (SOA) formation in an environmental chamber. We employ a single-particle soot photometer (SP2) to probe single-particle SOA coating growth dynamics and find that SOA growth on nonspherical BC aerosol is diffusion-limited. Aerosol composition measurements with an Aerodyne high resolution time-of-flight aerosol mass spectrometer (AMS) confirm that the presence of BC seed does not alter the composition of SOA as compared to self-nucleated SOA or condensed SOA on ammonium sulfate seed. We employ a 3-wavelength photoacoustic soot spectrometer (PASS-3) to measure optical properties of the systems studied, including fullerene soot as the surrogate BC seed, nucleated naphthalene SOA from high-NO_x photooxidation, and nucleated \u03b1-pinene SOA from low-NO_x photooxidation. A core-and-shell Mie scattering model of the light absorption enhancement is in good agreement with measured enhancements for both the low- and high-NO_x \u03b1-pinene photooxidation systems, reinforcing the assumption of a core-shell morphology for coated BC particles. A discrepancy between measured and modeled absorption enhancement factors in the naphthalene photooxidation system is attributed to the wavelength-dependence of refractive index of the naphthalene SOA. The coating of high-NO_x \u03b1-pinene SOA decreases after reaching a peak thickness during irradiation, reflecting a volatility change in the aerosol, as confirmed by the relative magnitudes of f_(43) and f_(44) in the AMS spectra. The protocol described here provides a framework by which future studies of SOA optical properties and single-particle growth dynamics may be explored in environmental chambers.", "doi": "10.1080/02786826.2012.750712", "issn": "0278-6826", "publisher": "Taylor & Francis", "publication": "Aerosol Science and Technology", "publication_date": "2013-03-01", "series_number": "3", "volume": "47", "issue": "3", "pages": "326-347" }, { "id": "authors:25v7m-rgx27", "collection": "authors", "collection_id": "25v7m-rgx27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130605-102705637", "type": "article", "title": "Oligomeric products and formation mechanisms from acid-catalyzed reactions of methyl vinyl ketone on acidic sulfate particles", "author": [ { "family_name": "Chan", "given_name": "Ka Man", "clpid": "Chan-Ka-Man" }, { "family_name": "Huang", "given_name": "Dan Dan", "clpid": "Huagn-Dan-Dan" }, { "family_name": "Li", "given_name": "Yong Jie", "clpid": "Li-Yong-Jie" }, { "family_name": "Chan", "given_name": "Man Nin", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Chan", "given_name": "Chak K.", "orcid": "0000-0001-9687-8771", "clpid": "Chan-Chak-Keung" } ], "abstract": "Methyl vinyl ketone (MVK) is a key first-generation product from atmospheric isoprene photo-oxidation, especially under high-NOx conditions. In this work, acid-catalyzed reactions of gas-phase MVK with ammonium sulfate (AS), ammonium bisulfate (ABS), and sulfuric acid (SA) particles were investigated in a flow reaction system at relative humidity (RH) of 40 % and 80 %. Ultra-performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry (UPLC/ESI-TOFMS) and gas chromatography-mass spectrometry (GC-MS) are utilized to identify particle-phase products for developing the reaction mechanisms. High-order oligomers such as dimers and tetramers were detected when ABS and SA particles were used, while no oligomeric products were found when AS particles were used. Particle-phase oligomeric products were formed via i) acid-catalyzed aldol reaction with or without dehydration and/or ii) acid-catalyzed hydration followed by oligomerization. Reactions on SA particles yield more abundant and higher-order oligomers up to hexamers than on ABS particles. Moreover, aldol reaction occurred only on SA particles, but hydration followed by oligomerization occurred in both ABS and SA particles. The high RH condition with the same type of acidic particles was found to favor hydration and facilitate the subsequent oligomerization, while the low RH condition with the same type of acidic particles was found to favor aldol reaction with dehydration (aldol condensation). Overall, the findings suggest acidic particles can facilitate the formation of high-order oligomers in the particle phase, with particle acidity and RH as key factors.", "doi": "10.1007/s10874-013-9248-7", "issn": "0167-7764", "publisher": "Springer", "publication": "Journal of Atmospheric Chemistry", "publication_date": "2013-03", "series_number": "1", "volume": "70", "issue": "1", "pages": "1-18" }, { "id": "authors:t6zfx-d3614", "collection": "authors", "collection_id": "t6zfx-d3614", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130620-075221175", "type": "article", "title": "Inorganic and black carbon aerosols in the Los Angeles Basin during CalNex", "author": [ { "family_name": "Ensberg", "given_name": "J. J.", "clpid": "Ensberg-J-J" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Walker", "given_name": "J. M.", "clpid": "Walker-J-M" } ], "abstract": "We evaluate predictions from the Community Multiscale Air Quality (CMAQ version 4.7.1) model against a suite of airborne and ground-based meteorological measurements, gas- and aerosol-phase inorganic measurements, and black carbon (BC) measurements over Southern California during the CalNex field campaign in May/June 2010. Ground-based measurements are from the CalNex Pasadena ground site, and airborne measurements took place onboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Navy Twin Otter and the NOAA WP-3D aircraft. BC predictions are in general agreement with observations at the Pasadena ground site and onboard the WP-3D, but are consistently overpredicted when compared to Twin Otter measurements. Adjustments to predicted inorganic mass concentrations, based on predicted aerosol size distributions and the AMS transmission efficiency, are shown to be significant. Owing to recent shipping emission reductions, the dominant source of sulfate in the L.A. Basin may now be long-range transport. Sensitivity studies suggest that severely underestimated ammonia emissions, and not the exclusion of crustal species (Ca^(2\u2009+), K^+, and Mg^(2\u2009+)), are the single largest contributor to measurement/model disagreement in the eastern part of the L.A. Basin. Despite overstated NO_x emissions, total nitrate concentrations are underpredicted, which suggests a missing source of HNO_3 and/or overprediction of deposition rates. Adding gas-phase NH_3 measurements and size-resolved measurements, up to 10 \u03bcm, of nitrate and various cations (e.g. Na^+, Ca^(2\u2009+), K^+) to routine monitoring stations in the L.A. Basin would greatly facilitate interpreting day-to-day fluctuations in fine and coarse inorganic aerosol.", "doi": "10.1029/2012JD018136", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2013-02-27", "series_number": "4", "volume": "118", "issue": "4", "pages": "1777-1803" }, { "id": "authors:5h7zf-63v55", "collection": "authors", "collection_id": "5h7zf-63v55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130409-092032721", "type": "article", "title": "Application of the Statistical Oxidation Model (SOM) to Secondary\n Organic Aerosol formation from photooxidation of C_(12) alkanes", "author": [ { "family_name": "Cappa", "given_name": "C. D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-C-D" }, { "family_name": "Zhang", "given_name": "X.", "clpid": "Zhang-Xuan" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-C-L" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Lee", "given_name": "Y. D.", "clpid": "Lee-Y-D" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Laboratory chamber experiments are the main\nsource of data on the mechanism of oxidation and the secondary\norganic aerosol (SOA) forming potential of volatile\norganic compounds. Traditional methods of representing the\nSOA formation potential of an organic do not fully capture\nthe dynamic, multi-generational nature of the SOA formation\nprocess. We apply the Statistical Oxidation Model (SOM) of\nCappa and Wilson (2012) to model the formation of SOA\nfrom the formation of the four C_(12) alkanes, dodecane, 2-\nmethyl undecane, cyclododecane and hexylcyclohexane, under\nboth high- and low-NO_x conditions, based upon data\nfrom the Caltech chambers. In the SOM, the evolution of\nreaction products is defined by the number of carbon (NC)\nand oxygen (N_O) atoms, and the model parameters are (1)\nthe number of oxygen atoms added per reaction, (2) the decrease\nin volatility upon addition of an oxygen atom and (3)\nthe probability that a given reaction leads to fragmentation\nof the molecules. Optimal fitting of the model to chamber\ndata is carried out using the measured SOA mass concentration\nand the aerosol O:C atomic ratio. The use of the kinetic,\nmulti-generational SOM is shown to provide insights into the\nSOA formation process and to offer promise for application\nto the extensive library of existing SOA chamber experiments\nthat is available.", "doi": "10.5194/acp-13-1591-2013", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2013-02-08", "series_number": "3", "volume": "13", "issue": "3", "pages": "1591-1606" }, { "id": "authors:rkec2-fes83", "collection": "authors", "collection_id": "rkec2-fes83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130328-110858557", "type": "article", "title": "A practical method for the calculation of liquid\u2013liquid equilibria in multicomponent organic\u2013water\u2013electrolyte systems using physicochemical constraints", "author": [ { "family_name": "Zuend", "given_name": "Andreas", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Liquid mixtures containing a variety of organic compounds, water, and dissolved electrolytes are prone to liquid\u2013liquid phase separation, owing to non-ideal interactions between water, ions, and organic compounds. Such systems are of practical importance in the design of chemical separation processes as well as the partitioning of semivolatile species in atmospheric aerosols. In this study, a practical phase separation calculation method based on a system of nonlinear equations is presented, applicable to multicomponent systems containing inorganic ions. Expressions are derived that allow consistent use of activity coefficients defined on molality basis for ionic species in combination with mole fraction-based activity coefficients for nonelectrolyte components. Physicochemical considerations are applied together with preliminary evaluation of generated trial compositions to automatically obtain a set of feasible initial guesses. A successive substitution procedure with component-specific step length damping is then employed, followed by a rapid convergence part using a globally convergent solver for systems of nonlinear equations. We discuss several examples that demonstrate the method's remarkable level of reliability even in the case of systems showing highly non-ideal mixing behavior, and we highlight the importance of providing a good initial guess.", "doi": "10.1016/j.fluid.2012.09.034", "issn": "0378-3812", "publisher": "Elsevier", "publication": "Fluid Phase Equilibria", "publication_date": "2013-01-15", "volume": "337", "pages": "201-213" }, { "id": "authors:7gyap-qrn48", "collection": "authors", "collection_id": "7gyap-qrn48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130131-111539315", "type": "article", "title": "Equilibration timescale of atmospheric secondary organic aerosol partitioning", "author": [ { "family_name": "Shiraiwa", "given_name": "Manabu", "orcid": "0000-0003-2532-5373", "clpid": "Shiraiwa-Manabu" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "[1] Secondary organic aerosol (SOA) formed from partitioning of oxidation products of anthropogenic and biogenic volatile organic compounds (VOCs) accounts for a substantial portion of atmospheric particulate matter. In describing SOA formation, it is generally assumed that VOC oxidation products rapidly adopt gas-aerosol equilibrium. Here we estimate the equilibration timescale, \u03c4_(eq), of SOA gas-particle partitioning using a state-of-the-art kinetic flux model. \u03a4_(eq) is found to be of order seconds to minutes for partitioning of relatively high volatility organic compounds into liquid particles, thereby adhering to equilibrium gas-particle partitioning. However, \u03c4_(eq) increases to hours or days for organic aerosol associated with semi-solid particles, low volatility, large particle size, and low mass loadings. Instantaneous equilibrium partitioning may lead to substantial overestimation of particle mass concentration and underestimation of gas-phase concentration.", "doi": "10.1029/2012GL054008", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2012-12-18", "volume": "39", "pages": "Art. No. L24801" }, { "id": "authors:qre5f-a4z98", "collection": "authors", "collection_id": "qre5f-a4z98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130124-083937535", "type": "article", "title": "Analysis of secondary organic aerosol formation and aging using positive matrix factorization of high-resolution aerosol mass spectra: application to the dodecane low-NO_x system", "author": [ { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Yee", "given_name": "L. D.", "clpid": "Yee-Lindsay-D" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Canagaratna", "given_name": "M. R.", "clpid": "Canagaratna-M-R" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-C-L" }, { "family_name": "Schilling", "given_name": "K. A.", "clpid": "Schilling-K-A" }, { "family_name": "Yatavelli", "given_name": "R. L. N.", "clpid": "Yatavelli-R-L-N" }, { "family_name": "Thornton", "given_name": "J. A.", "orcid": "0000-0002-5098-4867", "clpid": "Thornton-J-A" }, { "family_name": "Ziemann", "given_name": "P. J.", "clpid": "Ziemann-P-J" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Positive matrix factorization (PMF) of high-resolution laboratory chamber aerosol mass spectra is applied for the first time, the results of which are consistent with molecular level MOVI-HRToF-CIMS aerosol-phase and CIMS gas-phase measurements. Secondary organic aerosol was generated by photooxidation of dodecane under low-NOx conditions in the Caltech environmental chamber. The PMF results exhibit three factors representing a combination of gas-particle partitioning, chemical conversion in the aerosol, and wall deposition. The slope of the measured high-resolution aerosol mass spectrometer (HR-ToF-AMS) composition data on a Van Krevelen diagram is consistent with that of other low-NO_x alkane systems in the same O : C range. Elemental analysis of the PMF factor mass spectral profiles elucidates the combinations of functionality that contribute to the slope on the Van Krevelen diagram.", "doi": "10.5194/acp-12-11795-2012", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-12-17", "series_number": "24", "volume": "12", "issue": "24", "pages": "11795-11817" }, { "id": "authors:892t5-pre68", "collection": "authors", "collection_id": "892t5-pre68", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170408-154439855", "type": "article", "title": "Simulation of nitrate, sulfate, and ammonium aerosols over the United States", "author": [ { "family_name": "Walker", "given_name": "J. M.", "clpid": "Walker-J-M" }, { "family_name": "Philip", "given_name": "S.", "clpid": "Philip-S" }, { "family_name": "Martin", "given_name": "R. V.", "clpid": "Martin-R-V" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric concentrations of inorganic gases and aerosols (nitrate, sulfate, and ammonium) are simulated for 2009 over the United States using the chemical transport model GEOS-Chem. Predicted aerosol concentrations are compared with surface-level measurement data from the Interagency Monitoring of Protected Visual Environments (IMPROVE), the Clean Air Status and Trends Network (CASTNET), and the California Air Resources Board (CARB). Sulfate predictions nationwide are in reasonably good agreement with observations, while nitrate and ammonium are over-predicted in the East and Midwest, but under-predicted in California, where observed concentrations are the highest in the country. Over-prediction of nitrate in the East and Midwest is consistent with results of recent studies, which suggest that nighttime nitric acid formation by heterogeneous hydrolysis of N_2O_5 is over-predicted based on current values of the N_2O_5 uptake coefficient, \u03b3, onto aerosols. After reducing the value of \u03b3 by a factor of 10, predicted nitrate levels in the US Midwest and East still remain higher than those measured, and over-prediction of nitrate in this region remains unexplained. Comparison of model predictions with satellite measurements of ammonia from the Tropospheric Emissions Spectrometer (TES) indicates that ammonia emissions in GEOS-Chem are underestimated in California and that the nationwide seasonality applied to ammonia emissions in GEOS-Chem does not represent California very well, particularly underestimating winter emissions. An ammonia sensitivity study indicates that GEOS-Chem simulation of nitrate is ammonia-limited in southern California and much of the state, suggesting that an underestimate of ammonia emissions is likely the main cause for the under-prediction of nitrate aerosol in many areas of California. An approximate doubling of ammonia emissions is needed to reproduce observed nitrate concentrations in southern California and in other ammonia sensitive areas of California. However, even a tenfold increase in ammonia emissions yields predicted nitrate concentrations that are still biased low in the central valley of California. The under-prediction of nitrate aerosol in the central valley of California may arise in part from an under-prediction of both ammonia and nitric acid in this region. Since nitrate aerosols are particularly sensitive to mixed layer depths, owing to the gas-particle equilibrium, the nitrate under-prediction could also arise in part from a potential regional overestimate of GEOS-5 mixed layer depths in the central valley due to unresolved topography in this region.", "doi": "10.5194/acp-12-11213-2012", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-11-27", "series_number": "22", "volume": "12", "issue": "22", "pages": "11213-11227" }, { "id": "authors:zve2q-yj425", "collection": "authors", "collection_id": "zve2q-yj425", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121129-135155685", "type": "article", "title": "Are simulated aerosol-induced effects on deep convective clouds strongly dependent on saturation adjustment?", "author": [ { "family_name": "Lebo", "given_name": "Z. J.", "orcid": "0000-0002-1064-4833", "clpid": "Lebo-Z-J" }, { "family_name": "Morrison", "given_name": "H.", "orcid": "0000-0001-8480-9787", "clpid": "Morrison-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Three configurations of a bulk microphysics scheme in conjunction with a detailed bin scheme are implemented in the Weather Research and Forecasting (WRF) model to specifically address the role of the saturation adjustment assumption (i.e., condensing/evaporating the surplus/deficit water vapor relative to saturation in one time step) on aerosol-induced invigoration of deep convective clouds. The bulk model configurations are designed to treat cloud droplet condensation/evaporation using either saturation adjustment, as employed in most bulk models, or an explicit representation of supersaturation over a time step, as used in bin models. Results demonstrate that the use of saturation adjustment artificially enhances condensation and latent heating at low levels and limits the potential for an increase in aerosol concentration to increase buoyancy at mid to upper levels. This leads to a small weakening of the time- and domain-averaged convective mass flux (~-3%) in polluted compared to clean conditions. In contrast, the bin model and bulk scheme with explicit prediction of supersaturation simulate an increase in latent heating aloft and the convective updraft mass flux is weakly invigorated (~5%). The bin model also produces a large increase in domain-mean cumulative surface precipitation in polluted conditions (~18%), while all of the bulk model configurations simulate little change in precipitation. Finally, it is shown that the cold pool weakens substantially with increased aerosol loading when saturation adjustment is applied, which acts to reduce the low-level convergence and weaken the convective dynamics. With an explicit treatment of supersaturation in the bulk and bin models there is little change in cold pool strength, so that the convective response to polluted conditions is influenced more by changes in latent heating aloft. It is concluded that the use of saturation adjustment can explain differences in the response of cold pool evolution and convective dynamics with aerosol loading simulated by the bulk and bin models, but cannot explain large differences in the response of surface precipitation between these models.", "doi": "10.5194/acp-12-9941-2012", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-10-30", "series_number": "20", "volume": "12", "issue": "20", "pages": "9941-9964" }, { "id": "authors:ceekg-zad95", "collection": "authors", "collection_id": "ceekg-zad95", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121113-133911100", "type": "article", "title": "Ship impacts on the marine atmosphere: insights into the\n contribution of shipping emissions to the properties of marine\n aerosol and clouds", "author": [ { "family_name": "Coggon", "given_name": "M. M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-Matthew-M" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Wang", "given_name": "Z.", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Metcalf", "given_name": "A. R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-Andrew-R" }, { "family_name": "Frossard", "given_name": "A. A.", "orcid": "0000-0002-5728-0854", "clpid": "Frossard-Amanda-A" }, { "family_name": "Lin", "given_name": "J. J.", "clpid": "Lin-J-J" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-Jill-S" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We report properties of marine aerosol and clouds measured in the shipping lanes between Monterey Bay and San Francisco off the coast of Central California. Using a suite of aerosol instrumentation onboard the CIRPAS Twin Otter aircraft, these measurements represent a unique set of data contrasting the properties of clean and ship-impacted marine air masses in dry aerosol and cloud droplet residuals. Below-cloud aerosol exhibited average mass and number concentrations of 2 \u03bcg m^(\u22123) and 510 cm^(\u22123), respectively, which are consistent with previous studies performed off the coast of California. Enhancements in vanadium and cloud droplet number concentrations are observed concurrently with a decrease in cloud water pH, suggesting that periods of high aerosol loading are primarily linked to increased ship influence. Mass spectra from a compact time-of-flight Aerodyne aerosol mass spectrometer reveal an enhancement in the fraction of organic at m/z 42 (f_42) and 99 (f_99) in ship-impacted clouds. These ions are well correlated to each other (R^2>0.64) both in and out of cloud and constitute 14% (f_(44)) and 3% (f_(99)) of organic mass during periods of enhanced sulfate. High-resolution mass spectral analysis of these masses from ship measurements suggests that the ions responsible for this variation were oxidized, possibly due to cloud processing. We propose that the organic fractions of these ions be used as a metric for determining the extent to which cloud-processed ship emissions impact the marine atmosphere where (f_(42) > 0.15; f_(99) > 0.04) would imply heavy influence from shipping emissions, (0.05 < f_(42) < 0.15; 0.01 < f_(99) < 0.04) would imply moderate, but persistent, influences from ships, and (f_(42) < 0.05; f_(99) < 0.01) would imply clean, non-ship-influenced air.", "doi": "10.5194/acp-12-8439-2012", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-09-20", "series_number": "18", "volume": "12", "issue": "18", "pages": "8439-8458" }, { "id": "authors:fvz7q-vyx29", "collection": "authors", "collection_id": "fvz7q-vyx29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200529-093434315", "type": "article", "title": "Occurrence of lower cloud albedo in ship tracks", "author": [ { "family_name": "Chen", "given_name": "Y.-C.", "orcid": "0000-0001-7997-8578", "clpid": "Chen-Yi-Chun" }, { "family_name": "Christensen", "given_name": "M. W.", "clpid": "Christensen-M-W" }, { "family_name": "Xue", "given_name": "L.", "clpid": "Xue-L" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Stephens", "given_name": "G. L.", "clpid": "Stephens-G-L" }, { "family_name": "Rasmussen", "given_name": "R. M.", "clpid": "Rasmussen-R-M" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The concept of geoengineering by marine cloud brightening is based on seeding marine stratocumulus clouds with sub-micrometer sea-salt particles to enhance the cloud droplet number concentration and cloud albedo, thereby producing a climate cooling effect. The efficacy of this as a strategy for global cooling rests on the extent to which aerosol-perturbed marine clouds will respond with increased albedo. Ship tracks, quasi-linear cloud features prevalent in oceanic regions impacted by ship exhaust, are a well-known manifestation of the effect of aerosol injection on marine clouds. We present here an analysis of the albedo responses in ship tracks, based on in situ aircraft measurements and three years of satellite observations of 589 individual ship tracks. It is found that the sign (increase or decrease) and magnitude of the albedo response in ship tracks depends on the mesoscale cloud structure, the free tropospheric humidity, and cloud top height. In a closed cell structure (cloud cells ringed by a perimeter of clear air), nearly 30% of ship tracks exhibited a decreased albedo. Detailed cloud responses must be accounted for in global studies of the potential efficacy of sea-spray geoengineering as a means to counteract global warming.", "doi": "10.5194/acp-12-8223-2012", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-09-12", "series_number": "17", "volume": "12", "issue": "17", "pages": "8223-8235" }, { "id": "authors:b9nc9-ah303", "collection": "authors", "collection_id": "b9nc9-ah303", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121127-093941496", "type": "article", "title": "Organosulfates as Tracers for Secondary Organic Aerosol (SOA)\n Formation from 2\u2011Methyl-3-Buten-2-ol (MBO) in the Atmosphere", "author": [ { "family_name": "Zhang", "given_name": "Haofei", "clpid": "Zhang-Haofei" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "2-Methyl-3-buten-2-ol (MBO) is an important biogenic volatile organic compound (BVOC) emitted by pine trees and a potential precursor of atmospheric secondary organic aerosol (SOA) in forested regions. In the present study, hydroxyl radical (OH)-initiated oxidation of MBO was examined in smog chambers under varied initial nitric oxide (NO) and aerosol acidity levels. Results indicate measurable SOA from MBO under low-NO conditions. Moreover, increasing aerosol acidity was found to enhance MBO SOA. Chemical characterization of laboratory-generated MBO SOA reveals that an organosulfate species (C_5H_(12)O_6S, MW 200) formed and was substantially enhanced with elevated aerosol acidity. Ambient fine aerosol (PM_(2.5)) samples collected from the BEARPEX campaign during 2007 and 2009, as well as from the BEACHON-RoMBAS campaign during 2011, were also analyzed. The MBO-derived organosulfate characterized from laboratory-generated aerosol was observed in PM_(2.5) collected from these campaigns, demonstrating that it is a molecular tracer for MBO-initiated SOA in the atmosphere. Furthermore, mass concentrations of the MBO-derived organosulfate are well correlated with MBO mixing ratio, temperature, and acidity in the field campaigns. Importantly, this compound accounted for an average of 0.25% and as high as 1% of the total organic aerosol mass during BEARPEX 2009. An epoxide intermediate generated under low-NO conditions is tentatively proposed to produce MBO SOA.", "doi": "10.1021/es301648z", "pmcid": "PMC3557936", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2012-09-04", "series_number": "17", "volume": "46", "issue": "17", "pages": "9437-9446" }, { "id": "authors:t4hce-xe883", "collection": "authors", "collection_id": "t4hce-xe883", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121015-153502319", "type": "article", "title": "Cardiopulmonary response to inhalation of secondary organic aerosol derived from gas-phase oxidation of toluene", "author": [ { "family_name": "McDonald", "given_name": "Jacob D.", "clpid": "McDonald-Jacob-D" }, { "family_name": "Doyle-Eisele", "given_name": "Melanie", "clpid": "Doyle-Eisele-Melanie" }, { "family_name": "Kracko", "given_name": "Dean", "clpid": "Kracko-Dean" }, { "family_name": "Lund", "given_name": "Amie", "orcid": "0000-0002-0878-751X", "clpid": "Lund-Amie-K" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Hersey", "given_name": "Scott P.", "clpid": "Hersey-Scott-P" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Rohr", "given_name": "Annette C.", "clpid": "Rohr-Annette-C" }, { "family_name": "Knipping", "given_name": "Eladio M.", "orcid": "0000-0002-9654-9019", "clpid": "Knipping-Eladio-M" } ], "abstract": "The biological response to inhalation of secondary organic aerosol (SOA) was determined in rodents exposed to SOA derived from the oxidation of toluene, a precursor emitted from anthropogenic sources. SOA atmospheres were produced to yield 300 \u00b5g\u00b7m^(\u22123) of particulate matter (PM) plus accompanying gases. Whole-body exposures were conducted in mice to assess both pulmonary and cardiovascular effects. ApoE^(\u2212/\u2212) mice were exposed for 7 days and measurements of TBARS and gene expression of heme-oxygenase-1 (HO-1), endothelin-1 (ET-1), and matrix metalloproteinase-9 (MMP-9) were made in aorta. Pulmonary inflammatory responses in both species were measured by bronchoalveolar lavage fluid (BALF) cell counts. No pulmonary inflammation was observed. A mild response was observed in mouse aorta for the upregulation of ET-1 and HO-1, with a trend for increased MMP-9 and TBARS, and. Overall, toluene-derived SOA revealed limited biological response compared with previous studies using this exposure protocol with other environmental pollutants.", "doi": "10.3109/08958378.2012.712164", "issn": "0895-8378", "publisher": "Taylor & Francis", "publication": "Inhalation Toxicology", "publication_date": "2012-09", "series_number": "11", "volume": "24", "issue": "11", "pages": "689-697" }, { "id": "authors:3k33z-btr66", "collection": "authors", "collection_id": "3k33z-btr66", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121009-093600608", "type": "article", "title": "Peroxy radical chemistry and OH radical production during the NO_3-initiated oxidation of isoprene", "author": [ { "family_name": "Kwan", "given_name": "A. J.", "clpid": "Kwan-Alan-J" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Kjaergaard", "given_name": "H. G.", "orcid": "0000-0002-7275-8297", "clpid": "Kjaergaard-H-G" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "Peroxy radical reactions (RO_2 + RO_2) from the NO3-initiated oxidation of isoprene are studied with both gas chromatography and a chemical ionization mass spectrometry technique that allows for more specific speciation of products than in previous studies of this system. We find high nitrate yields (~ 80%), consistent with other studies. We further see evidence of significant hydroxyl radical (OH) formation in this system, which we propose comes from RO_2 + HO_2 reactions with a yield of ~38\u201358%. An additional OH source is the second generation oxidation of the nitrooxyhydroperoxide, which produces OH and a dinitrooxyepoxide with a yield of ~35%. The branching ratio of the radical propagating, carbonyl- and alcohol-forming, and organic peroxide-forming channels of the RO_2 + RO_2 reaction are found to be ~18\u201338%, ~59\u201377%, and ~3\u20134%, respectively. HO_2 formation in this system is lower than has been previously assumed. Addition of RO_2 to isoprene is suggested as a possible route to the formation of several isoprene C_(10)-organic peroxide compounds (ROOR). The nitrooxy, allylic, and C_5 peroxy radicals present in this system exhibit different behavior than the limited suite of peroxy radicals that have been studied to date.", "doi": "10.5194/acp-12-7499-2012", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-08-17", "series_number": "16", "volume": "12", "issue": "16", "pages": "7499-7515" }, { "id": "authors:bw7cf-g7881", "collection": "authors", "collection_id": "bw7cf-g7881", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121005-124120015", "type": "article", "title": "\u03b1-pinene photooxidation under controlled chemical conditions \u2013 Part 2: SOA yield and composition in low- and high-NO\u2093 environments", "author": [ { "family_name": "Eddingsaas", "given_name": "N. C.", "orcid": "0000-0003-1539-5415", "clpid": "Eddingsaas-Nathan-C" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-Christine-L" }, { "family_name": "Yee", "given_name": "L. D.", "orcid": "0000-0001-8965-9319", "clpid": "Yee-Lindsay-D" }, { "family_name": "Chan", "given_name": "M.", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Schilling", "given_name": "K. A.", "clpid": "Schilling-Katherine-A" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "The gas-phase oxidation of \u03b1-pinene produces a large amount of secondary organic aerosol (SOA) in the atmosphere. A number of carboxylic acids, organosulfates and nitrooxy organosulfates associated with \u03b1-pinene have been found in field samples and some are used as tracers of \u03b1-pinene oxidation. \u03b1-pinene reacts readily with OH and O\u2083 in the atmosphere followed by reactions with both HO\u2082 and NO. Due to the large number of potential reaction pathways, it can be difficult to determine what conditions lead to SOA. To better understand the SOA yield and chemical composition from low- and high-NO\u2093 OH oxidation of \u03b1-pinene, studies were conducted in the Caltech atmospheric chamber under controlled chemical conditions. Experiments used low O\u2083 concentrations to ensure that OH was the main oxidant and low \u03b1-pinene concentrations such that the peroxy radical (RO\u2082) reacted primarily with either HO\u2082 under low-NO\u2093 conditions or NO under high-NO\u2093 conditions. SOA yield was suppressed under conditions of high-NO\u2093. SOA yield under high-NO\u2093 conditions was greater when ammonium sulfate/sulfuric acid seed particles (highly acidic) were present prior to the onset of growth than when ammonium sulfate seed particles (mildly acidic) were present; this dependence was not observed under low-NO\u2093 conditions. When aerosol seed particles were introduced after OH oxidation, allowing for later generation species to be exposed to fresh inorganic seed particles, a number of low-NO\u2093 products partitioned to the highly acidic aerosol. This indicates that the effect of seed acidity and SOA yield might be under-estimated in traditional experiments where aerosol seed particles are introduced prior to oxidation. We also identify the presence of a number of carboxylic acids that are used as tracer compounds of \u03b1-pinene oxidation in the field as well as the formation of organosulfates and nitrooxy organosulfates. A number of the carboxylic acids were observed under all conditions, however, pinic and pinonic acid were only observed under low-NO\u2093 conditions. Evidence is provided for particle-phase sulfate esterification of multi-functional alcohols.", "doi": "10.5194/acp-12-7413-2012", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-08-16", "series_number": "16", "volume": "12", "issue": "16", "pages": "7413-7427" }, { "id": "authors:c0ebw-dz302", "collection": "authors", "collection_id": "c0ebw-dz302", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121003-090543069", "type": "article", "title": "\u03b1-pinene photooxidation under controlled chemical conditions \u2013 Part 1: Gas-phase composition in low- and high-NO\u2093 environments", "author": [ { "family_name": "Eddingsaas", "given_name": "N. C.", "orcid": "0000-0003-1539-5415", "clpid": "Eddingsaas-Nathan-C" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-Christine-L" }, { "family_name": "Yee", "given_name": "L. D.", "orcid": "0000-0001-8965-9319", "clpid": "Yee-Lindsay-D" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "The OH oxidation of \u03b1-pinene under both low- and high-NO\u2093 environments was studied in the Caltech atmospheric chambers. Ozone was kept low to ensure OH was the oxidant. The initial \u03b1-pinene concentration was 20\u201350 ppb to ensure that the dominant peroxy radical pathway under low-NO\u2093 conditions is reaction with HO\u2082, produced from reaction of OH with H\u2082O\u2082, and under high-NO\u2093 conditions, reactions with NO. Here we present the gas-phase results observed. Under low-NO\u2093 conditions the main first generation oxidation products are a number of \u03b1-pinene hydroxy hydroperoxides and pinonaldehyde, accounting for over 40% of the yield. In all, 65\u201375% of the carbon can be accounted for in the gas phase; this excludes first-generation products that enter the particle phase. We suggest that pinonaldehyde forms from RO\u2082 + HO\u2082 through an alkoxy radical channel that regenerates OH, a mechanism typically associated with acyl peroxy radicals, not alkyl peroxy radicals. The OH oxidation and photolysis of \u03b1-pinene hydroxy hydroperoxides leads to further production of pinonaldehyde, resulting in total pinonaldehyde yield from low-NO\u2093 OH oxidation of ~33%. The low-NO\u2093 OH oxidation of pinonaldehyde produces a number of carboxylic acids and peroxyacids known to be important secondary organic aerosol components. Under high-NO\u2093 conditions, pinonaldehyde was also found to be the major first-generation OH oxidation product. The high-NO\u2093 OH oxidation of pinonaldehyde did not produce carboxylic acids and peroxyacids. A number of organonitrates and peroxyacyl nitrates are observed and identified from \u03b1-pinene and pinonaldehyde.", "doi": "10.5194/acp-12-6489-2012", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-07-25", "series_number": "14", "volume": "12", "issue": "14", "pages": "6489-6504" }, { "id": "authors:bs3bq-8yz17", "collection": "authors", "collection_id": "bs3bq-8yz17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120418-114720485", "type": "article", "title": "Secondary Organic Aerosol Formation from Low-NO_x Photooxidation of Dodecane: Evolution of Multigeneration Gas-Phase Chemistry and Aerosol Composition", "author": [ { "family_name": "Yee", "given_name": "Lindsay D.", "clpid": "Yee-Lindsay-D" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-J-S" }, { "family_name": "Loza", "given_name": "Christine L.", "clpid": "Loza-C-L" }, { "family_name": "Schilling", "given_name": "Katherine A.", "clpid": "Schilling-K-A" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Canagaratna", "given_name": "Manjula R.", "clpid": "Canagaratna-M-R" }, { "family_name": "Ziemann", "given_name": "Paul J.", "clpid": "Ziemann-P-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The extended photooxidation of and secondary organic aerosol (SOA) formation from dodecane (C_(12)H_(26)) under low-NO_x conditions, such that RO_2 + HO_2 chemistry dominates the fate of the peroxy radicals, is studied in the Caltech Environmental Chamber based on simultaneous gas and particle-phase measurements. A mechanism simulation indicates that greater than 67% of the initial carbon ends up as fourth and higher generation products after 10 h of reaction, and simulated trends for seven species are supported by gas-phase measurements. A characteristic set of hydroperoxide gas-phase products are formed under these low-NO_x conditions. Production of semivolatile hydroperoxide species within three generations of chemistry is consistent with observed initial aerosol growth. Continued gas-phase oxidation of these semivolatile species produces multifunctional low volatility compounds. This study elucidates the complex evolution of the gas-phase photooxidation chemistry and subsequent SOA formation through a novel approach comparing molecular level information from a chemical ionization mass spectrometer (CIMS) and high m/z ion fragments from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Combination of these techniques reveals that particle-phase chemistry leading to peroxyhemiacetal formation is the likely mechanism by which these species are incorporated in the particle phase. The current findings are relevant toward understanding atmospheric SOA formation and aging from the \"unresolved complex mixture,\" comprising, in part, long-chain alkanes.", "doi": "10.1021/jp211531h", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2012-06-21", "series_number": "24", "volume": "116", "issue": "24", "pages": "6211-6230" }, { "id": "authors:k93qg-s8m80", "collection": "authors", "collection_id": "k93qg-s8m80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120619-093050732", "type": "article", "title": "Diffusion-Limited Versus Quasi-Equilibrium Aerosol Growth", "author": [ { "family_name": "Zhang", "given_name": "Xi", "clpid": "Zhang-Xi" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-S-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Condensation of gas-phase material onto particulate matter\nis the predominant route by which atmospheric aerosols evolve. The traditional approach to representing formation of secondary organic aerosols (SOAs) is to assume instantaneous partitioning equilibrium of semivolatile organic compounds between gas and particle phases. Growth occurs as the vapor concentration of the species increases owing to gas-phase chemistry. The fundamental mathematical basis of such a condensation growth mechanism (quasi-equilibrium growth) has been lacking. Analytical solutions\nfor the evolution of an organic aerosol size distribution undergoing quasi-equilibrium growth and irreversible diffusion-limited growth are obtained for open and closed systems. The quasi-equilibrium growth emerges as a limiting case for semivolatile species condensation when the rate of change of the ambient vapor concentration is slow compared with the rate of establishment of local gas-aerosol equilibrium. The results suggest that the growth mechanism in a particular situation might be inferred from the\ncharacteristics of the evolving size distribution. In certain conditions, a bimodal size distribution can occur during the condensation of a single species on an initially unimodal distribution.", "doi": "10.1080/02786826.2012.679344", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2012-06-13", "series_number": "8", "volume": "46", "issue": "8", "pages": "874-885" }, { "id": "authors:gps63-e3c37", "collection": "authors", "collection_id": "gps63-e3c37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120801-095327779", "type": "article", "title": "Characterisation and airborne deployment of a new counterflow virtual impactor inlet", "author": [ { "family_name": "Shingler", "given_name": "T.", "clpid": "Shingler-T" }, { "family_name": "Dey", "given_name": "S.", "clpid": "Dey-S-K" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Brechtel", "given_name": "F. J.", "clpid": "Brechtel-F-J" }, { "family_name": "Wang", "given_name": "Z.", "orcid": "0000-0002-7921-3134", "clpid": "Wang-Zhen" }, { "family_name": "Metcalf", "given_name": "A.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" }, { "family_name": "Coggon", "given_name": "M.", "orcid": "0000-0002-5763-1925", "clpid": "Coggon-M-M" }, { "family_name": "M\u00fclmenst\u00e4dt", "given_name": "J.", "orcid": "0000-0003-1105-6678", "clpid": "M\u00fclmenst\u00e4dt-J" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new counterflow virtual impactor (CVI) inlet is introduced with details of its design, laboratory characterisation tests and deployment on an aircraft during the 2011 Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE). The CVI inlet addresses three key issues in previous designs; in particular, the inlet operates with: (i) negligible organic contamination; (ii) a significant sample flow rate to downstream instruments (\u223c15 l min^(\u22121)) that reduces the need for dilution; and (iii) a high level of accessibility to the probe interior for cleaning. Wind tunnel experiments characterised the cut size of sampled droplets and the particle size-dependent transmission efficiency in various parts of the probe. For a range of counter-flow rates and air velocities, the measured cut size was between 8.7\u201313.1 \u03bcm. The mean percentage error between cut size measurements and predictions from aerodynamic drag theory is 1.7%. The CVI was deployed on the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter for thirty flights during E-PEACE to study aerosol-cloud-radiation interactions off the central coast of California in July and August 2011. Results are reported to assess the performance of the inlet including comparisons of particle number concentration downstream of the CVI and cloud drop number concentration measured by two independent aircraft probes. Measurements downstream of the CVI are also examined from one representative case flight coordinated with shipboard-emitted smoke that was intercepted in cloud by the Twin Otter.", "doi": "10.5194/amt-5-1259-2012", "issn": "1867-1381", "publisher": "European Geosciences Union", "publication": "Atmospheric Measurement Techniques", "publication_date": "2012-06-06", "series_number": "6", "volume": "5", "issue": "6", "pages": "1259-1269" }, { "id": "authors:dsee5-0ae62", "collection": "authors", "collection_id": "dsee5-0ae62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120529-102426650", "type": "article", "title": "Importance of composition and hygroscopicity of BC particles to the effect of BC mitigation on cloud properties: Application to California conditions", "author": [ { "family_name": "Bahadur", "given_name": "Ranjit", "clpid": "Bahadur-Ranjit" }, { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Jacobson", "given_name": "Mark Z.", "orcid": "0000-0002-4315-4128", "clpid": "Jacobson-Mark-Z" }, { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Adams", "given_name": "Peter", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Black carbon (BC) has many effects on climate including the direct effect on atmospheric absorption, indirect and semi-direct effects on clouds, snow effects, and others. While most of these are positive (warming), the first indirect effect is negative and quantifying its magnitude in addition to other BC feedbacks is important for supporting policies that mitigate BC. We use the detailed aerosol chemistry parcel model of Russell and Seinfeld (1998), observationally constrained by initial measured aerosol concentrations from five California sites, to provide simulated cloud drop number (CDN) concentrations against which two GCM calculations \u2013 one run at the global scale and one nested from the global-to-regional scale are compared. The GCM results reflect the combined effects of their emission inventories, advection schemes, and cloud parameterizations. BC-type particles contributed between 16 and 20% of cloud droplets at all sites even in the presence of more hygroscopic particles. While this chemically detailed parcel model result is based on simplified cloud dynamics and does not consider semi-direct or cloud absorption effects, the cloud drop number concentrations are similar to the simulations of both Chen et al. (2010b) and Jacobson (2010) for the average cloud conditions in California. Reducing BC particle concentration by 50% decreased the cloud droplet concentration by between 6% and 9% resulting in the formation of fewer, larger cloud droplets that correspond to a lower cloud albedo. This trend is similar to Chen et al. (2010b) and Jacobson (2010) when BC particles were modeled as hygroscopic. This reduction in CDN in California due to the decrease in activated BC particles supports the concern raised by Chen et al. (2010a) that the cloud albedo effect of BC particles has a cooling effect that partially offsets the direct forcing reduction if other warming effects of BC on clouds are unchanged. These results suggests that for regions like the California sites studied here, where BC mitigation targets fossil fuel sources, a critical aspect of the modeled reduction is the chemical composition and associated hygroscopicity of the BC particles removed as well as their relative contribution to the atmospheric particle concentrations.", "doi": "10.1029/2011JD017265", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2012-05-05", "series_number": "D9", "volume": "117", "issue": "D9", "pages": "Art. No. D09204" }, { "id": "authors:xb41s-3eg26", "collection": "authors", "collection_id": "xb41s-3eg26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120711-101634723", "type": "article", "title": "Modeling the gas-particle partitioning of secondary organic aerosol: the importance of liquid-liquid phase separation", "author": [ { "family_name": "Zuend", "given_name": "A.", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The partitioning of semivolatile organic compounds between the gas phase and aerosol particles is an important source of secondary organic aerosol (SOA). Gas-particle partitioning of organic and inorganic species is influenced by the physical state and water content of aerosols, and therefore ambient relative humidity (RH), as well as temperature and organic loading levels. We introduce a novel combination of the thermodynamic models AIOMFAC (for liquid mixture non-ideality) and EVAPORATION (for pure compound vapor pressures) with oxidation product information from the Master Chemical Mechanism (MCM) for the computation of gas-particle partitioning of organic compounds and water. The presence and impact of a liquid-liquid phase separation in the condensed phase is calculated as a function of variations in relative humidity, organic loading levels, and associated changes in aerosol composition. We show that a complex system of water, ammonium sulfate, and SOA from the ozonolysis of \u03b1-pinene exhibits liquid-liquid phase separation over a wide range of relative humidities (simulated from 30% to 99% RH). Since fully coupled phase separation and gas-particle partitioning calculations are computationally expensive, several simplified model approaches are tested with regard to computational costs and accuracy of predictions compared to the benchmark calculation. It is shown that forcing a liquid one-phase aerosol with or without consideration of non-ideal mixing bears the potential for vastly incorrect partitioning predictions. Assuming an ideal mixture leads to substantial overestimation of the particulate organic mass, by more than 100% at RH values of 80% and by more than 200% at RH values of 95%. Moreover, the simplified one-phase cases stress two key points for accurate gas-particle partitioning calculations: (1) non-ideality in the condensed phase needs to be considered and (2) liquid-liquid phase separation is a consequence of considerable deviations from ideal mixing in solutions containing inorganic ions and organics that cannot be ignored. Computationally much more efficient calculations relying on the assumption of a complete organic/electrolyte phase separation below a certain RH successfully reproduce gas-particle partitioning in systems in which the average oxygen-to-carbon (O:C) ratio is lower than ~0.6, as in the case of \u03b1-pinene SOA, and bear the potential for implementation in atmospheric chemical transport models and chemistry-climate models. A full equilibrium calculation is the method of choice for accurate offline (box model) computations, where high computational costs are acceptable. Such a calculation enables the most detailed predictions of phase compositions and provides necessary information on whether assuming a complete organic/electrolyte phase separation is a good approximation for a given aerosol system. Based on the group-contribution concept of AIOMFAC and O:C ratios as a proxy for polarity and hygroscopicity of organic mixtures, the results from the \u03b1-pinene system are also discussed from a more general point of view.", "doi": "10.5194/acp-12-3857-2012", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-05-03", "series_number": "9", "volume": "12", "issue": "9", "pages": "3857-3882" }, { "id": "authors:a4n5b-ara06", "collection": "authors", "collection_id": "a4n5b-ara06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120522-091301712", "type": "article", "title": "Black carbon aerosol over the Los Angeles Basin during CalNex", "author": [ { "family_name": "Metcalf", "given_name": "A. R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Ensberg", "given_name": "J. J.", "clpid": "Ensberg-J-J" }, { "family_name": "Brioude", "given_name": "J.", "clpid": "Brioude-J" }, { "family_name": "Angevine", "given_name": "W.", "clpid": "Angevine-W" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Duong", "given_name": "H. T.", "clpid": "Duong-Hanh-T" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Refractory black carbon (rBC) mass and number concentrations were quantified by a Single Particle Soot Photometer (SP2) in the CalNex 2010 field study on board the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter in the Los Angeles (LA) Basin in May, 2010. The mass concentrations of rBC in the LA Basin ranged from 0.002\u20130.530 \u03bcg m^(\u22123), with an average of 0.172 \u03bcg m^(\u22123). Lower concentrations were measured in the Basin outflow regions and above the inversion layer. The SP2 afforded a quantification of the mixing state of rBC aerosols through modeling the scattering cross-section with a core-and-shell Mie model to determine coating thickness. The rBC particles above the inversion layer were more thickly coated by a light-scattering substance than those below, indicating a more aged aerosol in the free troposphere. Near the surface, as the LA plume is advected from west to east with the sea breeze, a coating of scattering material grows on rBC particles, coincident with a clear growth of ammonium nitrate within the LA Basin and the persistence of water-soluble organic compounds as the plume travels through the outflow regions. Detailed analysis of the rBC mixing state reveals two modes of coated rBC particles; a mode with smaller rBC core diameters (\u223c90 nm) but thick (>200 nm) coating diameters and a mode with larger rBC cores (\u223c145 nm) with a thin (<75 nm) coating. The \"weekend effect\" in the LA Basin results in more thickly coated rBC particles, coinciding with more secondary formation of aerosol.", "doi": "10.1029/2011JD017255", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2012-04-20", "volume": "117", "pages": "D00V13" }, { "id": "authors:as8td-zk604", "collection": "authors", "collection_id": "as8td-zk604", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200529-093434201", "type": "article", "title": "Climatic effects of 1950-2050 changes in US anthropogenic aerosols - Part 1: Aerosol trends and radiative forcing", "author": [ { "family_name": "Leibensperger", "given_name": "E. M.", "orcid": "0000-0002-1906-2688", "clpid": "Leibensperger-Eric-M" }, { "family_name": "Mickley", "given_name": "L. J.", "orcid": "0000-0002-7859-3470", "clpid": "Mickley-Loretta-J" }, { "family_name": "Jacob", "given_name": "D. J.", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-Daniel-J" }, { "family_name": "Chen", "given_name": "W.-T.", "orcid": "0000-0002-9292-0933", "clpid": "Chen-Wei-Ting" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Adams", "given_name": "P. J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Streets", "given_name": "D. G.", "orcid": "0000-0002-0223-1350", "clpid": "Streets-David-G" }, { "family_name": "Kumar", "given_name": "N.", "clpid": "Kumar-N" }, { "family_name": "Rind", "given_name": "D.", "orcid": "0000-0002-7945-7622", "clpid": "Rind-David" } ], "abstract": "We calculate decadal aerosol direct and indirect (warm cloud) radiative forcings from US anthropogenic sources over the 1950\u20132050 period. Past and future aerosol distributions are constructed using GEOS-Chem and historical emission inventories and future projections from the IPCC A1B scenario. Aerosol simulations are evaluated with observed spatial distributions and 1980\u20132010 trends of aerosol concentrations and wet deposition in the contiguous US. Direct and indirect radiative forcing is calculated using the GISS general circulation model and monthly mean aerosol distributions from GEOS-Chem. The radiative forcing from US anthropogenic aerosols is strongly localized over the eastern US. We find that its magnitude peaked in 1970\u20131990, with values over the eastern US (east of 100\u00b0 W) of \u22122.0 W m\u207b\u00b2 for direct forcing including contributions from sulfate (\u22122.0 W m\u207b\u00b2), nitrate (\u22120.2 W m\u207b\u00b2), organic carbon (\u22120.2 W m\u207b\u00b2), and black carbon (+0.4 W m\u207b\u00b2). The uncertainties in radiative forcing due to aerosol radiative properties are estimated to be about 50%. The aerosol indirect effect is estimated to be of comparable magnitude to the direct forcing. We find that the magnitude of the forcing declined sharply from 1990 to 2010 (by 0.8 W m\u207b\u00b2 direct and 1.0 W m\u207b\u00b2 indirect), mainly reflecting decreases in SO\u2082 emissions, and project that it will continue declining post-2010 but at a much slower rate since US SO2 emissions have already declined by almost 60% from their peak. This suggests that much of the warming effect of reducing US anthropogenic aerosol sources has already been realized. The small positive radiative forcing from US BC emissions (+0.3 W m\u207b\u00b2 over the eastern US in 2010; 5% of the global forcing from anthropogenic BC emissions worldwide) suggests that a US emission control strategy focused on BC would have only limited climate benefit.", "doi": "10.5194/acp-12-3333-2012", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-04-10", "series_number": "7", "volume": "12", "issue": "7", "pages": "3333-3348" }, { "id": "authors:8hh91-4fp11", "collection": "authors", "collection_id": "8hh91-4fp11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200529-093434944", "type": "article", "title": "Climatic effects of 1950-2050 changes in US anthropogenic aerosols - Part 2: Climate response", "author": [ { "family_name": "Leibensperger", "given_name": "E. M.", "orcid": "0000-0002-1906-2688", "clpid": "Leibensperger-Eric-M" }, { "family_name": "Mickley", "given_name": "L. J.", "orcid": "0000-0002-7859-3470", "clpid": "Mickley-Loretta-J" }, { "family_name": "Jacob", "given_name": "D. J.", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-Daniel-J" }, { "family_name": "Chen", "given_name": "W.-T.", "orcid": "0000-0002-9292-0933", "clpid": "Chen-Wei-Ting" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Adams", "given_name": "P. J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Streets", "given_name": "D. G.", "orcid": "0000-0002-0223-1350", "clpid": "Streets-David-G" }, { "family_name": "Kumar", "given_name": "N.", "clpid": "Kumar-N" }, { "family_name": "Rind", "given_name": "D.", "orcid": "0000-0002-7945-7622", "clpid": "Rind-David" } ], "abstract": "We investigate the climate response to changing US anthropogenic aerosol sources over the 1950\u20132050 period by using the NASA GISS general circulation model (GCM) and comparing to observed US temperature trends. Time-dependent aerosol distributions are generated from the GEOS-Chem chemical transport model applied to historical emission inventories and future projections. Radiative forcing from US anthropogenic aerosols peaked in 1970\u20131990 and has strongly declined since due to air quality regulations. We find that the regional radiative forcing from US anthropogenic aerosols elicits a strong regional climate response, cooling the central and eastern US by 0.5\u20131.0 \u00b0C on average during 1970\u20131990, with the strongest effects on maximum daytime temperatures in summer and autumn. Aerosol cooling reflects comparable contributions from direct and indirect (cloud-mediated) radiative effects. Absorbing aerosol (mainly black carbon) has negligible warming effect. Aerosol cooling reduces surface evaporation and thus decreases precipitation along the US east coast, but also increases the southerly flow of moisture from the Gulf of Mexico resulting in increased cloud cover and precipitation in the central US. Observations over the eastern US show a lack of warming in 1960\u20131980 followed by very rapid warming since, which we reproduce in the GCM and attribute to trends in US anthropogenic aerosol sources. Present US aerosol concentrations are sufficiently low that future air quality improvements are projected to cause little further warming in the US (0.1 \u00b0C over 2010\u20132050). We find that most of the warming from aerosol source controls in the US has already been realized over the 1980\u20132010 period.", "doi": "10.5194/acp-12-3349-2012", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-04-10", "series_number": "7", "volume": "12", "issue": "7", "pages": "3349-3362" }, { "id": "authors:pggg1-cb661", "collection": "authors", "collection_id": "pggg1-cb661", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120511-112639412", "type": "article", "title": "Winter ozone formation and VOC incremental reactivities in the Upper Green River Basin of Wyoming", "author": [ { "family_name": "Carter", "given_name": "William P. L.", "clpid": "Carter-W-P-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The Upper Green River Basin (UGRB) in Wyoming experiences ozone episodes in the winter when the air is relatively stagnant and the ground is covered by snow. A modeling study was carried out to assess relative contributions of oxides of nitrogen (NO_x) and individual volatile organic compounds (VOCs), and nitrous acid (HONO) in winter ozone formation episodes in this region. The conditions of two ozone episodes, one in February 2008 and one in March 2011, were represented using a simplified box model with all pollutants present initially, but with the detailed SAPRC-07 chemical mechanism adapted for the temperature and radiation conditions arising from the high surface albedo of the snow that was present. Sensitivity calculations were conducted to assess effects of varying HONO inputs, ambient VOC speciation, and changing treatments of temperature and lighting conditions. The locations modeled were found to be quite different in VOC speciation and sensitivities to VOC and NO_x emissions, with one site modeled for the 2008 episode being highly NO_x-sensitive and insensitive to VOCs and HONO, and the other 2008 site and both 2011 sites being very sensitive to changes in VOC and HONO inputs. Incremental reactivity scales calculated for VOC-sensitive conditions in the UGRB predict far lower relative contributions of alkanes to ozone formation than in the traditional urban-based MIR scale and that the major contributors to ozone formation were the alkenes and the aromatics, despite their relatively small mass contributions. The reactivity scales are affected by the variable ambient VOC speciation and uncertainties in ambient HONO levels. These box model calculations are useful for indicating general sensitivities and reactivity characteristics of these winter UGRB episodes, but fully three-dimensional models will be required to assess ozone abatement strategies in the UGRB.", "doi": "10.1016/j.atmosenv.2011.12.025", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2012-04", "volume": "50", "pages": "255-266" }, { "id": "authors:wg4jv-14n84", "collection": "authors", "collection_id": "wg4jv-14n84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120416-154924442", "type": "article", "title": "Chemical Engineering: An Introduction By M. M. Denn", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A staple of the undergraduate chemical engineering\ncurriculum is the introductory course,\nusually taught in the first term of the sophomore\nyear, and often referred to as ''mass and\nenergy balances'', ''chemical process principles'',\nor just ''introduction to chemical engineering.''\nOver the years, a number of textbooks\nhave been available for this course; at\npresent, the most widely used text is Felder and\nRousseau, Elementary Principles of Chemical\nProcesses. Another noteworthy text is Murphy,\nIntroduction to Chemical Processes. The basic\nelements of most courses include fundamentals\nof material balances, including process flow\nsheets, single and multiphase systems, energy\nbalances on closed and open systems, and balances\non nonreactive and reactive processes.\nDetails of the chemical reactor and of particular\nseparation processes await the traditional subsequent\ncourses. The nature of the introductory\ncourse depends in many respects on the extent\nto which it bears a portion of the thermodynamics\ninstruction. Felder and Rousseau covers a\ngood deal of thermodynamics, and, therefore,\nfits well with a subsequent one-term thermodynamics\ncourse.", "doi": "10.1002/aic.13761", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "2012-04", "series_number": "4", "volume": "58", "issue": "4", "pages": "1308-1308" }, { "id": "authors:8fx0j-tz983", "collection": "authors", "collection_id": "8fx0j-tz983", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120316-135220544", "type": "article", "title": "Evolution of trace gases and particles emitted by\n a chaparral fire in California", "author": [ { "family_name": "Akagi", "given_name": "S. K.", "clpid": "Akagi-S-K" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Taylor", "given_name": "J. W.", "clpid": "Taylor-J-W" }, { "family_name": "McMeeking", "given_name": "G. R.", "clpid": "McMeeking-G-R" }, { "family_name": "Yokelson", "given_name": "R. J.", "orcid": "0000-0002-8415-6808", "clpid": "Yokelson-R-J" }, { "family_name": "Burling", "given_name": "I. R.", "clpid": "Burling-I-R" }, { "family_name": "Urbanski", "given_name": "S. P.", "clpid": "Urbanski-S-P" }, { "family_name": "Wold", "given_name": "C. E.", "clpid": "Wold-C-E" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Coe", "given_name": "H.", "clpid": "Coe-H" }, { "family_name": "Alvarado", "given_name": "M. J.", "clpid": "Alvarado-M-J" }, { "family_name": "Weise", "given_name": "D. R.", "clpid": "Weise-D-R" } ], "abstract": "Biomass burning (BB) is a major global source of trace gases and particles. Accurately representing the production and evolution of these emissions is an important goal for atmospheric chemical transport models. We measured a suite of gases and aerosols emitted from an 81 hectare prescribed fire in chaparral fuels on the central coast of California, US on 17 November 2009. We also measured physical and chemical changes that occurred in the isolated downwind plume in the first ~4 h after emission. The measurements were carried out onboard a Twin Otter aircraft outfitted with an airborne Fourier transform infrared spectrometer (AFTIR), aerosol mass spectrometer (AMS), single particle soot photometer (SP2), nephelometer, LiCor CO_2 analyzer, a chemiluminescence ozone instrument, and a wing-mounted meteorological probe. Our measurements included: CO_2; CO; NO_x; NH_3; non-methane organic compounds; organic aerosol (OA); inorganic aerosol (nitrate, ammonium, sulfate, and chloride); aerosol light scattering; refractory black carbon (rBC); and ambient temperature, relative humidity, barometric pressure, and three-dimensional wind velocity. The molar ratio of excess O_3 to excess CO in the plume (\u0394O_3/\u0394CO) increased from \u22125.13 (\u00b11.13) \u00d7 10^(\u22123) to 10.2 (\u00b12.16) \u00d7 10^(\u22122) in ~4.5 h following smoke emission. Excess acetic and formic acid (normalized to excess CO) increased by factors of 1.73 \u00b1 0.43 and 7.34 \u00b1 3.03 (respectively) over the same time since emission. Based on the rapid decay of C_2H_4 we infer an in-plume average OH concentration of 5.27 (\u00b10.97) \u00d7 10^6 molec cm^(\u22123), consistent with previous studies showing elevated OH concentrations in biomass burning plumes. Ammonium, nitrate, and sulfate all increased over the course of 4 h. The observed ammonium increase was a factor of 3.90 \u00b1 2.93 in about 4 h, but accounted for just ~36% of the gaseous ammonia lost on a molar basis. Some of the gas phase NH_3 loss may have been due to condensation on, or formation of, particles below the AMS detection range. NO_x was converted to PAN and particle nitrate with PAN production being about two times greater than production of observable nitrate in the first ~4 h following emission. The excess aerosol light scattering in the plume (normalized to excess CO_2) increased by a factor of 2.50 \u00b1 0.74 over 4 h. The increase in light scattering was similar to that observed in an earlier study of a biomass burning plume in Mexico where significant secondary formation of OA closely tracked the increase in scattering. In the California plume, however, \u0394OA/\u0394CO_2 decreased sharply for the first hour and then increased slowly with a net decrease of ~20% over 4 h. The fraction of thickly coated rBC particles increased up to ~85% over the 4 h aging period. Decreasing OA accompanied by increased scattering/particle coating in initial aging may be due to a combination of particle coagulation and evaporation processes. Recondensation of species initially evaporated from the particles may have contributed to the subsequent slow rise in OA. We compare our results to observations from other plume aging studies and suggest that differences in environmental factors such as smoke concentration, oxidant concentration, actinic flux, and RH contribute significantly to the variation in plume evolution observations.", "doi": "10.5194/acp-12-1397-2012", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-02", "series_number": "3", "volume": "12", "issue": "3", "pages": "1397-1421" }, { "id": "authors:fwckn-zps12", "collection": "authors", "collection_id": "fwckn-zps12", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120305-121637814", "type": "article", "title": "Chemical aging of m-xylene secondary organic aerosol: laboratory chamber study", "author": [ { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-Christine-L" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Yee", "given_name": "L. D.", "orcid": "0000-0001-8965-9319", "clpid": "Yee-Lindsay-D" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-Jill-S" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) can reside in the atmosphere for a week or more. While its initial formation from the gas-phase oxidation of volatile organic compounds tends to take place in the first few hours after emission, SOA can continue to evolve chemically over its atmospheric lifetime. Simulating this chemical aging over an extended time in the laboratory has proven to be challenging. We present here a procedure for studying SOA aging in laboratory chambers that is applied to achieve 36 h of oxidation. The formation and evolution of SOA from the photooxidation of m-xylene under low-NO\u2093 conditions and in the presence of either neutral or acidic seed particles is studied. In SOA aging, increasing molecular functionalization leads to less volatile products and an increase in SOA mass, whereas gas- or particle-phase fragmentation chemistry results in more volatile products and a loss of SOA. The challenge is to discern from measured chamber variables the extent to which these processes are important for a given SOA system. In the experiments conducted, m-xylene SOA mass, calculated under the assumption of size-invariant particle composition, increased over the initial 12\u201313 h of photooxidation and decreased beyond that time, suggesting the existence of fragmentation chemistry. The oxidation of the SOA, as manifested in the O:C elemental ratio and fraction of organic ion detected at m/z 44 measured by the Aerodyne aerosol mass spectrometer, increased continuously starting after 5 h of irradiation until the 36 h termination. This behavior is consistent with an initial period in which, as the mass of SOA increases, products of higher volatility partition to the aerosol phase, followed by an aging period in which gas- and particle-phase reaction products become increasingly more oxidized. When irradiation is stopped 12.4 h into one experiment, and OH generation ceases, minimal loss of SOA is observed, indicating that the loss of SOA is either light- or OH-induced. Chemical ionization mass spectrometry measurements of low-volatility m-xylene oxidation products exhibit behavior indicative of continuous photooxidation chemistry. A condensed chemical mechanism of m-xylene oxidation under low-NO\u2093 conditions is capable of reproducing the general behavior of gas-phase evolution observed here. Moreover, order of magnitude analysis of the mechanism suggests that gas-phase OH reaction of low volatility SOA precursors is the dominant pathway of aging in the m-xylene system although OH reaction with particle surfaces cannot be ruled out. Finally, the effect of size-dependent particle composition and size-dependent particle wall loss rates on different particle wall loss correction methods is discussed.", "doi": "10.5194/acp-12-151-2012", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2012-01-03", "series_number": "1", "volume": "12", "issue": "1", "pages": "151-167" }, { "id": "authors:hd94p-s4z89", "collection": "authors", "collection_id": "hd94p-s4z89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120328-111000629", "type": "article", "title": "Flight-based chemical characterization of biomass burning aerosols within two prescribed burn smoke plumes", "author": [ { "family_name": "Pratt", "given_name": "K. A.", "orcid": "0000-0003-4707-2290", "clpid": "Pratt-Kerri-A" }, { "family_name": "Murphy", "given_name": "S. M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Subramanian", "given_name": "R.", "clpid": "Subramanian-R" }, { "family_name": "DeMott", "given_name": "P. J.", "orcid": "0000-0002-3719-1889", "clpid": "DeMott-Paul-J" }, { "family_name": "Kok", "given_name": "G. L.", "clpid": "Kok-Gregory-L" }, { "family_name": "Campos", "given_name": "T.", "clpid": "Campos-T" }, { "family_name": "Rogers", "given_name": "D. C.", "clpid": "Rogers-D-C" }, { "family_name": "Prenni", "given_name": "A. J.", "orcid": "0000-0002-0256-5166", "clpid": "Prenni-Anthony-J" }, { "family_name": "Heymsfield", "given_name": "J.", "orcid": "0000-0003-4107-7533", "clpid": "Heymsfield-Andrew-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Prather", "given_name": "K. A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" } ], "abstract": "Biomass burning represents a major global source of aerosols impacting direct radiative forcing and cloud properties. Thus, the goal of a number of current studies involves developing a better understanding of how the chemical composition and mixing state of biomass burning aerosols evolve during atmospheric aging processes. During the Ice in Clouds Experiment-Layer Clouds (ICE-L) in the fall of 2007, smoke plumes from two small Wyoming Bureau of Land Management prescribed burns were measured by on-line aerosol instrumentation aboard a C-130 aircraft, providing a detailed chemical characterization of the particles. After ~2\u20134 min of aging, submicron smoke particles, produced primarily from sagebrush combustion, consisted predominantly of organics by mass, but were comprised primarily of internal mixtures of organic carbon, elemental carbon, potassium chloride, and potassium sulfate. Significantly, the fresh biomass burning particles contained minor mass fractions of nitrate and sulfate, suggesting that hygroscopic material is incorporated very near or at the point of emission. The mass fractions of ammonium, sulfate, and nitrate increased with aging up to ~81\u201388 min and resulted in acidic particles. Decreasing black carbon mass concentrations occurred due to dilution of the plume. Increases in the fraction of oxygenated organic carbon and the presence of dicarboxylic acids, in particular, were observed with aging. Cloud condensation nuclei measurements suggested all particles >100 nm were active at 0.5% water supersaturation in the smoke plumes, confirming the relatively high hygroscopicity of the freshly emitted particles. For immersion/condensation freezing, ice nuclei measurements at \u221232 \u00b0C suggested activation of ~0.03\u20130.07% of the particles with diameters greater than 500 nm.", "doi": "10.5194/acp-11-12549-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-12-15", "series_number": "24", "volume": "11", "issue": "24", "pages": "12549-12565" }, { "id": "authors:p91bb-aay90", "collection": "authors", "collection_id": "p91bb-aay90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120120-101247927", "type": "article", "title": "A continuous spectral aerosol-droplet microphysics model", "author": [ { "family_name": "Lebo", "given_name": "Z. J.", "orcid": "0000-0002-1064-4833", "clpid": "Lebo-Z-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A two-dimensional (2-D) continuous spectral aerosol-droplet microphysics model is presented and implemented into the Weather Research and Forecasting (WRF) model for large-eddy simulations (LES) of warm clouds. Activation and regeneration of aerosols are treated explicitly in the calculation of condensation/evaporation. The model includes a 2-D spectrum that encompasses wet aerosol particles (i.e., haze droplets), cloud droplets, and drizzle droplets in a continuous and consistent manner and allows for the explicit tracking of aerosol size within cloud droplets due to collision-coalescence. The system of differential equations describing condensation/evaporation (i.e., mass conservation and energy conservation) is solved simultaneously within each grid cell. The model is demonstrated by simulating a marine stratocumulus deck for two different aerosol loadings (100 and 500 cm^(\u22123)), and comparison with the more traditional microphysics modeling approaches (both 1-D bin and bulk schemes) is evaluated. The simulations suggest that in a 1-D bin microphysics scheme, without regeneration, too few particles are produced and hence the mode of the droplet size spectrum occurs at a larger size relative to the 2-D bin model results. Moreover, with regeneration, the 1-D scheme produces too many small droplets and thus shifts the mode toward smaller sizes. These large shifts in the droplet size distribution can potentially have significant effects on the efficiency of the collision-coalescence process, fall speeds, and ultimately precipitation.", "doi": "10.5194/acp-11-12297-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-12-08", "series_number": "23", "volume": "11", "issue": "23", "pages": "12297-12316" }, { "id": "authors:sznp4-zmg25", "collection": "authors", "collection_id": "sznp4-zmg25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111221-114535592", "type": "article", "title": "Insights on global warming", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The global temperature increase over the last century and a half (\u223c 0.8\u00b0C), and the last three decades in particular, is well outside of that which can be attributed to natural climate fluctuations. The increase of atmospheric CO_2 over this period has been conclusively demonstrated to be a result largely of fossil fuel burning. The global mean temperature change that results in response to a sustained perturbation of the Earth's energy balance after a time sufficiently long for both the atmosphere and oceans to come to thermal equilibrium is termed the Earth's climate sensitivity. The purely radiative (blackbody) warming from a doubling of CO_2 from its preindustrial level of 280 parts-per-million (ppm) to 560 ppm is \u223c 1.2\u00b0C; the actual warming that would result is considerably larger owing to amplification by climate feedbacks, including that owing to water vapor. Increases in greenhouse gas (GHG) levels are estimated to have contributed about +3.0 W m^(\u22122) perturbation (radiative forcing) to the Earth's energy balance. Particles (aerosols), on the whole, exert a cooling effect on climate, with a total forcing estimated by the Intergovernmental Panel on Climate Change (2007)1 as \u22121.2 W m^(\u22122), a value that is subject to considerable uncertainty. If the actual magnitude of aerosol forcing is close to the low end of its estimated uncertainty range, then it offsets a considerably smaller fraction of the GHG forcing and the total net forcing is at the high end of its range, \u223c 2.4 W m^(\u22122); at the other extreme, if the actual aerosol cooling is at the high end of its range, then aerosol forcing is currently offsetting a major fraction of GHG forcing, and the total net forcing is only \u223c 0.6 W m^(\u22122). To explain the actual global increase in temperature of \u223c 0.8\u00b0C, these two extremes have major implications in terms of the Earth's climate sensitivity. Climate sensitivity is determined by the strength of feedbacks, of which cloud feedback is the most uncertain. That the Earth has warmed and that GHGs are responsible is unequivocal; the Earth's climate sensitivity and the effect of aerosols complicate answers to the question: how much warming and how soon?", "doi": "10.1002/aic.12780", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "2011-12", "series_number": "12", "volume": "57", "issue": "12", "pages": "3259-3284" }, { "id": "authors:79thq-4nf52", "collection": "authors", "collection_id": "79thq-4nf52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111219-141325461", "type": "article", "title": "Water-soluble organic aerosol in the Los Angeles Basin and outflow regions: Airborne and ground measurements during the 2010 CalNex field campaign", "author": [ { "family_name": "Duong", "given_name": "Hanh T.", "clpid": "Duong-Hanh-T" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Craven", "given_name": "Jill S.", "clpid": "Craven-J-S" }, { "family_name": "Hersey", "given_name": "Scott P.", "clpid": "Hersey-S-P" }, { "family_name": "Metcalf", "given_name": "Andrew R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" }, { "family_name": "Zhang", "given_name": "Xiaolu", "clpid": "Zhang-Xiaolu" }, { "family_name": "Weber", "given_name": "Rodney J.", "clpid": "Weber-R-J" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A particle-into-liquid sampler coupled to a total organic carbon analyzer (PILS-TOC) quantified particulate water-soluble organic carbon (WSOC) mass concentrations during the May 2010 deployment of the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter in the CalNex field study. WSOC data collected during 16 flights provide the first spatiotemporal maps of WSOC in the San Joaquin Valley, Los Angeles Basin, and outflow regions of the Basin. WSOC was consistently higher in concentration within the Los Angeles Basin, where sea breeze transport and Basin topography strongly influence the spatial distribution of WSOC. The highest WSOC levels were associated with fire plumes, highlighting the importance of both primary and secondary sources for WSOC in the region. Residual pollution layers enriched with WSOC are observed aloft up to an altitude of 3.2 km and the highest WSOC levels for each flight were typically observed above 500 m. Simultaneous ground WSOC measurements during aircraft overpasses in Pasadena and Riverside typically exhibit lower levels, especially when relative humidity (RH) was higher aloft suggestive of the influence of aerosol-phase water. This points to the underestimation of the radiative effects of WSOC when using only surface measurements. Reduced aerosol-phase water in the eastern desert outflow region likely promotes the re-partitioning of WSOC to the gas phase and suppression of processes to produce these species (partitioning, multiphase chemistry, photolytic production); as a result, WSOC is reduced relative to sulfate (but not as much as nitrate) as aerosol is advected from the Basin to the outflows.", "doi": "10.1029/2011JD016674", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2011-11-18", "series_number": "D21", "volume": "116", "issue": "D21", "pages": "Art. No. D00V04" }, { "id": "authors:gnz6g-qmf06", "collection": "authors", "collection_id": "gnz6g-qmf06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111220-101336070", "type": "article", "title": "Yields of oxidized volatile organic compounds during the OH\n radical initiated oxidation of isoprene, methyl vinyl ketone, and methacrolein under high-NO_x conditions", "author": [ { "family_name": "Galloway", "given_name": "M. M.", "orcid": "0000-0002-8518-1888", "clpid": "Galloway-Melissa-M" }, { "family_name": "Huisman", "given_name": "A. J.", "clpid": "Huisman-A-J" }, { "family_name": "Yee", "given_name": "L. D.", "orcid": "0000-0001-8965-9319", "clpid": "Yee-Lindsay-D" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-Christine-L" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Keutsch", "given_name": "F. N.", "orcid": "0000-0002-1442-6200", "clpid": "Keutsch-Frank-N" } ], "abstract": "We present first-generation and total production yields of glyoxal, methylglyoxal, glycolaldehyde, and hydroxyacetone from the oxidation of isoprene, methyl vinyl ketone (MVK), and methacrolein (MACR) with OH under high NO_x conditions. Several of these first-generation yields are not included in commonly used chemical mechanisms, such as the Leeds Master Chemical Mechanism (MCM) v. 3.2. The first-generation yield of glyoxal from isoprene was determined to be 2.1 (\u00b10.6)%. Inclusion of first-generation production of glyoxal, glycolaldehyde and hydroxyacetone from isoprene greatly improves performance of an MCM based model during the initial part of the experiments. In order to further improve performance of the MCM based model, higher generation glyoxal production was reduced by lowering the first-generation yield of glyoxal from C5 hydroxycarbonyls. The results suggest that glyoxal production from reaction of OH with isoprene under high NO_x conditions can be approximated by inclusion of a first-generation production term together with secondary production only via glycolaldehyde. Analogously, methylglyoxal production can be approximated by a first-generation production term from isoprene, and secondary production via MVK, MACR and hydroxyacetone. The first-generation yields reported here correspond to less than 5% of the total oxidized yield from isoprene and thus only have a small effect on the fate of isoprene. However, due to the abundance of isoprene, the combination of first-generation yields and reduced higher generation production of glyoxal from C5 hydroxycarbonyls is important for models that include the production of the small organic molecules from isoprene.", "doi": "10.5194/acp-11-10779-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-11-02", "series_number": "21", "volume": "11", "issue": "21", "pages": "10779-10790" }, { "id": "authors:83ngk-7x212", "collection": "authors", "collection_id": "83ngk-7x212", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111128-115220934", "type": "article", "title": "Measurements of Isoprene-Derived Organosulfates in Ambient\n Aerosols by Aerosol Time-of-Flight Mass Spectrometry\u2014Part 2:\n Temporal Variability and Formation Mechanisms", "author": [ { "family_name": "Hatch", "given_name": "Lindsay E.", "orcid": "0000-0001-9037-9760", "clpid": "Hatch-Lindsay-E" }, { "family_name": "Creamean", "given_name": "Jessie M.", "orcid": "0000-0003-3819-5600", "clpid": "Creamean-Jessie-M" }, { "family_name": "Ault", "given_name": "Andrew P.", "orcid": "0000-0002-7313-8559", "clpid": "Ault-Andrew-P" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chan", "given_name": "Man Nin", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Edgerton", "given_name": "Eric S.", "clpid": "Edgerton-Eric-S" }, { "family_name": "Su", "given_name": "Yongxuan", "clpid": "Su-Yongxuan" }, { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" } ], "abstract": "Organosulfate species have recently gained attention for their potentially significant contribution to secondary organic aerosol (SOA); however, their temporal behavior in the ambient atmosphere has not been probed in detail. In this work, organosulfates derived from isoprene were observed in single particle mass spectra in Atlanta, GA during the 2002 Aerosol Nucleation and Characterization Experiment (ANARChE) and the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS). Real-time measurements revealed that the highest organosulfate concentrations occurred at night under a stable boundary layer, suggesting gas-to-particle partitioning and subsequent aqueous-phase processing of the organic precursors played key roles in their formation. Further analysis of the diurnal profile suggests possible contributions from multiple production mechanisms, including acid-catalysis and radical-initiation. This work highlights the potential for additional SOA formation pathways in biogenically influenced urban regions to enhance the organic aerosol burden.", "doi": "10.1021/es2011836", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2011-10-15", "series_number": "20", "volume": "45", "issue": "20", "pages": "8648-8655" }, { "id": "authors:x4rgj-6k728", "collection": "authors", "collection_id": "x4rgj-6k728", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111121-120104741", "type": "article", "title": "Origins and composition of fine atmospheric carbonaceous aerosol in the Sierra Nevada Mountains, California", "author": [ { "family_name": "Worton", "given_name": "D. R.", "orcid": "0000-0002-6558-5586", "clpid": "Worton-David-R" }, { "family_name": "Goldstein", "given_name": "A. H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-Allen-H" }, { "family_name": "Farmer", "given_name": "D. K.", "orcid": "0000-0002-6470-9970", "clpid": "Farmer-Delphine-K" }, { "family_name": "Docherty", "given_name": "K. S.", "clpid": "Docherty-Kenneth-S" }, { "family_name": "Jimenez", "given_name": "J. L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-Jos\u00e9-L" }, { "family_name": "Gilman", "given_name": "J. B.", "clpid": "Gilman-Jessica-B" }, { "family_name": "Kuster", "given_name": "W. C.", "clpid": "Kuster-W-C" }, { "family_name": "de Gouw", "given_name": "J.", "orcid": "0000-0002-0385-1826", "clpid": "de-Gouw-Joost-A" }, { "family_name": "Williams", "given_name": "B. J.", "clpid": "Williams-B-J" }, { "family_name": "Kreisberg", "given_name": "N. M.", "clpid": "Kreisberg-N-M" }, { "family_name": "Hering", "given_name": "S. V.", "orcid": "0000-0001-6536-310X", "clpid": "Hering-Susanne-V" }, { "family_name": "Bench", "given_name": "G.", "clpid": "Bench-G" }, { "family_name": "McKay", "given_name": "M.", "clpid": "McKay-M" }, { "family_name": "Kristensen", "given_name": "K.", "clpid": "Kristensen-K" }, { "family_name": "Glasius", "given_name": "M.", "clpid": "Glasius-M" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In this paper we report chemically resolved measurements \nof organic aerosol (OA) and related tracers during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) at the Blodgett Forest Research Station, California from 15 August\u201310 October 2007. OA contributed the majority of the mass to the fine atmospheric particles and was predominately oxygenated (OOA). The highest concentrations of OA were during sporadic wildfire influence when aged plumes were impacting the site. In \nsitu measurements of particle phase molecular markers were dominated by secondary compounds and along with gas phase compounds could be categorized into six factors or sources: (1) aged biomass burning emissions and oxidized urban emissions, (2) oxidized urban emissions (3) oxidation products of monoterpene emissions, (4) monoterpene emissions, (5) anthropogenic emissions and (6) local \nmethyl chavicol emissions and oxidation products. There were multiple biogenic components that contributed to OA at this site whose contributions varied diurnally, seasonally and in response to changing meteorological conditions, e.g. temperature and precipitation events. Concentrations of isoprene oxidation products were larger when temperatures were higher during the first half of the campaign (15 August\u201312 September) due to more substantial emissions of isoprene and enhanced photochemistry. The oxidation of methyl chavicol, an oxygenated terpene emitted by \nponderosa pine trees, contributed similarly to OA throughout the campaign. In contrast, the abundances of monoterpene oxidation products in the particle phase were greater during the cooler conditions in the latter half of the campaign (13 September\u201310 October), even though emissions of the precursors were lower, although the mechanism is not known. OA was correlated with the anthropogenic tracers 2-propyl nitrate and carbon monoxide (CO), consistent with previous observations, while being comprised of mostly non-fossil carbon (>75%). The correlation between OA and an anthropogenic tracer does not necessarily identify the source of the carbon as being anthropogenic but instead suggests a coupling between the anthropogenic and biogenic components in the air mass that might be related to the source of the oxidant and/or the aerosol sulfate. Observations of organosulfates of isoprene and \u03b1-pinene provided evidence for the likely importance of aerosol sulfate in spite of neutralized aerosol although acidic plumes might have played a role upwind of the site. This is in contrast to laboratory studies where strongly acidic seed aerosols were needed in order to form these compounds. These compounds together represented only a minor fraction (<1%) of the total OA mass, which may be the result of the neutralized aerosol at the site or because only a small number of organosulfates were quantified. The low contribution of organosulfates to total OA suggests that other mechanisms, e.g. NO_x enhancement of oxidant levels, are likely responsible for the majority of the anthropogenic enhancement of biogenic secondary organic aerosol observed at this site.", "doi": "10.5194/acp-11-10219-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-10-12", "series_number": "19", "volume": "11", "issue": "19", "pages": "10219-10241" }, { "id": "authors:v7mwd-y8h76", "collection": "authors", "collection_id": "v7mwd-y8h76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111031-111332320", "type": "article", "title": "A comprehensive numerical study of \n aerosol-cloud-precipitation interactions in marine stratocumulus", "author": [ { "family_name": "Chen", "given_name": "Y.-C.", "orcid": "0000-0001-7997-8578", "clpid": "Chen-Yi-Chun" }, { "family_name": "Xue", "given_name": "L.", "clpid": "Xue-L" }, { "family_name": "Lebo", "given_name": "Z. J.", "orcid": "0000-0002-1064-4833", "clpid": "Lebo-Z-J" }, { "family_name": "Wang", "given_name": "H.", "clpid": "Wang-H" }, { "family_name": "Rasmussen", "given_name": "R. M.", "clpid": "Rasmussen-R-M" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Three-dimensional large-eddy simulations (LES) with detailed bin-resolved microphysics are performed to explore the diurnal variation of marine stratocumulus (MSc) clouds under clean and polluted conditions. The sensitivity of the aerosol-cloud-precipitation interactions to variation of sea surface temperature, free tropospheric humidity, large-scale divergence rate, and wind speed is assessed. The comprehensive set of simulations corroborates previous studies that (1) with moderate/heavy drizzle, an increase in aerosol leads to an increase in cloud thickness; and (2) with non/light drizzle, an increase in aerosol results in a thinner cloud, due to the pronounced effect on entrainment. It is shown that for higher SST, stronger large-scale divergence, drier free troposphere, or lower wind speed, the cloud thins and precipitation decreases. The sign and magnitude of the Twomey effect, droplet dispersion effect, cloud thickness effect, and cloud optical depth susceptibility to aerosol perturbations (i.e., change in cloud optical depth to change in aerosol number concentration) are evaluated by LES experiments and compared with analytical formulations. The Twomey effect emerges as dominant in total cloud optical depth susceptibility to aerosol perturbations. The dispersion effect, that of aerosol perturbations on the cloud droplet size spectrum, is positive (i.e., increase in aerosol leads to spectral narrowing) and accounts for 3% to 10% of the total cloud optical depth susceptibility at nighttime, with greater influence in heavier drizzling clouds. The cloud thickness effect is negative (i.e., increase in aerosol leads to thinner cloud) for non/light drizzling cloud and positive for a moderate/heavy drizzling clouds; the cloud thickness effect contributes 5% to 22% of the nighttime total cloud susceptibility. Overall, the total cloud optical depth susceptibility ranges from ~0.28 to 0.53 at night; an increase in aerosol concentration enhances cloud optical depth, especially with heavier precipitation and in a more pristine environment. During the daytime, the range of magnitude for each effect is more variable owing to cloud thinning and decoupling. The good agreement between LES experiments and analytical formulations suggests that the latter may be useful in evaluations of the total cloud susceptibility. The ratio of the magnitude of the cloud thickness effect to that of the Twomey effect depends on cloud base height and cloud thickness in unperturbed (clean) clouds.", "doi": "10.5194/acp-11-9749-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-09-21", "series_number": "18", "volume": "11", "issue": "18", "pages": "9749-9769" }, { "id": "authors:sypmm-81226", "collection": "authors", "collection_id": "sypmm-81226", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111010-152618974", "type": "article", "title": "New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups", "author": [ { "family_name": "Zuend", "given_name": "A.", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Marcolli", "given_name": "C.", "clpid": "Marcolli-C" }, { "family_name": "Booth", "given_name": "A. M.", "orcid": "0000-0002-7339-0594", "clpid": "Booth-A-M" }, { "family_name": "Lienhard", "given_name": "D. M.", "clpid": "Lienhard-D-M" }, { "family_name": "Soonsin", "given_name": "V.", "clpid": "Soonsin-V" }, { "family_name": "Krieger", "given_name": "U. K.", "clpid": "Krieger-U-K" }, { "family_name": "Topping", "given_name": "D. O.", "clpid": "Topping-D-O" }, { "family_name": "McFiggans", "given_name": "G.", "clpid": "McFiggans-G" }, { "family_name": "Peter", "given_name": "T.", "clpid": "Peter-T" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H^+, Li^+, Na^+, K^+, NH_(4)^+, Mg^(2+), Ca^(2+), Cl^\u2212, Br^\u2212, NO_(3)^\u2212, HSO_(4)^\u2212, and SO_(4)^(2\u2212). Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization algorithms. A number of exemplary calculations for systems containing atmospherically relevant aerosol components are shown. Amongst others, we discuss aqueous mixtures of ammonium sulfate with dicarboxylic acids and with levoglucosan. Overall, the new parameterization of AIOMFAC agrees well with a large number of experimental datasets. However, due to various reasons, for certain mixtures important deviations can occur. The new parameterization makes AIOMFAC a versatile thermodynamic tool. It enables the calculation of activity coefficients of thousands of different organic compounds in organic-inorganic mixtures of numerous components. Models based on AIOMFAC can be used to compute deliquescence relative humidities, liquid-liquid phase separations, and gas-particle partitioning of multicomponent mixtures of relevance for atmospheric chemistry or in other scientific fields.", "doi": "10.5194/acp-11-9155-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-09-07", "series_number": "17", "volume": "11", "issue": "17", "pages": "9155-9206" }, { "id": "authors:93e0t-00034", "collection": "authors", "collection_id": "93e0t-00034", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111012-084703073", "type": "article", "title": "Elemental composition and oxidation of chamber organic aerosol", "author": [ { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Canagaratna", "given_name": "M. R.", "orcid": "0000-0002-8803-4007", "clpid": "Canagaratna-Manjula-R" }, { "family_name": "Corrigan", "given_name": "A. L.", "clpid": "Corrigan-A-L" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Worsnop", "given_name": "D. R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-Douglas-R" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recently, graphical representations of aerosol mass spectrometer (AMS) spectra and elemental composition have been developed to explain the oxidative and aging processes of secondary organic aerosol (SOA). It has been shown previously that oxygenated organic aerosol (OOA) components from ambient and laboratory data fall within a triangular region in the f\u2084\u2084 vs. f\u2084\u2083 space, where f\u2084\u2084 and f\u2084\u2083 are the ratios of the organic signal at m/z 44 and 43 to the total organic signal in AMS spectra, respectively; we refer to this graphical representation as the \"triangle plot.\" Alternatively, the Van Krevelen diagram has been used to describe the evolution of functional groups in SOA. In this study we investigate the variability of SOA formed in chamber experiments from twelve different precursors in both \"triangle plot\" and Van Krevelen domains. Spectral and elemental data from the high-resolution Aerodyne aerosol mass spectrometer are compared to offline species identification analysis and FTIR filter analysis to better understand the changes in functional and elemental composition inherent in SOA formation and aging. We find that SOA formed under high- and low-NO\u2093 conditions occupy similar areas in the \"triangle plot\" and Van Krevelen diagram and that SOA generated from already oxidized precursors allows for the exploration of areas higher on the \"triangle plot\" not easily accessible with non-oxidized precursors. As SOA ages, it migrates toward the top of the triangle along a path largely dependent on the precursor identity, which suggests increasing organic acid content and decreasing mass spectral variability. The most oxidized SOA come from the photooxidation of methoxyphenol precursors which yielded SOA O/C ratios near unity. \u03b1-pinene ozonolysis and naphthalene photooxidation SOA systems have had the highest degree of mass closure in previous chemical characterization studies and also show the best agreement between AMS elemental composition measurements and elemental composition of identified species within the uncertainty of the AMS elemental analysis. In general, compared to their respective unsaturated SOA precursors, the elemental composition of chamber SOA follows a slope shallower than \u22121 on the Van Krevelen diagram, which is indicative of oxidation of the precursor without substantial losss of hydrogen, likely due to the unsaturated nature of the precursors. From the spectra of SOA studied here, we are able to reproduce the triangular region originally constructed with ambient OOA compents with chamber aerosol showing that SOA becomes more chemically similar as it ages. Ambient data in the middle of the triangle represent the ensemble average of many different SOA precursors, ages, and oxidative processes.", "doi": "10.5194/acp-11-8827-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-09", "series_number": "17", "volume": "11", "issue": "17", "pages": "8827-8845" }, { "id": "authors:dn1x8-4at73", "collection": "authors", "collection_id": "dn1x8-4at73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111014-122742881", "type": "article", "title": "Analysis of photochemical and dark glyoxal uptake: Implications for SOA formation", "author": [ { "family_name": "Galloway", "given_name": "M. M.", "orcid": "0000-0002-8518-1888", "clpid": "Galloway-Melissa-M" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-Christine-L" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Yee", "given_name": "L. D.", "orcid": "0000-0001-8965-9319", "clpid": "Yee-Lindsay-D" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Keutsch", "given_name": "F. N.", "orcid": "0000-0002-1442-6200", "clpid": "Keutsch-Frank-N" } ], "abstract": "The dependence of glyoxal uptake onto deliquesced ammonium sulfate seed aerosol was studied under photochemical (light + hydroxyl radical (OH)) and dark conditions. In this study, the chemical composition of aerosol formed from glyoxal is identical in the presence or absence of OH. In addition, there was no observed OH dependence on either glyoxal uptake or glyoxal-driven aerosol growth for this study. These findings demonstrate that, for the system used here, glyoxal uptake is not affected by the presence of OH. In combination with previous studies, this shows that the exact nature of the type of seed aerosol, in particular the presence of a coating, has a large influence on fast photochemical uptake of glyoxal. Due to the challenge of relating this seed aerosol dependence to ambient conditions, this work highlights the resulting difficulty in quantitatively including SOA formation from glyoxal in models.", "doi": "10.1029/2011GL048514", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2011-09", "series_number": "17", "volume": "38", "issue": "17", "pages": "L17811" }, { "id": "authors:tamge-sz124", "collection": "authors", "collection_id": "tamge-sz124", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110909-121933949", "type": "article", "title": "Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation", "author": [ { "family_name": "Kirkby", "given_name": "Jasper", "clpid": "Kirkby-J" }, { "family_name": "Downard", "given_name": "Andrew", "clpid": "Downard-A-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric aerosols exert an important influence on climate through their effects on stratiform cloud albedo and lifetime and the invigoration of convective storms. Model calculations suggest that almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours, although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small. Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia. Here we present the first results from the CLOUD experiment at CERN. We find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume, or less, increase the nucleation rate of sulphuric acid particles more than 100\u20131,000-fold. Time-resolved molecular measurements reveal that nucleation proceeds by a base-stabilization mechanism involving the stepwise accretion of ammonia molecules. Ions increase the nucleation rate by an additional factor of between two and more than ten at ground-level galactic-cosmic-ray intensities, provided that the nucleation rate lies below the limiting ion-pair production rate. We find that ion-induced binary nucleation of H_(2)SO_(4)\u2013H_(2)O can occur in the mid-troposphere but is negligible in the boundary layer. However, even with the large enhancements in rate due to ammonia and ions, atmospheric concentrations of ammonia and sulphuric acid are insufficient to account for observed boundary-layer nucleation.", "doi": "10.1038/nature10343", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2011-08-25", "series_number": "7361", "volume": "476", "issue": "7361", "pages": "429-433" }, { "id": "authors:g3nnm-zq523", "collection": "authors", "collection_id": "g3nnm-zq523", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110906-114648003", "type": "article", "title": "Evaluation of an entraining droplet activation parameterization using in situ cloud data", "author": [ { "family_name": "Morales", "given_name": "R.", "clpid": "Morales-R" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Jonsson", "given_name": "H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This study investigates the ability of a droplet activation parameterization (which considers the effects of entrainment and mixing) to reproduce observed cloud droplet\nnumber concentration (CDNC) in ambient clouds. Predictions of the parameterization are compared against cloud averages of CDNC from ambient cumulus and stratocumulus clouds sampled during CRYSTAL\u2010FACE (Key West, Florida, July 2002) and CSTRIPE (Monterey, California, July 2003), respectively. The entrainment parameters required by the\nparameterization are derived from the observed liquid water content profiles. For the cumulus clouds considered in the study, CDNC is overpredicted by 45% with the adiabatic\nparameterization. When entrainment is accounted for, the predicted CDNC agrees within 3.5%. Cloud\u2010averaged CDNC for stratocumulus clouds is well captured when entrainment is\nnot considered. In all cases considered, the entraining parameterization compared favorably against a statistical correlation developed from observations to treat entrainment effects on droplet number. These results suggest that including entrainment effects in the calculation of CDNC, as presented here, could address important overprediction biases associated with using adiabatic CDNC to represent cloud\u2010scale average values.", "doi": "10.1029/2010JD015324", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2011-08-16", "series_number": "D15", "volume": "116", "issue": "D15", "pages": "Art. No. D15205" }, { "id": "authors:bm13e-7c783", "collection": "authors", "collection_id": "bm13e-7c783", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110922-143220228", "type": "article", "title": "Impact of a large wildfire on water-soluble organic aerosol in a major urban area: the 2009 Station Fire in Los Angeles County", "author": [ { "family_name": "Wonasch\u00fctz", "given_name": "A.", "clpid": "Wonasch\u00fctz-A" }, { "family_name": "Hersey", "given_name": "S. P.", "clpid": "Hersey-S-P" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Metcalf", "given_name": "A. R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This study examines the nature of water-soluble organic aerosol measured in Pasadena, CA, under typical conditions and under the influence of a large wildfire (the 2009 Station Fire). During non-fire periods, water-soluble organic carbon (WSOC) variability was driven by photochemical production processes and sea breeze transport, resulting in an average diurnal cycle with a maximum at 15:00 local time (up to 4.9 \u03bcg C m^(\u22123)). During the Station Fire, primary production was a key formation mechanism for WSOC. High concentrations of WSOC (up to 41 \u03bcg C m^(\u22123)) in smoke plumes advected to the site in the morning hours were tightly correlated with nitrate and chloride, numerous aerosol mass spectrometer (AMS) organic mass spectral markers, and total non-refractory organic mass. Processed residual smoke was transported to the measurement site by the sea breeze later in the day, leading to higher afternoon WSOC levels than on non-fire days. Parameters representing higher degrees of oxidation of organics, including the ratios of the organic metrics m/z 44:m/z 57 and m/z 44:m/z 43, were elevated in those air masses. Intercomparisons of relative amounts of WSOC, organics, m/z 44, and m/z 43 show that the fraction of WSOC comprising acid-oxygenates increased as a function of photochemical aging owing to the conversion of aliphatic and non-acid oxygenated organics to more acid-like organics. The contribution of water-soluble organic species to the organic mass budget (10th\u201390th percentile values) ranged between 27 %\u201372 % and 27 %\u201368 % during fire and non-fire periods, respectively. The seasonal incidence of wildfires in the Los Angeles Basin greatly enhances the importance of water-soluble organics, which has implications for the radiative and hygroscopic properties of the regional aerosol.", "doi": "10.5194/acp-11-8257-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-08-15", "series_number": "16", "volume": "11", "issue": "16", "pages": "8257-8270" }, { "id": "authors:e9cd9-yg775", "collection": "authors", "collection_id": "e9cd9-yg775", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110906-153541149", "type": "article", "title": "The Pasadena Aerosol Characterization Observatory (PACO): chemical and physical analysis of the Western Los Angeles basin aerosol", "author": [ { "family_name": "Hersey", "given_name": "S. P.", "clpid": "Hersey-S-P" }, { "family_name": "Craven", "given_name": "J. S.", "clpid": "Craven-J-S" }, { "family_name": "Schilling", "given_name": "K. A.", "clpid": "Schilling-K-A" }, { "family_name": "Metcalf", "given_name": "A. R.", "orcid": "0000-0003-0385-1356", "clpid": "Metcalf-A-R" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Chan", "given_name": "M. N.", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The Pasadena Aerosol Characterization Observatory (PACO) represents the first major aerosol characterization experiment centered in the Western/Central Los Angeles Basin. The sampling site, located on the campus of the California Institute of Technology in Pasadena, was positioned to sample a continuous afternoon influx of transported urban aerosol with a photochemical age of 1\u20132 h and generally free from major local contributions. Sampling spanned 5 months during the summer of 2009, which were broken into 3 regimes on the basis of distinct meteorological conditions. Regime I was characterized by a series of low pressure systems, resulting in high humidity and rainy periods with clean conditions. Regime II typified early summer meteorology, with significant morning marine layers and warm, sunny afternoons. Regime III was characterized by hot, dry conditions with little marine layer influence. Regardless of regime, organic aerosol (OA) is the most significant constituent of nonrefractory submicron Los Angeles aerosol (42, 43, and 55 % of total submicron mass in regimes I, II, and III, respectively). The overall oxidation state remains relatively constant on timescales of days to weeks (O:C = 0.44 \u00b1 0.08, 0.55 \u00b1 0.05, and 0.48 \u00b1 0.08 during regimes I, II, and III, respectively), with no difference in O:C between morning and afternoon periods. Periods characterized by significant morning marine layer influence followed by photochemically favorable afternoons displayed significantly higher aerosol mass and O:C ratio, suggesting that aqueous processes may be important in the generation of secondary aerosol and oxidized organic aerosol (OOA) in Los Angeles. Online analysis of water soluble organic carbon (WSOC) indicates that water soluble organic mass (WSOM) reaches maxima near 14:00\u201315:00 local time (LT), but the percentage of AMS organic mass contributed by WSOM remains relatively constant throughout the day. Sulfate and nitrate reside predominantly in accumulation mode aerosol, while afternoon SOA production coincides with the appearance of a distinct fine mode dominated by organics. Particulate NH_4NO_3 and (NH_4)_2SO_4 appear to be NH_3-limited in regimes I and II, but a significant excess of particulate NH_4^+ in the hot, dry regime III suggests less SO_4^(2\u2212) and the presence of either organic amines or NH_4^+-associated organic acids. C-ToF-AMS data were analyzed by Positive Matrix Factorization (PMF), which resolved three factors, corresponding to a hydrocarbon-like OA (HOA), semivolatile OOA (SV-OOA), and low-volatility OOA (LV-OOA). HOA appears to be a periodic plume source, while SV-OOA exhibits a strong diurnal pattern correlating with ozone. Peaks in SV-OOA concentration correspond to peaks in DMA number concentration and the appearance of a fine organic mode. LV-OOA appears to be an aged accumulation mode constituent that may be associated with aqueous-phase processing, correlating strongly with sulfate and representing the dominant background organic component. Periods characterized by high SV-OOA and LV-OOA were analyzed by filter analysis, revealing a complex mixture of species during periods dominated by SV-OOA and LV-OOA, with LV-OOA periods characterized by shorter-chain dicarboxylic acids (higher O:C ratio), as well as appreciable amounts of nitrate- and sulfate-substituted organics. Phthalic acid was ubiquitous in filter samples, suggesting that PAH photochemistry may be an important SOA pathway in Los Angeles. Aerosol composition was related to water uptake characteristics, and it is concluded that hygroscopicity is largely controlled by organic mass fraction (OMF). The hygroscopicity parameter \u03ba averaged 0.31 \u00b1 0.08, approaching 0.5 at low OMF and 0.1 at high OMF, with increasing OMF suppressing hygroscopic growth and increasing critical dry diameter for CCN activation (D_d). An experiment-averaged \u03ba_(org) of 0.14 was calculated, indicating that the highly-oxidized organic fraction of aerosol in Los Angeles is appreciably more hygroscopic than previously reported in urban areas. Finally, PACO will provide context for results forthcoming from the CalNex field campaign, which involved ground sampling in Pasadena during the spring and summer of 2010.", "doi": "10.5194/acp-11-7417-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-08-01", "series_number": "15", "volume": "11", "issue": "15", "pages": "7417-7443" }, { "id": "authors:pgjhv-s4431", "collection": "authors", "collection_id": "pgjhv-s4431", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110816-103548738", "type": "article", "title": "Explicit modelling of SOA formation from \u03b1-pinene photooxidation: sensitivity to vapour pressure estimation", "author": [ { "family_name": "Valorso", "given_name": "R.", "clpid": "Valorso-R" }, { "family_name": "Aumont", "given_name": "B.", "clpid": "Aumont-B" }, { "family_name": "Camredon", "given_name": "M.", "clpid": "Camredon-A" }, { "family_name": "Raventos-Duran", "given_name": "T.", "clpid": "Raventos-Duran-T" }, { "family_name": "Mouchel-Vallon", "given_name": "C.", "clpid": "Mouchel-Vallon-C" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Lee-Taylor", "given_name": "J.", "clpid": "Lee-Taylor-J" }, { "family_name": "Madronich", "given_name": "S.", "clpid": "Madronich-S" } ], "abstract": "The sensitivity of the formation of secondary organic aerosol (SOA) to the estimated vapour pressures of the condensable oxidation products is explored. A highly detailed reaction scheme was generated for \u03b1-pinene photooxidation using the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A). Vapour pressures (P^(vap)) were estimated with three \ncommonly used structure activity relationships. The values of P^(vap) were compared for the set of secondary species generated by GECKO-A to describe \u03b1-pinene oxidation. Discrepancies in the predicted vapour pressures were found to increase with the number of functional groups borne by the species. For semi-volatile organic compounds (i.e. organic species of interest for SOA formation), differences in the predicted Pvap range between a factor of 5 to 200 on average. The simulated SOA concentrations were compared to SOA observations in the Caltech chamber during three experiments performed under a range of NO_x conditions. While the model captures the qualitative features of SOA formation for the chamber experiments, SOA concentrations are systematically overestimated. For the conditions simulated, the modelled SOA speciation appears to be rather insensitive to the P^vap estimation method.", "doi": "10.5194/acp-11-6895-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-07-18", "series_number": "14", "volume": "11", "issue": "14", "pages": "6895-6910" }, { "id": "authors:b64cs-sr103", "collection": "authors", "collection_id": "b64cs-sr103", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200529-093434531", "type": "article", "title": "Explicit modelling of SOA formation from \u03b1-pinene photooxidation: sensitivity to vapour pressure estimation", "author": [ { "family_name": "Valorso", "given_name": "R.", "clpid": "Valorso-R" }, { "family_name": "Aumont", "given_name": "B.", "clpid": "Aumont-B" }, { "family_name": "Camredon", "given_name": "M.", "clpid": "Camredon-M" }, { "family_name": "Raventos-Duran", "given_name": "T.", "clpid": "Raventos-Duran-T" }, { "family_name": "Mouchel-Vallon", "given_name": "C.", "clpid": "Mouchel-Vallon-C" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Lee-Taylor", "given_name": "J.", "clpid": "Lee-Taylor-J" }, { "family_name": "Madronich", "given_name": "S.", "clpid": "Madronich-S" } ], "abstract": "The sensitivity of the formation of secondary organic aerosol (SOA) to the estimated vapour pressures of the condensable oxidation products is explored. A highly detailed reaction scheme was generated for \u03b1-pinene photooxidation using the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A). Vapour pressures (P\u1d5b\u1d43\u1d56) were estimated with three commonly used structure activity relationships. The values of P\u1d5b\u1d43\u1d56 were compared for the set of secondary species generated by GECKO-A to describe \u03b1-pinene oxidation. Discrepancies in the predicted vapour pressures were found to increase with the number of functional groups borne by the species. For semi-volatile organic compounds (i.e. organic species of interest for SOA formation), differences in the predicted P\u1d5b\u1d43\u1d56 range between a factor of 5 to 200 on average. The simulated SOA concentrations were compared to SOA observations in the Caltech chamber during three experiments performed under a range of NO_x conditions. While the model captures the qualitative features of SOA formation for the chamber experiments, SOA concentrations are systematically overestimated. For the conditions simulated, the modelled SOA speciation appears to be rather insensitive to the P\u1d5b\u1d43\u1d56 estimation method.", "doi": "10.5194/acp-11-6895-2011", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-07-18", "series_number": "14", "volume": "11", "issue": "14", "pages": "6895-6910" }, { "id": "authors:z3t0y-nx391", "collection": "authors", "collection_id": "z3t0y-nx391", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110914-114802427", "type": "article", "title": "Changes in organic aerosol composition with aging inferred from aerosol mass spectra", "author": [ { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Canagaratna", "given_name": "M. R.", "orcid": "0000-0002-8803-4007", "clpid": "Canagaratna-Manjula-R" }, { "family_name": "Jimenez", "given_name": "J. L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-Jos\u00e9-L" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Worsnop", "given_name": "D. R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-Douglas-R" } ], "abstract": "Organic aerosols (OA) can be separated with factor analysis of aerosol mass spectrometer (AMS) data into hydrocarbon-like OA (HOA) and oxygenated OA (OOA). We develop a new method to parameterize H:C of OOA in terms of f\u2084\u2083 (ratio of m/z 43, mostly C\u2082H\u2083O\u207a, to total signal in the component mass spectrum). Such parameterization allows for the transformation of large database of ambient OOA components from the f\u2084\u2084 (mostly CO\u2082\u207a, likely from acid groups) vs. f\u2084\u2083 space (\"triangle plot\") (Ng et al., 2010) into the Van Krevelen diagram (H:C vs. O:C) (Van Krevelen, 1950). Heald et al. (2010) examined the evolution of total OA in the Van Krevelen diagram. In this work total OA is deconvolved into components that correspond to primary (HOA and others) and secondary (OOA) organic aerosols. By deconvolving total OA into different components, we remove physical mixing effects between secondary and primary aerosols which allows for examination of the evolution of OOA components alone in the Van Krevelen space. This provides a unique means of following ambient secondary OA evolution that is analogous to and can be compared with trends observed in chamber studies of secondary organic aerosol formation. The triangle plot in Ng et al. (2010) indicates that f\u2084\u2084 of OOA components increases with photochemical age, suggesting the importance of acid formation in OOA evolution. Once they are transformed with the new parameterization, the triangle plot of the OOA components from all sites occupy an area in Van Krevelen space which follows a \u0394H:C/\u0394O:C slope of ~ \u22120.5. This slope suggests that ambient OOA aging results in net changes in chemical composition that are equivalent to the addition of both acid and alcohol/peroxide functional groups without fragmentation (i.e. C-C bond breakage), and/or the addition of acid groups with fragmentation. These results provide a framework for linking the bulk aerosol chemical composition evolution to molecular-level studies.", "doi": "10.5194/acp-11-6465-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-07-01", "series_number": "13", "volume": "11", "issue": "13", "pages": "6465-6474" }, { "id": "authors:j785y-qbt15", "collection": "authors", "collection_id": "j785y-qbt15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110628-111859989", "type": "article", "title": "Measurements of Isoprene-Derived Organosulfates in Ambient\n Aerosols by Aerosol Time-of-Flight Mass Spectrometry - Part 1:\n Single Particle Atmospheric Observations in Atlanta", "author": [ { "family_name": "Hatch", "given_name": "Lindsay E.", "orcid": "0000-0001-9037-9760", "clpid": "Hatch-Lindsay-E" }, { "family_name": "Creamean", "given_name": "Jessie M.", "orcid": "0000-0003-3819-5600", "clpid": "Creamean-Jessie-M" }, { "family_name": "Ault", "given_name": "Andrew P.", "orcid": "0000-0002-7313-8559", "clpid": "Ault-Andrew-P" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chan", "given_name": "Man Nin", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Edgerton", "given_name": "Eric S.", "clpid": "Edgerton-Eric-S" }, { "family_name": "Su", "given_name": "Yongxuan", "clpid": "Su-Yongxuan" }, { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" } ], "abstract": "Organosulfate species have recently been identified as a potentially significant class of secondary organic aerosol (SOA) species, yet little is known about their behavior in the atmosphere. In this work, organosulfates were observed in individual ambient aerosols using single particle mass spectrometry in Atlanta, GA during the 2002 Aerosol Nucleation and Characterization Experiment (ANARChE) and the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS). Organosulfates derived from biogenically produced isoprene were detected as deprotonated molecular ions in negative-ion spectra measured by aerosol time-of-flight mass spectrometry; comparison to high-resolution mass spectrometry data obtained from filter samples corroborated the peak assignments. The size-resolved chemical composition measurements revealed that organosulfate species were mostly detected in submicrometer aerosols and across a range of aerosols from different sources, consistent with secondary reaction products. Detection of organosulfates in a large fraction of negative-ion ambient spectra \u2212 ca. 90\u221295% during ANARChE and ~65% of submicrometer particles in AMIGAS \u2212 highlights the ubiquity of organosulfate species in the ambient aerosols of biogenically influenced urban environments.", "doi": "10.1021/es103944a", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2011-06-15", "series_number": "12", "volume": "45", "issue": "12", "pages": "5105-5111" }, { "id": "authors:9gned-htd15", "collection": "authors", "collection_id": "9gned-htd15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110421-095939714", "type": "article", "title": "Mass spectrometric characterization of isomeric terpenoic acids from the oxidation of \u03b1-pinene, \u03b2-pinene, d-limonene, and \u0394^3-carene in fine forest aerosol", "author": [ { "family_name": "Yasmeen", "given_name": "Farhat", "clpid": "Yasmeen-Farhat" }, { "family_name": "Szmigielski", "given_name": "Rafal", "orcid": "0000-0003-3389-9318", "clpid": "Szmigielski-Rafal" }, { "family_name": "Vermeylen", "given_name": "Reinhilde", "clpid": "Vermeylen-Reinhilde" }, { "family_name": "G\u00f3mez-Gonz\u00e1lez", "given_name": "Yadian", "orcid": "0000-0002-8673-2610", "clpid": "G\u00f3mez-Gonz\u00e1lez-Yadian" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chan", "given_name": "Arthur W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Maenhaut", "given_name": "Willy", "orcid": "0000-0002-4715-4627", "clpid": "Maenhaut-Willy" }, { "family_name": "Claeys", "given_name": "Magda", "orcid": "0000-0003-2278-8014", "clpid": "Claeys-Magda" } ], "abstract": "In this study, we present liquid chromatographic and mass spectral data for predominant terpenoic acids formed through oxidation of \u03b1-pinene, \u03b2-pinene, d-limonene, and \u0394^3-carene that occur in fine forest aerosol from K-puszta, Hungary, a rural site with coniferous vegetation. Characterization of these secondary organic aerosol tracers in fine ambient aerosol is important because it allows one to gain information on monoterpene precursors and source processes such as oxidation and aging processes. The mass spectral data were obtained using electrospray ionization in the negative ion mode, accurate mass measurements, and linear ion trap tandem mass spectrometric experiments. Emphasis is given to the mass spectrometric differentiation of isobaric terpenoic acids, such as, e.g. the molecular weight (MW) 186 terpenoic acids, cis-pinic, cis-caric, homoterpenylic, ketolimononic, and limonic acids. Other targeted isobaric terpenoic acids are the MW 184 terpenoic acids, cis-pinonic and cis-caronic acids, and the MW 204 tricarboxylic acids, 3-methyl-1,2,3-butanetricarboxylic and 3-carboxyheptanedioic acids. Fragmentation pathways are proposed to provide a rational explanation for the observed isomeric differences and/or to support the suggested tentative structures. For the completeness of the data set, data obtained for recently reported lactone-containing terpenoic acids (i.e. terpenylic and terebic acids), related or isobaric compounds (i.e. norpinic acid, diaterpenylic acid acetate, and unknown MW 188 compounds) are also included, the rationale being that other groups working on this topic could use this data compilation as a reference.", "doi": "10.1002/jms.1911", "issn": "1076-5174", "publisher": "Wiley", "publication": "Journal of Mass Spectrometry", "publication_date": "2011-04", "series_number": "4", "volume": "46", "issue": "4", "pages": "425-442" }, { "id": "authors:wmwcp-wzr67", "collection": "authors", "collection_id": "wmwcp-wzr67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110404-100259820", "type": "article", "title": "Influence of aerosol acidity on the chemical composition of secondary organic aerosol from \u03b2-caryophyllene", "author": [ { "family_name": "Chan", "given_name": "M. N.", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Schilling", "given_name": "K.", "clpid": "Schilling-Katherine-A" }, { "family_name": "Offenberg", "given_name": "John H.", "orcid": "0000-0002-0213-4024", "clpid": "Offenberg-John-H" }, { "family_name": "Lewandowski", "given_name": "M.", "orcid": "0000-0002-0058-956X", "clpid": "Lewandowski-Michael" }, { "family_name": "Edney", "given_name": "E. O.", "clpid": "Edney-Edward-O" }, { "family_name": "Kleindienst", "given_name": "T. E.", "orcid": "0000-0002-3024-1564", "clpid": "Kleindienst-Tadeusz-E" }, { "family_name": "Jaoui", "given_name": "M.", "orcid": "0000-0002-2728-9137", "clpid": "Jaoui-Mohammed" }, { "family_name": "Edgerton", "given_name": "E. S.", "clpid": "Edgerton-Eric-S" }, { "family_name": "Tanner", "given_name": "R. L.", "clpid": "Tanner-Roger-L" }, { "family_name": "Shaw", "given_name": "S. L.", "orcid": "0000-0001-8198-4184", "clpid": "Shaw-Stephanie-L" }, { "family_name": "Zheng", "given_name": "M.", "clpid": "Zheng-Mei" }, { "family_name": "Knipping", "given_name": "E. M.", "orcid": "0000-0002-9654-9019", "clpid": "Knipping-Eladio-M" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The secondary organic aerosol (SOA) yield of \u03b2-caryophyllene photooxidation is enhanced by aerosol acidity. In the present study, the influence of aerosol acidity on the chemical composition of \u03b2-caryophyllene SOA is investigated using ultra performance liquid chromatography/electrospray ionization-time-of-flight mass spectrometry (UPLC/ESI-TOFMS). A number of first-, second- and higher-generation gas-phase products having carbonyl and carboxylic acid functional groups are detected in the particle phase. Particle-phase reaction products formed via hydration and organosulfate formation processes are also detected. Increased acidity leads to different effects on the abundance of individual products; significantly, abundances of organosulfates are correlated with aerosol acidity. To our knowledge, this is the first detection of organosulfates and nitrated organosulfates derived from a sesquiterpene. The increase of certain particle-phase reaction products with increased acidity provides chemical evidence to support the acid-enhanced SOA yields. Based on the agreement between the chromatographic retention times and accurate mass measurements of chamber and field samples, three \u03b2-caryophyllene products (i.e., \u03b2-nocaryophyllon aldehyde, \u03b2-hydroxynocaryophyllon aldehyde, and \u03b2-dihydroxynocaryophyllon aldehyde) are suggested as chemical tracers for \u03b2-caryophyllene SOA. These compounds are detected in both day and night ambient samples collected in downtown Atlanta, GA and rural Yorkville, GA during the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS).", "doi": "10.5194/acp-11-1735-2011", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011-02-25", "series_number": "4", "volume": "11", "issue": "4", "pages": "1735-1751" }, { "id": "authors:xc5ah-pnv18", "collection": "authors", "collection_id": "xc5ah-pnv18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110805-140754489", "type": "article", "title": "Theoretical basis for convective invigoration due to increased aerosol concentration", "author": [ { "family_name": "Lebo", "given_name": "Z. J.", "orcid": "0000-0002-1064-4833", "clpid": "Lebo-Z-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The potential effects of increased aerosol loading on the development of deep convective clouds and resulting precipitation amounts are studied by employing the Weather Research and Forecasting (WRF) model as a detailed high-resolution cloud resolving model (CRM) with both detailed bulk and bin microphysics schemes. Both models include a physically-based activation scheme that incorporates a size-resolved aerosol population. We demonstrate that the aerosol-induced effect is controlled by the balance between latent heating and the increase in condensed water aloft, each having opposing effects on buoyancy. It is also shown that under polluted conditions, increases in the CCN number concentration reduce the cumulative precipitation due to the competition between the sedimentation and evaporation/sublimation timescales. The effect of an increase in the IN number concentration on the dynamics of deep convective clouds is small and the resulting decrease in domain-averaged cumulative precipitation is shown not to be statistically significant, but may act to suppress precipitation. It is also shown that even in the presence of a decrease in the domain-averaged cumulative precipitation, an increase in the precipitation variance, or in other words, andincrease in rainfall intensity, may be expected in more polluted environments, especially in moist environments.\n\nA significant difference exists between the predictions based on the bin and bulk microphysics schemes of precipitation and the influence of aerosol perturbations on updraft velocity within the convective core. The bulk microphysics scheme shows little change in the latent heating rates due to an increase in the CCN number concentration, while the bin microphysics scheme demonstrates significant increases in the latent heating aloft with increasing CCN number concentration. This suggests that even a detailed two-bulk microphysics scheme, coupled to a detailed activation scheme, may not be sufficient to predict small changes that result from perturbations in aerosol loading.", "doi": "10.5194/acp-11-5407-2011", "issn": "1680-7316", "publisher": "european Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2011", "series_number": "11", "volume": "11", "issue": "11", "pages": "5407-5429" }, { "id": "authors:mz4vf-vxr22", "collection": "authors", "collection_id": "mz4vf-vxr22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120816-094502355", "type": "conference_item", "title": "Formation of organosulfates from the photooxidation of isoprene and a-pinene", "author": [ { "family_name": "Eddingsaas", "given_name": "N. C.", "orcid": "0000-0003-1539-5415", "clpid": "Eddingsaas-Nathan-C" }, { "family_name": "Chan", "given_name": "A. W.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Chan", "given_name": "M.", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-Christine-L" }, { "family_name": "Yee", "given_name": "L. D.", "orcid": "0000-0001-8965-9319", "clpid": "Yee-Lindsay-D" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "Organosulfates of a no. of biogenic volatile org. compds. (BVOCs) have been obsd. both in lab.-generated and ambient\nsecondary org. aerosol (SOA). While organosulfates are potentially an important component of SOA, relatively little is\nknown about how they form and their aerosol mass concns. Organosulfates are most prevalent in acidic aerosols contg.\nhigh concns. of sulfate. A no. of mechanisms have been proposed for the aerosol-phase formation of organosulfates,\nincluding alc. esterification, aldehyde esterification, epoxide ring-opening, and sulfate-radical initiated reactions. In order\nto det. which mechanism produces organosulfates from a given VOC, the gas-phase precursor must first be detd. To\nelucidate the gas-phase precursor of organosulfates from isoprene and a-pinene, photooxidn. expts. were performed in\nthe Caltech dual 28-m3 environmental chamber in the presence of a no. of different aerosol seeds varying in acidity and\nsulfate concn. The gas-phase compn. was followed by chem. ionization mass spectrometry and GC-FID and the\naerosol-phase compn. was detd. by aerosol mass spectrometry and a no. of off-line mass spectrometric techniques from\nchamber filter samples. For isoprene, epoxydiols were detd. to be a main gas-phase precursor of the C5 trihydroxy\nsulfate ester found in many aerosol samples. The aq.-phase ring-opening reactions of epoxydiols was studied by NMR\nfrom solns. of H2SO4/Na2SO4 where trihydroxy sulfate esters were found to form in yields of up to 32% in solns. contg.\n1 M SO42-. Similar studies were also performed to det. the gas-phase precursor of organosulfates from the photooxidn.\nof \u03b1-pinene.", "publisher": "Caltech Library", "publication_date": "2010-12" }, { "id": "authors:gzf8z-yxc33", "collection": "authors", "collection_id": "gzf8z-yxc33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20101206-120501313", "type": "article", "title": "Constraining the contribution of organic acids and AMS m/z 44 to the organic aerosol budget: On the importance of meteorology, aerosol hygroscopicity, and region", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-S-M" }, { "family_name": "Hersey", "given_name": "Scott", "clpid": "Hersey-S-P" }, { "family_name": "Bahreini", "given_name": "Roya", "clpid": "Bahreini-R" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Airborne measurements in regions of varying meteorology and pollution are used to quantify the contribution of organic acids and a mass spectral marker for oxygenated aerosols, m/z 44, to the total organic aerosol budget. Organic acids and m/z 44 separately are shown to exhibit their highest organic mass fractions in the vicinity of clouds. The contribution of such oxygenated species is shown to increase as a function of relative humidity, aerosol hygroscopicity (and decreasing organic mass fraction), and is typically greater off the California coast versus the continental atmospheres studied. Reasons include more efficient chemistry and partitioning of organic acid precursors with increasing water in the reaction medium, and high aqueous-phase processing times in boundary layers with higher cloud volume fractions. These results highlight the importance of secondary organic aerosol formation in both wet aerosols and cloud droplets.", "doi": "10.1029/2010GL044951", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2010-11-04", "series_number": "21", "volume": "37", "issue": "21", "pages": "Art. No. L21807" }, { "id": "authors:4pmwv-jp791", "collection": "authors", "collection_id": "4pmwv-jp791", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100920-102004558", "type": "article", "title": "Computation of liquid-liquid equilibria and phase stabilities: implications for RH-dependent gas/particle partitioning of organic-inorganic aerosols", "author": [ { "family_name": "Zuend", "given_name": "A.", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Marcolli", "given_name": "C.", "clpid": "Marcolli-C" }, { "family_name": "Peter", "given_name": "T.", "clpid": "Peter-T" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Semivolatile organic and inorganic aerosol species partition between the gas and aerosol particle phases to maintain thermodynamic equilibrium. Liquid-liquid phase separation into an organic-rich and an aqueous electrolyte phase can occur in the aerosol as a result of the salting-out effect. Such liquid-liquid equilibria (LLE) affect the gas/particle partitioning of the different semivolatile compounds and might significantly alter both particle mass and composition as compared to a one-phase particle. We present a new liquid-liquid equilibrium and gas/particle partitioning model, using as a basis the group-contribution model AIOMFAC (Zuend et al., 2008). This model allows the reliable computation of the liquid-liquid coexistence curve (binodal), corresponding tie-lines, the limit of stability/metastability (spinodal), and further thermodynamic properties of multicomponent systems. Calculations for ternary and multicomponent alcohol/polyol-water-salt mixtures suggest that LLE are a prevalent feature of organic-inorganic aerosol systems. A six-component polyol-water-ammonium sulphate system is used to simulate effects of relative humidity (RH) and the presence of liquid-liquid phase separation on the gas/particle partitioning. RH, salt concentration, and hydrophilicity (water-solubility) are identified as key features in defining the region of a miscibility gap and govern the extent to which compound partitioning is affected by changes in RH. The model predicts that liquid-liquid phase separation can lead to either an increase or decrease in total particulate mass, depending on the overall composition of a system and the particle water content, which is related to the hydrophilicity of the different organic and inorganic compounds. Neglecting non-ideality and liquid-liquid phase separations by assuming an ideal mixture leads to an overestimation of the total particulate mass by up to 30% for the composition and RH range considered in the six-component system simulation. For simplified partitioning parametrizations, we suggest a modified definition of the effective saturation concentration, C_j^*, by including water and other inorganics in the absorbing phase. Such a C_j^* definition reduces the RH-dependency of the gas/particle partitioning of semivolatile organics in organic-inorganic aerosols by an order of magnitude as compared to the currently accepted definition, which considers the organic species only.", "doi": "10.5194/acp-10-7795-2010", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2010-08-24", "series_number": "16", "volume": "10", "issue": "16", "pages": "7795-7820" }, { "id": "authors:q0vkn-77781", "collection": "authors", "collection_id": "q0vkn-77781", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100831-091347403", "type": "article", "title": "Observation of playa salts as nuclei in orographic wave clouds", "author": [ { "family_name": "Pratt", "given_name": "Kerri A.", "orcid": "0000-0003-4707-2290", "clpid": "Pratt-Kerri-A" }, { "family_name": "Twohy", "given_name": "Cynthia H.", "orcid": "0000-0001-9092-1134", "clpid": "Twohy-Cynthia-H" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Moffet", "given_name": "Ryan C.", "clpid": "Moffet-Ryan-C" }, { "family_name": "Heymsfield", "given_name": "Andrew J.", "orcid": "0000-0003-4107-7533", "clpid": "Heymsfield-Andrew-J" }, { "family_name": "Gaston", "given_name": "Cassandra J.", "clpid": "Gaston-Cassandra-J" }, { "family_name": "DeMott", "given_name": "Paul J.", "orcid": "0000-0002-3719-1889", "clpid": "DeMott-Paul-J" }, { "family_name": "Field", "given_name": "Paul R.", "clpid": "Field-Paul-R" }, { "family_name": "Henn", "given_name": "Tobias R.", "clpid": "Henn-Tobias-R" }, { "family_name": "Rogers", "given_name": "David C.", "clpid": "Rogers-David-C" }, { "family_name": "Gilles", "given_name": "Mary K.", "clpid": "Gilles-Mary-K" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" } ], "abstract": "During the Ice in Clouds Experiment-Layer Clouds (ICE-L), dry lakebed, or playa, salts from the Great Basin region of the United States were observed as cloud nuclei in orographic wave clouds over Wyoming. Using a counterflow virtual impactor in series with a single-particle mass spectrometer, sodium-potassium-magnesium-calcium-chloride salts were identified as residues of cloud droplets. Importantly, these salts produced similar mass spectral signatures to playa salts with elevated cloud condensation nuclei (CCN) efficiencies close to sea salt. Using a suite of chemical characterization instrumentation, the playa salts were observed to be internally mixed with oxidized organics, presumably produced by cloud processing, as well as carbonate. These salt particles were enriched as residues of large droplets (>19 \u03bcm) compared to smaller droplets (>7 \u03bcm). In addition, a small fraction of silicate-containing playa salts were hypothesized to be important in the observed heterogeneous ice nucleation processes. While the high CCN activity of sea salt has been demonstrated to play an important role in cloud formation in marine environments, this study provides direct evidence of the importance of playa salts in cloud formation in continental North America has not been shown previously. Studies are needed to model and quantify the impact of playas on climate globally, particularly because of the abundance of playas and expected increases in the frequency and intensity of dust storms in the future due to climate and land use changes.", "doi": "10.1029/2009JD013606", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2010-08-16", "series_number": "D15", "volume": "115", "issue": "D15", "pages": "Art. No. D15301" }, { "id": "authors:pdk4n-mep40", "collection": "authors", "collection_id": "pdk4n-mep40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100915-133230350", "type": "article", "title": "Role of aldehyde chemistry and NO_x concentrations in secondary organic aerosol formation", "author": [ { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Chan", "given_name": "M. N.", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Loza", "given_name": "C. L.", "clpid": "Loza-Christine-L" }, { "family_name": "Crounse", "given_name": "J. D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-John-D" }, { "family_name": "Yee", "given_name": "L. D.", "orcid": "0000-0001-8965-9319", "clpid": "Yee-Lindsay-D" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene), the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA) via methacrolein (a C_4-unsaturated aldehyde) under urban high-NO_x conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN) as the important intermediate to isoprene and methacrolein SOA in this NO_x regime. Here we show that as a result of this chemistry, NO_2 enhances SOA formation from methacrolein and two other \u03b1, \u03b2-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NO_x effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO_2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are \u03b1, \u03b2-unsaturated and contain an additional methyl group on the \u03b1-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232) is insignificant, even under high-NO_2 conditions, as PAN (peroxy acyl nitrate, RC(O)OONO_2) formation is structurally unfavorable. At atmospherically relevant NO_2/NO ratios (3\u20138), the SOA yields from isoprene high-NO_x photooxidation are 3 times greater than previously measured at lower NO_2/NO ratios. At sufficiently high NO_2 concentrations, in systems of \u03b1, \u03b2-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO_2 can exceed that from RO_2+HO_2 reactions under the same inorganic seed conditions, making RO_2+NO_2 an important channel for SOA formation.", "doi": "10.5194/acp-10-7169-2010", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2010-08-04", "series_number": "15", "volume": "10", "issue": "15", "pages": "7169-7188" }, { "id": "authors:3qspx-w9e06", "collection": "authors", "collection_id": "3qspx-w9e06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100921-142838366", "type": "article", "title": "In Situ Chemical Characterization of Aged Biomass-Burning Aerosols Impacting Cold Wave Clouds", "author": [ { "family_name": "Pratt", "given_name": "Kerri A.", "orcid": "0000-0003-4707-2290", "clpid": "Pratt-Kerri-A" }, { "family_name": "Heymsfield", "given_name": "Andrew J.", "orcid": "0000-0003-4107-7533", "clpid": "Heymsfield-Andrew-J" }, { "family_name": "Twohy", "given_name": "Cynthia H.", "orcid": "0000-0001-9092-1134", "clpid": "Twohy-Cynthia-H" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "DeMott", "given_name": "Paul J.", "orcid": "0000-0002-3719-1889", "clpid": "DeMott-Paul-J" }, { "family_name": "Hudson", "given_name": "James G.", "clpid": "Hudson-James-G" }, { "family_name": "Subramanian", "given_name": "R.", "clpid": "Subramanian-R" }, { "family_name": "Wang", "given_name": "Zhien", "clpid": "Wang-Zhien" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" } ], "abstract": "During the Ice in Clouds Experiment\u2013Layer Clouds (ICE-L), aged biomass-burning particles were identified within two orographic wave cloud regions over Wyoming using single-particle mass spectrometry and electron microscopy. Using a suite of instrumentation, particle chemistry was characterized in tandem with cloud microphysics. The aged biomass-burning particles comprised ~30%\u201340% by number of the 0.1\u20131.0-\u03bcm clear-air particles and were composed of potassium, organic carbon, elemental carbon, and sulfate. Aerosol mass spectrometry measurements suggested these cloud-processed particles were predominantly sulfate by mass. The first cloud region sampled was characterized by primarily homogeneously nucleated ice particles formed at temperatures near \u221240\u00b0C. The second cloud period was characterized by high cloud droplet concentrations (~150\u2013300 cm^(\u22123)) and lower heterogeneously nucleated ice concentrations (7\u201318 L^(\u22121)) at cloud temperatures of \u221224\u00b0 to \u221225\u00b0C. As expected for the observed particle chemistry and dynamics of the observed wave clouds, few significant differences were observed between the clear-air particles and cloud residues. However, suggestive of a possible heterogeneous nucleation mechanism within the first cloud region, ice residues showed enrichments in the number fractions of soot and mass fractions of black carbon, measured by a single-particle mass spectrometer and a single-particle soot photometer, respectively. In addition, enrichment of biomass-burning particles internally mixed with oxalic acid in both the homogeneously nucleated ice and cloud droplets compared to clear air suggests either preferential activation as cloud condensation nuclei or aqueous phase cloud processing.", "doi": "10.1175/2010JAS3330.1", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2010-08", "series_number": "8", "volume": "67", "issue": "8", "pages": "2451-2468" }, { "id": "authors:y5s4t-0t258", "collection": "authors", "collection_id": "y5s4t-0t258", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100921-090324884", "type": "article", "title": "Relationships of Biomass-Burning Aerosols to Ice in Orographic Wave Clouds", "author": [ { "family_name": "Twohy", "given_name": "Cynthia H.", "orcid": "0000-0001-9092-1134", "clpid": "Twohy-Cynthia-H" }, { "family_name": "DeMott", "given_name": "Paul J.", "orcid": "0000-0002-3719-1889", "clpid": "DeMott-Paul-J" }, { "family_name": "Pratt", "given_name": "Kerri A.", "clpid": "Pratt-Kerri-A" }, { "family_name": "Subramanian", "given_name": "R.", "clpid": "Subramanian-R" }, { "family_name": "Kok", "given_name": "Gregory L.", "clpid": "Kok-Gregory-L" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Lersch", "given_name": "Traci", "clpid": "Lersch-Traci" }, { "family_name": "Heymsfield", "given_name": "Andrew J.", "orcid": "0000-0003-4107-7533", "clpid": "Heymsfield-Andrew-J" }, { "family_name": "Wang", "given_name": "Zhien", "clpid": "Wang-Zhien" }, { "family_name": "Prather", "given_name": "Kim A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Ice concentrations in orographic wave clouds at temperatures between \u221224\u00b0 and \u221229\u00b0C were shown to be related to aerosol characteristics in nearby clear air during five research flights over the Rocky Mountains. When clouds with influence from colder temperatures were excluded from the dataset, mean ice nuclei and cloud ice number concentrations were very low, on the order of 1\u20135 L^(\u22121). In this environment, ice number concentrations were found to be significantly correlated with the number concentration of larger particles, those larger than both 0.1- and 0.5-\u03bcm diameter. A variety of complementary techniques was used to measure aerosol size distributions and chemical composition. Strong correlations were also observed between ice concentrations and the number concentrations of soot and biomass-burning aerosols. Ice nuclei concentrations directly measured in biomass-burning plumes were the highest detected during the project. Taken together, this evidence indicates a potential role for biomass-burning aerosols in ice formation, particularly in regions with relatively low concentrations of other ice nucleating aerosols.", "doi": "10.1175/2010JAS3310.1", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2010-08", "series_number": "8", "volume": "67", "issue": "8", "pages": "2437-2450" }, { "id": "authors:kd7kb-r6t40", "collection": "authors", "collection_id": "kd7kb-r6t40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100921-090503654", "type": "article", "title": "Ice Initiation by Aerosol Particles: Measured and Predicted Ice Nuclei Concentrations versus Measured Ice Crystal Concentrations in an Orographic Wave Cloud", "author": [ { "family_name": "Eidhammer", "given_name": "T.", "orcid": "0000-0003-2281-9351", "clpid": "Eidhammer-Trude" }, { "family_name": "DeMott", "given_name": "P. J.", "orcid": "0000-0002-3719-1889", "clpid": "DeMott-Paul-J" }, { "family_name": "Prenni", "given_name": "A. J.", "orcid": "0000-0002-0256-5166", "clpid": "Prenni-Anthony-J" }, { "family_name": "Petters", "given_name": "M. D.", "clpid": "Petters-M-D" }, { "family_name": "Twohy", "given_name": "C. H.", "orcid": "0000-0001-9092-1134", "clpid": "Twohy-Cynthia-H" }, { "family_name": "Rogers", "given_name": "D. C.", "clpid": "Rogers-David-C" }, { "family_name": "Stith", "given_name": "J.", "clpid": "Stith-J" }, { "family_name": "Heymsfield", "given_name": "A.", "orcid": "0000-0003-4107-7533", "clpid": "Heymsfield-Andrew-J" }, { "family_name": "Wang", "given_name": "Z.", "clpid": "Wang-Zhien" }, { "family_name": "Pratt", "given_name": "K. A.", "orcid": "0000-0003-4707-2290", "clpid": "Pratt-Kerri-A" }, { "family_name": "Prather", "given_name": "K. A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" }, { "family_name": "Murphy", "given_name": "S. M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Subramanian", "given_name": "R.", "clpid": "Subramanian-R" }, { "family_name": "Kreidenweis", "given_name": "S. M.", "orcid": "0000-0002-2561-2914", "clpid": "Kreidenweis-Sonia-M" } ], "abstract": "The initiation of ice in an isolated orographic wave cloud was compared with expectations based on ice nucleating aerosol concentrations and with predictions from new ice nucleation parameterizations applied in a cloud parcel model. Measurements of ice crystal number concentrations were found to be in good agreement both with measured number concentrations of ice nuclei feeding the clouds and with ice nuclei number concentrations determined from the residual nuclei of cloud particles collected by a counterflow virtual impactor. Using lognormal distributions fitted to measured aerosol size distributions and measured aerosol chemical compositions, ice nuclei and ice crystal concentrations in the wave cloud were reasonably well predicted in a 1D parcel model framework. Two different empirical parameterizations were used in the parcel model: a parameterization based on aerosol chemical type and surface area and a parameterization that links ice nuclei number concentrations to the number concentrations of particles with diameters larger than 0.5 \u03bcm. This study shows that aerosol size distribution and composition measurements can be used to constrain ice initiation by primary nucleation in models. The data and model results also suggest the likelihood that the dust particle mode of the aerosol size distribution controls the number concentrations of the heterogeneous ice nuclei, at least for the lower temperatures examined in this case.", "doi": "10.1175/2010JAS3266.1", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2010-08", "series_number": "8", "volume": "67", "issue": "8", "pages": "2417-2436" }, { "id": "authors:jf9hf-61443", "collection": "authors", "collection_id": "jf9hf-61443", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100719-104821305", "type": "article", "title": "Characterization of Vapor Wall Loss in Laboratory Chambers", "author": [ { "family_name": "Loza", "given_name": "Christine L.", "clpid": "Loza-C-L" }, { "family_name": "Chan", "given_name": "Arthur W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Galloway", "given_name": "Melissa M.", "orcid": "0000-0002-8518-1888", "clpid": "Galloway-M-M" }, { "family_name": "Keutsch", "given_name": "Frank N.", "clpid": "Keutsch-F-N" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Laboratory chambers used to study atmospheric chemistry and aerosol formation are subject to wall loss of vapors and particles that must be accounted for in calculating aerosol yields. While particle wall loss in chambers is relatively well-understood and routinely accounted for, that of vapor is less so. Here we address experimental measurement and modeling of vapor losses in environmental chambers. We identify two compounds that exhibit wall loss: 2,3-epoxy-1,4-butanediol (BEPOX), an analog of an important isoprene oxidation product; and glyoxal, a common volatile organic compound oxidation product. Dilution experiments show that BEPOX wall loss is irreversible on short time scales but is reversible on long time scales, and glyoxal wall loss is reversible for all time scales. BEPOX exhibits minimal uptake onto clean chamber walls under dry conditions, with increasing rates of uptake over the life of an in-use chamber. By performing periodic BEPOX wall loss experiments, it is possible to assess quantitatively the aging of chamber walls.", "doi": "10.1021/es100727v", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2010-07-01", "series_number": "13", "volume": "44", "issue": "13", "pages": "5074-5078" }, { "id": "authors:exf2r-yv705", "collection": "authors", "collection_id": "exf2r-yv705", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100720-085423874", "type": "article", "title": "Global climate response to anthropogenic aerosol indirect effects: Present day and year 2100", "author": [ { "family_name": "Chen", "given_name": "Wei-Ting", "orcid": "0000-0002-9292-0933", "clpid": "Chen-Wei-Ting" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Adams", "given_name": "Peter J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Li", "given_name": "Jui-Lin F.", "clpid": "Li-Jui-Lin-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aerosol indirect effects (AIE) are a principal source of uncertainty in future climate predictions. The present study investigates the equilibrium response of the climate system to present-day and future AIE using the general circulation model (GCM), Goddard Institute for Space Studies (GISS) III. A diagnostic formulation correlating cloud droplet number concentration (N_c) with concentrations of aerosol soluble ions is developed as a basis for the calculation. Explicit dependence on N_c is introduced in the treatments of liquid-phase stratiform clouds in GISS III. The model is able to reproduce the general patterns of present-day cloud frequency, droplet size, and radiative balance observed by CloudSat, Moderate Resolution Imaging Spectroradiometer, and Earth Radiation Budget Experiment. For perturbations of N_c from preindustrial to present day, a net AIE forcing of \u22121.67 W m^(\u22122) is estimated, with a global mean surface cooling of 1.12 K, precipitation reduction of 3.36%, a southward shift of the Intertropical Convergence Zone, and a hydrological sensitivity of +3.00% K^(\u22121). For estimated perturbations of N_c from present day to year 2100, a net AIE forcing of \u22120.58 W m^(\u22122), a surface cooling of 0.47 K, and a decrease in precipitation of 1.7% are predicted. Sensitivity calculations show that the assumption of a background minimum N_c value has more significant effects on AIE forcing in the future than on that in present day. When AIE-related processes are included in the GCM, a decrease in stratiform precipitation is predicted over future greenhouse gas (GHG)-induced warming scenario, as opposed to the predicted increase when only GHG and aerosol direct effects are considered.", "doi": "10.1029/2008JD011619", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2010-06-27", "series_number": "D12", "volume": "115", "issue": "D12", "pages": "Art. No. D12207" }, { "id": "authors:1w5pr-7pt09", "collection": "authors", "collection_id": "1w5pr-7pt09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100719-112033490", "type": "article", "title": "Atmospheric chemistry-climate feedbacks", "author": [ { "family_name": "Raes", "given_name": "Frank", "clpid": "Raes-F" }, { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Chen", "given_name": "Wei-Ting", "orcid": "0000-0002-9292-0933", "clpid": "Chen-Wei-Ting" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We extend the theory of climate feedbacks to include atmospheric chemistry. A change in temperature caused by a radiative forcing will include, in general, a contribution from the chemical change that is fed back into the climate system; likewise, the change in atmospheric burdens caused by a chemical forcing will include a contribution from the associated climate change that is fed back into the chemical system. The theory includes two feedback gains, G_(che) and G_(cli). G_(che) is defined as the ratio of the change in equilibrium global mean temperature owing to long-lived greenhouse gas radiative forcing, under full climate-chemistry coupling, to that in the absence of coupling. G_(cli) is defined as the ratio of the change in equilibrium mean aerosol or gas-phase burdens owing to chemical forcing under full coupling, to that in the absence of coupling. We employ a climate-atmospheric chemistry model based on the Goddard Institute for Space Studies (GISS) GCM II', including tropospheric gas-phase chemistry, sulfate, nitrate, ammonium, black carbon, and organic carbon. While the model describes many essential couplings between climate and atmospheric chemistry, not all couplings are accounted for, such as indirect aerosol forcing and the role of natural dust and sea salt aerosols. Guided by the feedback theory, we perform perturbation experiments to quantify G_(che) and G_(cli). We find that G_(che) for surface air temperature is essentially equal to 1.00 on a planetary scale. Regionally, G_(che) is estimated to be 0.80\u20131.30. The gains are small compared to those of the physical feedbacks in the climate system (e.g., water vapor, and cloud feedbacks). These values for G_(che) are robust for the specific model used, but may change when using more comprehensive climate-atmospheric chemistry models. Our perturbation experiments do not allow one to obtain robust values for G_(cli). Globally averaged, the values range from 0.99 to 1.28, depending on the chemical species, while, in areas of high pollution, G_(cli) can be up to 1.15 for ozone, and as large as 1.40 for total aerosol. These preliminary values indicate a significant role of climate feedbacks in the atmospheric chemistry system.", "doi": "10.1029/2009JD013300", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research B", "publication_date": "2010-06-26", "volume": "115", "pages": "Art. No. D12121" }, { "id": "authors:6707x-9x778", "collection": "authors", "collection_id": "6707x-9x778", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100706-092745845", "type": "article", "title": "Characterization and Quantification of Isoprene-Derived Epoxydiols in Ambient Aerosol in the Southeastern United States", "author": [ { "family_name": "Chan", "given_name": "Man Nin", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Claeys", "given_name": "Magda", "orcid": "0000-0003-2278-8014", "clpid": "Claeys-Magda" }, { "family_name": "Edgerton", "given_name": "Eric S.", "clpid": "Edgerton-Eric-S" }, { "family_name": "Tanner", "given_name": "Roger L.", "clpid": "Tanner-Roger-L" }, { "family_name": "Shaw", "given_name": "Stephanie L.", "orcid": "0000-0001-8198-4184", "clpid": "Shaw-Stephanie-L" }, { "family_name": "Zheng", "given_name": "Mei", "clpid": "Zheng-Mei" }, { "family_name": "Knipping", "given_name": "Eladio M.", "orcid": "0000-0002-9654-9019", "clpid": "Knipping-Eladio-M" }, { "family_name": "Eddingsaas", "given_name": "Nathan C.", "orcid": "0000-0003-1539-5415", "clpid": "Eddingsaas-Nathan-C" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Isoprene-derived epoxydiols (IEPOX) are identified in ambient aerosol samples for the first time, together with other previously identified isoprene tracers (i.e., 2-methyltetrols, 2-methylglyceric acid, C5-alkenetriols, and organosulfate derivatives of 2-methyltetrols). Fine ambient aerosol collected in downtown Atlanta, GA and rural Yorkville, GA during the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS) was analyzed using both gas chromatography/quadrupole mass spectrometry (GC/MS) and gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) with prior trimethylsilylation. Mass concentrations of IEPOX ranged from ~1 to 24 ng m^(\u22123) in the aerosol collected from the two sites. Detection of particle-phase IEPOX in the AMIGAS samples supports recent laboratory results that gas-phase IEPOX produced from the photooxidation of isoprene under low-NO_x conditions is a key precursor of ambient isoprene secondary organic aerosol (SOA) formation. On average, the sum of the mass concentrations of IEPOX and the measured isoprene SOA tracers accounted for about 3% of the organic carbon, demonstrating the significance of isoprene oxidation to the formation of ambient aerosol in this region.", "doi": "10.1021/es100596b", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2010-06-15", "series_number": "12", "volume": "44", "issue": "12", "pages": "4590-4596" }, { "id": "authors:e66z7-kgq86", "collection": "authors", "collection_id": "e66z7-kgq86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100706-091228446", "type": "article", "title": "Evidence for High Molecular Weight Nitrogen-Containing Organic Salts in Urban Aerosols", "author": [ { "family_name": "Wang", "given_name": "Xiaofei", "clpid": "Wang-Xiaofei" }, { "family_name": "Gao", "given_name": "Song", "orcid": "0000-0001-7427-6681", "clpid": "Gao-Song" }, { "family_name": "Yang", "given_name": "Xing", "clpid": "Yang-Xing" }, { "family_name": "Chen", "given_name": "Hong", "clpid": "Chen-Hong" }, { "family_name": "Chen", "given_name": "Jianmin", "orcid": "0000-0001-5859-3070", "clpid": "Chen-Jianmin" }, { "family_name": "Zhuang", "given_name": "Guoshun", "clpid": "Zhuang-Guoshun" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chan", "given_name": "Man Nin", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "High molecular weight (M_w) species were observed at substantial intensities in the positive-ion mass spectra in urban Shanghai aerosols collected from a single-particle time-of-flight mass spectrometer (in the m/z range 250\u2212500) during three separate periods over 2007\u22122009. These species correlate well with the CN\u2212 mass signal, suggesting that C\u2212N bonds are prevalent and that the observed high-M_w species are potentially nitrogen-containing organic salts. Anti-correlation with the ambient O_3 concentration suggests that photochemical oxidants are not involved directly in the formation of these species. The Mannich reaction, among amines (or ammonia), formaldehyde, and carbonyls with an adjacent, acidic proton, is proposed as a plausible pathway leading to these organic salts. Although the high-M_w species observed in the single-particle mass spectra appear to be nitrogen-containing organics, further chemical confirmation is desired to verify if the proposed Mannich reaction can explain the formation of these high-M_w species in regions where ammonia, amines, and carbonyls are prevalent.", "doi": "10.1021/es1001117", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2010-06-15", "series_number": "12", "volume": "44", "issue": "12", "pages": "4441-4446" }, { "id": "authors:r4q17-np813", "collection": "authors", "collection_id": "r4q17-np813", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100630-143230769", "type": "article", "title": "Organic aerosol components observed in Northern Hemispheric\n datasets from Aerosol Mass Spectrometry", "author": [ { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Canagaratna", "given_name": "M. R.", "orcid": "0000-0002-8803-4007", "clpid": "Canagaratna-Manjula-R" }, { "family_name": "Zhang", "given_name": "Q.", "orcid": "0000-0002-8376-131X", "clpid": "Zhang-Qiang" }, { "family_name": "Jimenez", "given_name": "J. L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-Jos\u00e9-L" }, { "family_name": "Tian", "given_name": "J.", "clpid": "Tian-J" }, { "family_name": "Ulbrich", "given_name": "I. M.", "clpid": "Ulbrich-Ingrid-M" }, { "family_name": "Kroll", "given_name": "J. H.", "orcid": "0000-0002-6275-521X", "clpid": "Kroll-Jesse-H" }, { "family_name": "Docherty", "given_name": "K. S.", "clpid": "Docherty-Kenneth-S" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Bahreini", "given_name": "R.", "orcid": "0000-0001-8292-5338", "clpid": "Bahreini-Roya" }, { "family_name": "Murphy", "given_name": "S. M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Hildebrandt", "given_name": "L.", "clpid": "Hildebrandt-Lea" }, { "family_name": "Donahue", "given_name": "N. M.", "orcid": "0000-0003-3054-2364", "clpid": "Donahue-Neil-M" }, { "family_name": "DeCarlo", "given_name": "P. F.", "orcid": "0000-0001-6385-7149", "clpid": "DeCarlo-Peter-F" }, { "family_name": "Lanz", "given_name": "V. A.", "clpid": "Lanz-V-A" }, { "family_name": "Pr\u00e9v\u00f4t", "given_name": "A. S. H.", "orcid": "0000-0002-9243-8194", "clpid": "Pr\u00e9v\u00f4t-Andre-S-H" }, { "family_name": "Dinar", "given_name": "E.", "clpid": "Dinar-E" }, { "family_name": "Rudich", "given_name": "Y.", "orcid": "0000-0003-3149-0201", "clpid": "Rudich-Yinon" }, { "family_name": "Worsnop", "given_name": "D. R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-Douglas-R" } ], "abstract": "In this study we compile and present results from the factor analysis of 43 Aerosol Mass Spectrometer (AMS) datasets (27 of the datasets are reanalyzed in this work). The components from all sites, when taken together, provide a holistic overview of Northern Hemisphere organic aerosol (OA) and its evolution in the atmosphere. At most sites, the OA can be separated into oxygenated OA (OOA), hydrocarbon-like OA (HOA), and sometimes other components such as biomass burning OA (BBOA). We focus on the OOA components in this work. In many analyses, the OOA can be further deconvolved into low-volatility OOA (LV-OOA) and semi-volatile OOA (SV-OOA). Differences in the mass spectra of these components are characterized in terms of the two main ions m/z 44 (CO\u2082\u207a) and m/z 43 (mostly C\u2082H\u2083O\u207a), which are used to develop a new mass spectral diagnostic for following the aging of OA components in the atmosphere. The LV-OOA component spectra have higher f\u2084\u2084 (ratio of m/z 44 to total signal in the component mass spectrum) and lower f\u2084\u2083 (ratio of m/z 43 to total signal in the component mass spectrum) than SV-OOA. A wide range of f44 and O:C ratios are observed for both LV-OOA (0.17\u00b10.04, 0.73\u00b10.14) and SV-OOA (0.07\u00b10.04, 0.35\u00b10.14) components, reflecting the fact that there is a continuum of OOA properties in ambient aerosol. The OOA components (OOA, LV-OOA, and SV-OOA) from all sites cluster within a well-defined triangular region in the f\u2084\u2084 vs. f\u2084\u2083 space, which can be used as a standardized means for comparing and characterizing any OOA components (laboratory or ambient) observed with the AMS. Examination of the OOA components in this triangular space indicates that OOA component spectra become increasingly similar to each other and to fulvic acid and HULIS sample spectra as f\u2084\u2084 (a surrogate for O:C and an indicator of photochemical aging) increases. This indicates that ambient OA converges towards highly aged LV-OOA with atmospheric oxidation. The common features of the transformation between SV-OOA and LV-OOA at multiple sites potentially enable a simplified description of the oxidation of OA in the atmosphere. Comparison of laboratory SOA data with ambient OOA indicates that laboratory SOA are more similar to SV-OOA and rarely become as oxidized as ambient LV-OOA, likely due to the higher loadings employed in the experiments and/or limited oxidant exposure in most chamber experiments.", "doi": "10.5194/acp-10-4625-2010", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2010-05-20", "series_number": "10", "volume": "10", "issue": "10", "pages": "4625-4641" }, { "id": "authors:4p1pb-8d756", "collection": "authors", "collection_id": "4p1pb-8d756", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100610-121931263", "type": "article", "title": "A global perspective on aerosol from low-volatility organic compounds", "author": [ { "family_name": "Pye", "given_name": "H. O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-H-O-T" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Global production of organic aerosol from primary emissions of semivolatile (SVOCs) and intermediate (IVOCs) volatility organic compounds is estimated using the global chemical transport model, GEOS-Chem. SVOC oxidation is predicted to be a larger global source of net aerosol production than oxidation of traditional parent hydrocarbons (terpenes, isoprene, and aromatics). Using a prescribed rate constant and reduction in volatility for atmospheric oxidation, the yield of aerosol from SVOCs is predicted to be about 75% on a global, annually-averaged basis. For IVOCs, the use of a naphthalene-like surrogate with different high-NOx and low-NOx parameterizations produces a global aerosol yield of about 30%, or roughly 5 Tg/yr of aerosol. Estimates of the total global organic aerosol source presented here range between 60 and 100 Tg/yr. This range reflects uncertainty in the parameters for SVOC volatility, SVOC oxidation, SVOC emissions, and IVOC emissions, as well as wet deposition. The highest estimates result if SVOC emissions are significantly underestimated (by more than a factor of 2) or if wet deposition of the gas-phase semivolatile species is less effective than previous estimates. A significant increase in SVOC emissions, a reduction of the volatility of the SVOC emissions, or an increase in the enthalpy of vaporization of the organic aerosol all lead to an appreciable reduction of prediction/measurement discrepancy. In addition, if current primary organic aerosol (POA) inventories capture only about one-half of the SVOC emission and the Henrys Law coefficient for oxidized semivolatiles is on the order of 10^3 M/atm, a global estimate of OA production is not inconsistent with the top-down estimate of 140 Tg/yr by (Goldstein and Galbally, 2007). Additional information is needed to constrain the emissions and treatment of SVOCs and IVOCs, which have traditionally not been included in models.", "doi": "10.5194/acp-10-4377-2010", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2010-05-12", "series_number": "9", "volume": "10", "issue": "9", "pages": "4377-4401" }, { "id": "authors:1yehe-am169", "collection": "authors", "collection_id": "1yehe-am169", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100602-081939482", "type": "article", "title": "Elemental analysis of chamber organic aerosol using an Aerodyne high-resolution aerosol mass spectrometer", "author": [ { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The elemental composition of laboratory chamber secondary organic aerosol (SOA) from glyoxal uptake, \u03b1-pinene ozonolysis, isoprene photooxidation, single-ring aromatic photooxidation, and naphthalene photooxidation is evaluated using Aerodyne high-resolution time-of-flight mass spectrometer data. SOA O/C ratios range from 1.13 for glyoxal uptake experiments to 0.30\u20130.43 for \u03b1-pinene ozonolysis. The elemental composition of \u03b1-pinene and naphthalene SOA is also confirmed by offline mass spectrometry. The fraction of organic signal at m/z 44 is generally a good measure of SOA oxygenation for \u03b1-pinene/O\u2083, isoprene/high-NO\u2093, and naphthalene SOA systems. The agreement between measured and estimated O/C ratios tends to get closer as the fraction of organic signal at m/z 44 increases. This is in contrast to the glyoxal uptake system, in which m/z 44 substantially underpredicts O/C. Although chamber SOA has generally been considered less oxygenated than ambient SOA, single-ring aromatic- and naphthalene-derived SOA can reach O/C ratios upward of 0.7, well within the range of ambient PMF component OOA, though still not as high as some ambient measurements. The spectra of aromatic and isoprene-high-NO\u2093 SOA resemble that of OOA, but the spectrum of glyoxal uptake does not resemble that of any ambient organic aerosol PMF component.", "doi": "10.5194/acp-10-4111-2010", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2010-05-03", "series_number": "9", "volume": "10", "issue": "9", "pages": "4111-4131" }, { "id": "authors:d1tym-zg968", "collection": "authors", "collection_id": "d1tym-zg968", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100524-143110498", "type": "article", "title": "Will black carbon mitigation dampen aerosol indirect forcing?", "author": [ { "family_name": "Chen", "given_name": "W.-T.", "orcid": "0000-0002-9292-0933", "clpid": "Chen-Wei-Ting" }, { "family_name": "Lee", "given_name": "Y. H.", "clpid": "Lee-Yong-Hee" }, { "family_name": "Adams", "given_name": "P. J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "[1] If mitigation of black carbon (BC) particulate matter is accompanied by a decrease in particle number emissions, and thereby by a decrease in global cloud condensation nuclei (CCN) concentrations, a decrease in global cloud radiative forcing (a reverse \"cloud albedo effect\") results. We consider two present-day mitigation scenarios: 50% reduction of primary black carbon/organic carbon (BC/OC) mass and number emissions from fossil fuel combustion (termed HF), and 50% reduction of primary BC/OC mass and number emissions from all primary carbonaceous sources (fossil fuel, domestic biofuel, and biomass burning) (termed HC). Radiative forcing effects of these scenarios are assessed through present-day equilibrium climate simulations. Global average top-of-the-atmosphere changes in radiative forcing for the two scenarios, relative to present day conditions, are +0.13 \u00b1 0.33 W m^(\u22122) (HF) and + 0.31 \u00b1 0.33 W m^(\u22122) (HC).", "doi": "10.1029/2010GL042886", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2010-05", "series_number": "9", "volume": "37", "issue": "9", "pages": "Art. No. L09801" }, { "id": "authors:r3zgd-5hq40", "collection": "authors", "collection_id": "r3zgd-5hq40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100527-135521520", "type": "article", "title": "Reactive intermediates revealed in secondary organic aerosol formation from isoprene", "author": [ { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chan", "given_name": "Arthur W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Eddingsaas", "given_name": "Nathan C.", "orcid": "0000-0003-1539-5415", "clpid": "Eddingsaas-Nathan-C" }, { "family_name": "Chan", "given_name": "ManNin", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Loza", "given_name": "Christine L.", "clpid": "Loza-Christine-L" }, { "family_name": "Kwan", "given_name": "Alan J.", "clpid": "Kwan-Alan-J" }, { "family_name": "Hersey", "given_name": "Scott P.", "clpid": "Hersey-Scott-P" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Isoprene is a significant source of atmospheric organic aerosol; however, the oxidation pathways that lead to secondary organic aerosol (SOA) have remained elusive. Here, we identify the role of two key reactive intermediates, epoxydiols of isoprene (IEPOX = \u03b2-IEPOX + \u03b4-IEPOX) and methacryloylperoxynitrate (MPAN), which are formed during isoprene oxidation under low- and high-NO_x conditions, respectively. Isoprene low-NO_x SOA is enhanced in the presence of acidified sulfate seed aerosol (mass yield 28.6%) over that in the presence of neutral aerosol (mass yield 1.3%). Increased uptake of IEPOX by acid-catalyzed particle-phase reactions is shown to explain this enhancement. Under high-NO_x conditions, isoprene SOA formation occurs through oxidation of its second-generation product, MPAN. The similarity of the composition of SOA formed from the photooxidation of MPAN to that formed from isoprene and methacrolein demonstrates the role of MPAN in the formation of isoprene high-NO_x SOA. Reactions of IEPOX and MPAN in the presence of anthropogenic pollutants (i.e., acidic aerosol produced from the oxidation of SO_2 and NO_2, respectively) could be a substantial source of \"missing urban SOA\" not included in current atmospheric models.", "doi": "10.1073/pnas.0911114107", "pmcid": "PMC2872383", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2010-04-13", "series_number": "15", "volume": "107", "issue": "15", "pages": "6640-6645" }, { "id": "authors:0c31j-1ay28", "collection": "authors", "collection_id": "0c31j-1ay28", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100525-150120905", "type": "article", "title": "Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry", "author": [ { "family_name": "Farmer", "given_name": "D. K.", "orcid": "0000-0002-6470-9970", "clpid": "Farmer-Delphine-K" }, { "family_name": "Matsunaga", "given_name": "A.", "clpid": "Matsunaga-A" }, { "family_name": "Docherty", "given_name": "K. S.", "clpid": "Docherty-Kenneth-S" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Ziemann", "given_name": "P. J.", "orcid": "0000-0001-7419-0044", "clpid": "Ziemann-Paul-L" }, { "family_name": "Jimenez", "given_name": "J. L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-Jos\u00e9-L" } ], "abstract": "Organonitrates (ON) are important products of gas-phase oxidation of volatile organic compounds in the troposphere; some models predict, and laboratory studies show, the formation of large, multifunctional ON with vapor pressures low enough to partition to the particle phase. Organosulfates (OS) have also been recently detected in secondary organic aerosol. Despite their potential importance, ON and OS remain a nearly unexplored aspect of atmospheric chemistry because few studies have quantified particulate ON or OS in ambient air. We report the response of a high-resolution time-of-flight aerosol mass spectrometer (AMS) to aerosol ON and OS standards and mixtures. We quantify the potentially substantial underestimation of organic aerosol O/C, commonly used as a metric for aging, and N/C. Most of the ON-nitrogen appears as NO_x^+ ions in the AMS, which are typically dominated by inorganic nitrate. Minor organonitrogen ions are observed although their identity and intensity vary between standards. We evaluate the potential for using NO_x^+ fragment ratios, organonitrogen ions, HNO_3^+ ions, the ammonium balance of the nominally inorganic ions, and comparison to ion-chromatography instruments to constrain the concentrations of ON for ambient datasets, and apply these techniques to a field study in Riverside, CA. OS manifests as separate organic and sulfate components in the AMS with minimal organosulfur fragments and little difference in fragmentation from inorganic sulfate. The low thermal stability of ON and OS likely causes similar detection difficulties for other aerosol mass spectrometers using vaporization and/or ionization techniques with similar or larger energy, which has likely led to an underappreciation of these species.", "doi": "10.1073/pnas.0912340107", "pmcid": "PMC2872396", "issn": "0027-8424", "publisher": "National Academy of Sciences", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "publication_date": "2010-04-13", "series_number": "15", "volume": "107", "issue": "15", "pages": "6670-6675" }, { "id": "authors:ach5p-xff77", "collection": "authors", "collection_id": "ach5p-xff77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100317-085129359", "type": "article", "title": "Results from the CERN pilot CLOUD experiment", "author": [ { "family_name": "Duplissy", "given_name": "J.", "clpid": "Duplissy-J" }, { "family_name": "Enghoff", "given_name": "M. B.", "clpid": "Enghoff-M-B" }, { "family_name": "Aplin", "given_name": "K. L.", "clpid": "Aplin-K-L" }, { "family_name": "Arnold", "given_name": "F.", "clpid": "Arnold-F" }, { "family_name": "Aufmhoff", "given_name": "H.", "clpid": "Aufmhoff-H" }, { "family_name": "Avngaard", "given_name": "M.", "clpid": "Avngaard-M" }, { "family_name": "Baltensperger", "given_name": "U.", "clpid": "Baltensperger-U" }, { "family_name": "Bondo", "given_name": "T.", "clpid": "Bondo-T" }, { "family_name": "Bingham", "given_name": "R.", "clpid": "Bingham-R" }, { "family_name": "Carslaw", "given_name": "K.", "clpid": "Carslaw-K-S" }, { "family_name": "Curtius", "given_name": "J.", "clpid": "Curtius-J" }, { "family_name": "David", "given_name": "A.", "clpid": "David-A" }, { "family_name": "Fastrup", "given_name": "B.", "clpid": "Fastrup-B" }, { "family_name": "Gagn\u00e9", "given_name": "S.", "clpid": "Gagn\u00e9-S" }, { "family_name": "Hahn", "given_name": "F.", "clpid": "Hahn-F" }, { "family_name": "Harrison", "given_name": "R. G.", "clpid": "Harrison-R-G" }, { "family_name": "Kellett", "given_name": "B.", "clpid": "Kellett-B" }, { "family_name": "Kirkby", "given_name": "J.", "clpid": "Kirkby-J" }, { "family_name": "Kulmala", "given_name": "M.", "clpid": "Kulmala-M" }, { "family_name": "Laakso", "given_name": "L.", "clpid": "Laakso-L" }, { "family_name": "Laaksonen", "given_name": "A.", "clpid": "Laaksonen-A" }, { "family_name": "Lillestol", "given_name": "E.", "clpid": "Lillestol-E" }, { "family_name": "Lockwood", "given_name": "M.", "clpid": "Lockwood-M" }, { "family_name": "M\u00e4kel\u00e4", "given_name": "J.", "clpid": "M\u00e4kel\u00e4-J" }, { "family_name": "Makhmutov", "given_name": "V.", "clpid": "Makhmutov-V" }, { "family_name": "Marsh", "given_name": "N. D.", "clpid": "Marsh-N-D" }, { "family_name": "Nieminen", "given_name": "T.", "clpid": "Nieminen-T" }, { "family_name": "Onnela", "given_name": "A.", "clpid": "Onnela-A" }, { "family_name": "Pedersen", "given_name": "E.", "clpid": "Pedersen-E" }, { "family_name": "Pedersen", "given_name": "J. O. P.", "clpid": "Pedersen-J-O-P" }, { "family_name": "Polny", "given_name": "J.", "clpid": "Polny-J" }, { "family_name": "Reichl", "given_name": "U.", "clpid": "Reichl-U" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Sipil\u00e4", "given_name": "M.", "clpid": "Sipil\u00e4-M" }, { "family_name": "Stozhkov", "given_name": "Y.", "clpid": "Stozhkov-Y" }, { "family_name": "Stratmann", "given_name": "F.", "clpid": "Stratmann-F" }, { "family_name": "Svensmark", "given_name": "H.", "clpid": "Svensmark-H" }, { "family_name": "Svensmark", "given_name": "J.", "clpid": "Svensmark-J" }, { "family_name": "Svensmark", "given_name": "R.", "clpid": "Svensmark-r" }, { "family_name": "Veenhof", "given_name": "B.", "clpid": "Veenhof-b" }, { "family_name": "Viisanen", "given_name": "Y.", "clpid": "Viisanen-Y" }, { "family_name": "Wagner", "given_name": "P. E.", "clpid": "Wagner-P-E" }, { "family_name": "Wehrle", "given_name": "G.", "clpid": "Wehrle-G" }, { "family_name": "Weingartner", "given_name": "E.", "clpid": "Weingartner-E" }, { "family_name": "Wex", "given_name": "H.", "clpid": "Wex-H" }, { "family_name": "Wilhelmsson", "given_name": "M.", "clpid": "Wilhelmsson-M" }, { "family_name": "Winkler", "given_name": "P. M.", "clpid": "Winkler-P-M" } ], "abstract": "During a 4-week run in October\u2013November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H_2SO_4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm^(\u22123)s^(\u22121), and growth rates between 2 and 37 nm h^(\u22121). The corresponding H_2SO_4 concentrations were typically around 106 cm^(\u22123) or less. The experimentally-measured formation rates and H_2SO_4 concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1 \u00b0C).", "doi": "10.5194/acp-10-1635-2010", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2010-02-15", "series_number": "4", "volume": "10", "issue": "4", "pages": "1635-1647" }, { "id": "authors:vh4qs-t9t59", "collection": "authors", "collection_id": "vh4qs-t9t59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100225-165528156", "type": "article", "title": "Response to Comment on \"Unexpected Epoxide Formation in the Gas-Phase Photooxidation of Isoprene\"", "author": [ { "family_name": "Paulot", "given_name": "Fabien", "orcid": "0000-0001-7534-4922", "clpid": "Paulot-F" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Kjaergaard", "given_name": "Henrik G.", "orcid": "0000-0002-7275-8297", "clpid": "Kjaergaard-H-G" }, { "family_name": "K\u00fcrten", "given_name": "Andreas", "orcid": "0000-0002-8955-4450", "clpid": "K\u00fcrten-A" }, { "family_name": "St. Clair", "given_name": "Jason M.", "orcid": "0000-0002-9367-5749", "clpid": "St-Clair-J-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "Claeys questions whether gaseous epoxydiol is formed from the oxidation of isoprene and whether it is relevant to the formation of isoprene-derived secondary organic aerosol (iSOA). We argue that the alternative mechanism she proposes for iSOA applies primarily to chamber studies with high isoprene and is not as important in the atmosphere, where isoprene concentrations are much lower.", "doi": "10.1126/science.1181689", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2010-02-05", "series_number": "5966", "volume": "327", "issue": "5966", "pages": "644" }, { "id": "authors:023zs-wj654", "collection": "authors", "collection_id": "023zs-wj654", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100607-085410213", "type": "article", "title": "Cardiopulmonary response to inhalation of biogenic secondary organic aerosol", "author": [ { "family_name": "McDonald", "given_name": "Jacob D.", "clpid": "McDonald-Jacob-D" }, { "family_name": "Doyle-Eisele", "given_name": "Melanie", "clpid": "Doyle-Eisele-Melanie" }, { "family_name": "Campen", "given_name": "Matthew J.", "clpid": "Campen-Matthew-J" }, { "family_name": "Seagrave", "given_name": "JeanClare", "clpid": "Seagrave-JeanClare" }, { "family_name": "Holmes", "given_name": "Tom", "orcid": "0000-0003-2116-8147", "clpid": "Holmes-Tom" }, { "family_name": "Lund", "given_name": "Amie", "orcid": "0000-0002-0878-751X", "clpid": "Lund-Amie-K" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Rohr", "given_name": "Annette C.", "clpid": "Rohr-Annette-C" }, { "family_name": "Knipping", "given_name": "Eladio M.", "orcid": "0000-0002-9654-9019", "clpid": "Knipping-Eladio-M" } ], "abstract": "An irradiation chamber designed for reproducible generation of inhalation test atmospheres of secondary organic aerosol (SOA) was used to evaluate cardiopulmonary responses in rodents exposed to SOA derived from the oxidation of \u03b1-pinene. SOA atmospheres were produced with 10:1 ratios of \u03b1-pinene:nitrogen oxides (NO_x) and 10:1:1 ratios of \u03b1-pinene:nitrogen oxides:sulfur dioxide (SO_2). SOA atmospheres were produced to yield 200 \u03bcg m^(\u22123) of particulate matter (PM). Exposures were conducted downstream of honeycomb denuders employed to remove the gas-phase precursors and reaction products. Nose-only exposures were conducted with both rats (pulmonary effects) and mice (pulmonary and cardiovascular effects). Composition of the atmospheres was optimized to ensure that the SOA generated resembled SOA observed in previous irradiation studies, and contained specific SOA compounds of interest (e.g., organosulfates) identified in ambient air. Pulmonary and cardiovascular toxicity were measured in two different rodent species. In situ chemiluminescence and thiobarbituric acid\u2013 reactive substances (TBARS) were used to evaluate oxidative reactions in the F344 rats. ApoE^(\u2212/\u2212) mice were exposed for 7 days and measurements of TBARS and gene expression of heme oxygenase-1 (HO-1), endothelin-1 (ET-1), matrix metalloproteinase-9 (MMP-9) were made in aorta. Pulmonary inflammatory responses in both species were measured by bronchoalveolar lavage fluid (BALF) cell counts. No pulmonary inflammation was observed in either species. A mild response was observed in mouse aorta for the upregulation of HO-1 and MMP-9, but was not seen for ET-1. Overall, \u03b1-pinene\u2013derived SOA, including SOA that included organosulfate compounds, revealed limited biological response after short-term inhalation exposures.", "doi": "10.3109/08958370903148114", "issn": "0895-8378", "publisher": "Taylor & Francis", "publication": "Inhalation Toxicology", "publication_date": "2010-02", "series_number": "3", "volume": "22", "issue": "3", "pages": "253-265" }, { "id": "authors:93d3n-5fd34", "collection": "authors", "collection_id": "93d3n-5fd34", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100316-130917161", "type": "article", "title": "Water-soluble SOA from Alkene ozonolysis: composition and droplet activation kinetics inferences from analysis of CCN activity", "author": [ { "family_name": "Asa-Awuku", "given_name": "A.", "clpid": "Asa-Awuku-Akua" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Gao", "given_name": "S.", "orcid": "0000-0001-7427-6681", "clpid": "Gao-Song" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Cloud formation characteristics of the water-soluble organic fraction (WSOC) of secondary organic aerosol (SOA) formed from the ozonolysis of alkene hydrocarbons (terpinolene, 1-methlycycloheptene and cycloheptene) are studied. Based on size-resolved measurements of CCN activity (of the pure and salted WSOC samples) we estimate the average molar volume and surface tension depression associated with the WSOC using K\u00f6hler Theory Analysis (KTA). Consistent with known speciation, the results suggest that the WSOC are composed of low molecular weight species, with an effective molar mass below 200 g mol^(\u22121). The water-soluble carbon is also surface-active, depressing surface tension 10\u201315% from that of pure water (at CCN-relevant concentrations). The inherent hygroscopicity parameter, \u03ba, of the WSOC ranges between 0.17 and 0.25; if surface tension depression and molar volume effects are considered in \u03ba, a remarkably constant \"apparent\" hygroscopicity ~0.3 emerges for all samples considered. This implies that the volume fraction of soluble material in the parent aerosol is the key composition parameter required for prediction of the SOA hygroscopicity, as shifts in molar volume across samples are compensated by changes in surface tension. Finally, using \"threshold droplet growth analysis\", the water-soluble organics in all samples considered do not affect CCN activation kinetics.", "doi": "10.5194/acp-10-1585-2010", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2010-02", "series_number": "4", "volume": "10", "issue": "4", "pages": "1585-1597" }, { "id": "authors:q04wx-g1e86", "collection": "authors", "collection_id": "q04wx-g1e86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100128-134602813", "type": "article", "title": "Chemical Composition of Gas- and Aerosol-Phase Products from the Photooxidation of Naphthalene", "author": [ { "family_name": "Kautzman", "given_name": "K.", "clpid": "Kautzman-K" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chan", "given_name": "M. N.", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Hersey", "given_name": "S. P.", "clpid": "Hersey-Scott-P" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Dalleska", "given_name": "N. F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The current work focuses on the detailed evolution of the chemical composition of both the gas- and aerosol-phase constituents produced from the OH-initiated photooxidation of naphthalene under low- and high-NO\u2093 conditions. Under high-NO\u2093 conditions ring-opening products are the primary gas-phase products, suggesting that the mechanism involves dissociation of alkoxy radicals (RO) formed through an RO\u2082 + NO pathway, or a bicyclic peroxy mechanism. In contrast to the high-NO\u2093 chemistry, ring-retaining compounds appear to dominate the low-NO\u2093 gas-phase products owing to the RO\u2082 + HO\u2082 pathway. We are able to chemically characterize 53\u221268% of the secondary organic aerosol (SOA) mass. Atomic oxygen-to-carbon (O/C), hydrogen-to-carbon (H/C), and nitrogen-to-carbon (N/C) ratios measured in bulk samples by high-resolution electrospray ionization time-of-flight mass spectrometry (HR-ESI-TOFMS) are the same as the ratios observed with online high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS), suggesting that the chemical compositions and oxidation levels found in the chemically-characterized fraction of the particle phase are representative of the bulk aerosol. Oligomers, organosulfates (R-OSO\u2083), and other high-molecular-weight (MW) products are not observed in either the low- or high-NO\u2093 SOA; however, in the presence of neutral ammonium sulfate seed aerosol, an organic sulfonic acid (R-SO\u2083), characterized as hydroxybenzene sulfonic acid, is observed in naphthalene SOA produced under both high- and low-NO\u2093 conditions. Acidic compounds and organic peroxides are found to account for a large fraction of the chemically characterized high- and low-NO\u2093 SOA. We propose that the major gas- and aerosol-phase products observed are generated through the formation and further reaction of 2-formylcinnamaldehyde or a bicyclic peroxy intermediate. The chemical similarity between the laboratory SOA and ambient aerosol collected from Birmingham, Alabama (AL) and Pasadena, California (CA) confirm the importance of PAH oxidation in the formation of aerosol within the urban atmosphere.", "doi": "10.1021/jp908530s", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2010-01-21", "series_number": "2", "volume": "114", "issue": "2", "pages": "913-934" }, { "id": "authors:8sn00-pz591", "collection": "authors", "collection_id": "8sn00-pz591", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110105-081712578", "type": "article", "title": "Global modeling of organic aerosol: the importance of reactive nitrogen (NO\u2093 and NO\u2083)", "author": [ { "family_name": "Pye", "given_name": "H. O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-H-O-T" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Barkley", "given_name": "M. P.", "clpid": "Barkley-M-P" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Reactive nitrogen compounds, specifically NO\u2093 and NO\u2083, likely influence global organic aerosol levels. To assess these interactions, GEOS-Chem, a chemical transport model, is updated to include improved biogenic emissions (following MEGAN v2.1/2.04), a new organic aerosol tracer lumping scheme, aerosol from nitrate radical (NO\u2083) oxidation of isoprene, and NO\u2093-dependent monoterpene and sesquiterpene aerosol yields. As a result of significant nighttime terpene emissions, fast reaction of monoterpenes with the nitrate radical, and relatively high aerosol yields from NO\u2083 oxidation, biogenic hydrocarbon-NO\u2083 reactions are expected to be a major contributor to surface level aerosol concentrations in anthropogenically influenced areas such as the United States. By including aerosol from nitrate radical oxidation in GEOS-Chem, terpene (monoterpene + sesquiterpene) aerosol approximately doubles and isoprene aerosol is enhanced by 30 to 40% in the Southeast United States. In terms of the global budget of organic aerosol, however, aerosol from nitrate radical oxidation is somewhat minor (slightly more than 3 Tg/yr) due to the relatively high volatility of organic-NO\u2083 oxidation products in the yield parameterization. Globally, 69 to 88 Tg/yr of organic aerosol is predicted to be produced annually, of which 14–15 Tg/yr is from oxidation of monoterpenes and sesquiterpenes and 8–9 Tg/yr from isoprene.
", "doi": "10.5194/acp-10-11261-2010", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2010", "series_number": "22", "volume": "10", "issue": "22", "pages": "11261-11276" }, { "id": "authors:1kvaa-fvj98", "collection": "authors", "collection_id": "1kvaa-fvj98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100119-103146516", "type": "article", "title": "Marine stratocumulus aerosol-cloud relationships in the MASE-II experiment: Precipitation susceptibility in eastern Pacific marine stratocumulus", "author": [ { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Feingold", "given_name": "Graham", "clpid": "Feingold-G" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Observational data on aerosol-cloud-drizzle relationships in marine stratocumulus are presented from the second Marine Stratus/Stratocumulus Experiment (MASE-II) carried out in July 2007 over the eastern Pacific near Monterey, California. Observations, carried out in regions of essentially uniform meteorology with localized aerosol enhancements due to ship exhaust (\"ship tracks\"), demonstrate, in accord with those from numerous other field campaigns, that increased cloud drop number concentration Nc and decreased cloud top effective radius r_e are associated with increased subcloud aerosol concentration. Modulation of drizzle by variations in aerosol levels is\nlevels is clearly evident.\nVariations of cloud base drizzle rate R_(cb) are found to be consistent with the proportionality,\nR_(cb) / H^3/N_c, where H is cloud depth. Simultaneous aircraft and A-Train satellite\nobservations are used to quantify the precipitation susceptibility of clouds to aerosol\nperturbations in the eastern Pacific region.", "doi": "10.1029/2009JD012774", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2009-12-22", "series_number": "24", "volume": "114", "issue": "24", "pages": "Art. No. D24203" }, { "id": "authors:366z7-g9174", "collection": "authors", "collection_id": "366z7-g9174", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091104-103810438", "type": "article", "title": "On the link between ocean biota emissions, aerosol, and maritime clouds: Airborne, ground, and satellite measurements off the coast of California", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Padr\u00f3", "given_name": "Luz T.", "clpid": "Padr\u00f3-Luz-T" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Feingold", "given_name": "Graham", "orcid": "0000-0002-0774-2926", "clpid": "Feingold-Graham" }, { "family_name": "McComiskey", "given_name": "Allison", "clpid": "McComiskey-Allison" }, { "family_name": "Hersey", "given_name": "Scott P.", "clpid": "Hersey-Scott-P" }, { "family_name": "Gates", "given_name": "Harmony", "clpid": "Gates-Harmony" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Miller", "given_name": "Steven D.", "clpid": "Miller-Steven-D" }, { "family_name": "Stephens", "given_name": "Graeme L.", "orcid": "0000-0002-9860-0287", "clpid": "Stephens-Graeme-L" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Surface, airborne, and satellite measurements over the eastern Pacific Ocean off the coast of California during the period between 2005 and 2007 are used to explore the relationship between ocean chlorophyll a, aerosol, and marine clouds. Periods of enhanced chlorophyll a and wind speed are coincident with increases in particulate diethylamine and methanesulfonate concentrations. The measurements indicate that amines are a source of secondary organic aerosol in the marine atmosphere. Subsaturated aerosol hygroscopic growth measurements indicate that the organic component during periods of high chlorophyll a and wind speed exhibit considerable water uptake ability. Increased average cloud condensation nucleus (CCN) activity during periods of increased chlorophyll a levels likely results from both size distribution and aerosol composition changes. The available data over the period of measurements indicate that the cloud microphysical response, as represented by either cloud droplet number concentration or cloud droplet effective radius, is likely influenced by a combination of atmospheric dynamics and aerosol perturbations during periods of high chlorophyll a concentrations.", "doi": "10.1029/2009GB003464", "issn": "0886-6236", "publisher": "American Geophysical Union", "publication": "Global Biogeochemical Cycles", "publication_date": "2009-12", "series_number": "4", "volume": "23", "issue": "4", "pages": "GB4007" }, { "id": "authors:qa2z4-bk975", "collection": "authors", "collection_id": "qa2z4-bk975", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091030-075831706", "type": "article", "title": "New Directions: Climate change and air pollution abatement: A bumpy road", "author": [ { "family_name": "Raes", "given_name": "Frank", "clpid": "Raes-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "[No abstract]", "doi": "10.1016/j.atmosenv.2009.06.001", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2009-10", "series_number": "32", "volume": "43", "issue": "32", "pages": "5132-5133" }, { "id": "authors:qqyn6-dgv27", "collection": "authors", "collection_id": "qqyn6-dgv27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091013-093449812", "type": "article", "title": "Observations of marine stratocumulus microphysics and implications for processes controlling droplet spectra: Results from the Marine Stratus/Stratocumulus Experiment", "author": [ { "family_name": "Wang", "given_name": "Jian", "clpid": "Wang-Jian" }, { "family_name": "Daum", "given_name": "Peter H.", "clpid": "Daum-P-H" }, { "family_name": "Yum", "given_name": "Seong Soo", "clpid": "Yum-Seong-Soo" }, { "family_name": "Liu", "given_name": "Yangang", "clpid": "Liu-Yangang" }, { "family_name": "Senum", "given_name": "Gunnar I.", "clpid": "Senum-G-I" }, { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" } ], "abstract": "During the Marine Stratus/Stratocumulus Experiment, cloud and aerosol microphysics were measured in the eastern Pacific off the coast of northern California on board Department of Energy Gulfstream-1 in July 2005. Three cases with uniform aerosol concentration and minimal drizzle concentration were examined to study cloud microphysical behavior. For these three cases, the average droplet number concentration increased with increasing altitude, while the average interstitial aerosol concentration decreased with altitude. The data show enhanced growth of large droplets and spectral broadening in cloud parcels with low liquid water mixing ratio. Three mixing models, including inhomogeneous mixing, entity type entrainment mixing, and circulation mixing proposed in this study, are examined with regard to their influences on cloud microphysics. The observed cloud microphysical behavior is most consistent with the circulation mixing, which describes the mixing between cloud parcels with different lifting condensation levels during their circulations driven by evaporative and radiative cooling. The enhanced growth and spectrum broadening resulting from the circulation mixing reduce cloud albedo at the same liquid water path and facilitate the formation of precipitation embryos.", "doi": "10.1029/2008JD011035", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2009-09-23", "series_number": "18", "volume": "114", "issue": "18", "pages": "D18210" }, { "id": "authors:7paw4-7kg58", "collection": "authors", "collection_id": "7paw4-7kg58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090923-143136924", "type": "article", "title": "Terpenylic Acid and Related Compounds from the Oxidation of \u03b1-Pinene: Implications for New Particle Formation and Growth above Forests", "author": [ { "family_name": "Claeys", "given_name": "Magda", "orcid": "0000-0003-2278-8014", "clpid": "Claeys-Magda" }, { "family_name": "Iinuma", "given_name": "Yoshiteru", "orcid": "0000-0001-5052-6906", "clpid": "Iinuma-Yoshiteru" }, { "family_name": "Szmigielski", "given_name": "Rafal", "orcid": "0000-0003-3389-9318", "clpid": "Szmigielski-Rafal" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Blockhuys", "given_name": "Frank", "orcid": "0000-0002-2201-6682", "clpid": "Blockhuys-Frank" }, { "family_name": "Van Alsenoy", "given_name": "Christian", "clpid": "Van-Alsenoy-Christian" }, { "family_name": "B\u00f6ge", "given_name": "Olaf", "orcid": "0000-0002-3290-3007", "clpid": "B\u00f6ge-Olaf" }, { "family_name": "Sierau", "given_name": "Berko", "clpid": "Sierau-Berko" }, { "family_name": "G\u00f3mez-Gonz\u00e1lez", "given_name": "Yadian", "orcid": "0000-0002-8673-2610", "clpid": "G\u00f3mez-Gonz\u00e1lez-Yadian" }, { "family_name": "Vermeylen", "given_name": "Reinhilde", "clpid": "Vermeylen-Reinhilde" }, { "family_name": "Van der Veken", "given_name": "Pieter", "clpid": "Van-der-Veken-Pieter" }, { "family_name": "Shahgholi", "given_name": "Mona", "orcid": "0000-0002-8879-4305", "clpid": "Shahgholi-Mona" }, { "family_name": "Chan", "given_name": "Arthur W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Herrmann", "given_name": "Hartmut", "orcid": "0000-0001-7044-2101", "clpid": "Herrmann-Hartmut" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Maenhaut", "given_name": "Willy", "orcid": "0000-0002-4715-4627", "clpid": "Maenhaut-Willy" } ], "abstract": "Novel secondary organic aerosol (SOA) products from the monoterpene \u03b1-pinene with unique dimer-forming properties have been identified as lactone-containing terpenoic acids, i.e., terpenylic and 2-hydroxyterpenylic acid, and diaterpenylic acid acetate. The structural characterizations were based on the synthesis of reference compounds and detailed interpretation of mass spectral data. Terpenylic acid and diaterpenylic acid acetate are early oxidation products generated upon both photooxidation and ozonolysis, while 2-hydroxyterpenylic acid is an abundant SOA tracer in ambient fine aerosol that can be explained by further oxidation of terpenylic acid. Quantum chemical calculations support that noncovalent dimer formation involving double hydrogen bonding interactions between carboxyl groups of the monomers is energetically favorable. The molecular properties allow us to explain initial particle formation in laboratory chamber experiments and are suggested to play a role in new particle formation and growth above forests, a natural phenomenon that has fascinated scientists for more than a century.", "doi": "10.1021/es9007596", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2009-09-15", "series_number": "18", "volume": "43", "issue": "18", "pages": "6976-6982" }, { "id": "authors:skmqq-5f747", "collection": "authors", "collection_id": "skmqq-5f747", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090923-143137436", "type": "article", "title": "Inverse modeling and mapping US air quality influences of inorganic PM_(2.5) precursor emissions using the adjoint of GEOS-Chem", "author": [ { "family_name": "Henze", "given_name": "D. K.", "clpid": "Henze-D-K" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Shindell", "given_name": "D. T.", "clpid": "Sindell-D-T" } ], "abstract": "Influences of specific sources of inorganic PM_(2.5) on peak and ambient aerosol concentrations in the US are evaluated using a combination of inverse modeling and sensitivity analysis. First, sulfate and nitrate aerosol measurements from the IMPROVE network are assimilated using the four-dimensional variational (4D-Var) method into the GEOS-Chem chemical transport model in order to constrain emissions estimates in four separate month-long inversions (one per season). Of the precursor emissions, these observations primarily constrain ammonia (NH_3). While the net result is a decrease in estimated US~NH_3 emissions relative to the original inventory, there is considerable variability in adjustments made to NH_3 emissions in different locations, seasons and source sectors, such as focused decreases in the midwest during July, broad decreases throughout the US~in January, increases in eastern coastal areas in April, and an effective redistribution of emissions from natural to anthropogenic sources. Implementing these constrained emissions, the adjoint model is applied to quantify the influences of emissions on representative PM_(2.5) air quality metrics within the US. The resulting sensitivity maps display a wide range of spatial, sectoral and seasonal variability in the susceptibility of the air quality metrics to absolute emissions changes and the effectiveness of incremental emissions controls of specific source sectors. NH_3 emissions near sources of sulfur oxides (SO_x) are estimated to most influence peak inorganic PM_(2.5) levels in the East; thus, the most effective controls of NH_3 emissions are often disjoint from locations of peak NH_3 emissions. Controls of emissions from industrial sectors of SO_x and NO_x are estimated to be more effective than surface emissions, and changes to NH_3 emissions in regions dominated by natural sources are disproportionately more effective than regions dominated by anthropogenic sources. NOx controls are most effective in northern states in October; in January, SO_x controls may be counterproductive. When considering ambient inorganic PM_(2.5) concentrations, intercontinental influences are small, though transboundary influences within North America are significant, with SO_x emissions from surface sources in Mexico contributing almost a fourth of the total influence from this sector.", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2009-08-19", "series_number": "16", "volume": "9", "issue": "16", "pages": "5877-5903" }, { "id": "authors:e949e-f0k31", "collection": "authors", "collection_id": "e949e-f0k31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090826-112856345", "type": "article", "title": "Modeling of secondary organic aerosol yields from laboratory chamber data", "author": [ { "family_name": "Chan", "given_name": "M. N.", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Laboratory chamber data serve as the basis for constraining models of secondary organic aerosol (SOA) formation. Current models fall into three categories: empirical two-product (Odum), product-specific, and volatility basis set. The product-specific and volatility basis set models are applied here to represent laboratory data on the ozonolysis of \u03b1-pinene under dry, dark, and low-NOx conditions in the presence of ammonium sulfate seed aerosol. Using five major identified products, the model is fit to the chamber data. From the optimal fitting, SOA oxygen-to-carbon (O/C) and hydrogen-to-carbon (H/C) ratios are modeled. The discrepancy between measured H/C ratios and those based on the oxidation products used in the model fitting suggests the potential importance of particle-phase reactions. Data fitting is also carried out using the volatility basis set, wherein oxidation products are parsed into volatility bins. The product-specific model is most likely hindered by lack of explicit inclusion of particle-phase accretion compounds. While prospects for identification of the majority of SOA products for major volatile organic compounds (VOCs) classes remain promising, for the near future empirical product or volatility basis set models remain the approaches of choice.", "doi": "10.5194/acp-9-5669-2009", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2009-08-10", "series_number": "15", "volume": "9", "issue": "15", "pages": "5669-5680" }, { "id": "authors:yfrgd-8hw59", "collection": "authors", "collection_id": "yfrgd-8hw59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090817-144809010", "type": "article", "title": "Unexpected Epoxide Formation in the Gas-Phase Photooxidation of Isoprene", "author": [ { "family_name": "Paulot", "given_name": "Fabien", "orcid": "0000-0001-7534-4922", "clpid": "Paulot-F" }, { "family_name": "Crounse", "given_name": "John D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Kjaergaard", "given_name": "Henrik G.", "orcid": "0000-0002-7275-8297", "clpid": "Kjaergaard-H-G" }, { "family_name": "Kuerten", "given_name": "Adreas", "clpid": "Kuerten-A" }, { "family_name": "St. Clair", "given_name": "Jason M.", "orcid": "0000-0002-9367-5749", "clpid": "St-Clair-J-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "Emissions of nonmethane hydrocarbon compounds to the atmosphere from the biosphere exceed those from anthropogenic activity. Isoprene, a five-carbon diene, contributes more than 40% of these emissions. Once emitted to the atmosphere, isoprene is rapidly oxidized by the hydroxyl radical OH. We report here that under pristine conditions isoprene is oxidized primarily to hydroxyhydroperoxides. Further oxidation of these hydroxyhydroperoxides by OH leads efficiently to the formation of dihydroxyepoxides and OH reformation. Global simulations show an enormous flux -\u2014 nearly 100 teragrams of carbon per year -\u2014 of these epoxides to the atmosphere. The discovery of these highly soluble epoxides provides a missing link tying the gas-phase degradation of isoprene to the observed formation of organic aerosols.", "doi": "10.1126/science.1172910", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2009-08-07", "series_number": "5941", "volume": "325", "issue": "5941", "pages": "730-733" }, { "id": "authors:0tc3s-z5b50", "collection": "authors", "collection_id": "0tc3s-z5b50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090817-144820295", "type": "article", "title": "The formation, properties and impact of secondary organic aerosol: current and emerging issues", "author": [ { "family_name": "Hallquist", "given_name": "M.", "orcid": "0000-0001-5691-1231", "clpid": "Hallquist-Mattias" }, { "family_name": "Wenger", "given_name": "J. C.", "orcid": "0000-0002-4109-976X", "clpid": "Wenger-John-C" }, { "family_name": "Baltensperger", "given_name": "U.", "orcid": "0000-0003-0079-8713", "clpid": "Baltensperger-Urs" }, { "family_name": "Rudich", "given_name": "Y.", "orcid": "0000-0003-3149-0201", "clpid": "Rudich-Yinon" }, { "family_name": "Simpson", "given_name": "D.", "clpid": "Simpson-D" }, { "family_name": "Claeys", "given_name": "M.", "orcid": "0000-0003-2278-8014", "clpid": "Claeys-Magda" }, { "family_name": "Dommen", "given_name": "J.", "orcid": "0000-0002-0006-0009", "clpid": "Dommen-Josef" }, { "family_name": "Donahue", "given_name": "N. M.", "orcid": "0000-0003-3054-2364", "clpid": "Donahue-Neil-M" }, { "family_name": "George", "given_name": "C.", "clpid": "George-C" }, { "family_name": "Goldstein", "given_name": "A. H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-Allen-H" }, { "family_name": "Hamilton", "given_name": "J. F.", "clpid": "Hamilton-J-F" }, { "family_name": "Herrmann", "given_name": "H.", "orcid": "0000-0001-7044-2101", "clpid": "Herrmann-Hartmut" }, { "family_name": "Hoffmann", "given_name": "T.", "orcid": "0000-0003-0939-271X", "clpid": "Hoffmann-Thorsten" }, { "family_name": "Iinuma", "given_name": "Y.", "orcid": "0000-0001-5052-6906", "clpid": "Iinuma-Yoshiteru" }, { "family_name": "Jang", "given_name": "M.", "clpid": "Jang-M" }, { "family_name": "Jenkin", "given_name": "M. E.", "clpid": "Jenkin-M-E" }, { "family_name": "Jimenez", "given_name": "J. L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-Jos\u00e9-L" }, { "family_name": "Kiendler-Scharr", "given_name": "A.", "orcid": "0000-0003-3166-2253", "clpid": "Kiendler-Scharr-Astrid" }, { "family_name": "Maenhaut", "given_name": "W.", "orcid": "0000-0002-4715-4627", "clpid": "Maenhaut-Willy" }, { "family_name": "McFiggans", "given_name": "G.", "orcid": "0000-0002-3423-7896", "clpid": "McFiggans-Gordon" }, { "family_name": "Mentel", "given_name": "Th. F.", "orcid": "0000-0003-0810-3541", "clpid": "Mentel-Thomas-F" }, { "family_name": "Monod", "given_name": "A.", "orcid": "0000-0002-2049-0356", "clpid": "Monod-Anne" }, { "family_name": "Pr\u00e9v\u00f4t", "given_name": "A. S. H.", "orcid": "0000-0002-9243-8194", "clpid": "Pr\u00e9v\u00f4t-A-S-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Szmigielski", "given_name": "R.", "orcid": "0000-0003-3389-9318", "clpid": "Szmigielski-Rafal" }, { "family_name": "Wildt", "given_name": "J.", "clpid": "Wildt-J\u00fcrgen" } ], "abstract": "Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.", "doi": "10.5194/acp-9-5155-2009", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2009-07-29", "series_number": "14", "volume": "9", "issue": "14", "pages": "5155-5236" }, { "id": "authors:3151r-rys92", "collection": "authors", "collection_id": "3151r-rys92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090814-113136745", "type": "article", "title": "Photooxidation of 2-methyl-3-buten-2-ol (MBO) as a potential source of secondary organic aerosol", "author": [ { "family_name": "Chan", "given_name": "Arthur W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Galloway", "given_name": "Melissa M.", "orcid": "0000-0002-8518-1888", "clpid": "Galloway-Melissa-M" }, { "family_name": "Kwan", "given_name": "Allan J.", "clpid": "Kwan-Allan-J" }, { "family_name": "Chhabra", "given_name": "Puneet S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Keutsch", "given_name": "Frank N.", "orcid": "0000-0002-1442-6200", "clpid": "Keutsch-Frank-N" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "2-Methyl-3-buten-2-ol (MBO) is an important biogenic hydrocarbon emitted in large quantities by pine forests. Atmospheric photooxidation of MBO is known to lead to oxygenated compounds, such as glycolaldehyde, which is the precursor to glyoxal. Recent studies have shown that the reactive uptake of glyoxal onto aqueous particles can lead to formation of secondary organic aerosol (SOA). In this work, MBO photooxidation under high- and low-NO\u2093 conditions was performed in dual laboratory chambers to quantify the yield of glyoxal and investigate the potential for SOA formation. The yields of glycolaldehyde and 2-hydroxy-2-methylpropanal (HMPR), fragmentation products of MBO photooxidation, were observed to be lower at lower NO\u2093 concentrations. Overall, the glyoxal yield from MBO photooxidation was 25% under high-NO\u2093 and 4% under low-NO\u2093 conditions. In the presence of wet ammonium sulfate seed and under high-NO\u2093 conditions, glyoxal uptake and SOA formation were not observed conclusively, due to relatively low (<30 ppb) glyoxal concentrations. Slight aerosol formation was observed under low-NO\u2093 and dry conditions, with aerosol mass yields on the order of 0.1%. The small amount of SOA was not related to glyoxal uptake, but is likely a result of reactions similar to those that generate isoprene SOA under low-NO\u2093 conditions. The difference in aerosol yields between MBO and isoprene photooxidation under low-NO\u2093 conditions is consistent with the difference in vapor pressures between triols (from MBO) and tetrols (from isoprene). Despite its structural similarity to isoprene, photooxidation of MBO is not expected to make a significant contribution to SOA formation.", "doi": "10.1021/es802560w", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2009-07-01", "series_number": "13", "volume": "43", "issue": "13", "pages": "4647-4652" }, { "id": "authors:er66t-97975", "collection": "authors", "collection_id": "er66t-97975", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090901-134607712", "type": "article", "title": "Comprehensive Simultaneous Shipboard and Airborne Characterization of Exhaust from a Modern Container Ship at Sea", "author": [ { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Agrawal", "given_name": "Harshit", "clpid": "Agrawal-Harshit" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Padr\u00f3", "given_name": "Luz T.", "clpid": "Padr\u00f3-Luz-T" }, { "family_name": "Gates", "given_name": "Harmony", "clpid": "Gates-Harmony" }, { "family_name": "Hersey", "given_name": "Scott", "clpid": "Hersey-Scott-P" }, { "family_name": "Welch", "given_name": "W. A.", "clpid": "Welch-W-A" }, { "family_name": "Jung", "given_name": "H.", "clpid": "Jung-H" }, { "family_name": "Miller", "given_name": "J. W.", "clpid": "Miller-J-W" }, { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-David-R-III" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We report the first joint shipboard and airborne study focused on the chemical composition and water-uptake behavior of particulate ship emissions. The study focuses on emissions from the main propulsion engine of a Post-Panamax class container ship cruising off the central coast of California and burning heavy fuel oil. Shipboard sampling included micro-orifice uniform deposit impactors (MOUDI) with subsequent off-line analysis, whereas airborne measurements involved a number of real-time analyzers to characterize the plume aerosol, aged from a few seconds to over an hour. The mass ratio of particulate organic carbon to sulfate at the base of the ship stack was 0.23 \u00b1 0.03, and increased to 0.30 \u00b1 0.01 in the airborne exhaust plume, with the additional organic mass in the airborne plume being concentrated largely in particles below 100 nm in diameter. The organic to sulfate mass ratio in the exhaust aerosol remained constant during the first hour of plume dilution into the marine boundary layer. The mass spectrum of the organic fraction of the exhaust aerosol strongly resembles that of emissions from other diesel sources and appears to be predominantly hydrocarbon-like organic (HOA) material. Background aerosol which, based on air mass back trajectories, probably consisted of aged ship emissions and marine aerosol, contained a lower organic mass fraction than the fresh plume and had a much more oxidized organic component. A volume-weighted mixing rule is able to accurately predict hygroscopic growth factors in the background aerosol but measured and calculated growth factors do not agree for aerosols in the ship exhaust plume. Calculated CCN concentrations, at supersaturations ranging from 0.1 to 0.33%, agree well with measurements in the ship-exhaust plume. Using size-resolved chemical composition instead of bulk submicrometer composition has little effect on the predicted CCN concentrations because the cutoff diameter for CCN activation is larger than the diameter where the mass fraction of organic aerosol begins to increase significantly. The particle number emission factor estimated from this study is 1.3 \u00d7 10^(16) (kg fuel)^(\u22121), with less than 1/10 of the particles having diameters above 100 nm; 24% of particles (>10 nm in diameter) activate into cloud droplets at 0.3% supersaturation.", "doi": "10.1021/es802413j", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2009-07-01", "series_number": "13", "volume": "43", "issue": "13", "pages": "4626-4640" }, { "id": "authors:g9z90-jhx71", "collection": "authors", "collection_id": "g9z90-jhx71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090811-154004114", "type": "article", "title": "Parameterization of cloud droplet size distributions: comparison with parcel models and observations", "author": [ { "family_name": "Hsieh", "given_name": "W. C.", "clpid": "Hsieh-W-C" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Buzorius", "given_name": "G.", "clpid": "Buzorius-Gintautas" }, { "family_name": "Jonsson", "given_name": "H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" } ], "abstract": "This work examines the efficacy of various physically based approaches derived from one-dimensional adiabatic parcel model frameworks (a numerical model and a simplified parameterization) to parameterize the cloud droplet distribution characteristics for computing cloud effective radius and autoconversion rate in regional/global atmospheric models. Evaluations are carried out for integrations with single (average) and distributions of updraft velocity, assuming that (1) conditions at s_(max) are reflective of the cloud column or (2) cloud properties vary vertically, in agreement with one-dimensional parcel theory. The predicted droplet distributions are then compared against in situ cloud droplet observations obtained during the CRYSTAL-FACE and CSTRIPE missions. Good agreement of droplet relative dispersion between parcel model frameworks indicates that the parameterized parcel model essentially captures one-dimensional dynamics; the predicted distributions are overly narrow, with relative dispersion being a factor of 2 lower than observations. However, if conditions at cloud maximum supersaturation are used to predict relative dispersion and applied throughout the cloud column, better agreement is seen with observations, especially if integrations are carried out over the distribution of updraft velocity. When considering the efficiency of the method, calculating cloud droplet spectral dispersion at s_(max) is preferred for linking aerosol with droplet distributions in large-scale models.", "doi": "10.1029/2008JD011387", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2009-06-09", "series_number": "D11", "volume": "114", "issue": "D11", "pages": "Art. No. D11205" }, { "id": "authors:vsj5b-a1y36", "collection": "authors", "collection_id": "vsj5b-a1y36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090820-133254405", "type": "article", "title": "Glyoxal uptake on ammonium sulphate seed aerosol: reaction products and reversibility of uptake under dark and irradiated conditions", "author": [ { "family_name": "Galloway", "given_name": "M. M.", "orcid": "0000-0002-8518-1888", "clpid": "Galloway-Melissa-M" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Keutsch", "given_name": "F. N.", "orcid": "0000-0002-1442-6200", "clpid": "Keutsch-Frank-N" } ], "abstract": "Chamber studies of glyoxal uptake onto ammonium sulphate aerosol were performed under dark and irradiated conditions to gain further insight into processes controlling glyoxal uptake onto ambient aerosol. Organic fragments from glyoxal dimers and trimers were observed within the aerosol under dark and irradiated conditions. Glyoxal monomers and oligomers were the dominant organic compounds formed under the conditions of this study; glyoxal oligomer formation and overall organic growth were found to be reversible under dark conditions. Analysis of high-resolution time-of-flight aerosol mass spectra provides evidence for irreversible formation of carbon-nitrogen (C-N) compounds in the aerosol. We have identified 1H-imidazole-2-carboxaldehyde as one C-N product. To the authors' knowledge, this is the first time C-N compounds resulting from condensed phase reactions with ammonium sulphate seed have been detected in aerosol. Organosulphates were not detected under dark conditions. However, active photochemistry was found to occur within aerosol during irradiated experiments. Carboxylic acids and organic esters were identified within the aerosol. An organosulphate, which had been previously assigned as glyoxal sulphate in ambient samples and chamber studies of isoprene oxidation, was observed only in the irradiated experiments. Comparison with a laboratory synthesized standard and chemical considerations strongly suggest that this organosulphate is glycolic acid sulphate, an isomer of the previously proposed glyoxal sulphate. Our study shows that reversibility of glyoxal uptake should be taken into account in SOA models and also demonstrates the need for further investigation of C-N compound formation and photochemical processes, in particular organosulphate formation.", "doi": "10.5194/acp-9-3331-2009", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2009-05-25", "series_number": "10", "volume": "9", "issue": "10", "pages": "3331-3345" }, { "id": "authors:an3ed-qz651", "collection": "authors", "collection_id": "an3ed-qz651", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090804-105757770", "type": "article", "title": "Effect of chemistry-aerosol-climate coupling on predictions of future climate and future levels of tropospheric ozone and aerosols", "author": [ { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Zhang", "given_name": "Ying", "clpid": "Zhang-Ying" }, { "family_name": "Chen", "given_name": "Wei-Ting", "orcid": "0000-0002-9292-0933", "clpid": "Chen-Wei-Ting" }, { "family_name": "Raes", "given_name": "Frank", "clpid": "Raes-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We explore the extent to which chemistry-aerosol-climate coupling influences predictions of future ozone and aerosols as well as future climate using the Goddard Institute for Space Studies (GISS) general circulation model II' with on-line simulation of tropospheric ozone-NO_x-hydrocarbon chemistry and sulfate, nitrate, ammonium, black carbon, primary organic carbon, and secondary organic carbon aerosols. Based on IPCC scenario A2, year 2100 ozone, aerosols, and climate simulated with full chemistry-aerosol-climate coupling are compared with those simulated from a stepwise approach. In the stepwise method year 2100 ozone and aerosols are first simulated using present-day climate and year 2100 emissions (denoted as simulation CHEM2100sw) and year 2100 climate is then predicted using offline monthly fields of O_3 and aerosols from CHEM2100sw (denoted as simulation CLIM2100sw). The fully coupled chemistry-aerosol-climate simulation predicts a 15% lower global burden of O_3 for year 2100 than the simulation CHEM2100sw which does not account for future changes in climate. Relative to CHEM2100sw, year 2100 column burdens of all aerosols in the fully coupled simulation exhibit reductions of 10\u201320 mg m^\u22122 in DJF and up to 10 mg m^\u22122 in JJA in mid to high latitudes in the Northern Hemisphere, reductions of up to 20 mg m^\u22122 over the eastern United States, northeastern China, and Europe in DJF, and increases of 30\u201350 mg m^\u22122 over populated and biomass burning areas in JJA. As a result, relative to year 2100 climate simulated from CLIM2100sw, full chemistry-aerosol-climate coupling leads to a stronger net global warming by greenhouse gases, tropospheric ozone and aerosols in year 2100, with a global and annual mean surface air temperature higher by 0.42 K. For simulation of year 2100 aerosols, we conclude that it is important to consider the positive feedback between future aerosol direct radiative forcing and future aerosol concentrations; increased aerosol concentrations lead to reductions in convection and precipitation (or wet deposition of aerosols), further increasing lower tropospheric aerosol concentrations.", "doi": "10.1029/2008JD010984", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2009-05-23", "volume": "114", "pages": "D10306" }, { "id": "authors:y5jr4-rxn55", "collection": "authors", "collection_id": "y5jr4-rxn55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090814-103729079", "type": "article", "title": "Secondary organic aerosol formation from photooxidation of naphthalene and alkylnaphthalenes: implications for oxidation of intermediate volatility organic compounds (IVOCs)", "author": [ { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Kautzman", "given_name": "K. E.", "clpid": "Kautzman-K-E" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chan", "given_name": "M. N.", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Crounse", "given_name": "J. D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-John-D" }, { "family_name": "K\u00fcrten", "given_name": "A.", "orcid": "0000-0002-8955-4450", "clpid": "K\u00fcrten-Andreas" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Current atmospheric models do not include secondary organic aerosol (SOA) production from gas-phase reactions of polycyclic aromatic hydrocarbons (PAHs). Recent studies have shown that primary emissions undergo oxidation in the gas phase, leading to SOA formation. This opens the possibility that low-volatility gas-phase precursors are a potentially large source of SOA. In this work, SOA formation from gas-phase photooxidation of naphthalene, 1-methylnaphthalene (1-MN), 2-methylnaphthalene (2-MN), and 1,2-dimethylnaphthalene (1,2-DMN) is studied in the Caltech dual 28-m3 chambers. Under high-NOx conditions and aerosol mass loadings between 10 and 40 \u03bcg m\u22123, the SOA yields (mass of SOA per mass of hydrocarbon reacted) ranged from 0.19 to 0.30 for naphthalene, 0.19 to 0.39 for 1-MN, 0.26 to 0.45 for 2-MN, and constant at 0.31 for 1,2-DMN. Under low-NOx conditions, the SOA yields were measured to be 0.73, 0.68, and 0.58, for naphthalene, 1-MN, and 2-MN, respectively. The SOA was observed to be semivolatile under high-NOx conditions and essentially nonvolatile under low-NOx conditions, owing to the higher fraction of ring-retaining products formed under low-NOx conditions. When applying these measured yields to estimate SOA formation from primary emissions of diesel engines and wood burning, PAHs are estimated to yield 3\u20135 times more SOA than light aromatic compounds over photooxidation timescales of less than 12 h. PAHs can also account for up to 54% of the total SOA from oxidation of diesel emissions, representing a potentially large source of urban SOA.", "doi": "10.5194/acp-9-3049-2009", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2009-05-12", "series_number": "9", "volume": "9", "issue": "9", "pages": "3049-3060" }, { "id": "authors:3f9we-q2532", "collection": "authors", "collection_id": "3f9we-q2532", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-132349508", "type": "article", "title": "International Consortium for Atmospheric Research on Transport and Transformation (ICARTT): North America to Europe \u2014 Overview of the 2004 summer field study", "author": [ { "family_name": "Fehsenfeld", "given_name": "F. C.", "clpid": "Fehsenfeld-F-C" }, { "family_name": "Ancellet", "given_name": "G.", "clpid": "Ancellet-G" }, { "family_name": "Bates", "given_name": "T. S.", "clpid": "Bates-T-S" }, { "family_name": "Goldstein", "given_name": "A. H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" }, { "family_name": "Hardesty", "given_name": "R. M.", "clpid": "Hardesty-R-M" }, { "family_name": "Honrath", "given_name": "R.", "clpid": "Honrath-R-E" }, { "family_name": "Law", "given_name": "K. S.", "clpid": "Law-K-S" }, { "family_name": "Lewis", "given_name": "A. C.", "clpid": "Lewis-A-C" }, { "family_name": "Leaitch", "given_name": "R.", "clpid": "Leaitch-R" }, { "family_name": "McKeen", "given_name": "S.", "clpid": "McKeen-S-A" }, { "family_name": "Meagher", "given_name": "J.", "clpid": "Meagher-J-F" }, { "family_name": "Parrish", "given_name": "D. D.", "clpid": "Parrish-D-D" }, { "family_name": "Pszenny", "given_name": "A. A. P.", "clpid": "Pszenny-A-A-P" }, { "family_name": "Russell", "given_name": "P. B.", "clpid": "Russell-P-B" }, { "family_name": "Schlager", "given_name": "H.", "clpid": "Schlager-H" }, { "family_name": "Seinfeld", "given_name": "J.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Talbot", "given_name": "R.", "clpid": "Talbot-R-W" }, { "family_name": "Zbinden", "given_name": "R.", "clpid": "Zbinden-R" } ], "abstract": "In the summer of 2004 several separate field programs intensively studied the photochemical, heterogeneous chemical and radiative environment of the troposphere over North America, the North Atlantic Ocean, and western Europe. Previous studies have indicated that the transport of continental emissions, particularly from North America, influences the concentrations of trace species in the troposphere over the North Atlantic and Europe. An international team of scientists, representing over 100 laboratories, collaborated under the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) umbrella to coordinate the separate field programs in order to maximize the resulting advances in our understanding of regional air quality, the transport, chemical transformation and removal of aerosols, ozone, and their precursors during intercontinental transport, and the radiation balance of the troposphere. Participants utilized nine aircraft, one research vessel, several ground-based sites in North America and the Azores, a network of aerosol-ozone lidars in Europe, satellites, balloon borne sondes, and routine commercial aircraft measurements. In this special section, the results from a major fraction of those platforms are presented. This overview is aimed at providing operational and logistical information for those platforms, summarizing the principal findings and conclusions that have been drawn from the results, and directing readers to specific papers for further details.", "doi": "10.1029/2009JD011842", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2009-04-16", "series_number": "D7", "volume": "111", "issue": "D7", "pages": "Art. No. D23S01" }, { "id": "authors:mn7md-wjt93", "collection": "authors", "collection_id": "mn7md-wjt93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090817-144817060", "type": "article", "title": "Cloud condensation nuclei activity, closure, and droplet growth kinetics of Houston aerosol during the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS)", "author": [ { "family_name": "Lance", "given_name": "Sara", "orcid": "0000-0002-2396-2582", "clpid": "Lance-Sara" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Mazzoleni", "given_name": "Claudio", "orcid": "0000-0002-2398-0721", "clpid": "Mazzoleni-Claudio" }, { "family_name": "Dubey", "given_name": "Manvendra K.", "orcid": "0000-0002-3492-790X", "clpid": "Dubey-Manvendra-K" }, { "family_name": "Gates", "given_name": "Harmony", "clpid": "Gates-Harmony" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-Varuntida" }, { "family_name": "Rissman", "given_name": "Tracey A.", "clpid": "Rissman-Tracey-A" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Feingold", "given_name": "Graham", "orcid": "0000-0002-0774-2926", "clpid": "Feingold-Graham" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" } ], "abstract": "In situ cloud condensation nuclei (CCN) measurements were obtained in the boundary layer over Houston, Texas, during the 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) campaign onboard the CIRPAS Twin Otter. Polluted air masses in and out of cloudy regions were sampled for a total of 22 flights, with CCN measurements obtained for 17 of these flights. In this paper, we focus on CCN closure during two flights, within and downwind of the Houston regional plume and over the Houston Ship Channel. During both flights, air was sampled with particle concentrations exceeding 25,000 cm^(\u22123) and CCN concentrations exceeding 10,000 cm^(\u22123). CCN closure is evaluated by comparing measured concentrations with those predicted on the basis of measured aerosol size distributions and aerosol mass spectrometer particle composition. Different assumptions concerning the internally mixed chemical composition result in average CCN overprediction ranging from 3% to 36% (based on a linear fit). It is hypothesized that the externally mixed fraction of the aerosol contributes much of the CCN closure scatter, while the internally mixed fraction largely controls the overprediction bias. On the basis of the droplet sizes of activated CCN, organics do not seem to impact, on average, the CCN activation kinetics.", "doi": "10.1029/2008JD011699", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2009-04-16", "series_number": "D7", "volume": "114", "issue": "D7", "pages": "D00F15" }, { "id": "authors:143s8-tzt35", "collection": "authors", "collection_id": "143s8-tzt35", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090903-160613221", "type": "article", "title": "Overview of the Second Texas Air Quality Study (TexAQS II) and the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS)", "author": [ { "family_name": "Parrish", "given_name": "D. D.", "clpid": "Parrish-D-D" }, { "family_name": "Allen", "given_name": "D. T.", "clpid": "Allen-D-T" }, { "family_name": "Bates", "given_name": "T. S.", "clpid": "Bates-T-S" }, { "family_name": "Fehsenfeld", "given_name": "F. C.", "clpid": "Fehsenfeld-F-C" }, { "family_name": "Feingold", "given_name": "G.", "clpid": "Feingold-G" }, { "family_name": "Ferrare", "given_name": "R.", "clpid": "Ferrare-R" }, { "family_name": "Hardesty", "given_name": "R. M.", "clpid": "Hardesty-R-M" }, { "family_name": "Meagher", "given_name": "J. F.", "clpid": "Meagher-J-F" }, { "family_name": "Nielsen-Gammon", "given_name": "J. W.", "clpid": "Nielsen-Gammon-J-W" }, { "family_name": "Pierce", "given_name": "R. B.", "clpid": "Pierce-R-B" }, { "family_name": "Ryerson", "given_name": "T. B.", "orcid": "0000-0003-2800-7581", "clpid": "Ryerson-T-B" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Williams", "given_name": "E. J.", "clpid": "Williams-E-J" } ], "abstract": "The Second Texas Air Quality Study (TexAQS II) was conducted in eastern Texas during 2005 and 2006. This 2-year study included an intensive field campaign, TexAQS 2006/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS), conducted in August\u2013October 2006. The results reported in this special journal section are based on observations collected on four aircraft, one research vessel, networks of ground-based air quality and meteorological (surface and radar wind profiler) sites in eastern Texas, a balloon-borne ozonesonde-radiosonde network (part of Intercontinental Transport Experiment Ozonesonde Network Study (IONS-06)), and satellites. This overview paper provides operational and logistical information for those platforms and sites, summarizes the principal findings and conclusions that have thus far been drawn from the results, and directs readers to appropriate papers for the full analysis. Two of these findings deserve particular emphasis. First, despite decreases in actual emissions of highly reactive volatile organic compounds (HRVOC) and some improvements in inventory estimates since the TexAQS 2000 study, the current Houston area emission inventories still underestimate HRVOC emissions by approximately 1 order of magnitude. Second, the background ozone in eastern Texas, which represents the minimum ozone concentration that is likely achievable through only local controls, can approach or exceed the current National Ambient Air Quality Standard of 75 ppbv for an 8-h average. These findings have broad implications for air quality control strategies in eastern Texas.", "doi": "10.1029/2009JD011842", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2009-04-16", "series_number": "D7", "volume": "114", "issue": "D7", "pages": "Art. No. D00F13" }, { "id": "authors:75rfr-99a10", "collection": "authors", "collection_id": "75rfr-99a10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090714-080423619", "type": "article", "title": "Aerosol hygroscopicity in the marine atmosphere: a closure study using high-time-resolution, multiple-RH DASH-SP and size-resolved C-ToF-AMS data", "author": [ { "family_name": "Hersey", "given_name": "S. P.", "clpid": "Hersey-S-P" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Murphy", "given_name": "S. M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-S-M" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We have conducted the first airborne hygroscopic growth closure study to utilize data from an Aerodyne compact Time-of-Flight Aerosol Mass Spectrometer (C-ToF-AMS) coupled with size-resolved, multiple-RH, high-time-resolution hygroscopic growth factor (GF) measurements from the differential aerosol sizing and hygroscopicity spectrometer probe (DASH-SP). These data were collected off the coast of Central California during seven of the 16 flights carried out during the MASE-II field campaign in July 2007. Two of the seven flights were conducted in airmasses characterized by continental origin. These flights exhibited elevated organic volume fractions (VF_(organic)=0.56\u00b10.19, as opposed to 0.39\u00b10.20 for all other flights), corresponding to significantly suppressed GFs at high RH (1.61\u00b10.14 at 92% RH, as compared with 1.91\u00b10.07 for all other flights), more moderate GF suppression at intermediate RH (1.53\u00b10.10 at 85%, compared with 1.58\u00b10.08 for all other flights), and no measurable GF suppression at low RH (1.31\u00b10.06 at 74%, compared with 1.31\u00b10.07 for all other flights). Organic loadings were slightly elevated in above-cloud aerosols, as compared with below-cloud aerosols, and corresponded to a similar trend of significantly suppressed GF at high RH, but more moderate impacts at lower values of RH. A hygroscopic closure based on a volume-weighted mixing rule provided good agreement with DASH-SP measurements (R^2=0.78). Minimization of root mean square error between observations and predictions indicated mission-averaged organic GFs of 1.22, 1.45, and 1.48 at 74, 85, and 92% RH, respectively. These values agree with previously reported values for water-soluble organics such as dicarboxylic and multifunctional acids, and correspond to a highly oxidized, presumably water-soluble, organic fraction (mission-averaged O:C=0.92\u00b10.33). Finally, a backward stepwise linear regression revealed that, other than RH, the most important predictor for GF is VF_(organic), indicating that a simple emperical model relating GF, RH, and the relative abundance of organic material can provide accurate predictions (R^2=0.77) of hygroscopic growth for the California coast.", "doi": "10.5194/acp-9-2543-2009", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2009-04-07", "series_number": "7", "volume": "9", "issue": "7", "pages": "2543-2554" }, { "id": "authors:23smv-5ys66", "collection": "authors", "collection_id": "23smv-5ys66", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090610-095123943", "type": "article", "title": "On the representation of droplet coalescence and autoconversion: evaluation using ambient cloud droplet size distributions", "author": [ { "family_name": "Hsieh", "given_name": "W. C.", "clpid": "Hsieh-W-C" }, { "family_name": "Jonsson", "given_name": "H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Wang", "given_name": "L.-P.", "clpid": "Wang-L-P" }, { "family_name": "Buzorius", "given_name": "G.", "clpid": "Buzorius-Buzorius" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" } ], "abstract": "In this study, we evaluate eight autoconversion parameterizations against integration of the Kinetic Collection Equation (KCE) for cloud size distributions measured during the NASA CRYSTAL\u2010FACE and CSTRIPE campaigns. KCE calculations are done using both the observed data and fits of these data to a gamma distribution function; it is found that the fitted distributions provide a good approximation for calculations of total coalescence but not for autoconversion because of fitting errors near the drop\u2010drizzle separation size. Parameterizations that explicitly compute autoconversion tend to be in better agreement with KCE but are subject to substantial uncertainty, about an order of magnitude in autoconversion rate. Including turbulence effects on droplet collection increases autoconversion by a factor of 1.82 and 1.24 for CRYSTAL\u2010FACE and CSTRIPE clouds, respectively; this enhancement never exceeds a factor of 3, even under the most aggressive collection conditions. Shifting the droplet\u2010drizzle separation radius from 20 to 25 \u03bcm results in about a twofold uncertainty in autoconversion rate. The polynomial approximation to the gravitation collection kernel used to develop parameterizations provides computation of autoconversion that agree to within 30%. Collectively, these uncertainties have an important impact on autoconversion but are all within the factor of 10 uncertainty of autoconversion parameterizations. Incorporating KCE calculations in GCM simulations of aerosol\u2010cloud interactions studies is computationally feasible by using precalculated collection kernel tables and can quantify the autoconversion uncertainty associated with application of parameterizations.", "doi": "10.1029/2008JD010502", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2009-04-01", "series_number": "7", "volume": "114", "issue": "7", "pages": "D07201" }, { "id": "authors:9xw4j-wcz86", "collection": "authors", "collection_id": "9xw4j-wcz86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090413-143557131", "type": "article", "title": "Isoprene photooxidation : new insights into the production of acids and organic nitrates", "author": [ { "family_name": "Paulot", "given_name": "F.", "orcid": "0000-0001-7534-4922", "clpid": "Paulot-F" }, { "family_name": "Crounse", "given_name": "J. D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-J-D" }, { "family_name": "Kjaergaard", "given_name": "H. G.", "orcid": "0000-0002-7275-8297", "clpid": "Kjaergaard-H-G" }, { "family_name": "Kroll", "given_name": "J. H.", "clpid": "Kroll-J-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "We describe a nearly explicit chemical mechanism for isoprene photooxidation guided by chamber studies that include time-resolved observation of an extensive suite of volatile compounds. We provide new constraints on the chemistry of the poorly-understood isoprene \u03b4-hydroxy channels, which account for more than one third of the total isoprene carbon flux and a larger fraction of the nitrate yields. We show that the cis branch dominates the chemistry of the \u03b4-hydroxy channel with less than 5% of the carbon following the trans branch. The modelled yield of isoprene nitrates is 12\u00b13% with a large difference between the \u03b4 and \u03b2 branches. The oxidation of these nitrates releases about 50% of the NOx. Methacrolein nitrates (modelled yield \u224315\u00b13% from methacrolein) and methylvinylketone nitrates (modelled yield \u224311\u00b13% yield from methylvinylketone) are also observed. Propanone nitrate, produced with a yield of 1% from isoprene, appears to be the longest-lived nitrate formed in the total oxidation of isoprene. We find a large molar yield of formic acid and suggest a novel mechanism leading to its formation from the organic nitrates. Finally, the most important features of this mechanism are summarized in a condensed scheme appropriate for use in global chemical transport models.", "doi": "10.5194/acp-9-1479-2009", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2009-02-23", "series_number": "4", "volume": "9", "issue": "4", "pages": "1479-1501" }, { "id": "authors:66nsy-ybd87", "collection": "authors", "collection_id": "66nsy-ybd87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PYEjgrd09", "type": "article", "title": "Effect of changes in climate and emissions on future sulfate-nitrate-ammonium aerosol levels in the United States", "author": [ { "family_name": "Pye", "given_name": "H. O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-H-O-T" }, { "family_name": "Liao", "given_name": "H.", "clpid": "Liao-H" }, { "family_name": "Wu", "given_name": "S.", "clpid": "Wu-S" }, { "family_name": "Mickley", "given_name": "L. J.", "orcid": "0000-0002-7859-3470", "clpid": "Mickley-L-J" }, { "family_name": "Jacob", "given_name": "D. J.", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-D-J" }, { "family_name": "Henze", "given_name": "D. K.", "clpid": "Henze-D-K" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Global simulations of sulfate, nitrate, and ammonium aerosols are performed for the present day and 2050 using the chemical transport model GEOS-Chem. Changes in climate and emissions projected by the IPCC A1B scenario are imposed separately and together, with the primary focus of the work on future inorganic aerosol levels over the United States. Climate change alone is predicted to lead to decreases in levels of sulfate and ammonium in the southeast U.S. but increases in the Midwest and northeast U.S. Nitrate concentrations are projected to decrease across the U.S. as a result of climate change alone. In the U.S., climate change alone can cause changes in annually averaged sulfate-nitrate-ammonium of up to 0.61 \u03bcg/m^3, with seasonal changes often being much larger in magnitude. When changes in anthropogenic emissions are considered (with or without changes in climate), domestic sulfate concentrations are projected to decrease because of sulfur dioxide emission reductions, and nitrate concentrations are predicted to generally increase because of higher ammonia emissions combined with decreases in sulfate despite reductions in emissions of nitrogen oxides. The ammonium burden is projected to increase from 0.24 to 0.36 Tg, and the sulfate burden to increase from 0.28 to 0.40 Tg S as a result of globally higher ammonia and sulfate emissions in the future. The global nitrate burden is predicted to remain essentially constant at 0.35 Tg, with changes in both emissions and climate as a result of the competing effects of higher precursor emissions and increased temperature.", "doi": "10.1029/2008JD010701", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2009-01-09", "series_number": "1", "volume": "114", "issue": "1", "pages": "2008JD010701" }, { "id": "authors:2we9m-cn836", "collection": "authors", "collection_id": "2we9m-cn836", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:DOCest08", "type": "article", "title": "Apportionment of primary and secondary organic aerosols in Southern California during the 2005 Study of Organic Aerosols in Riverside (SOAR-1)", "author": [ { "family_name": "Docherty", "given_name": "Kenneth S.", "clpid": "Docherty-K-S" }, { "family_name": "Stone", "given_name": "Elizabeth A.", "clpid": "Stone-E-A" }, { "family_name": "Ulbrich", "given_name": "Ingrid M.", "clpid": "Ulbrich-I-M" }, { "family_name": "DeCarlo", "given_name": "Peter F.", "clpid": "DeCarlo-P-F" }, { "family_name": "Snyder", "given_name": "David C.", "clpid": "Snyder-D-C" }, { "family_name": "Schauer", "given_name": "James J.", "clpid": "Schauer-J-J" }, { "family_name": "Peltier", "given_name": "Richard E.", "clpid": "Peltier-R-E" }, { "family_name": "Weber", "given_name": "Rodney J.", "clpid": "Weber-R-J" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-S-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Grover", "given_name": "Brett D.", "clpid": "Grover-B-D" }, { "family_name": "Eatough", "given_name": "Delbert J.", "clpid": "Eatough-D-J" }, { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" } ], "abstract": "Ambient sampling was conducted in Riverside, California during the 2005 Study of Organic Aerosols in Riverside to characterize the composition and sources of organic aerosol using a variety of state-of-the-art instrumentation and source apportionment techniques. The secondary organic aerosol (SOA) mass is estimated by elemental carbon and carbon monoxide tracer methods, water soluble organic carbon content, chemical mass balance of organic molecular markers, and positive matrix factorization of high-resolution aerosol mass spectrometer data. Estimates obtained from each of these methods indicate that the organic fraction in ambient aerosol is overwhelmingly secondary in nature during a period of several weeks with moderate ozone concentrations and that SOA is the single largest component of PM1 aerosol in Riverside. Average SOA/OA contributions of 70\u221290% were observed during midday periods, whereas minimum SOA contributions of ~45% were observed during peak morning traffic periods. These results are contrary to previous estimates of SOA throughout the Los Angeles Basin which reported that, other than during severe photochemical smog episodes, SOA was lower than primary OA. Possible reasons for these differences are discussed.", "doi": "10.1021/es8008166", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2008-10-15", "series_number": "20", "volume": "42", "issue": "20", "pages": "7655-7662" }, { "id": "authors:wk3aa-51j14", "collection": "authors", "collection_id": "wk3aa-51j14", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SURjpca08", "type": "article", "title": "Organosulfate Formation in Biogenic Secondary Organic Aerosol", "author": [ { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "G\u00f3mez-Gonz\u00e1lez", "given_name": "Yadlan", "clpid": "G\u00f3mez-Gonz\u00e1lez-Yadlan" }, { "family_name": "Chan", "given_name": "Arthur W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Vermeylen", "given_name": "Reinhilde", "clpid": "Vermeylen-Reinhilde" }, { "family_name": "Shahgholi", "given_name": "Mona", "orcid": "0000-0002-8879-4305", "clpid": "Shahgholi-Mona" }, { "family_name": "Kleindienst", "given_name": "Tadeusz E.", "orcid": "0000-0002-3024-1564", "clpid": "Kleindienst-Tadeusz-E" }, { "family_name": "Edney", "given_name": "Edward O.", "clpid": "Edney-Edward-O" }, { "family_name": "Offenberg", "given_name": "John H.", "orcid": "0000-0002-0213-4024", "clpid": "Offenberg-John-H" }, { "family_name": "Lewandowski", "given_name": "Michael", "orcid": "0000-0002-0058-956X", "clpid": "Lewandowski-Michael" }, { "family_name": "Jaoui", "given_name": "Mohammed", "orcid": "0000-0002-2728-9137", "clpid": "Jaoui-Mohammed" }, { "family_name": "Maenhaut", "given_name": "Willy", "orcid": "0000-0002-4715-4627", "clpid": "Maenhaut-Willy" }, { "family_name": "Claeys", "given_name": "Magda", "orcid": "0000-0003-2278-8014", "clpid": "Claeys-Magda" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Organosulfates of isoprene, \u03b1-pinene, and \u03b2-pinene have recently been identified in both laboratory-generated and ambient secondary organic aerosol (SOA). In this study, the mechanism and ubiquity of organosulfate formation in biogenic SOA is investigated by a comprehensive series of laboratory photooxidation (i.e., OH-initiated oxidation) and nighttime oxidation (i.e., NO\u2083-initiated oxidation under dark conditions) experiments using nine monoterpenes (\u03b1-pinene, \u03b2-pinene, d-limonene, l-limonene, \u03b1-terpinene, \u03b3-terpinene, terpinolene, \u0394\u00b3-carene, and \u03b2-phellandrene) and three monoterpenes (\u03b1-pinene, d-limonene, and l-limonene), respectively. Organosulfates were characterized using liquid chromatographic techniques coupled to electrospray ionization combined with both linear ion trap and high-resolution time-of-flight mass spectrometry. Organosulfates are formed only when monoterpenes are oxidized in the presence of acidified sulfate seed aerosol, a result consistent with prior work. Archived laboratory-generated isoprene SOA and ambient filter samples collected from the southeastern U.S. were reexamined for organosulfates. By comparing the tandem mass spectrometric and accurate mass measurements collected for both the laboratory-generated and ambient aerosol, previously uncharacterized ambient organic aerosol components are found to be organosulfates of isoprene, \u03b1-pinene, \u03b2-pinene, and limonene-like monoterpenes (e.g., myrcene), demonstrating the ubiquity of organosulfate formation in ambient SOA. Several of the organosulfates of isoprene and of the monoterpenes characterized in this study are ambient tracer compounds for the occurrence of biogenic SOA formation under acidic conditions. Furthermore, the nighttime oxidation experiments conducted under highly acidic conditions reveal a viable mechanism for the formation of previously identified nitrooxy organosulfates found in ambient nighttime aerosol samples. We estimate that the organosulfate contribution to the total organic mass fraction of ambient aerosol collected from K-puszta, Hungary, a field site with a similar organosulfate composition as that found in the present study for the southeastern U.S., can be as high as 30%.", "doi": "10.1021/jp802310p", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2008-09-11", "series_number": "36", "volume": "112", "issue": "36", "pages": "8345-8378" }, { "id": "authors:3a6y5-5as38", "collection": "authors", "collection_id": "3a6y5-5as38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-111456879", "type": "article", "title": "Aerosol-cloud relationships in continental shallow cumulus", "author": [ { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "Feingold", "given_name": "Graham", "clpid": "Feingold-G" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Chuang", "given_name": "Patrick Y.", "orcid": "0000-0003-2290-8346", "clpid": "Chuang-Patrick-Y" }, { "family_name": "Gates", "given_name": "Harmony", "clpid": "Gates-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aerosol-cloud relationships are derived from 14 warm continental cumuli cases sampled during the 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) by the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. Cloud droplet number concentration is clearly proportional to the subcloud accumulation mode aerosol number concentration. An inverse correlation between cloud top effective radius and subcloud aerosol number concentration is observed when cloud depth variations are accounted for. There are no discernable aerosol effects on cloud droplet spectral dispersion; the averaged spectral relative dispersion is 0.30 \u00b1 0.04. Aerosol-cloud relationships are also identified from comparison of two isolated cloud cases that occurred under different degrees of anthropogenic influence. Cloud liquid water content, cloud droplet number concentration, and cloud top effective radius exhibit subadiabaticity resulting from entrainment mixing processes. The degree of LWC subadiabaticity is found to increase with cloud depth. Impacts of subadiabaticity on cloud optical properties are assessed. It is estimated that owing to entrainment mixing, cloud LWP, effective radius, and cloud albedo are decreased by 50\u201385%, 5\u201335%, and 2\u201326%, respectively, relative to adiabatic values of a plane-parallel cloud. The impact of subadiabaticity on cloud albedo is largest for shallow clouds. Results suggest that the effect of entrainment mixing must be accounted for when evaluating the aerosol indirect effect.", "doi": "10.1029/2007JD009354", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2008-08-16", "series_number": "D15", "volume": "113", "issue": "D15", "pages": "Art. No. D15201" }, { "id": "authors:bxshk-03x25", "collection": "authors", "collection_id": "bxshk-03x25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NGNacp08", "type": "article", "title": "Secondary organic aerosol (SOA) formation from reaction of isoprene with nitrate radicals (NO\u2083)", "author": [ { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Kwan", "given_name": "A. J.", "clpid": "Kwan-Alan-J" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Pye", "given_name": "Havala O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-Havala-O-T" }, { "family_name": "Crounse", "given_name": "J. D.", "orcid": "0000-0001-5443-729X", "clpid": "Crounse-John-D" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) formation from the reaction of isoprene with nitrate radicals (NO\u2083) is investigated in the Caltech indoor chambers. Experiments are performed in the dark and under dry conditions (RH < 10%) using N\u2082O\u2085 as a source of NO\u2083 radicals. For an initial isoprene concentration of 18.4 to 101.6 ppb, the SOA yield (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted) ranges from 4.3% to 23.8%. By examining the time evolutions of gas-phase intermediate products and aerosol volume in real time, we are able to constrain the chemistry that leads to the formation of low-volatility products. Although the formation of ROOR from the reaction of two peroxy radicals (RO\u2082) has generally been considered as a minor channel, based on the gas-phase and aerosol-phase data it appears that RO\u2082+RO\u2082 reaction (self reaction or cross-reaction) in the gas phase yielding ROOR products is a dominant SOA formation pathway. A wide array of organic nitrates and peroxides are identified in the aerosol formed and mechanisms for SOA formation are proposed. Using a uniform SOA yield of 10% (corresponding to M\u2092 \u2245 10 \u03bcg m\u207b\u00b3), it is estimated that ~2 to 3 Tg yr\u207b\u00b9 of SOA results from isoprene + NO\u2083. The extent to which the results from this study can be applied to conditions in the atmosphere depends on the fate of peroxy radicals in the nighttime troposphere.", "doi": "10.5194/acp-8-4117-2008", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2008-08-01", "series_number": "14", "volume": "8", "issue": "14", "pages": "4117-4140" }, { "id": "authors:cq7tr-k1b51", "collection": "authors", "collection_id": "cq7tr-k1b51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-111331379", "type": "article", "title": "Statistical comparison of properties of simulated and observed cumulus clouds in the vicinity of Houston during the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS)", "author": [ { "family_name": "Jiang", "given_name": "Hongli", "clpid": "Jiang-Hongli" }, { "family_name": "Feingold", "given_name": "Graham", "clpid": "Feingold-G" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "Chuang", "given_name": "Patrick Y.", "orcid": "0000-0003-2290-8346", "clpid": "Chuang-Patrick-Y" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We present statistical comparisons of properties of clouds generated by Large Eddy Simulations (LES) with aircraft observations of nonprecipitating, warm cumulus clouds made in the vicinity of Houston, TX during the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS), carried out in the summer of 2006. Aircraft data were sampled with the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter airplane. Five flights (days) that are most suitable for studying aerosol-cloud interactions are selected from the 22 flights. The model simulations are initiated with observed environmental profiles. The simulations are used to generate an ensemble of thousands of cumulus clouds for statistically meaningful evaluations. Statistical comparisons focus on the properties of a set of dynamical and thermodynamical variables, sampled either in the cloud or the cloud updraft core. The set of variables includes cloud liquid water content (LWC), number mixing ratio of cloud droplets (Nd), cloud effective radius (re), updraft velocity (w), and the distribution of cloud sizes. In general, good agreement between the simulated and observed clouds is achieved in the normalized frequency distribution functions, the profiles averaged over the cloudy regions, the cross-cloud averages, and the cloud size distributions, despite big differences in sample size between the model output and the aircraft data. Some unresolved differences in frequency distributions of w and possible differences in cloud fraction are noted. These comparisons suggest that the LES is able to successfully generate the cumulus cloud populations that were present during GoMACCS. The extent to which this is true will depend on the specific application.", "doi": "10.1029/2007JD009304", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2008-07-16", "series_number": "D13", "volume": "113", "issue": "D13", "pages": "Art. No. D13205" }, { "id": "authors:6bmbq-0ff50", "collection": "authors", "collection_id": "6bmbq-0ff50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-111625670", "type": "article", "title": "Rapid, Size-Resolved Aerosol Hygroscopic Growth Measurements: Differential Aerosol Sizing and Hygroscopicity Spectrometer Probe (DASH-SP)", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Hersey", "given_name": "Scott", "clpid": "Hersey-S-P" }, { "family_name": "Brechtel", "given_name": "Fred J.", "clpid": "Brechtel-F-J" }, { "family_name": "Corless", "given_name": "Andrew", "clpid": "Corless-A" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We report on a new instrument developed to perform rapid, size-resolved aerosol hygroscopicity measurements. The differential aerosol sizing and hygroscopicity spectrometer probe (DASH-SP) employs differential mobility analysis in-concert with multiple humidification and optical sizing steps to determine dry optical size and hygroscopic growth factors for size-selected aerosols simultaneously at three elevated relative humidities. The DASH-SP has been designed especially for aircraft-based measurements, with time resolution as short as a few seconds. The minimum particle diameter detected with 50% efficiency in the optical particle counters (OPCs) is 135 \u00b1 8 nm, while the maximum detectable particle diameter is in excess of 1 \u03bcm. An iterative data processing algorithm quantifies growth factors and \"effective\" refractive indices for humidified particles using an empirically derived three-dimensional surface (OPC pulse height\u2013refractive index\u2013particle size), based on a calculated value of the \"effective\" dry particle refractive index. Excellent agreement is obtained between DASH-SP laboratory data and thermodynamic model predictions for growth factor dependence on relative humidity for various inorganic salts. Growth factor data are also presented for several organic acids. Oxalic, malonic, glutaric, and glyoxylic acids grow gradually with increasing relative humidity up to 94%, while succinic and adipic acids show no growth. Airborne measurements of hygroscopic growth factors of ship exhaust aerosol during the 2007 Marine Stratus/Stratocumulus Experiment (MASE II) field campaign off the central coast of California are presented as the first report of the aircraft integration of the DASH-SP.", "doi": "10.1080/02786820802178506", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2008-06", "series_number": "6", "volume": "42", "issue": "6", "pages": "445-464" }, { "id": "authors:mtwcg-rhq07", "collection": "authors", "collection_id": "mtwcg-rhq07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HENacp08", "type": "article", "title": "Global modeling of secondary organic aerosol formation from aromatic hydrocarbons: high- vs. low-yield pathways", "author": [ { "family_name": "Henze", "given_name": "D. K.", "clpid": "Henze-D-K" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Kroll", "given_name": "J. H.", "clpid": "Kroll-J-H" }, { "family_name": "Fu", "given_name": "T.-M.", "clpid": "Fu-T-M" }, { "family_name": "Jacob", "given_name": "D. J.", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-D-J" }, { "family_name": "Heald", "given_name": "C. L.", "clpid": "Heald-C-L" } ], "abstract": "Formation of SOA from the aromatic species toluene, xylene, and, for the first time, benzene, is added to a global chemical transport model. A simple mechanism is presented that accounts for competition between low and high-yield pathways of SOA formation, wherein secondary gas-phase products react further with either nitric oxide (NO) or hydroperoxy radical (HO_2) to yield semi- or non-volatile products, respectively. Aromatic species yield more SOA when they react with OH in regions where the [NO]/[HO_2] ratios are lower. The SOA yield thus depends upon the distribution of aromatic emissions, with biomass burning emissions being in areas with lower [NO]/[HO_2] ratios, and the reactivity of the aromatic with respect to OH, as a lower initial reactivity allows transport away from industrial source regions, where [NO]/[HO_2] ratios are higher, to more remote regions, where this ratio is lower and, hence, the ultimate yield of SOA is higher. As a result, benzene is estimated to be the most important aromatic species with regards to global formation of SOA, with a total production nearly equal that of toluene and xylene combined. Global production of SOA from aromatic sources via the mechanisms identified here is estimated at 3.5 Tg/yr, resulting in a global burden of 0.08 Tg, twice as large as previous estimates. The contribution of these largely anthropogenic sources to global SOA is still small relative to biogenic sources, which are estimated to comprise 90% of the global SOA burden, about half of which comes from isoprene. Uncertainty in these estimates owing to factors ranging from the atmospheric relevance of chamber conditions to model deficiencies result in an estimated range of SOA production from aromatics of 2\u201312 Tg/yr. Though this uncertainty range affords a significant anthropogenic contribution to global SOA, it is evident from comparisons to recent observations that additional pathways for production of anthropogenic SOA still exist beyond those accounted for here. Nevertheless, owing to differences in spatial distributions of sources and seasons of peak production, regions exist in which aromatic SOA produced via the mechanisms identified here are predicted to contribute substantially to, and even dominate, the local SOA concentrations, such as outflow regions from North America and South East Asia during the wintertime, though total modeled SOA concentrations there are small (~0.1 \u03bcg/m^3).", "doi": "10.5194/acp-8-2405-2008", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2008-05-07", "series_number": "9", "volume": "8", "issue": "9", "pages": "2405-2421" }, { "id": "authors:j23jk-atr33", "collection": "authors", "collection_id": "j23jk-atr33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CLEacp08b", "type": "article", "title": "Effects of uncertainties in the thermodynamic properties of aerosol components in an air quality model \u2013 Part 2: Predictions of the vapour pressures of organic compounds", "author": [ { "family_name": "Clegg", "given_name": "S. L.", "clpid": "Clegg-S-L" }, { "family_name": "Kleeman", "given_name": "M. J.", "clpid": "Kleeman-M-J" }, { "family_name": "Griffin", "given_name": "R. J.", "clpid": "Griffin-R-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Air quality models that generate the concentrations of semi-volatile and other condensable organic compounds using an explicit reaction mechanism require estimates of the vapour pressures of the organic compounds that partition between the aerosol and gas phases. The model of Griffin, Kleeman and co-workers (e.g., Griffin et al., 2005) assumes that aerosol particles consist of an aqueous phase, containing inorganic electrolytes and soluble organic compounds, and a hydrophobic phase containing mainly primary hydrocarbon material. Thirty eight semi-volatile reaction products are grouped into ten surrogate species. In Part 1 of this work (Clegg et al., 2008) the thermodynamic elements of the gas/aerosol partitioning calculation are examined, and the effects of uncertainties and approximations assessed, using a simulation for the South Coast Air Basin around Los Angeles as an example. Here we compare several different methods of predicting vapour pressures of organic compounds, and use the results to determine the likely uncertainties in the vapour pressures of the semi-volatile surrogate species in the model. These are typically an order of magnitude or greater, and are further increased when the fact that each compound represents a range of reaction products (for which vapour pressures can be independently estimated) is taken into account. The effects of the vapour pressure uncertainties associated with the water-soluble semi-volatile species are determined over a wide range of atmospheric liquid water contents. The vapour pressures of the eight primary hydrocarbon surrogate species present in the model, which are normally assumed to be involatile, are also predicted. The results suggest that they have vapour pressures high enough to exist in both the aerosol and gas phases under typical atmospheric conditions.", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2008-02-27", "series_number": "4", "volume": "8", "issue": "4", "pages": "1087-1103" }, { "id": "authors:6t27b-nz554", "collection": "authors", "collection_id": "6t27b-nz554", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CLEacp08a", "type": "article", "title": "Effects of uncertainties in the thermodynamic properties of aerosol components in an air quality model \u2013 Part 1: Treatment of inorganic electrolytes and organic compounds in the condensed phase", "author": [ { "family_name": "Clegg", "given_name": "S. L.", "clpid": "Clegg-S-L" }, { "family_name": "Kleeman", "given_name": "M. J.", "clpid": "Kleeman-M-J" }, { "family_name": "Griffin", "given_name": "R. J.", "clpid": "Griffin-R-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Air quality models that generate the concentrations of semi-volatile and other condensable organic compounds using an explicit reaction mechanism require estimates of the physical and thermodynamic properties of the compounds that affect gas/aerosol partitioning: vapour pressure (as a subcooled liquid), and activity coefficients in the aerosol phase. The model of Griffin, Kleeman and co-workers (e.g., Griffin et al., 2003; Kleeman et al., 1999) assumes that aerosol particles consist of an aqueous phase, containing inorganic electrolytes and soluble organic compounds, and a hydrophobic phase containing mainly primary hydrocarbon material. Thirty eight semi-volatile reaction products are grouped into ten surrogate species which partition between the gas phase and both phases in the aerosol. Activity coefficients of the organic compounds are calculated using UNIFAC. In a companion paper (Clegg et al., 2008) we examine the likely uncertainties in the vapour pressures of the semi-volatile compounds and their effects on partitioning over a range of atmospheric relative humidities. In this work a simulation for the South Coast Air Basin surrounding Los Angeles, using lower vapour pressures of the semi-volatile surrogate compounds consistent with estimated uncertainties in the boiling points on which they are based, yields a doubling of the predicted 24-h average secondary organic aerosol concentrations. The dependency of organic compound partitioning on the treatment of inorganic electrolytes in the air quality model, and the performance of this component of the model, are determined by analysing the results of a trajectory calculation using an extended version of the Aerosol Inorganics Model of Wexler and Clegg (2002). Simplifications are identified where substantial efficiency gains can be made, principally: the omission of dissociation of the organic acid surrogates; restriction of aerosol organic compounds to one of the two phases (aqueous or hydrophobic) where equilibrium calculations suggest partitioning strongly in either direction; a single calculation of activity coefficients of the organic compounds for simulations where they are determined by the presence of one component at high concentration in either phase (i.e., water in the aqueous phase, or a hydrocarbon surrogate compound P8 in the hydrophobic phase) and are therefore almost invariant. The implications of the results for the development of aerosol models are discussed.", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2008-02-27", "series_number": "4", "volume": "8", "issue": "4", "pages": "1027-1085" }, { "id": "authors:96zjx-y1g08", "collection": "authors", "collection_id": "96zjx-y1g08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180802-141641450", "type": "article", "title": "Climate Change", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Over the past century global average temperature has increased by about 0.8 \u00b0C. Any substantial change in the Earth's temperature must be the result of a perturbation, or so-called radiative forcing, of the planet's energy balance. The equilibrium global temperature response to a particular amount of radiative forcing is termed the Earth's climate sensitivity. Once the Earth's energy balance is perturbed, feedbacks arise that act either to enhance or suppress the perturbation. The positive feedback arising from changes in the water vapor level in the atmosphere resulting from a change in temperature is key. In this article, we evaluate the possible causes of the recent warming of the Earth. We review measured variations in the solar output, as well as the historical paleoclimate record, especially the glacial-interglacial cycles. Atmospheric greenhouse gases, carbon dioxide, methane, and nitrous oxide, have increased substantially over the last century; the radiative forcing resulting from these increases can be accurately calculated. The forcing attributable to the increase in levels of airborne particles (aerosols) is considerably more uncertain. All these factors must be taken into account to arrive at an explanation of the recent warming.", "doi": "10.1515/REVCE.2008.24.1.1", "issn": "2191-0235", "publisher": "De Gruyter", "publication": "Reviews in Chemical Engineering", "publication_date": "2008-02", "series_number": "1", "volume": "24", "issue": "1", "pages": "1-65" }, { "id": "authors:mfc2w-0cj03", "collection": "authors", "collection_id": "mfc2w-0cj03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141103-144756849", "type": "article", "title": "Black carbon and brown clouds", "author": [ { "family_name": "Seinfeld", "given_name": "John", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In aerosol hot spots around the globe, solar radiation is dimmed down on its way to the Earth's surface. The resulting surface cooling turns out to be almost in balance with heating of the atmosphere due to black carbon.", "doi": "10.1038/ngeo.2007.62", "issn": "1752-0894", "publisher": "Nature Publishing Group", "publication": "Nature Geoscience", "publication_date": "2008-01", "series_number": "1", "volume": "1", "issue": "1", "pages": "15-16" }, { "id": "authors:x5hxj-h5012", "collection": "authors", "collection_id": "x5hxj-h5012", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SORacp08", "type": "article", "title": "Comprehensive airborne characterization of aerosol from a major bovine source", "author": [ { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Murphy", "given_name": "S. M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Hersey", "given_name": "S.", "clpid": "Hersey-Scott-P" }, { "family_name": "Gates", "given_name": "H.", "clpid": "Gates-H" }, { "family_name": "Padro", "given_name": "L. T.", "clpid": "Padr\u00f3-Luz-T" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Brechtel", "given_name": "F. J.", "orcid": "0000-0002-2375-8741", "clpid": "Brechtel-Frederick-J" }, { "family_name": "Jonsson", "given_name": "H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We report an extensive airborne characterization of aerosol downwind of a massive bovine source in the San Joaquin Valley (California) on two flights during July 2007. The Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter probed chemical composition, particle size distribution, mixing state, sub- and supersaturated water uptake behavior, light scattering properties, and the interrelationship between these parameters and meteorology. Total PM_(1.0) levels and concentrations of organics. nitrate. and ammonium were enhanced in the plume from the source as compared to the background aerosol. Organics dominated the plume aerosol mass (~56-64%), followed either by sulfate or nitrate. and then ammonium. Particulate amines were detected in the plume aerosol by a particle-into-liquid sampler (PILS) and via mass spectral inarkers in the Aerodvne C-ToF-AMS. Amines were found to be a significant atmospheric base even in the presence of arnmonia; particulate amine concentrations are estimated as at least 14-23% of that of ammonium in the plume. Enhanced sub- and supersaturated water uptake and reduced refractive indices were coincident with lower organic mass fractions, higher nitrate mass fractions, and the detection of amines. The likelihood of suppressed droplet growth owing to kinetic limitations from hydrophobic organic material is explored. After removing effects associated with size distribution and mixing state, the normalized activated fraction of cloud condensation nuclei (CCN) increased as a function of the subsaturated hygroscopic growth factor, with the highest activated fractions being consistent with relatively lower organic mass fractions and higher nitrate mass fractions. Subsaturated hygroscopic growth factors for the organic fraction of the aerosol are estimated based on employing the Zdanovskii-Stokes Robinson (ZSR) mixing rule. Representative values for a parameterization treating particle water uptake in both the sub- and supersaturated regimes are reported for incorporation into atmospheric models.", "doi": "10.5194/acp-8-5489-2008", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2008", "series_number": "17", "volume": "8", "issue": "17", "pages": "5489-5520" }, { "id": "authors:wvhak-evv79", "collection": "authors", "collection_id": "wvhak-evv79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-153036030", "type": "article", "title": "A phase equilibrium model for atmospheric aerosols containing inorganic electrolytes and organic compounds (UHAERO), with application to dicarboxylic acids", "author": [ { "family_name": "Amundson", "given_name": "N. R.", "clpid": "Amundson-N-R" }, { "family_name": "Caboussat", "given_name": "A.", "clpid": "Caboussat-A" }, { "family_name": "He", "given_name": "J. W.", "clpid": "He-J-W" }, { "family_name": "Martynenko", "given_name": "A. V.", "clpid": "Martynenko-A-V" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Computation of phase and chemical equilibria of water-organic-inorganic mixtures is of significant interest in atmospheric aerosol modeling. A new version of the phase partitioning model, named UHAERO, is presented here, which allows one to compute the phase behavior for atmospheric aerosols containing inorganic electrolytes and organic compounds. The computational implementation of the model is based on standard minimization of the Gibbs free energy using a primal-dual method, coupled to a Newton iteration. Water uptake and deliquescence properties of mixtures of aqueous solutions of salts and dicarboxylic acids, including oxalic, malonic, succinic, glutaric, maleic, malic, or methyl succinic acids, are based on a hybrid thermodynamic approach for the modeling of activity coefficients (Clegg and Seinfeld, 2006a, 2006b). UHAERO currently considers ammonium salts and the neutralization of dicarboxylic acids and sulfuric acid. Phase diagrams for sulfate/ammonium/water/dicarboxylic acid systems are presented as a function of relative humidity at 298.15 K over the complete space of compositions.", "doi": "10.1029/2007JD008424", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2007-12-27", "series_number": "D24", "volume": "112", "issue": "D24", "pages": "Art. No. D24S13" }, { "id": "authors:srqab-qeg92", "collection": "authors", "collection_id": "srqab-qeg92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170320-064605024", "type": "article", "title": "The Adjoint of CMAQ", "author": [ { "family_name": "Hakami", "given_name": "Amir", "clpid": "Hakami-A" }, { "family_name": "Henze", "given_name": "Daven K.", "clpid": "Henze-D-K" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Singh", "given_name": "Kumaresh", "clpid": "Singh-K" }, { "family_name": "Sandu", "given_name": "Adrian", "clpid": "Sandu-A" }, { "family_name": "Kim", "given_name": "Soontae", "clpid": "Kim-Soontae" }, { "family_name": "Byun", "given_name": "Daewon", "clpid": "Byun-Daewon" }, { "family_name": "Li", "given_name": "Qinbin", "clpid": "Li-Qinbin" } ], "abstract": "An adjoint model for the internationally used Community Multiscale Air Quality (CMAQ) modeling platform of the U.S. EPA is developed. The adjoint version for CMAQ (CMAQ-ADJ) provides the user community with forward (decoupled direct method or DDM) and backward (adjoint) sensitivity analysis capabilities. Current implementation is for gas-phase processes. Discrete adjoints are implemented for all processes with the exception of horizontal advection, for which, because of inherent discontinuities in the advection scheme, the continuous approach is superior. The adjoint of chemistry is constructed by interfacing CMAQ with the kinetic pre-processor, which provides for increased flexibility in the choice of chemical solver and facilitates the implementation of new chemical mechanisms. The adjoint implementation is evaluated both on a process-by-process basis and for the full model. In general, adjoint results show good agreement with brute-force and DDM sensitivities. As expected for a continuous adjoint implementation in a nonlinear scheme, the agreement is not perfect for horizontal transport. Sensitivities of various air quality, public health, and environmental metrics with respect to emissions are calculated using the adjoint method. In order to show applicability to regional climate studies, as an example, the sensitivities of these metrics with respect to local temperatures are calculated.", "doi": "10.1021/es070944p", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2007-11-15", "series_number": "22", "volume": "41", "issue": "22", "pages": "7807-7817" }, { "id": "authors:fr2pr-0kv37", "collection": "authors", "collection_id": "fr2pr-0kv37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-133029685", "type": "article", "title": "Role of isoprene in secondary organic aerosol formation on a regional scale", "author": [ { "family_name": "Zhang", "given_name": "Yang", "orcid": "0000-0002-4168-9225", "clpid": "Zhang-Yang" }, { "family_name": "Huang", "given_name": "Jian-Ping", "clpid": "Huang-Jian-Ping" }, { "family_name": "Henze", "given_name": "Daven K.", "clpid": "Henze-D-K" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The role of isoprene as a source of secondary organic aerosol (SOA) is studied using laboratory-derived SOA yields and the U.S. Environmental Protection Agency regional-scale Community Multiscale Air Quality (CMAQ) modeling system over a domain comprising the contiguous United States, southern Canada, and northern Mexico. Isoprene is predicted to be a significant source of biogenic SOA, leading to increases up to 3.8 \u03bcg m^(\u22123) in the planetary boundary layer (PBL, defined as 0\u20132.85 km) and 0.44 \u03bcg m^(\u22123) in the free troposphere over that in the absence of isoprene. While the addition of isoprene to the class of SOA-forming organics in CMAQ increases appreciably predicted fine-particle organic carbon (OC_(2.5)) in the eastern and southeastern U.S., total OC_(2.5) is still underpredicted in these regions. SOA formation is highly sensitive to the value of the enthalpy of vaporization of the SOA. The role of isoprene SOA is examined in a sensitivity study at values of 42 and 156 kJ mol^(\u22121); both are commonly used in 3-D aerosol models. Prediction of ambient levels of SOA in atmospheric models remains a challenging problem because of the importance of emissions inventories for SOA-forming organics, representation of gas phase atmospheric chemistry leading to semivolatile products, and treatment of the physics and chemistry of aerosol formation and removal.", "doi": "10.1029/2007JD008675", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2007-10-23", "series_number": "D20", "volume": "112", "issue": "D20", "pages": "Art. No. D20207" }, { "id": "authors:7zfns-th917", "collection": "authors", "collection_id": "7zfns-th917", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HENacpd07", "type": "article", "title": "Global modeling of secondary organic aerosol formation from aromatic hydrocarbons: high- vs low-yield pathways", "author": [ { "family_name": "Henze", "given_name": "D. K.", "clpid": "Henze-D-K" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Kroll", "given_name": "J. H.", "clpid": "Kroll-J-H" }, { "family_name": "Fu", "given_name": "T.-M.", "clpid": "Fu-T-M" }, { "family_name": "Jacob", "given_name": "D. J.", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-D-J" }, { "family_name": "Heald", "given_name": "C. L.", "clpid": "Heald-C-L" } ], "abstract": "Formation of SOA from the aromatic species toluene, xylene, and, for the first time, benzene, is added to a global chemical transport model. A simple mechanism is presented that accounts for competition between low and high-yield pathways of SOA formation, wherein secondary gas-phase products react further with either nitrogen oxide (NO) or hydroperoxy radical (HO2) to yield semi- or non-volatile products, respectively. Aromatic species yield more SOA when they react with OH in regions where the [NO]/[HO2] ratios are lower. The SOA yield thus depends upon the distribution of aromatic emissions, with biomass burning emissions being in areas with lower [NO]/[HO2] ratios, and the reactivity of the aromatic with respect to OH, as a lower initial reactivity allows transport away from industrial source regions, where [NO]/[HO2] ratios are higher, to more remote regions, where this ratio is lower and, hence, the ultimate yield of SOA is higher. As a result, benzene is estimated to be the most important aromatic species with regards to formation of SOA, with a total production nearly equal that of toluene and xylene combined. In total, while only 39% percent of the aromatic species react via the low-NOx pathway, 72% of the aromatic SOA is formed via this mechanism. Predicted SOA concentrations from aromatics in the Eastern United States and Eastern Europe are actually largest during the summer, when the [NO]/[HO2] ratio is lower. Global production of SOA from aromatic sources is estimated at 3.5 Tg/yr, resulting in a global burden of 0.08 Tg, twice as large as previous estimates. The contribution of these largely anthropogenic sources to global SOA is still small relative to biogenic sources, which are estimated to comprise 90% of the global SOA burden, about half of which comes from isoprene. Compared to recent observations, it would appear there are additional pathways beyond those accounted for here for production of anthropogenic SOA. However, owing to differences in spatial distributions of sources and seasons of peak production, there are still regions in which aromatic SOA produced via the mechanisms identified here are predicted to contribute substantially to, and even dominate, the local SOA concentrations, such as outflow regions from North America and South East Asia during the wintertime, though total SOA concentrations there are small (~0.1 \u03bcg/m^\u00b3).", "issn": "1680-7367", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2007-10-15", "series_number": "5", "volume": "7", "issue": "5", "pages": "14569-14601" }, { "id": "authors:169p6-03m44", "collection": "authors", "collection_id": "169p6-03m44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:STIacp07", "type": "article", "title": "Aerosol absorption and radiative forcing", "author": [ { "family_name": "Stier", "given_name": "P.", "clpid": "Stier-P" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Kinne", "given_name": "S.", "clpid": "Kinne-S" }, { "family_name": "Boucher", "given_name": "O.", "clpid": "Boucher-O" } ], "abstract": "We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006) significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA) radiative forcing clear-sky from \u22120.79 to \u22120.53 W m^\u22122 (33%) and all-sky from \u22120.47 to \u22120.13 W m^\u22122 (72%). Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m^\u22122 (36%) clear-sky and of 0.12 W m^\u22122 (92%) all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W m^\u22122 and a positive TOA forcing perturbation of 0.02 W m^\u22122. The long-wave aerosol radiative effects are small for anthropogenic aerosols but become of relevance for the larger natural dust and sea-salt aerosols.", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2007-10-10", "series_number": "19", "volume": "7", "issue": "19", "pages": "5237-5261" }, { "id": "authors:996k7-hft57", "collection": "authors", "collection_id": "996k7-hft57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SEItownhall07", "type": "conference_item", "title": "Global Climate Change", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "[No abstract]", "publisher": "Caltech Library", "publication_date": "2007-10-08" }, { "id": "authors:4xw5d-ztz34", "collection": "authors", "collection_id": "4xw5d-ztz34", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NGNacp07b", "type": "article", "title": "Effect of NO\u2093 level on secondary organic aerosol (SOA) formation from the photooxidation of terpenes", "author": [ { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Kroll", "given_name": "J. H.", "orcid": "0000-0002-6275-521X", "clpid": "Kroll-Jesse-H" }, { "family_name": "Kwan", "given_name": "A. J.", "clpid": "Kwan-Alan-J" }, { "family_name": "McCabe", "given_name": "D. C.", "clpid": "McCabe-David-C" }, { "family_name": "Wennberg", "given_name": "P. O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Murphy", "given_name": "S. M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Dalleska", "given_name": "N. F.", "orcid": "0000-0002-2059-1587", "clpid": "Dalleska-Nathan-F" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) formation from the photooxidation of one monoterpene (\u03b1-pinene) and two sesquiterpenes (longifolene and aromadendrene) is investigated in the Caltech environmental chambers. The effect of NOx on SOA formation for these biogenic hydrocarbons is evaluated by performing photooxidation experiments under varying NO\u2093 conditions. The NO\u2093 dependence of \u03b1-pinene SOA formation follows the same trend as that observed previously for a number of SOA precursors, including isoprene, in which SOA yield (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted) decreases as NO\u2093 level increases. The NO\u2093 dependence of SOA yield for the sesquiterpenes, longifolene and aromadendrene, however, differs from that determined for isoprene and \u03b1-pinene; the aerosol yield under high-NO\u2093 conditions substantially exceeds that under low-NO\u2093 conditions. The reversal of the NO\u2093 dependence of SOA formation for the sesquiterpenes is consistent with formation of relatively low-volatility organic nitrates, and/or the isomerization of large alkoxy radicals leading to less volatile products. Analysis of the aerosol chemical composition for longifolene confirms the presence of organic nitrates under high-NO\u2093 conditions. Consequently the formation of SOA from certain biogenic hydrocarbons such as sesquiterpenes (and possibly large anthropogenic hydrocarbons as well) may be more efficient in polluted air.", "doi": "10.5194/acp-7-5159-2007", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2007-10-08", "series_number": "19", "volume": "7", "issue": "19", "pages": "5159-5174" }, { "id": "authors:xxgd9-28253", "collection": "authors", "collection_id": "xxgd9-28253", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AMUacp07", "type": "article", "title": "A new atmospheric aerosol phase equilibrium model (UHAERO): organic systems", "author": [ { "family_name": "Amundson", "given_name": "N. R.", "clpid": "Amundson-N-R" }, { "family_name": "Caboussat", "given_name": "A.", "clpid": "Caboussat-A" }, { "family_name": "He", "given_name": "J. W.", "clpid": "He-J-W" }, { "family_name": "Martynenko", "given_name": "A. V.", "clpid": "Martynenko-A-V" }, { "family_name": "Landry", "given_name": "C.", "clpid": "Landry-C" }, { "family_name": "Tong", "given_name": "C.", "clpid": "Tong-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In atmospheric aerosols, water and volatile inorganic and organic species are distributed between the gas and aerosol phases in accordance with thermodynamic equilibrium. Within an atmospheric particle, liquid and solid phases can exist at equilibrium. Models exist for computation of phase equilibria for inorganic/water mixtures typical of atmospheric aerosols; when organic species are present, the phase equilibrium problem is complicated by organic/water interactions as well as the potentially large number of organic species. We present here an extension of the UHAERO inorganic thermodynamic model (Amundson et al., 2006c) to organic/water systems. Phase diagrams for a number of model organic/water systems characteristic of both primary and secondary organic aerosols are computed. Also calculated are inorganic/organic/water phase diagrams that show the effect of organics on inorganic deliquescence behavior. The effect of the choice of activity coefficient model for organics on the computed phase equilibria is explored.", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2007-09-14", "series_number": "17", "volume": "7", "issue": "17", "pages": "4675-4698" }, { "id": "authors:8b8ap-q3v17", "collection": "authors", "collection_id": "8b8ap-q3v17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHAacp07", "type": "article", "title": "Kinetic modeling of secondary organic aerosol formation: effects of particle- and gas-phase reactions of semivolatile products", "author": [ { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Kroll", "given_name": "J. H.", "clpid": "Kroll-J-H" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The distinguishing mechanism of formation of secondary organic aerosol (SOA) is the partitioning of semivolatile hydrocarbon oxidation products between the gas and aerosol phases. While SOA formation is typically described in terms of partitioning only, the rate of formation and ultimate yield of SOA can also depend on the kinetics of both gas- and aerosol-phase processes. We present a general equilibrium/kinetic model of SOA formation that provides a framework for evaluating the extent to which the controlling mechanisms of SOA formation can be inferred from laboratory chamber data. With this model we examine the effect on SOA formation of gas-phase oxidation of first-generation products to either more or less volatile species, of particle-phase reaction (both first- and second-order kinetics), of the rate of parent hydrocarbon oxidation, and of the extent of reaction of the parent hydrocarbon. The effect of pre-existing organic aerosol mass on SOA yield, an issue of direct relevance to the translation of laboratory data to atmospheric applications, is examined. The importance of direct chemical measurements of gas- and particle-phase species is underscored in identifying SOA formation mechanisms.", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2007-08-07", "series_number": "15", "volume": "7", "issue": "15", "pages": "4135-4147" }, { "id": "authors:gwpjk-60626", "collection": "authors", "collection_id": "gwpjk-60626", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170426-101818056", "type": "article", "title": "Effect of Acidity on Secondary Organic Aerosol Formation from Isoprene", "author": [ { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Lewandowski", "given_name": "Michael", "orcid": "0000-0002-0058-956X", "clpid": "Lewandowski-Michael" }, { "family_name": "Offenberg", "given_name": "John H.", "orcid": "0000-0002-0213-4024", "clpid": "Offenberg-John-H" }, { "family_name": "Jaoui", "given_name": "Mohammed", "orcid": "0000-0002-2728-9137", "clpid": "Jaoui-Mohammed" }, { "family_name": "Kleindienst", "given_name": "Tadeusz E.", "orcid": "0000-0002-3024-1564", "clpid": "Kleindienst-Tadeusz-E" }, { "family_name": "Edney", "given_name": "Edward O.", "clpid": "Edney-Edward-O" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The effect of particle-phase acidity on secondary organic aerosol (SOA) formation from isoprene is investigated in a laboratory chamber study, in which the acidity of the inorganic seed aerosol was controlled systematically. The observed enhancement in SOA mass concentration is closely correlated to increasing aerosol acidity (R\u00b2 = 0.979). Direct chemical evidence for acid-catalyzed particle-phase reactions was obtained from the SOA chemical analyses. Aerosol mass concentrations for the 2-methyltetrols, as well as the newly identified sulfate esters, both of which serve as tracers for isoprene SOA in ambient aerosols, increased significantly with enhanced aerosol acidity. Aerosol acidities, as measured in nmol of H\u207a m\u207b\u00b3, employed in the present study are in the same range as those observed in tropospheric aerosol collected from the eastern U.S.", "doi": "10.1021/es0704176", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2007-08-01", "series_number": "15", "volume": "41", "issue": "15", "pages": "5363-5369" }, { "id": "authors:fmr24-njf67", "collection": "authors", "collection_id": "fmr24-njf67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CLEacpd07b", "type": "article", "title": "Effects of uncertainties in the thermodynamic properties of aerosol components in an air quality model \u2013 Part II: Predictions of the vapour pressures of organic compounds", "author": [ { "family_name": "Clegg", "given_name": "S. L.", "clpid": "Clegg-S-L" }, { "family_name": "Kleeman", "given_name": "M. J.", "clpid": "Kleeman-M-J" }, { "family_name": "Griffin", "given_name": "R. J.", "clpid": "Griffin-R-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Air quality models that generate the concentrations of semi-volatile and other condensable organic compounds using an explicit reaction mechanism require estimates of the vapour pressures of the organic compounds that partition between the aerosol and gas phases. The model of Griffin, Kleeman and co-workers (e.g., Griffin et al., 2005) assumes that aerosol particles consist of an aqueous phase, containing inorganic electrolytes and soluble organic compounds, and a hydrophobic phase containing mainly primary hydrocarbon material. Thirty eight semi-volatile reaction products are grouped into ten surrogate species. In Part I of this work (Clegg et al., 2007) the thermodynamic elements of the gas/aerosol partitioning calculation are examined, and the effects of uncertainties and approximations assessed, using a simulation for the South Coast Air Basin around Los Angeles as an example. Here we compare several different methods of predicting vapour pressures of organic compounds, and use the results to determine the likely uncertainties in the vapour pressures of the semi-volatile surrogate species in the model. These are typically an order of magnitude or greater, and are further increased when the fact that each compound represents a range of reaction products (for which vapour pressures can be independently estimated) is taken into account. The effects of the vapour pressure uncertainties associated with the water-soluble semi-volatile species are determined over a wide range of atmospheric liquid water contents. The vapour pressures of the eight primary hydrocarbon surrogate species present in the model, which are normally assumed to be involatile, are also predicted. The results suggest that they have vapour pressures high enough to exist in both the aerosol and gas phases under typical atmospheric conditions.", "issn": "1680-7367", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2007-07-26", "series_number": "4", "volume": "7", "issue": "4", "pages": "11049-11089" }, { "id": "authors:3vy9y-he496", "collection": "authors", "collection_id": "3vy9y-he496", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-132859054", "type": "article", "title": "Future climate impacts of direct radiative forcing of anthropogenic aerosols, tropospheric ozone, and long-lived greenhouse gases", "author": [ { "family_name": "Chen", "given_name": "Wei-Ting", "orcid": "0000-0002-9292-0933", "clpid": "Chen-Wei-Ting" }, { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Long-lived greenhouse gases (GHGs) are the most important driver of climate change over the next century. Aerosols and tropospheric ozone (O_3) are expected to induce significant perturbations to the GHG-forced climate. To distinguish the equilibrium climate responses to changes in direct radiative forcing of anthropogenic aerosols, tropospheric ozone, and GHG between present day and year 2100, four 80-year equilibrium climates are simulated using a unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies (GISS) general circulation model (GCM) II\u2032. Concentrations of sulfate, nitrate, primary organic (POA) carbon, secondary organic (SOA) carbon, black carbon (BC) aerosols, and tropospheric ozone for present day and year 2100 are obtained a priori by coupled chemistry-aerosol GCM simulations, with emissions of aerosols, ozone, and precursors based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenario (SRES) A2. Changing anthropogenic aerosols, tropospheric ozone, and GHG from present day to year 2100 is predicted to perturb the global annual mean radiative forcing by +0.18 (considering aerosol direct effects only), +0.65, and +6.54 W m^(\u22122) at the tropopause, and to induce an equilibrium global annual mean surface temperature change of +0.14, +0.32, and +5.31 K, respectively, with the largest temperature response occurring at northern high latitudes. Anthropogenic aerosols, through their direct effect, are predicted to alter the Hadley circulation owing to an increasing interhemispheric temperature gradient, leading to changes in tropical precipitation. When changes in both aerosols and tropospheric ozone are considered, the predicted patterns of change in global circulation and the hydrological cycle are similar to those induced by aerosols alone. GHG-induced climate changes, such as amplified warming over high latitudes, weakened Hadley circulation, and increasing precipitation over the Tropics and high latitudes, are consistent with predictions of a number of previous GCM studies. Finally, direct radiative forcing of anthropogenic aerosols is predicted to induce strong regional cooling over East and South Asia. Wintertime rainfall over southeastern China and the Indian subcontinent is predicted to decrease because of the increased atmospheric stability and decreased surface evaporation, while the geographic distribution of precipitation is also predicted to be altered as a result of aerosol-induced changes in wind flow.", "doi": "10.1029/2006JD008051", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2007-07-26", "series_number": "D14", "volume": "112", "issue": "D14", "pages": "Art. No. D14209" }, { "id": "authors:e4qs2-k7769", "collection": "authors", "collection_id": "e4qs2-k7769", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CLEacpd07a", "type": "article", "title": "Effects of uncertainties in the thermodynamic properties of aerosol components in an air quality model \u2013 Part I: Treatment of inorganic electrolytes and organic compounds in the condensed phase", "author": [ { "family_name": "Clegg", "given_name": "S. L.", "clpid": "Clegg-S-L" }, { "family_name": "Kleeman", "given_name": "M. J.", "clpid": "Kleeman-M-J" }, { "family_name": "Griffin", "given_name": "R. J.", "clpid": "Griffin-R-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Air quality models that generate the concentrations of semi-volatile and other condensable organic compounds using an explicit reaction mechanism require estimates of the physical and thermodynamic properties of the compounds that affect gas/aerosol partitioning: vapour pressure (as a subcooled liquid), and activity coefficients in the aerosol phase. The model of Griffin, Kleeman and co-workers (e.g., Griffin et al., 1999; Kleeman et al., 1999) assumes that aerosol particles consist of an aqueous phase, containing inorganic electrolytes and soluble organic compounds, and a hydrophobic phase containing mainly primary hydrocarbon material. Thirty eight semi-volatile reaction products are grouped into ten surrogate species which partition between the gas phase and both phases in the aerosol. Activity coefficients of the organic compounds are calculated using UNIFAC. In a companion paper (Clegg et al., 2007) we examine the likely uncertainties in the vapour pressures of the semi-volatile compounds and their effects on partitioning over a range of atmospheric relative humidities. In this work a simulation for the South Coast Air Basin surrounding Los Angeles, using lower vapour pressures of the semi-volatile surrogate compounds consistent with estimated uncertainties in the boiling points on which they are based, yields a doubling of the predicted 24-h average secondary organic aerosol concentrations. The dependency of organic compound partitioning on the treatment of inorganic electrolytes in the air quality model, and the performance of this component of the model, are determined by analysing the results of a trajectory calculation using an extended version of the Aerosol Inorganics Model of Wexler and Clegg (2002). Simplifications are identified where substantial efficiency gains can be made, principally: the omission of dissociation of the organic acid surrogates; restriction of aerosol organic compounds to one of the two phases (aqueous or hydrophobic) where equilibrium calculations suggest partitioning strongly in either direction; a single calculation of activity coefficients of the organic compounds for simulations where they are determined by the presence of one component at high concentration in either phase (i.e., water in the aqueous phase, or a hydrocarbon surrogate compound P8 in the hydrophobic phase) and are therefore almost invariant. The implications of the results for the development of aerosol models are discussed.", "issn": "1680-7367", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2007-07-26", "series_number": "4", "volume": "7", "issue": "4", "pages": "10971-11047" }, { "id": "authors:9h3ef-4zj72", "collection": "authors", "collection_id": "9h3ef-4zj72", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NGNacp07", "type": "article", "title": "Secondary organic aerosol formation from m-xylene, toluene, and benzene", "author": [ { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Kroll", "given_name": "J. H.", "orcid": "0000-0002-6275-521X", "clpid": "Kroll-Jesse-H" }, { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) formation from the photooxidation of m-xylene, toluene, and benzene is investigated in the Caltech environmental chambers. Experiments are performed under two limiting NO\u2093 conditions; under high-NO\u2093 conditions the peroxy radicals (RO\u2082) react only with NO, while under low-NO\u2093 conditions they react only with HO\u2082. For all three aromatics studied (m-xylene, toluene, and benzene), the SOA yields (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted) under low-NOx conditions substantially exceed those under high-NOx conditions, suggesting the importance of peroxy radical chemistry in SOA formation. Under low-NO\u2093 conditions, the SOA yields for m-xylene, toluene, and benzene are constant (36%, 30%, and 37%, respectively), indicating that the SOA formed is effectively nonvolatile under the range of M\u2092 (>10 \u03bcg m\u207b\u00b3) studied. Under high-NO\u2093 conditions, aerosol growth occurs essentially immediately, even when NO concentration is high. The SOA yield curves exhibit behavior similar to that observed by Odum et al. (1996, 1997a, b), although the values are somewhat higher than in the earlier study. The yields measured under high-NOx conditions are higher than previous measurements, suggesting a \"rate effect\" in SOA formation, in which SOA yields are higher when the oxidation rate is faster. Experiments carried out in the presence of acidic seed aerosol reveal no change of SOA yields from the aromatics as compared with those using neutral seed aerosol.", "doi": "10.5194/acp-7-3909-2007", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2007-07-24", "series_number": "14", "volume": "7", "issue": "14", "pages": "3909-3922" }, { "id": "authors:93vtw-j6g92", "collection": "authors", "collection_id": "93vtw-j6g92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-151856371", "type": "article", "title": "Particulate organic acids and overall water-soluble aerosol composition measurements from the 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS)", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Chan", "given_name": "Arthur W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Feingold", "given_name": "Graham", "clpid": "Feingold-G" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter participated in the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) mission during August\u2013September 2006. A particle-into-liquid sampler (PILS) coupled to ion chromatography was used to characterize the water-soluble ion composition of aerosol and cloud droplet residual particles (976 5-min PM_(1.0) samples in total). Sulfate and ammonium dominated the water-soluble mass (NH_4+ + SO_4^(2\u2212) = 84 \u00b1 14%), while organic acids contributed 3.4 \u00b1 3.7%. The average NH_4^+:SO_4^(2\u2212) molar ratio was 1.77 \u00b1 0.85. Particulate concentrations of organic acids increased with decreasing carbon number from C_9 to C_2. Organic acids were most abundant above cloud, presumably as a result of aqueous phase chemistry in cloud droplets, followed by subsequent droplet evaporation above cloud tops; the main product of this chemistry was oxalic acid. The evolution of organic acids with increasing altitude in cloud provides evidence for the multistep nature of oxalic acid production; predictions from a cloud parcel model are consistent with the observed oxalate:glyoxylate ratio as a function of altitude in GoMACCS cumuli. Suppressed organic acid formation was observed in clouds with relatively acidic droplets, as determined by high particulate nitrate concentrations (presumably high HNO_3 levels too) and lower liquid water content, as compared to other cloud fields probed. In the Houston Ship Channel region, an area with significant volatile organic compound emissions, oxalate, acetate, formate, benzoate, and pyruvate, in decreasing order, were the most abundant organic acids. Photo-oxidation of m-xylene in laboratory chamber experiments leads to a particulate organic acid product distribution consistent with the Ship Channel area observations.", "doi": "10.1029/2007JD008537", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2007-07-16", "series_number": "D3", "volume": "112", "issue": "D3", "pages": "Art. No. D13201" }, { "id": "authors:skts8-pqv20", "collection": "authors", "collection_id": "skts8-pqv20", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-111158831", "type": "article", "title": "On the Source of Organic Acid Aerosol Layers above Clouds", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "Brechtel", "given_name": "Fred J.", "clpid": "Brechtel-F-J" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Feingold", "given_name": "Graham", "clpid": "Feingold-G" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "During the July 2005 Marine Stratus/Stratocumulus Experiment (MASE) and the August\u2212September 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS), the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter probed aerosols and cumulus clouds in the eastern Pacific Ocean off the coast of northern California and in southeastern Texas, respectively. An on-board particle-into-liquid sampler (PILS) quantified inorganic and organic acid species with \u22645-min time resolution. Ubiquitous organic aerosol layers above cloud with enhanced organic acid levels were observed in both locations. The data suggest that aqueous-phase reactions to produce organic acids, mainly oxalic acid, followed by droplet evaporation is a source of elevated organic acid aerosol levels above cloud. Oxalic acid is observed to be produced more efficiently relative to sulfate as the cloud liquid water content increases, corresponding to larger and less acidic droplets. As derived from large eddy simulations of stratocumulus under the conditions of MASE, both Lagrangian trajectory analysis and diurnal cloudtop evolution provide evidence that a significant fraction of the aerosol mass concentration above cloud can be accounted for by evaporated droplet residual particles. Methanesulfonate data suggest that entrainment of free tropospheric aerosol can also be a source of organic acids above boundary layer clouds.", "doi": "10.1021/es0630442", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2007-07-01", "series_number": "13", "volume": "41", "issue": "13", "pages": "4647-4654" }, { "id": "authors:zva1c-2gr19", "collection": "authors", "collection_id": "zva1c-2gr19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-132541118", "type": "article", "title": "Cloud condensation nuclei prediction error from application of K\u00f6hler theory: Importance for the aerosol indirect effect", "author": [ { "family_name": "Sotiropoulou", "given_name": "Rafaella-Eleni P.", "orcid": "0000-0002-6319-9577", "clpid": "Sotiropoulou-Rafaella-Eleni-P" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Adams", "given_name": "Peter J.", "clpid": "Adams-Peter-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In situ observations of aerosol and cloud condensation nuclei (CCN) and the GISS GCM Model II' with an online aerosol simulation and explicit aerosol-cloud interactions are used to quantify the uncertainty in radiative forcing and autoconversion rate from application of K\u00f6hler theory. Simulations suggest that application of K\u00f6hler theory introduces a 10\u201320% uncertainty in global average indirect forcing and 2\u201311% uncertainty in autoconversion. Regionally, the uncertainty in indirect forcing ranges between 10\u201320%, and 5\u201350% for autoconversion. These results are insensitive to the range of updraft velocity and water vapor uptake coefficient considered. This study suggests that K\u00f6hler theory (as implemented in climate models) is not a significant source of uncertainty for aerosol indirect forcing but can be substantial for assessments of aerosol effects on the hydrological cycle in climatically sensitive regions of the globe. This implies that improvements in the representation of GCM subgrid processes and aerosol size distribution will mostly benefit indirect forcing assessments. Predictions of autoconversion, by nature, will be subject to considerable uncertainty; its reduction may require explicit representation of size-resolved aerosol composition and mixing state.", "doi": "10.1029/2006JD007834", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2007-06-27", "series_number": "D12", "volume": "112", "issue": "D12", "pages": "Art. No. D12202" }, { "id": "authors:68s1c-ec259", "collection": "authors", "collection_id": "68s1c-ec259", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AMUacpd07", "type": "article", "title": "A new atmospheric aerosol phase equilibrium model (UHAERO): organic systems", "author": [ { "family_name": "Amundson", "given_name": "N. R.", "clpid": "Amundson-N-R" }, { "family_name": "Caboussat", "given_name": "A.", "clpid": "Caboussat-A" }, { "family_name": "He", "given_name": "J. W.", "clpid": "He-J-W" }, { "family_name": "Martynenko", "given_name": "A. V.", "clpid": "Martynenko-A-V" }, { "family_name": "Landry", "given_name": "C.", "clpid": "Landry-C" }, { "family_name": "Tong", "given_name": "C.", "clpid": "Tong-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In atmospheric aerosols, water and volatile inorganic and organic species are distributed between the gas and aerosol phases in accordance with thermodynamic equilibrium. Within an atmospheric particle, liquid and solid phases can exist at equilibrium. Models exist for computation of phase equilibria for inorganic/water mixtures typical of atmospheric aerosols; when organic species are present, the phase equilibrium problem is complicated by organic/water interactions as well as the potentially large number of organic species. We present here an extension of the UHAERO inorganic thermodynamic model (Amundson et al., 2006c) to organic/water systems. Phase diagrams for a number of model organic/water systems characteristic of both primary and secondary organic aerosols are computed. Also calculated are inorganic/organic/water phase diagrams that show the effect of organics on inorganic deliquescence behavior. The effect of the choice of activity coefficient model for organics on the computed phase equilibria is explored.", "issn": "1680-7367", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2007-06-22", "series_number": "3", "volume": "7", "issue": "3", "pages": "8709-8754" }, { "id": "authors:xcg3j-gwr88", "collection": "authors", "collection_id": "xcg3j-gwr88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:RISacp07", "type": "article", "title": "Cloud condensation nucleus (CCN) behavior of organic aerosol particles generated by atomization of water and methanol solutions", "author": [ { "family_name": "Rissman", "given_name": "T. A.", "clpid": "Rissman-Tracey-A" }, { "family_name": "Varutbangkul", "given_name": "V.", "clpid": "Varutbangkul-Varuntida" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Topping", "given_name": "D. O.", "clpid": "Topping-D-O" }, { "family_name": "McFiggans", "given_name": "G.", "orcid": "0000-0002-3423-7896", "clpid": "McFiggans-Gordon" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Cloud condensation nucleus (CCN) experiments were carried out for malonic acid, succinic acid, oxalacetic acid, DL-malic acid, glutaric acid, DL-glutamic acid monohydrate, and adipic acid, using both water and methanol as atomization solvents, at three operating supersaturations (0.11%, 0.21%, and 0.32%) in the Caltech three-column CCN instrument (CCNC3). Predictions of CCN behavior for five of these compounds were made using the Aerosol Diameter Dependent Equilibrium Model (ADDEM). The experiments presented here expose important considerations associated with the laboratory measurement of the CCN behavior of organic compounds. Choice of atomization solvent results in significant differences in CCN activation for some of the compounds studied, which could result from residual solvent, particle morphology differences, and chemical reactions between the particle and gas phases. Also, significant changes in aerosol size distribution occurred after classification in a differential mobility analyzer (DMA) for malonic acid and glutaric acid, preventing confident interpretation of experimental data for these two compounds. Filter analysis of adipic acid atomized from methanol solution indicates that gas-particle phase reactions may have taken place after atomization and before methanol was removed from the sample gas stream. Careful consideration of these experimental issues is necessary for successful design and interpretation of laboratory CCN measurements.", "doi": "10.5194/acp-7-2949-2007", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2007-06-12", "series_number": "11", "volume": "7", "issue": "11", "pages": "2949-2971" }, { "id": "authors:pkaka-7fd80", "collection": "authors", "collection_id": "pkaka-7fd80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:STIacpd07", "type": "article", "title": "Aerosol absorption and radiative forcing", "author": [ { "family_name": "Stier", "given_name": "P.", "clpid": "Stier-P" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Kinne", "given_name": "S.", "clpid": "Kinne-S" }, { "family_name": "Boucher", "given_name": "O.", "clpid": "Boucher-O" } ], "abstract": "We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006) significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA) radiative forcing clear-sky from \u20130.79 to \u20130.53 W m^\u22122 (33%) and all-sky from \u20130.47 to \u20130.13 W m^\u22122 (72%). Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m^\u22122 (36%) clear-sky and of 0.12 W m^\u22122 (92%) all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W m^\u22122 and a positive TOA forcing perturbation of 0.02 W m^\u22122. The long-wave aerosol radiative effects are small for anthropogenic aerosols but become of relevance for the larger natural dust and sea-salt aerosols.", "issn": "1680-7367", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2007-05-30", "series_number": "3", "volume": "7", "issue": "3", "pages": "7171-7233" }, { "id": "authors:km9b0-zmf53", "collection": "authors", "collection_id": "km9b0-zmf53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-141131411", "type": "article", "title": "The Marine Stratus/Stratocumulus Experiment (MASE): Aerosol-cloud relationships in marine stratocumulus", "author": [ { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-W-C" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The Marine Stratus/Stratocumulus Experiment (MASE) field campaign was undertaken in July 2005 off the coast of Monterey, California to evaluate aerosol-cloud relationships in the climatically important regime of eastern Pacific marine stratocumulus. Aerosol and cloud properties were measured onboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. One cloud that was clearly impacted by ship emissions as well as the ensemble of clouds observed over the entire mission are analyzed in detail. Results at both the individual and ensemble scales clearly confirm the Twomey effect (first indirect effect of aerosols) and demonstrate drizzle suppression at elevated aerosol number concentration. For the ship track impacted cloud, suppressed drizzle in the track led to a larger cloud liquid water path (LWP) at the same cloud thickness, in accord with the so-called second indirect effect. Ensemble averages over all clouds sampled over the entire 13-flight mission show the opposite effect of aerosol number concentration on LWP, presumably the result of other dynamic influences (e.g., updraft velocity and ambient sounding profile). Individual polluted clouds were found to exhibit a narrower cloud drop spectral width in accord with theoretical prediction (M.-L. Lu and J. H. Seinfeld, Effect of aerosol number concentration on cloud droplet dispersion: A large-eddy simulation study and implications for aerosol indirect forcing, Journal of Geophysical Research, 2006). This field experiment demonstrates both the indirect aerosol effect on ship track perturbed clouds, as well as the subtleties involved in extracting these effects over an ensemble of clouds sampled over a 1-month period.", "doi": "10.1029/2006JD007985", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2007-05-27", "series_number": "D10", "volume": "112", "issue": "D10", "pages": "Art. No. D10209" }, { "id": "authors:1dbxw-qah13", "collection": "authors", "collection_id": "1dbxw-qah13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-142422118", "type": "article", "title": "Regional variation of organic functional groups in aerosol particles on four U.S. east coast platforms during the International Consortium for Atmospheric Research on Transport and Transformation 2004 campaign", "author": [ { "family_name": "Gilardoni", "given_name": "S.", "clpid": "Gilardoni-S" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Bates", "given_name": "T. S.", "clpid": "Bates-T-S" }, { "family_name": "Quinn", "given_name": "P. K.", "clpid": "Quinn-P-K" }, { "family_name": "Allan", "given_name": "J. D.", "clpid": "Allan-J-D" }, { "family_name": "Williams", "given_name": "B.", "clpid": "Williams-B" }, { "family_name": "Goldstein", "given_name": "A. H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" }, { "family_name": "Onasch", "given_name": "T. B.", "clpid": "Onasch-T-B" }, { "family_name": "Worsnop", "given_name": "D. R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-D-R" } ], "abstract": "Submicron atmospheric aerosol samples were collected during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) 2004 campaign on four platforms: Chebogue Point (Nova Scotia, Canada), Appledore Island (Maine), the CIRPAS Twin Otter over Ohio, and the NOAA R/V Ronald H. Brown in the Gulf of Maine. Saturated aliphatic C-C-H, unsaturated aliphatic C=C\u2212H, aromatic C=C\u2212H, organosulfur C-O-S, carbonyl C=O, and organic hydroxyl C-OH functional groups were measured by calibrated Fourier Transform Infrared (FTIR) spectroscopy at all four sampling platforms. The ratio of molar concentrations of carbonyl C=O to saturated aliphatic C-C-H groups was nearly constant at each sampling platform, with the Twin Otter samples having the lowest ratio at 0.1 and the three more coastal platforms having ratios of 0.4 and 0.5. Organic mass (OM) to organic carbon (OC) ratios follow similar trends for the four platforms, with the Twin Otter having the lowest ratio of 1.4 and the coastal platforms having slightly higher values typically between 1.5 and 1.6. Organosulfur compounds were occasionally observed. Collocated organic aerosol sampling with two Aerodyne aerosol mass spectrometers for OM, a Sunset Laboratory thermo-optical analysis instrument for OC, and an ion chromatography-particle into liquid sampler (IC-PILS) for speciated carboxylic acids provided comparable results for most of the project, tracking the time series of FTIR OM, OC, and carbonyl groups, respectively, and showing simultaneous peaks of similar magnitude during most of the project. The FTIR/IC-PILS comparison suggests that about 9% of the carbonyl groups found in submicron organic particles on the Twin Otter are typically associated with low molecular weight carboxylic acids.", "doi": "10.1029/2006JD007737", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2007-05-27", "series_number": "D10", "volume": "112", "issue": "D10", "pages": "Art. No. D10S27" }, { "id": "authors:83n0a-21311", "collection": "authors", "collection_id": "83n0a-21311", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-140023116", "type": "article", "title": "Aerosol\u2013cloud drop concentration closure for clouds sampled during the International Consortium for Atmospheric Research on Transport and Transformation 2004 campaign", "author": [ { "family_name": "Fountoukis", "given_name": "Christos", "orcid": "0000-0002-3657-823X", "clpid": "Fountoukis-Christos" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Meskhidze", "given_name": "Nicholas", "orcid": "0000-0001-5628-8777", "clpid": "Meskhidze-Nicholas" }, { "family_name": "Bahreini", "given_name": "Roya", "orcid": "0000-0001-8292-5338", "clpid": "Bahreini-Roya" }, { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-William-C" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Murphy", "given_name": "Shane", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-Varuntida" }, { "family_name": "Brechtel", "given_name": "Fred J.", "orcid": "0000-0002-2375-8741", "clpid": "Brechtel-Frederick-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This study analyzes 27 cumuliform and stratiform clouds sampled aboard the CIRPAS Twin Otter during the 2004 International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) experiment. The data set was used to assess cloud droplet closure using (1) a detailed adiabatic cloud parcel model and (2) a state-of-the-art cloud droplet activation parameterization. A unique feature of the data set is the sampling of highly polluted clouds within the vicinity of power plant plumes. Remarkable closure was achieved (much less than the 20% measurement uncertainty) for both parcel model and parameterization. The highly variable aerosol did not complicate the cloud droplet closure, since the clouds had low maximum supersaturation and were not sensitive to aerosol variations (which took place at small particle sizes). The error in predicted cloud droplet concentration was mostly sensitive to updraft velocity. Optimal closure is obtained if the water vapor uptake coefficient is equal to 0.06, but can range between 0.03 and 1.0. The sensitivity of cloud droplet prediction error to changes in the uptake coefficient, organic solubility and surface tension depression suggest that organics exhibit limited solubility. These findings can serve as much needed constraints in modeling of aerosol-cloud interactions in the North America; future in situ studies will determine the robustness of our findings.", "doi": "10.1029/2006JD007272", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2007-05-27", "series_number": "D10", "volume": "112", "issue": "D10", "pages": "Art. No. D10S30" }, { "id": "authors:myv1k-j4s45", "collection": "authors", "collection_id": "myv1k-j4s45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHAacpd07", "type": "article", "title": "Kinetic modeling of Secondary Organic Aerosol formation: effects of particle- and gas-phase reactions of semivolatile products", "author": [ { "family_name": "Chan", "given_name": "A. W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Kroll", "given_name": "J. H.", "clpid": "Kroll-J-H" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The distinguishing mechanism of formation of secondary organic aerosol (SOA) is the partitioning of semivolatile hydrocarbon oxidation products between the gas and aerosol phases. While SOA formation is typically described in terms of partitioning only, the rate of formation and ultimate yield of SOA can also depend on the kinetics of both gas- and aerosol-phase processes. We present a general equilibrium/kinetic model of SOA formation that provides a framework for evaluating the extent to which the controlling mechanisms of SOA formation can be inferred from laboratory chamber data. With this model we examine the effect on SOA formation of gas-phase oxidation of first-generation products to either more or less volatile species, of particle-phase reaction (both first- and second-order kinetics), of the rate of parent hydrocarbon oxidation, and of the extent of reaction of the parent hydrocarbon. The effect of pre-existing organic aerosol mass on SOA yield, an issue of direct relevance to the translation of laboratory data to atmospheric applications, is examined. The importance of direct chemical measurements of gas- and particle-phase species is underscored in identifying SOA formation mechanisms.", "issn": "1680-7367", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2007-05-24", "series_number": "3", "volume": "7", "issue": "3", "pages": "7051-7085" }, { "id": "authors:ehr7c-ga065", "collection": "authors", "collection_id": "ehr7c-ga065", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-111021453", "type": "article", "title": "Reactions of Semivolatile Organics and Their Effects on Secondary Organic Aerosol Formation", "author": [ { "family_name": "Kroll", "given_name": "Jesse H.", "clpid": "Kroll-J-H" }, { "family_name": "Chan", "given_name": "Arthur W. H.", "orcid": "0000-0001-7392-4237", "clpid": "Chan-Arthur-W-H" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) constitutes a significant fraction of total atmospheric particulate loading, but there is evidence that SOA yields based on laboratory studies may underestimate atmospheric SOA. Here we present chamber data on SOA growth from the photooxidation of aromatic hydrocarbons, finding that SOA yields are systematically lower when inorganic seed particles are not initially present. This indicates that concentrations of semivolatile oxidation products are influenced by processes beyond gas-particle partitioning, such as chemical reactions and/or loss to chamber walls. Predictions of a kinetic model in which semivolatile compounds may undergo reactions in both the gas and particle phases in addition to partitioning are qualitatively consistent with the observed seed effect, as well as with a number of other recently observed features of SOA formation chemistry. The behavior arises from a kinetic competition between uptake to the particle phase and reactive loss of the semivolatile product. It is shown that when hydrocarbons react in the absence of preexisting organic aerosol, such loss processes may lead to measured SOA yields lower than would occur under atmospheric conditions. These results underscore the need to conduct studies of SOA formation in the presence of atmospherically relevant aerosol loadings.", "doi": "10.1021/es062059x", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2007-05-15", "series_number": "10", "volume": "41", "issue": "10", "pages": "3545-3550" }, { "id": "authors:bxf7s-vs472", "collection": "authors", "collection_id": "bxf7s-vs472", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HENacp07", "type": "article", "title": "Development of the adjoint of GEOS-Chem", "author": [ { "family_name": "Henze", "given_name": "D. K.", "clpid": "Henze-D-K" }, { "family_name": "Hakami", "given_name": "A.", "clpid": "Hakami-A" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We present the adjoint of the global chemical transport model GEOS-Chem, focusing on the chemical and thermodynamic relationships between sulfate \u2013 ammonium \u2013 nitrate aerosols and their gas-phase precursors. The adjoint model is constructed from a combination of manually and automatically derived discrete adjoint algorithms and numerical solutions to continuous adjoint equations. Explicit inclusion of the processes that govern secondary formation of inorganic aerosol is shown to afford efficient calculation of model sensitivities such as the dependence of sulfate and nitrate aerosol concentrations on emissions of SOx, NOx, and NH3. The accuracy of the adjoint model is extensively verified by comparing adjoint to finite difference sensitivities, which are shown to agree within acceptable tolerances. We explore the robustness of these results, noting how discontinuities in the advection routine hinder, but do not entirely preclude, the use of such comparisons for validation of the adjoint model. The potential for inverse modeling using the adjoint of GEOS-Chem is assessed in a data assimilation framework using simulated observations, demonstrating the feasibility of exploiting gas- and aerosol-phase measurements for optimizing emission inventories of aerosol precursors.", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2007-05-11", "series_number": "9", "volume": "7", "issue": "9", "pages": "2413-2433" }, { "id": "authors:e5w29-n9394", "collection": "authors", "collection_id": "e5w29-n9394", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MURacp07", "type": "article", "title": "Secondary aerosol formation from atmospheric reactions of aliphatic amines", "author": [ { "family_name": "Murphy", "given_name": "S. M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Sorooshian", "given_name": "A.", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Kroll", "given_name": "J. H.", "orcid": "0000-0002-6275-521X", "clpid": "Kroll-Jesse-H" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Chhabra", "given_name": "P. S.", "clpid": "Chhabra-Puneet-S" }, { "family_name": "Tong", "given_name": "C.", "clpid": "Tong-C" }, { "family_name": "Surratt", "given_name": "J. D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Knipping", "given_name": "E.", "orcid": "0000-0002-9654-9019", "clpid": "Knipping-Eladio-M" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Although aliphatic amines have been detected in both urban and rural atmospheric aerosols, little is known about the chemistry leading to particle formation or the potential aerosol yields from reactions of gas-phase amines. We present here the first systematic study of aerosol formation from the atmospheric reactions of amines. Based on laboratory chamber experiments and theoretical calculations, we evaluate aerosol formation from reaction of OH, ozone, and nitric acid with trimethylamine, methylamine, triethylamine, diethylamine, ethylamine, and ethanolamine. Entropies of formation for alkylammonium nitrate salts are estimated by molecular dynamics calculations enabling us to estimate equilibrium constants for the reactions of amines with nitric acid. Though subject to significant uncertainty, the calculated dissociation equilibrium constant for diethylammonium nitrate is found to be sufficiently small to allow for its atmospheric formation, even in the presence of ammonia which competes for available nitric acid. Experimental chamber studies indicate that the dissociation equilibrium constant for triethylammonium nitrate is of the same order of magnitude as that for ammonium nitrate. All amines studied form aerosol when photooxidized in the presence of NOx with the majority of the aerosol mass present at the peak of aerosol growth consisting of aminium (R3NH+) nitrate salts, which repartition back to the gas phase as the parent amine is consumed. Only the two tertiary amines studied, trimethylamine and triethylamine, are found to form significant non-salt organic aerosol when oxidized by OH or ozone; calculated organic mass yields for the experiments conducted are similar for ozonolysis (15% and 5% respectively) and photooxidation (23% and 8% respectively). The non-salt organic aerosol formed appears to be more stable than the nitrate salts and does not quickly repartition back to the gas phase.", "doi": "10.5194/acp-7-2313-2007", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2007-05-08", "series_number": "9", "volume": "7", "issue": "9", "pages": "2313-2337" }, { "id": "authors:d3e61-ba622", "collection": "authors", "collection_id": "d3e61-ba622", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AMUcrm07.56", "type": "article", "title": "A dynamic optimization problem related to organic aerosols", "author": [ { "family_name": "Amundson", "given_name": "Neal R.", "clpid": "Amundson-Neal-R" }, { "family_name": "Caboussat", "given_name": "Alexandre", "clpid": "Caboussat-Alexandre" }, { "family_name": "He", "given_name": "Jiwen", "clpid": "He-Jiwen" }, { "family_name": "Landry", "given_name": "Chantal", "clpid": "Landry-Chantal" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A model that rigorously computes the gas\u2013particle partitioning and liquid\u2013liquid equilibrium for organic atmospheric aerosol particles is presented. The dynamics of the mass transfers between the particle and the gas phase are modeled with differential equations and are coupled with a constrained optimization problem for the thermodynamic equilibrium inside the particle. The nonlinear system composed by the first order optimality conditions coupled with the discretized differential equations is solved with an interior-point method and a Newton method. The resulting linear system is decoupled with sequential quadratic programming techniques. Numerical results and comparisons of time scales show the accuracy and efficiency of our algorithm.", "doi": "10.1016/j.crma.2007.03.002", "issn": "1631-073X", "publisher": "Elsevier", "publication": "Comptes Rendus Mathematique", "publication_date": "2007-04-15", "series_number": "8", "volume": "344", "issue": "8", "pages": "519-522" }, { "id": "authors:95pm7-yby58", "collection": "authors", "collection_id": "95pm7-yby58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-134833364", "type": "article", "title": "Biogenic secondary organic aerosol over the United States: Comparison of climatological simulations with observations", "author": [ { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Henze", "given_name": "Daven K.", "clpid": "Henze-D-K" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wu", "given_name": "Shiliang", "clpid": "Wu-Shiliang" }, { "family_name": "Mickley", "given_name": "Loretta J.", "orcid": "0000-0002-7859-3470", "clpid": "Mickley-L-J" } ], "abstract": "Understanding the effects of global climate change on regional air quality is central in future air quality planning. We report here on the use of the Goddard Institute for Space Studies (GISS) general circulation model (GCM) III to drive the GEOS-CHEM global atmospheric chemical transport model to simulate climatological present-day aerosol levels over the United States. Evaluation of model predictions using surface measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network indicates that the GISS GCM III/GEOS-CHEM model is a suitable tool for simulating aerosols over the United States in the present climate. The model reproduces fairly well the concentrations of sulfate (mean bias of \u22120.36 \u03bcg m^(\u22123), normalized mean bias (NMB) of \u221225.9%), black carbon (\u22120.004 \u03bcg m^(\u22123), \u22121.9%), organic carbon that comprises primary and secondary components (\u22120.56 \u03bcg m^(\u22123), \u221234.2%), and PM_(2.5) (\u22120.87 \u03bcg m^(\u22123), \u221220.4%). Nitrate concentrations are overpredicted in the western United States (west of 95\u00b0W) with a NMB of +75.6% and underestimated in the eastern United States with a NMB of \u221254.4%. Special attention is paid to biogenic secondary organic aerosol (SOA). The highest predicted seasonal mean SOA concentrations of 1\u20132 \u03bcg m^(\u22123) and 0.5\u20131.5 \u03bcg m^(\u22123) are predicted over the northwestern and southeastern United States, respectively, in the months of June\u2013July\u2013August. Isoprene is predicted to contribute 49.5% of the biogenic SOA burden over the United States, with the rest explained by the oxidation of terpenes. Predicted biogenic SOA concentrations are in reasonable agreement with inferred SOA levels from IMPROVE measurements. On an annual basis, SOA is predicted to contribute 10\u201320% of PM_(2.5) mass in the southeastern United States, as high as 38% in the northwest and about 5\u201315% in other regions, indicating the important role of SOA in understanding air quality and visibility over the United States.", "doi": "10.1029/2006JD007813", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2007-03-27", "series_number": "D6", "volume": "112", "issue": "D6", "pages": "Art. No. D06201" }, { "id": "authors:kzaty-ce721", "collection": "authors", "collection_id": "kzaty-ce721", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUZast07.102", "type": "article", "title": "Aerosol Properties Computed from Aircraft-Based Observations During the ACE-Asia Campaign: 2. A Case Study of Lidar Ratio Closure", "author": [ { "family_name": "Kuzmanoski", "given_name": "M.", "orcid": "0000-0001-5759-6333", "clpid": "Kuzmanoski-M" }, { "family_name": "Box", "given_name": "M. A.", "clpid": "Box-M-A" }, { "family_name": "Schmid", "given_name": "B.", "clpid": "Schmid-B" }, { "family_name": "Box", "given_name": "G. P.", "clpid": "Box-G-P" }, { "family_name": "Wang", "given_name": "J.", "clpid": "Wang-J" }, { "family_name": "Russell", "given_name": "P. B.", "clpid": "Russell-P-B" }, { "family_name": "Bates", "given_name": "D.", "clpid": "Bates-D" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Welton", "given_name": "E.J.", "orcid": "0000-0003-0208-4861", "clpid": "Welton-Ellsworth-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "For a vertical profile with three distinct layers (marine boundary, pollution, and dust layers), observed during the ACE-Asia campaign, we carried out a comparison between the modeled lidar ratio vertical profile and that obtained from co-located airborne NASA AATS-14 sunphotometer and shipborne Micro-Pulse Lidar (MPL) measurements. The vertically resolved lidar ratio was calculated from two size distribution vertical profiles\u2014one obtained by inversion of sunphotometer-derived extinction spectra, and one measured in-situ\u2014combined with the same refractive index model based on aerosol chemical composition. The aerosol model implies single scattering albedos of 0.78\u20130.81 and 0.93\u20130.96 at 0.523 \u03bcm (the wavelength of the lidar measurements), in the pollution and dust layers, respectively. The lidar ratios calculated from the two size distribution profiles agree closely in the dust layer; they are however, significantly lower than the lidar ratios derived from combined lidar and sunphotometer measurements. Uncertainties in aerosol size distributions and refractive index only partly explain these differences, suggesting that particle nonsphericity in this layer is an additional explanation. In the pollution layer, the two size distribution profiles yield lidar ratios that agree within the estimated uncertainties. The retrieved size distributions result in a lidar ratio which is in closer agreement with that derived from lidar/sunphotometer measurements in this layer, with still large differences at certain altitudes (the largest relative difference was 46%). We explain these differences by non-uniqueness of the result of the size distribution retrieval, by a lack of information on the mixing state of particles, and the vertical variability of the particle refractive index.", "doi": "10.1080/02786820601146977", "issn": "0278-6826", "publisher": "Taylor & Francis", "publication": "Aerosol Science and Technology", "publication_date": "2007-03", "series_number": "3", "volume": "41", "issue": "3", "pages": "231-243" }, { "id": "authors:sr0db-xwv73", "collection": "authors", "collection_id": "sr0db-xwv73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141103-144131843", "type": "article", "title": "2006 Fuchs Memorial Award recipients", "author": [ { "family_name": "Seinfeld", "given_name": "John", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Horvath", "given_name": "Helmut", "clpid": "Horvath-Helmut" }, { "family_name": "Kasper", "given_name": "Gerhard", "clpid": "Kasper-Gerhard" }, { "family_name": "Liu", "given_name": "Benjamin", "clpid": "Liu-Benjamin" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Otani", "given_name": "Yoshio", "clpid": "Otani-Yoshio" } ], "abstract": "The Fuchs Memorial Award was established in honor of the great aerosol scientist, Prof. Nikolai Albertovich Fuchs\n(1895\u20131983) of Russia, during the 1986 International Aerosol Conference in Berlin. It is jointly sponsored by the\nfollowing three aerosol societies:\n\u2022 The American Association for Aerosol Research.\n\u2022 The Japan Association for Aerosol Science and Technology.\n\u2022 The Gesellschaft f\u00fcr Aerosolforschung.\n\nThe recipients of the fifth Fuchs Memorial Award are Prof. Richard C. Flagan of the California Institute of\nTechnology and Prof. Peter H. McMurry of the University of Minnesota. The Award was presented at the Seventh\nInternational Aerosol Conference, held September 10\u201315, 2006, in St. Paul, Minnesota.", "doi": "10.1016/j.jaerosci.2007.01.005", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "2007-03", "series_number": "3", "volume": "38", "issue": "3", "pages": "370-372" }, { "id": "authors:srnf8-c5291", "collection": "authors", "collection_id": "srnf8-c5291", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CLEae07.257", "type": "article", "title": "Detection and quantification of 2-methyltetrols in ambient aerosol in the southeastern United States", "author": [ { "family_name": "Clements", "given_name": "Andrea L.", "orcid": "0000-0003-0764-5584", "clpid": "Clements-Andrea-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Filters collected from the Southeastern Aerosol Research and Characterization (SEARCH) air monitoring network were analyzed for the presence of 2-methyltetrols, namely 2-methylthreitol and 2-methylerythritol, two compounds that are products of the photooxidation of isoprene and have been detected in aerosol at a variety of sites around the globe. The 2-methytetrols were detected in ambient filter samples collected at the four SEARCH sites, Birmingham, AL, Centreville, AL, Pensacola, FL, and at Jefferson Street in Atlanta, GA, in late June 2004. Average atmospheric concentrations of 11.9 and 4.8 ng m\u207b\u00b3 were measured for 2-methylerythritol and 2-methylthreitol, respectively, at the inland sampling sites, whereas average concentrations of 4.9 and 1.6 ng m\u207b\u00b3 were measured at the coastal sampling location (Pensacola). On average, the aerosol loading from these two compounds accounts for approximately 0.42% and 0.21% of the organic mass collected on a given sampling day at the inland and coastal sites, respectively. The present data on these compounds, which are particulate-phase fingerprints of isoprene photooxidation, add to the growing body of ambient data on secondary organic aerosol from isoprene.", "doi": "10.1016/j.atmosenv.2006.10.056", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2007-03", "series_number": "9", "volume": "41", "issue": "9", "pages": "1825-1830" }, { "id": "authors:vadkv-pr175", "collection": "authors", "collection_id": "vadkv-pr175", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUZast07.101", "type": "article", "title": "Aerosol Properties Computed from Aircraft-Based Observations during the ACE-Asia Campaign: 1. Aerosol Size Distributions Retrieved from Optical Thickness Measurements", "author": [ { "family_name": "Kuzmanoski", "given_name": "M.", "clpid": "Kuzmanoski-M" }, { "family_name": "Box", "given_name": "M. A.", "clpid": "Box-M-A" }, { "family_name": "Box", "given_name": "G. P.", "clpid": "Box-G-P" }, { "family_name": "Schmid", "given_name": "B.", "clpid": "Schmid-B" }, { "family_name": "Wang", "given_name": "J.", "clpid": "Wang-J" }, { "family_name": "Russell", "given_name": "P. B.", "clpid": "Russell-P-B" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In this article, aerosol size distributions retrieved from aerosol layer optical thickness spectra, derived from the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) measurements during the ACE-Asia campaign, are presented. Focusing on distinct aerosol layers (with different particle characteristics) observed in four vertical profiles, we compare the results of two different retrieval methods: constrained linear inversion and a non-linear least squares method. While the former does not use any assumption about the analytical form of the size distribution, the latter was used to retrieve parameters of a bimodal lognormal size distribution. Furthermore, comparison of the retrieved size distributions with those measured in-situ, aboard the same aircraft on which the sunphotometer was flown, was carried out. Results of the two retrieval methods showed good agreement in the radius ranges from \u223c0.1 \u03bcm to \u223c1.2\u20132.0 \u03bcm, close to the range of retrievable size distributions from the AATS-14 measurements. In this radius interval, shapes of retrieved and measured size distributions were similar, in accord with close wavelength dependencies of the corresponding optical thicknesses. Additionally, the effect of a size-resolved refractive index on the retrieved size spectra was investigated in selected cases. Retrieval using a constant refractive index pertaining to particle sizes within the range of retrievable size distributions resulted in a size distribution very close to the one retrieved using a size-resolved refractive index.", "doi": "10.1080/02786820601126789", "issn": "0278-6826", "publisher": "Taylor & Francis", "publication": "Aerosol Science and Technology", "publication_date": "2007-02", "series_number": "2", "volume": "41", "issue": "2", "pages": "202-216" }, { "id": "authors:ff21y-tg891", "collection": "authors", "collection_id": "ff21y-tg891", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-110218604", "type": "article", "title": "Evidence for Organosulfates in Secondary Organic Aerosol", "author": [ { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Kroll", "given_name": "Jesse H.", "orcid": "0000-0002-6275-521X", "clpid": "Kroll-Jesse-H" }, { "family_name": "Kleindienst", "given_name": "Tadeusz E.", "orcid": "0000-0002-3024-1564", "clpid": "Kleindienst-Tadeusz-E" }, { "family_name": "Edney", "given_name": "Edward O.", "clpid": "Edney-Edward-O" }, { "family_name": "Claeys", "given_name": "Magda", "orcid": "0000-0003-2278-8014", "clpid": "Claeys-Magda" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Offenberg", "given_name": "John H.", "orcid": "0000-0002-0213-4024", "clpid": "Offenberg-John-H" }, { "family_name": "Lewandowski", "given_name": "Michael", "orcid": "0000-0002-0058-956X", "clpid": "Lewandowski-Michael" }, { "family_name": "Jaoui", "given_name": "Mohammed", "orcid": "0000-0002-2728-9137", "clpid": "Jaoui-Mohammed" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recent work has shown that particle-phase reactions contribute to the formation of secondary organic aerosol (SOA), with enhancements of SOA yields in the presence of acidic seed aerosol. In this study, the chemical composition of SOA from the photooxidations of \u03b1-pinene and isoprene, in the presence or absence of sulfate seed aerosol, is investigated through a series of controlled chamber experiments in two separate laboratories. By using electrospray ionization\u2212mass spectrometry, sulfate esters in SOA produced in laboratory photooxidation experiments are identified for the first time. Sulfate esters are found to account for a larger fraction of the SOA mass when the acidity of seed aerosol is increased, a result consistent with aerosol acidity increasing SOA formation. Many of the isoprene and \u03b1-pinene sulfate esters identified in these chamber experiments are also found in ambient aerosol collected at several locations in the southeastern U.S. It is likely that this pathway is important for other biogenic terpenes, and may be important in the formation of humic-like substances (HULIS) in ambient aerosol.", "doi": "10.1021/es062081q", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2007-01-15", "series_number": "2", "volume": "41", "issue": "2", "pages": "517-527" }, { "id": "authors:w5922-b5p71", "collection": "authors", "collection_id": "w5922-b5p71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SZMjms07.198", "type": "article", "title": "Characterization of 2-methylglyceric acid oligomers in secondary organic aerosol formed from the photooxidation of isoprene using trimethylsilylation and gas chromatography/ion trap mass spectrometry", "author": [ { "family_name": "Szmigielski", "given_name": "Rafal", "orcid": "0000-0003-3389-9318", "clpid": "Szmigielski-Rafal" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Vermeylen", "given_name": "Reinhilde", "clpid": "Vermeylen-Reinhilde" }, { "family_name": "Szmigielska", "given_name": "Katarzyna", "orcid": "0000-0002-7413-228X", "clpid": "Szmigielska-Katarzyna" }, { "family_name": "Kroll", "given_name": "Jesse H.", "orcid": "0000-0002-6275-521X", "clpid": "Kroll-Jesse-H" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Claeys", "given_name": "Magda", "orcid": "0000-0003-2278-8014", "clpid": "Claeys-Magda" } ], "abstract": "In the present work, we have characterized in detail the chemical structures of secondary organic aerosol (SOA) components that were generated in a smog chamber and result from the photooxidation of isoprene under high-NOx conditions typical for a polluted atmosphere. Isoprene high-NOx SOA contains 2-methylglyceric acid (2-MG) and oligoester derivatives thereof. Trimethylsilylation, in combination with capillary gas chromatography (GC)/ion trap mass spectrometry (MS) and detailed interpretation of the MS data, allowed structural characterization the polar oxygenated compounds present in isoprene SOA up to 2-MG trimers. GC separation was achieved between 2-MG linear and branched dimers or trimers, as well as between the 2-MG linear dimer and isomeric mono-acetate derivatives thereof. The electron ionization (EI) spectra of the trimethylsilyl derivatives contain a wealth of structural information, including information about the molecular weight (MW), oligoester linkages, terminal carboxylic and hydroxymethyl groups, and esterification sites. Only part of this information can be achieved with a soft ionization technique such as electrospray (ESI) in combination with collision-induced dissociation (CID). The methane chemical ionization (CI) data were used to obtain supporting MW information. Interesting EI spectral differences were observed between the trimethylsilyl derivatives of 2-MG linear and branched dimers or trimers and between 2-MG linear dimer mono-acetate isomers.", "doi": "10.1002/jms.1146", "issn": "1076-5174", "publisher": "Wiley", "publication": "Journal of Mass Spectrometry", "publication_date": "2007-01", "series_number": "1", "volume": "42", "issue": "1", "pages": "101-116" }, { "id": "authors:tgxpt-x8229", "collection": "authors", "collection_id": "tgxpt-x8229", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200603-084113107", "type": "book_section", "title": "Localized Ensemble Kalman Dynamic Data Assimilation for Atmospheric Chemistry", "book_title": "Computational Science \u2013 ICCS 2007", "author": [ { "family_name": "Sandu", "given_name": "Adrian", "clpid": "Sandu-A" }, { "family_name": "Constantinescu", "given_name": "Emil M.", "clpid": "Constantinescu-E-M" }, { "family_name": "Carmichael", "given_name": "Gregory R.", "clpid": "Carmichael-G-R" }, { "family_name": "Chai", "given_name": "Tianfeng", "clpid": "Chai-Tianfeng" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "D\u0103escu", "given_name": "Dacian", "clpid": "D\u0103escu-D" } ], "contributor": [ { "family_name": "Shi", "given_name": "Yong", "clpid": "Shi-Yong" }, { "family_name": "van Albada", "given_name": "Geert Dick", "clpid": "van-Albada-G-D" }, { "family_name": "Dongarra", "given_name": "Jack", "clpid": "Dongarra-J" }, { "family_name": "Sloot", "given_name": "Peter M. A.", "clpid": "Sloot-P-M-A" } ], "abstract": "The task of providing an optimal analysis of the state of the atmosphere requires the development of dynamic data-driven systems (DDDAS) that efficiently integrate the observational data and the models. Data assimilation, the dynamic incorporation of additional data into an executing application, is an essential DDDAS concept with wide applicability. In this paper we discuss practical aspects of nonlinear ensemble Kalman data assimilation applied to atmospheric chemical transport models. We highlight the challenges encountered in this approach such as filter divergence and spurious corrections, and propose solutions to overcome them, such as background covariance inflation and filter localization. The predictability is further improved by including model parameters in the assimilation process. Results for a large scale simulation of air pollution in North-East United States illustrate the potential of nonlinear ensemble techniques to assimilate chemical observations.", "doi": "10.1007/978-3-540-72584-8_134", "isbn": "978-3-540-72583-1", "publisher": "Springer", "place_of_publication": "Berlin", "publication_date": "2007", "pages": "1018-1025" }, { "id": "authors:6v4g6-8w392", "collection": "authors", "collection_id": "6v4g6-8w392", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141103-135521536", "type": "article", "title": "International Consortium for Atmospheric Research on Transport and Transformation (ICARTT): North America to Europe\u2014Overview of the 2004 summer field study", "author": [ { "family_name": "Fehsenfeld", "given_name": "F. C.", "clpid": "Fehsenfeld-F-C" }, { "family_name": "Ancellet", "given_name": "G.", "clpid": "Ancellet-G" }, { "family_name": "Bates", "given_name": "T. S.", "clpid": "Bates-T-S" }, { "family_name": "Goldstein", "given_name": "A. H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" }, { "family_name": "Hardesty", "given_name": "R. M.", "clpid": "Hardesty-R-M" }, { "family_name": "Honrath", "given_name": "R.", "clpid": "Honrath-R-E" }, { "family_name": "Law", "given_name": "K. S.", "clpid": "Law-K-S" }, { "family_name": "Lewis", "given_name": "A. C.", "clpid": "Lewis-A-C" }, { "family_name": "Leaitch", "given_name": "R.", "clpid": "Leaitch-R" }, { "family_name": "McKeen", "given_name": "S.", "clpid": "McKeen-S-A" }, { "family_name": "Meagher", "given_name": "J.", "clpid": "Meagher-J-F" }, { "family_name": "Parrish", "given_name": "D. D.", "clpid": "Parrish-D-D" }, { "family_name": "Pszenny", "given_name": "A. A. P.", "clpid": "Pszenny-A-A-P" }, { "family_name": "Russell", "given_name": "P. B.", "clpid": "Russell-P-B" }, { "family_name": "Schlager", "given_name": "H.", "clpid": "Schlager-H" }, { "family_name": "Seinfeld", "given_name": "J.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Talbot", "given_name": "R.", "clpid": "Talbot-R-W" }, { "family_name": "Zbinden", "given_name": "R.", "clpid": "Zbinden-R" } ], "abstract": "In the summer of 2004 several separate field programs intensively studied the photochemical, heterogeneous chemical and radiative environment of the troposphere over North America, the North Atlantic Ocean, and western Europe. Previous studies have indicated that the transport of continental emissions, particularly from North America, influences the concentrations of trace species in the troposphere over the North Atlantic and Europe. An international team of scientists, representing over 100 laboratories, collaborated under the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) umbrella to coordinate the separate field programs in order to maximize the resulting advances in our understanding of regional air quality, the transport, chemical transformation and removal of aerosols, ozone, and their precursors during intercontinental transport, and the radiation balance of the troposphere. Participants utilized nine aircraft, one research vessel, several ground-based sites in North America and the Azores, a network of aerosol-ozone lidars in Europe, satellites, balloon borne sondes, and routine commercial aircraft measurements. In this special section, the results from a major fraction of those platforms are presented. This overview is aimed at providing operational and logistical information for those platforms, summarizing the principal findings and conclusions that have been drawn from the results, and directing readers to specific papers for further details.", "doi": "10.1029/2006JD007829", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2006-12-16", "series_number": "D23", "volume": "111", "issue": "D23", "pages": "Art. No. D23S01" }, { "id": "authors:je8wd-4g569", "collection": "authors", "collection_id": "je8wd-4g569", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-114508152", "type": "article", "title": "Oxalic acid in clear and cloudy atmospheres: Analysis of data from International Consortium for Atmospheric Research on Transport and Transformation 2004", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Brechtel", "given_name": "Fred J.", "clpid": "Brechtel-F-J" }, { "family_name": "Ervens", "given_name": "Barbara", "clpid": "Ervens-B" }, { "family_name": "Feingold", "given_name": "Graham", "clpid": "Feingold-G" }, { "family_name": "Bahreini", "given_name": "Roya", "clpid": "Bahreini-R" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-S-M" }, { "family_name": "Holloway", "given_name": "John S.", "clpid": "Holloway-J-S" }, { "family_name": "Atlas", "given_name": "Elliot L.", "orcid": "0000-0003-3847-5346", "clpid": "Atlas-E-L" }, { "family_name": "Buzorius", "given_name": "Gintas", "clpid": "Buzorius-G" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Oxalic acid is often the leading contributor to the total dicarboxylic acid mass in ambient organic aerosol particles. During the 2004 International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) field campaign, nine inorganic ions (including SO_4^(2\u2212)) and five organic acid ions (including oxalate) were measured on board the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter research aircraft by a particle-into-liquid sampler (PILS) during flights over Ohio and surrounding areas. Five local atmospheric conditions were studied: (1) cloud-free air, (2) power plant plume in cloud-free air with precipitation from scattered clouds overhead, (3) power plant plume in cloud-free air, (4) power plant plume in cloud, and (5) clouds uninfluenced by local pollution sources. The aircraft sampled from two inlets: a counterflow virtual impactor (CVI) to isolate droplet residuals in clouds and a second inlet for sampling total aerosol. A strong correlation was observed between oxalate and SO_4^(2\u2212) when sampling through both inlets in clouds. Predictions from a chemical cloud parcel model considering the aqueous-phase production of dicarboxylic acids and SO_4^(2\u2212) show good agreement for the relative magnitude of SO_4^(2\u2212) and oxalate growth for two scenarios: power plant plume in clouds and clouds uninfluenced by local pollution sources. The relative contributions of the two aqueous-phase routes responsible for oxalic acid formation were examined; the oxidation of glyoxylic acid was predicted to dominate over the decay of longer-chain dicarboxylic acids. Clear evidence is presented for aqueous-phase oxalic acid production as the primary mechanism for oxalic acid formation in ambient aerosols.", "doi": "10.1029/2005JD006880", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2006-12-16", "series_number": "D23", "volume": "111", "issue": "D23", "pages": "Art. No. D23S45" }, { "id": "authors:syk4j-f4g82", "collection": "authors", "collection_id": "syk4j-f4g82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HEAgpr06.234", "type": "article", "title": "Concentrations and sources of organic carbon aerosols in the free troposphere over North America", "author": [ { "family_name": "Heald", "given_name": "Colette L.", "orcid": "0000-0003-2894-5738", "clpid": "Heald-Colette-L" }, { "family_name": "Jacob", "given_name": "Daniel J.", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-Daniel-J" }, { "family_name": "Turquety", "given_name": "Sol\u00e8ne", "orcid": "0000-0002-0398-547X", "clpid": "Turquety-Sol\u00e8ne" }, { "family_name": "Hudman", "given_name": "Rynda C.", "clpid": "Hudman-Rynda-C" }, { "family_name": "Weber", "given_name": "Rodney J.", "orcid": "0000-0003-0765-8035", "clpid": "Weber-Rodney-J" }, { "family_name": "Sullivan", "given_name": "Amy P.", "orcid": "0000-0003-0143-8197", "clpid": "Sullivan-Amy-P" }, { "family_name": "Peltier", "given_name": "Richard E.", "orcid": "0000-0002-0402-0979", "clpid": "Peltier-Richard-E" }, { "family_name": "Atlas", "given_name": "Eliot L.", "clpid": "Atlas-Eliot-L" }, { "family_name": "de Gouw", "given_name": "Joost A.", "orcid": "0000-0002-0385-1826", "clpid": "de-Gouw-Joost-A" }, { "family_name": "Warneke", "given_name": "Carsten", "orcid": "0000-0003-3811-8496", "clpid": "Warneke-Carsten" }, { "family_name": "Holloway", "given_name": "John S.", "orcid": "0000-0002-4585-9594", "clpid": "Holloway-John S." }, { "family_name": "Neuman", "given_name": "J. Andrew", "orcid": "0000-0002-3986-1727", "clpid": "Neuman-J-Andrew" }, { "family_name": "Flocke", "given_name": "Frank M.", "orcid": "0000-0002-2661-6394", "clpid": "Flocke-Frank-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aircraft measurements of water-soluble organic carbon (WSOC) aerosol over NE North America during summer 2004 (ITCT-2K4) are simulated with a global chemical transport model (GEOS-Chem) to test our understanding of the sources of organic carbon (OC) aerosol in the free troposphere (FT). Elevated concentrations were observed in plumes from boreal fires in Alaska and Canada. WSOC aerosol concentrations outside of these plumes average 0.9 \u00b1 0.9 \u03bcg C m\u207b\u00b3 in the FT (2\u20136 km). The corresponding model value is 0.7 \u00b1 0.6 \u03bcg C m\u207b\u00b3, including 42% from biomass burning, 36% from biogenic secondary organic aerosol (SOA), and 22% from anthropogenic emissions. Previous OC aerosol observations over the NW Pacific in spring 2001 (ACE-Asia) averaged 3.3 \u00b1 2.8 \u03bcg C m\u207b\u00b3 in the FT, compared to a model value of 0.3 \u00b1 0.3 \u03bcg C m\u207b\u00b3. WSOC aerosol concentrations in the boundary layer (BL) during ITCT-2K4 are consistent with OC aerosol observed at the IMPROVE surface network. The model is low in the boundary layer by 30%, which we attribute to secondary formation at a rate comparable to primary anthropogenic emission. Observed WSOC aerosol concentrations decrease by a factor of 2 from the BL to the FT, as compared to a factor of 10 decrease for sulfate, indicating that most of the WSOC aerosol in the FT originates in situ. Despite reproducing mean observed WSOC concentrations in the FT to within 25%, the model cannot account for the variance in the observations (R = 0.21). Covariance analysis of FT WSOC aerosol with other measured chemical variables suggests an aqueous-phase mechanism for SOA generation involving biogenic precursors.", "doi": "10.1029/2006JD007705", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2006-12-16", "series_number": "D23", "volume": "111", "issue": "D23", "pages": "Art. No. D23S47" }, { "id": "authors:jxf83-m4r53", "collection": "authors", "collection_id": "jxf83-m4r53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HENacpd06", "type": "article", "title": "Development of the adjoint of GEOS-Chem", "author": [ { "family_name": "Henze", "given_name": "D. K.", "clpid": "Henze-D-K" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We present the adjoint of the global chemical transport model GEOS-Chem, focusing on the chemical and thermodynamic relationships between sulfate \u2013 ammonium \u2013 nitrate aerosols and their gas-phase precursors. The adjoint model is constructed from a combination of manually and automatically derived discrete adjoint algorithms and numerical solutions to continuous adjoint equations. Explicit inclusion of the processes that govern secondary formation of inorganic aerosol is shown to afford efficient calculation of model sensitivities such as the dependence of sulfate and nitrate aerosol concentrations on emissions of SOx, NOx, and NH3. The adjoint model is extensively validated by comparing adjoint to finite difference sensitivities, which are shown to agree within acceptable tolerances; most sets of comparisons have a nearly 1:1 correlation and R2>0.9. We explore the robustness of these results, noting how insufficient observations or nonlinearities in the advection routine can degrade the adjoint model performance. The potential for inverse modeling using the adjoint of GEOS-Chem is assessed in a data assimilation framework through a series of tests using simulated observations, demonstrating the feasibility of exploiting gas- and aerosol-phase measurements for optimizing emission inventories of aerosol precursors.", "issn": "1680-7367", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2006-10-19", "series_number": "5", "volume": "6", "issue": "5", "pages": "10591-10648" }, { "id": "authors:17rdq-f4298", "collection": "authors", "collection_id": "17rdq-f4298", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ERDae06.552", "type": "article", "title": "Prediction of activity coefficients in liquid aerosol particles containing organic compounds, dissolved inorganic salts, and water\u2014Part 3: Organic compounds, water, and ionic constituents by consideration of short-, mid-, and long-range effects using X-UNIFAC.3", "author": [ { "family_name": "Erdakos", "given_name": "Garnet B.", "clpid": "Erdakos-Garnet-B" }, { "family_name": "Chang", "given_name": "Elsi I.", "clpid": "Chang-Elsi-I" }, { "family_name": "Pankow", "given_name": "James F.", "orcid": "0000-0002-8602-9159", "clpid": "Pankow-James-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "X-UNIFAC.3, a group contribution method for estimating activity coefficients of neutral and ionic components in liquid mixtures of organic compounds, inorganic salts, and water, is presented here. It is an extended UNIFAC method, in that traditional UNIFAC terms for short-range energetic interaction effects are extended to include ions as mixture components, and are combined with a Debye\u2013H\u00fcckel long-range effect term and a second virial coefficient-type mid-range effect term. The method is formulated for application in modeling the formation of liquid aerosol particles consisting of general organic+inorganic salt+water solutions in which phase separation is likely to occur. Existing extended UNIFAC activity coefficient estimation methods can be problematic in modeling phase separation, since they require independent reference state corrections that may introduce significant errors. In X-UNIFAC.3, this problem is avoided by selecting appropriate reference states for all solution components, and imposing additional constraints on method parameters, when necessary, by inclusion of reference state correction terms within the activity coefficient expressions. Interaction parameters in the X-UNIFAC.3 equations are optimized for 12 different chemical groups (CH\u2083\u2013, \u2013CH\u2082\u2013, , , \u2212OH, \u2212COOH, H\u2082O, NH\u2084\u207a, Na\u207a, Cl\u207b, , and ) using available data for systems containing multi-functional oxygenated organic compounds and/or inorganic salts that are relevant to atmospheric aerosol applications. Estimations of water activities and mean ionic activity coefficients using X-UNIFAC.3 are compared with those of other extended UNIFAC methods. To demonstrate the use of X-UNIFAC.3 in predicting phase separation, the method is also applied to the butanoic acid+NaCl+water system, for which experimental liquid\u2013liquid equilibrium data is available. The method performs well for aqueous salt solutions with salt concentrations within 30 mol kg\u207b\u00b9 and for organic+inorganic salt+water solutions with salt concentrations less than or equal to 10 mol kg\u207b\u00b9. Suggestions are proposed for improving the predictive capabilities of the method in future work.", "doi": "10.1016/j.atmosenv.2006.04.001", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2006-10", "series_number": "33", "volume": "40", "issue": "33", "pages": "6437-6452" }, { "id": "authors:v92rd-e3637", "collection": "authors", "collection_id": "v92rd-e3637", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ERDate06.551", "type": "article", "title": "Prediction of activity coefficients in liquid aerosol particles containing organic compounds, dissolved inorganic salts, and water\u2014Part 1: Organic compounds and water by consideration of short- and long-range effects using X-UNIFAC.1", "author": [ { "family_name": "Erdakos", "given_name": "Garnet B.", "clpid": "Erdakos-Garnet-B" }, { "family_name": "Asher", "given_name": "William E.", "orcid": "0000-0002-1521-0233", "clpid": "Asher-William-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pankow", "given_name": "James F.", "orcid": "0000-0002-8602-9159", "clpid": "Pankow-James-F" } ], "abstract": "The semi-empirical group contribution method (GCM) of Kikic et al. [Chem. Eng. Sci. 46 (1991) 2775\u20132780] for estimating activity coefficient (\u03b6) values of neutral organic compounds and water in solutions composed of organic compounds, dissolved inorganic salts, and water is adapted for application to atmospheric particulate matter (PM). It is assumed that \u03b6 values are determined by a combination of short- and long-range interactions. The \u03b6 expression involves conventional UNIFAC terms and a Debye\u2013H\u00fcckel term, with the former computed using group\u2013group interaction parameters. Organic\u2013organic interaction parameters are assigned the values from the UNIFAC-LLE model of Magnussen et al. [Ind. Eng. Chem. Process Design Develop. 20 (1981) 331\u2013339]. Forty interaction parameters (ion\u2013solvent group and anion\u2013cation) were obtained from Kikic et al. [Chem. Eng. Sci. 46 (1991) 2775\u20132780], Achard et al. [Fluid Phase Equilibria 98 (1994) 71\u201389], and Ming and Russell [Am. Inst. Chem. Eng. J. 48 (2002) 1331\u20131348]. Twenty additional interaction parameters (ion\u2013solvent group) are estimated based on 879 UNIQUAC-fitted \u03b6 values for organic compounds and water. The fitted \u03b6 values are based on liquid\u2013liquid equilibrium (LLE) data for a range of ternary and quaternary organic/inorganic salt/water mixtures at 293\u2013308 K. The UNIQUAC fits are analogous to those described by Fredenslund et al. [Vapor\u2013Liquid Equilibria Using UNIFAC: A Group-Contribution Method, Elsevier Scientific Publishing, New York, 1977]. The LLE mixture compositions range from primarily organic solutions to primarily aqueous solutions with maximum ionic strengths of \u223c5 mol kg\u207b\u00b9. The groups characteristic of organic compounds found in atmospheric PM considered here include: CH\u2083\u2013, \u2013CH\u2082\u2013, \u2013OH, \u2013CH\u2082CO\u2013, and \u2013COOH. These are: single bonded carbon with three, two, one, and zero hydrogens, respectively, hydroxyl, \u2013CH\u2082-carbonyl, and carboxyl, respectively. The inorganic salts represented in the mixture data include NaCl, NaNO\u2083, Na\u2082SO\u2084, (NH\u2084)\u2082SO\u2084, and CaCl\u2082 so that the cations and anions considered include Na\u207a, NH\u2084\u207a, and Ca\u00b2\u207a, and Cl\u207b, and, respectively. The method predicts the UNIQUAC-fitted \u03b6 values for all datasets with an average error of \u223c20%. In an application of the method, \u03b6 values are predicted in an aerosol PM phase containing four oxidation products (from \u03b1-pinene/O\u2083) and water, without and with 1 and 2 mol kg\u207b\u00b9 dissolved (NH\u2084)\u2082SO\u2084. The presence of the dissolved salt can cause significant increases in the \u03b6 values of the oxidation products considered, reflecting a potential \"salting-out\" effect for (NH\u2084)\u2082SO\u2084 on the oxidation products considered. Results indicate an important role played by dissolved salts in affecting the thermodynamic properties of atmospheric organic PM and the utility of X-UNIFAC.1 as a tool for evaluating those effects.", "doi": "10.1016/j.atmosenv.2006.04.030", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2006-10", "series_number": "33", "volume": "40", "issue": "33", "pages": "6410-6421" }, { "id": "authors:3v842-68d97", "collection": "authors", "collection_id": "3v842-68d97", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:STIgpr06.406", "type": "article", "title": "Impact of nonabsorbing anthropogenic aerosols on clear-sky atmospheric absorption", "author": [ { "family_name": "Stier", "given_name": "Philip", "orcid": "0000-0002-1191-0128", "clpid": "Stier-Philip" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Kinne", "given_name": "Stefan", "clpid": "Kinne-Stefan" }, { "family_name": "Feichter", "given_name": "Johann", "clpid": "Feichter-Johann" }, { "family_name": "Boucher", "given_name": "Olivier", "orcid": "0000-0003-2328-5769", "clpid": "Boucher-Olivier" } ], "abstract": "Absorption of solar radiation by atmospheric aerosol has become recognized as important in regional and global climate. Nonabsorbing, hydrophilic aerosols, such as sulfate, potentially affect atmospheric absorption in opposing ways: first, decreasing absorption through aging initially hydrophobic black carbon (BC) to a hydrophilic state, enhancing its removal by wet scavenging, and consequently decreasing BC lifetime and abundance, and second, increasing absorption through enhancement of the BC absorption efficiency by internal mixing as well as through increasing the amount of diffuse solar radiation in the atmosphere. On the basis of General Circulation Model studies with an embedded microphysical aerosol module we systematically demonstrate the significance of these mechanisms both on the global and regional scales. In remote transport regions, the first mechanism prevails, reducing atmospheric absorption, whereas in the vicinity of source regions, despite enhanced wet scavenging, absorption is enhanced owing to the prevalence of the second mechanisms. Our findings imply that the sulfur to BC emission ratio plays a key role in aerosol absorption.", "doi": "10.1029/2006JD007147", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2006-09-27", "series_number": "D18", "volume": "111", "issue": "D18", "pages": "Art. No. D18201" }, { "id": "authors:a9141-w4522", "collection": "authors", "collection_id": "a9141-w4522", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-114015557", "type": "article", "title": "Gas-phase products and secondary aerosol yields from the photooxidation of 16 different terpenes", "author": [ { "family_name": "Lee", "given_name": "Anita", "clpid": "Lee-Anita" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" }, { "family_name": "Kroll", "given_name": "Jesse H.", "clpid": "Kroll-J-H" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The photooxidation of isoprene, eight monoterpenes, three oxygenated monoterpenes, and four sesquiterpenes were conducted individually at the Caltech Indoor Chamber Facility under atmospherically relevant HC:NO_x ratios to monitor the time evolution and yields of SOA and gas-phase oxidation products using PTR-MS. Several oxidation products were calibrated in the PTR-MS, including formaldehyde, acetaldehyde, formic acid, acetone, acetic acid, nopinone, methacrolein + methyl vinyl ketone; other oxidation products were inferred from known fragmentation patterns, such as pinonaldehyde; and other products were identified according to their mass to charge (m/z) ratio. Numerous unidentified products were formed, and the evolution of first- and second-generation products was clearly observed. SOA yields from the different terpenes ranged from 1 to 68%, and the total gas- plus particle-phase products accounted for \u223c50\u2013100% of the reacted carbon. The carbon mass balance was poorest for the sesquiterpenes, suggesting that the observed products were underestimated or that additional products were formed but not detected by PTR-MS. Several second-generation products from isoprene photooxidation, including m/z 113, and ions corresponding to glycolaldehyde, hydroxyacetone, methylglyoxal, and hydroxycarbonyls, were detected. The detailed time series and relative yields of identified and unidentified products aid in elucidating reaction pathways and structures for the unidentified products. Many of the unidentified products from these experiments were also observed within and above the canopy of a Ponderosa pine plantation, confirming that many products of terpene oxidation can be detected in ambient air using PTR-MS, and are indicative of concurrent SOA formation.", "doi": "10.1029/2006JD007050", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2006-09-16", "series_number": "D17", "volume": "111", "issue": "D17", "pages": "Art. No. D17305," }, { "id": "authors:an858-h7842", "collection": "authors", "collection_id": "an858-h7842", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AMUota06.558", "type": "article", "title": "Primal-Dual Interior-Point Method for an Optimization Problem Related to the Modeling of Atmospheric Organic Aerosols", "author": [ { "family_name": "Amundson", "given_name": "N. R.", "clpid": "Amundson-Neal-R" }, { "family_name": "Caboussat", "given_name": "A.", "clpid": "Caboussat-Alexandre" }, { "family_name": "He", "given_name": "J. W.", "clpid": "He-J-W" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A mathematical model for the computation of the phase equilibrium related to atmospheric organic aerosols is presented. The phase equilibrium is given by the global minimum of the Gibbs free energy for a system that involves water and organic components. This minimization problem is equivalent to the determination of the convex hull of the corresponding molar Gibbs free energy function. A geometrical notion of phase simplex related to the convex hull is introduced to characterize mathematically the phases at equilibrium. A primal-dual interior-point algorithm for the efficient solution of the phase equilibrium problem is presented. A novel initialization of the algorithm, based on the properties of the phase simplex, is proposed to ensure the convergence to a global minimum of the Gibbs free energy. For a finite termination of the interior-point method, an active phase identification procedure is incorporated. Numerical results show the robustness and efficiency of the approach for the prediction of liquid-liquid equilibrium in multicomponent mixtures.", "doi": "10.1007/s10957-006-9110-z", "issn": "0022-3239", "publisher": "Springer", "publication": "Journal of Optimization Theory and Applications", "publication_date": "2006-09", "series_number": "3", "volume": "130", "issue": "3", "pages": "377-409" }, { "id": "authors:a5pcq-9gb04", "collection": "authors", "collection_id": "a5pcq-9gb04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-105639496", "type": "article", "title": "Chemical Composition of Secondary Organic Aerosol Formed from the Photooxidation of Isoprene", "author": [ { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-Shane-M" }, { "family_name": "Kroll", "given_name": "Jesse H.", "orcid": "0000-0002-6275-521X", "clpid": "Kroll-Jesse-H" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Hildebrandt", "given_name": "Lea", "clpid": "Hildebrandt-Lea" }, { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-Armin" }, { "family_name": "Szmigielski", "given_name": "Rafal", "orcid": "0000-0003-3389-9318", "clpid": "Szmigielski-Rafal" }, { "family_name": "Vermeylen", "given_name": "Reinhilde", "clpid": "Vermeylen-Reinhilde" }, { "family_name": "Maenhaut", "given_name": "Willy", "orcid": "0000-0002-4715-4627", "clpid": "Maenhaut-Willy" }, { "family_name": "Claeys", "given_name": "Magda", "orcid": "0000-0003-2278-8014", "clpid": "Claeys-Magda" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recent work in our laboratory has shown that the photooxidation of isoprene (2-methyl-1,3-butadiene, C5H8) leads to the formation of secondary organic aerosol (SOA). In the current study, the chemical composition of SOA from the photooxidation of isoprene over the full range of NO\u2093 conditions is investigated through a series of controlled laboratory chamber experiments. SOA composition is studied using a wide range of experimental techniques:\u2009 electrospray ionization\u2212mass spectrometry, matrix-assisted laser desorption ionization\u2212mass spectrometry, high-resolution mass spectrometry, online aerosol mass spectrometry, gas chromatography/mass spectrometry, and an iodometric-spectroscopic method. Oligomerization was observed to be an important SOA formation pathway in all cases; however, the nature of the oligomers depends strongly on the NO\u2093 level, with acidic products formed under high-NO\u2093 conditions only. We present, to our knowledge, the first evidence of particle-phase esterification reactions in SOA, where the further oxidation of the isoprene oxidation product methacrolein under high-NO\u2093 conditions produces polyesters involving 2-methylglyceric acid as a key monomeric unit. These oligomers comprise \u223c22\u221234% of the high-NO\u2093 SOA mass. Under low-NO\u2093 conditions, organic peroxides contribute significantly to the low-NO_x SOA mass (\u223c61% when SOA forms by nucleation and \u223c25\u221230% in the presence of seed particles). The contribution of organic peroxides in the SOA decreases with time, indicating photochemical aging. Hemiacetal dimers are found to form from C\u2085 alkene triols and 2-methyltetrols under low-NO\u2093 conditions; these compounds are also found in aerosol collected from the Amazonian rainforest, demonstrating the atmospheric relevance of these low-NO\u2093 chamber experiments.", "doi": "10.1021/jp061734m", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2006-08-10", "series_number": "31", "volume": "110", "issue": "31", "pages": "9665-9690" }, { "id": "authors:gkjs4-c5z79", "collection": "authors", "collection_id": "gkjs4-c5z79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:GAOgpr06.202", "type": "article", "title": "Characterization of polar organic components in fine aerosols in the southeastern United States: Identity, origin, and evolution", "author": [ { "family_name": "Gao", "given_name": "Song", "clpid": "Gao-Song" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Knipping", "given_name": "Eladio M.", "orcid": "0000-0002-9654-9019", "clpid": "Knipping-Eladio-M" }, { "family_name": "Edgerton", "given_name": "Eric S.", "clpid": "Edgerton-Eric-S" }, { "family_name": "Shahgholi", "given_name": "Mona", "orcid": "0000-0002-8879-4305", "clpid": "Shahgholi-Mona" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Filter samples of fine aerosols collected in the Southeastern United States in June 2004 were analyzed for the characterization of polar organic components. Four analytical techniques, liquid chromatography-mass spectrometry, ion trap mass spectrometry, laser desorption ionization mass spectrometry, and high-resolution mass spectrometry, were used for identification and quantification. Forty distinct species were detected, comprising on average 7.2% and 1.1% of the total particulate organic mass at three inland sites and a coastal site, respectively. The relative abundance of these species displays a rather consistent distribution pattern in the inland region, whereas a different pattern is found at the coastal site. Chemical and correlation analyses suggest that the detected species are secondary in nature and originate from terpene oxidation, with possible participation of NOx and SO2. It is estimated that polar, acidic components in fine aerosols in the Southeastern United States cover a molecular weight range of 150-400 Da and do not appear to be oligomeric. Other components with MW up to 800 Da may also be present. The detected polar organic species are similar to humic-like substances (HULIS) commonly found in fine aerosols in other rural areas. We present the first, direct evidence that atmospheric processing of biogenic emissions can lead to the formation of certain HULIS species in fine aerosols, and that this may be a typical pathway in the background atmosphere in continental regions; nevertheless, a natural source for HULIS, such as from aquatic and/or terrestrial humic/fulvic acids and their degradation products, cannot be precluded.", "doi": "10.1029/2005JD006601", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2006-07-27", "series_number": "D14", "volume": "111", "issue": "D14", "pages": "Art. No. D14314" }, { "id": "authors:saeek-1dv76", "collection": "authors", "collection_id": "saeek-1dv76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:VARacp06", "type": "article", "title": "Hygroscopicity of secondary organic aerosols formed by oxidation of cycloalkenes, monoterpenes, sesquiterpenes, and related compounds", "author": [ { "family_name": "Varutbangkul", "given_name": "V.", "clpid": "Varutbangkul-V" }, { "family_name": "Brechtel", "given_name": "F. J.", "clpid": "Brechtel-F-J" }, { "family_name": "Bahreini", "given_name": "R.", "clpid": "Bahreini-R" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Keywood", "given_name": "M. D.", "clpid": "Keywood-M-D" }, { "family_name": "Kroll", "given_name": "J. H.", "clpid": "Kroll-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Lee", "given_name": "A.", "clpid": "Lee-Anita" }, { "family_name": "Goldstein", "given_name": "A. H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" } ], "abstract": "A series of experiments has been conducted in the Caltech indoor smog chamber facility to investigate the water uptake properties of aerosol formed by oxidation of various organic precursors. Secondary organic aerosol (SOA) from simple and substituted cycloalkenes (C5-C8) is produced in dark ozonolysis experiments in a dry chamber (RH~5%). Biogenic SOA from monoterpenes, sesquiterpenes, and oxygenated terpenes is formed by photooxidation in a humid chamber (~50% RH). Using the hygroscopicity tandem differential mobility analyzer (HTDMA), we measure the diameter-based hygroscopic growth factor (GF) of the SOA as a function of time and relative humidity. All SOA studied is found to be slightly hygroscopic, with smaller water uptake than that of typical inorganic aerosol substances. The aerosol water uptake increases with time early in the experiments for the cycloalkene SOA, but decreases with time for the sesquiterpene SOA. This behavior could indicate competing effects between the formation of more highly oxidized polar compounds (more hygroscopic), and formation of longer-chained oligomers (less hygroscopic). All SOA also exhibit a smooth water uptake with RH with no deliquescence or efflorescence. The water uptake curves are found to be fitted well with an empirical three-parameter functional form. The measured pure organic GF values at 85% RH are between 1.09\u20131.16 for SOA from ozonolysis of cycloalkenes, 1.01\u20131.04 for sesquiterpene photooxidation SOA, and 1.06\u20131.10 for the monoterpene and oxygenated terpene SOA. The GF of pure SOA (GForg) in experiments in which inorganic seed aerosol is used is determined by assuming volume-weighted water uptake (Zdanovskii-Stokes-Robinson or \"ZSR\" approach) and using the size-resolved organic mass fraction measured by the Aerodyne Aerosol Mass Spectrometer. Knowing the water content associated with the inorganic fraction yields GForg values. However, for each precursor, the GForg values computed from different HTDMA-classified diameters agree with each other to varying degrees. Comparing growth factors from different precursors, we find that GForg is inversely proportional to the precursor molecular weight and SOA yield, which is likely a result of the fact that higher-molecular weight precursors tend to produce larger and less hygroscopic oxidation products.", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2006-06-29", "series_number": "9", "volume": "6", "issue": "9", "pages": "2367-2388" }, { "id": "authors:bbscp-e9563", "collection": "authors", "collection_id": "bbscp-e9563", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIAgpr06.588", "type": "article", "title": "Role of climate change in global predictions of future tropospheric ozone and aerosols", "author": [ { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Chen", "given_name": "Wei-Ting", "orcid": "0000-0002-9292-0933", "clpid": "Chen-Wei-Ting" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies general circulation model II\u2032 is applied to simulate an equilibrium CO\u2082-forced climate in the year 2100 to examine the effects of climate change on global distributions of tropospheric ozone and sulfate, nitrate, ammonium, black carbon, primary organic carbon, secondary organic carbon, sea salt, and mineral dust aerosols. The year 2100 CO\u2082 concentration as well as the anthropogenic emissions of ozone precursors and aerosols/aerosol precursors are based on the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (SRES) A2. Year 2100 global O\u2083 and aerosol burdens predicted with changes in both climate and emissions are generally 5\u201320% lower than those simulated with changes in emissions alone; as exceptions, the nitrate burden is 38% lower, and the secondary organic aerosol burden is 17% higher. Although the CO\u2082-driven climate change alone is predicted to reduce the global O\u2083 burden as a result of faster removal of O\u2083 in a warmer climate, it is predicted to increase surface layer O\u2083 concentrations over or near populated and biomass burning areas because of slower transport, enhanced biogenic hydrocarbon emissions, decomposition of peroxyacetyl nitrate at higher temperatures, and the increase of O\u2083 production by increased water vapor at high NO_x levels. The warmer climate influences aerosol burdens by increasing aerosol wet deposition, altering climate-sensitive emissions, and shifting aerosol thermodynamic equilibrium. Climate change affects the estimates of the year 2100 direct radiative forcing as a result of the climate-induced changes in burdens and different climatological conditions; with full gas-aerosol coupling and accounting for ozone and aerosols from both natural and anthropogenic sources, year 2100 global mean top of the atmosphere direct radiative forcings by O\u2083, sulfate, nitrate, black carbon, and organic carbon are predicted to be +0.93, \u22120.72, \u22121.0, +1.26, and \u22120.56 W m\u207b\u00b2, respectively, using present-day climate and year 2100 emissions, while they are predicted to be +0.76, \u22120.72, \u22120.74, +0.97, and \u22120.58 W m\u207b\u00b2, respectively, with year 2100 climate and emissions.", "doi": "10.1029/2005JD006852", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2006-06-27", "series_number": "D12", "volume": "111", "issue": "D12", "pages": "Art. No. D12304" }, { "id": "authors:xgpn4-6et54", "collection": "authors", "collection_id": "xgpn4-6et54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170315-105316568", "type": "article", "title": "Adjoint Sensitivity Analysis of Ozone Nonattainment over the Continental United States", "author": [ { "family_name": "Hakami", "given_name": "Amir", "clpid": "Hakami-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Chai", "given_name": "Tianfeng", "clpid": "Chai-Tianfeng" }, { "family_name": "Tang", "given_name": "Youhua", "clpid": "Tang-Youhua" }, { "family_name": "Carmichael", "given_name": "Gregory R.", "clpid": "Carmichael-G-R" }, { "family_name": "Sandu", "given_name": "Adrian", "clpid": "Sandu-A" } ], "abstract": "An application of the adjoint method in air quality management is demonstrated. We use a continental scale chemical transport model (STEM) to calculate the sensitivities of a nationwide U.S. ozone national ambient air quality standard (NAAQS) nonattainment metric to precursor emissions for the period July 1 to August 15, 2004. The model shows low bias and error (\u22124 and 24%, respectively), particularly for areas with high ozone concentrations. The nonattainment metric accounts for both 1-h and 8-h ozone standards, but is dominated by the 8-h exceedances (97% of the combined metric). Largest values of sensitivities are found to be with respect to emissions in the south and southeast U.S., Ohio River Valley, and California. When nonattainment sensitivities are integrated over the entire U.S., NOx emissions account for the largest contribution (62% of the total), followed by biogenic and anthropogenic VOCs (24% and 14%, respectively). For NO_x emissions, point/area and mobile sources account for 54% and 46% of the total sensitivities, respectively. We also provide a state-by-state comparison for the nonattainment magnitude, nonattainment sensitivity, and emission magnitudes to explore the influence of interstate transport of ozone and its precursors, and policy implications of the results. Our analysis of the nationwide ozone nonattainment metric suggests that simple cap-and-trade programs may prove inadequate in achieving sought-after air quality objectives.", "doi": "10.1021/es052135g", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2006-06-15", "series_number": "12", "volume": "40", "issue": "12", "pages": "3855-3864" }, { "id": "authors:w7zy1-89w16", "collection": "authors", "collection_id": "w7zy1-89w16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-105347712", "type": "article", "title": "Modeling and Characterization of a Particle-into-Liquid Sampler (PILS)", "author": [ { "family_name": "Sorooshian", "given_name": "Armin", "orcid": "0000-0002-2243-2264", "clpid": "Sorooshian-A" }, { "family_name": "Brechtel", "given_name": "Fred J.", "clpid": "Brechtel-F-J" }, { "family_name": "Ma", "given_name": "Yilin", "clpid": "Ma-Yilin" }, { "family_name": "Weber", "given_name": "Rodney J.", "clpid": "Weber-R-J" }, { "family_name": "Corless", "given_name": "Andrew", "clpid": "Corless-A" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A modified particle-into-liquid sampler (PILS), based on the original design of Weber et al. (2001), is presented. The principal modification in this design is that collected liquid sample is delivered to vials held on a rotating carousel as opposed to an on-line analytical detector. A model is developed to predict aerosol mass concentrations measured by a PILS based on operating parameters and characteristics of the sampled aerosol. A backward model predicts the concentrations of the sampled aerosol based on operating parameters and concentrations measured by the PILS. Both models, which consider plumbing transmission efficiencies, droplet growth, mixing effects, and volatilization losses, predict mass concentrations that are consistent with laboratory tests for step changes in concentration. The average collection efficiency for species (Na^+, K^+, SO_4^(2\u2212), Cl^\u2212, NO_3^\u2212) from a variety of aerosols compared to simultaneous measurements with a differential mobility analyzer (DMA) exceeded 96% except for NH_4^+ (88%); NH_4^+ is theoretically shown to be the most vulnerable to volatilization, followed by Cl^- and then NO_3^\u2212 , with greater losses caused by increasing droplet pH and temperature. The characterization tests highlight the importance of reducing NH_4^+ volatilization by keeping a stable tip temperature of 100\u00b0C at the point where steam and ambient air mix in the condensation chamber. Maintaining a stable tip temperature also avoids fluctuations in supersaturations that lead to increased deposition losses of larger droplets. Sample data from the 2004 International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) field campaign are presented.", "doi": "10.1080/02786820600632282", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2006-06", "series_number": "6", "volume": "40", "issue": "6", "pages": "396-409" }, { "id": "authors:r3jde-87419", "collection": "authors", "collection_id": "r3jde-87419", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170607-065959479", "type": "article", "title": "Thermodynamic Models of Aqueous Solutions Containing Inorganic Electrolytes and Dicarboxylic Acids at 298.15 K. 2. Systems Including Dissociation Equilibria", "author": [ { "family_name": "Clegg", "given_name": "Simon L.", "clpid": "Clegg-S-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric aerosols contain a significant fraction of water-soluble organic compounds, including dicarboxylic acids. Pitzer activity coefficient models are developed, using a wide range of data at 298.15 K, for the following systems containing succinic acid (H_2Succ) and/or succinate salts:\u2009{H^+, Li^+, Na^+, K^+, Rb^+, Cs^+}Cl^-\u2212H_2Succ\u2212H_2O, HNO_3\u2212H_2Succ\u2212H_2O, H^+\u2212NH_4^+\u2212HSucc^-\u2212Succ^(2-)\u2212NH_3\u2212H_2Succ\u2212H_2O, NH_4Cl\u2212(NH_4)_2Succ\u2212H_2O, H^+\u2212Na^+\u2212HSucc^-\u2212Succ^(2-)\u2212Cl^-\u2212H_2Succ\u2212H_2O, NH_4NO_3\u2212H_2Succ\u2212H_2O, and H_2SO_4\u2212H_2Succ\u2212H_2O. The above compositions are given in terms of ions in the cases where acid dissociation was considered. Pitzer models were also developed for the following systems containing malonic acid (H_2Malo):\u2009H^+\u2212Na^+\u2212HMalo^-\u2212Malo^(2-)\u2212Cl^-\u2212H_2Malo\u2212H_2O, and H_2Malo\u2212H_2SO_4\u2212H_2O. The models are used to evaluate the extended Zdanovskii\u2212Stokes\u2212Robinson (ZSR) model proposed by Clegg and Seinfeld (J. Phys. Chem. A 2004, 108, 1008\u22121017) for calculating water and solute activities in solutions in which dissociation equilibria occur. The ZSR model yields satisfactory results only for systems that contain moderate to high concentrations of (nondissociating) supporting electrolyte. A practical modeling scheme is proposed for aqueous atmospheric aerosols containing both electrolytes and dissociating (organic) nonelectrolytes.", "doi": "10.1021/jp056150j", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2006-05-04", "series_number": "17", "volume": "110", "issue": "17", "pages": "5718-5734" }, { "id": "authors:4hrjw-bwr90", "collection": "authors", "collection_id": "4hrjw-bwr90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170607-104630062", "type": "article", "title": "Thermodynamic Models of Aqueous Solutions Containing Inorganic Electrolytes and Dicarboxylic Acids at 298.15 K. 1. The Acids as Nondissociating Components", "author": [ { "family_name": "Clegg", "given_name": "Simon L.", "clpid": "Clegg-S-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric aerosols contain a significant fraction of water-soluble organic compounds, including dicarboxylic acids. Water activities at \u223c298.15 K (including data for highly supersaturated solutions) of oxalic, malonic, succinic, glutaric, maleic, malic, and methyl succinic acids are first correlated as a function of concentration, treating the acids as nondissociating components. Methods proposed by Clegg et al. (J. Aerosol. Sci. 2001, 32, 713\u2212738), and by Clegg and Seinfeld (J. Phys. Chem. A 2004, 108, 1008\u22121017) for estimating water activities and solute activity coefficients in aqueous mixtures containing both electrolytes and uncharged solutes are then evaluated from comparisons with literature data. These data include water activities, solubilities, and determinations of the eutonic points of solutions containing up to five acids, and solutions containing one or more acids and the salts (NH_4)_2SO_4, NH_4NO_3, or NaCl. The extended Zdanovskii\u2212Stokes\u2212Robinson approach of Clegg and Seinfeld yields the more accurate predictions for aqueous mixtures containing dicarboxylic acids only, and for aqueous mixtures of the acids and salts (though by a lesser margin). A number of hybrid modeling approaches, which contain elements of both methods, are outlined.", "doi": "10.1021/jp056149k", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2006-05-04", "series_number": "17", "volume": "110", "issue": "17", "pages": "5692-5717" }, { "id": "authors:cftxc-2hg03", "collection": "authors", "collection_id": "cftxc-2hg03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HENgrl06.367", "type": "article", "title": "Global secondary organic aerosol from isoprene oxidation", "author": [ { "family_name": "Henze", "given_name": "Daven K.", "orcid": "0000-0001-6431-4963", "clpid": "Henze-Daven-K" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Inclusion of isoprene as a source of secondary organic aerosol (SOA) in a global model increases the global burden of SOA from all sources by more than a factor of two. The isoprene source substantially increases SOA concentrations in the free troposphere, because isoprene, and, more importantly, isoprene's oxidation products, have much greater concentrations at higher altitudes than other biogenic SOA precursors, highlighting the importance of semi-volatile organics for SOA formation. These results are robust with respect to increases in partitioning of non-isoprene oxidation products at higher altitudes and increased wet removal of isoprene oxidation products. This additional source of SOA enhances production of SOA from other parent hydrocarbons by 17%, and leads to an overall distribution of SOA that differs enough from previous predictions to warrant reevaluation of the radiative effects of organic carbon aerosol.", "doi": "10.1029/2006GL025976", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2006-05", "series_number": "9", "volume": "33", "issue": "9", "pages": "Art. No. L09812" }, { "id": "authors:nn6rf-cke69", "collection": "authors", "collection_id": "nn6rf-cke69", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-104456196", "type": "article", "title": "Contribution of First- versus Second-Generation Products to Secondary Organic Aerosols Formed in the Oxidation of Biogenic Hydrocarbons", "author": [ { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Kroll", "given_name": "Jesse H.", "clpid": "Kroll-J-H" }, { "family_name": "Keywood", "given_name": "Melita D.", "clpid": "Keywood-M-D" }, { "family_name": "Bahreini", "given_name": "Roya", "clpid": "Bahreini-R" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Lee", "given_name": "Anita", "clpid": "Lee-Anita" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" } ], "abstract": "Biogenic hydrocarbons emitted by vegetation are important contributors to secondary organic aerosol (SOA), but the aerosol formation mechanisms are incompletely understood. In this study, the formation of aerosols and gas-phase products from the ozonolysis and photooxidation of a series of biogenic hydrocarbons (isoprene, 8 monoterpenes, 4 sesquiterpenes, and 3 oxygenated terpenes) are examined. By comparing aerosol growth (measured by Differential Mobility Analyzers, DMAs) and gas-phase concentrations (monitored by a Proton Transfer Reaction Mass Spectrometer, PTR-MS), we study the general mechanisms of SOA formation. Aerosol growth data are presented in terms of a \"growth curve\", a plot of aerosol mass formed versus the amount of hydrocarbon reacted. From the shapes of the growth curves, it is found that all the hydrocarbons studied can be classified into two groups based entirely on the number of double bonds of the hydrocarbon, regardless of the reaction systems (ozonolysis or photooxidation) and the types of hydrocarbons studied:\u2009 compounds with only one double bond and compounds with more than one double bond. For compounds with only one double bond, the first oxidation step is rate-limiting, and aerosols are formed mainly from low volatility first-generation oxidation products; whereas for compounds with more than one double bond, the second oxidation step may also be rate-limiting and second-generation products contribute substantially to SOA growth. This behavior is characterized by a vertical section in the growth curve, in which continued aerosol growth is observed even after all the parent hydrocarbon is consumed.", "doi": "10.1021/es052269u", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2006-04-01", "series_number": "7", "volume": "40", "issue": "7", "pages": "2283-2297" }, { "id": "authors:yz6hn-1kk41", "collection": "authors", "collection_id": "yz6hn-1kk41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170314-153218668", "type": "article", "title": "Secondary Organic Aerosol Formation by Heterogeneous Reactions of Aldehydes and Ketones: A Quantum Mechanical Study", "author": [ { "family_name": "Tong", "given_name": "Chinghang", "clpid": "Tong-Chinghang" }, { "family_name": "Blanco", "given_name": "Mario", "clpid": "Blanco-Mario" }, { "family_name": "Goddard", "given_name": "William A., III", "orcid": "0000-0003-0097-5716", "clpid": "Goddard-W-A-III" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Experimental studies have provided convincing evidence that aerosol-phase heterogeneous chemical reactions (possibly acid-catalyzed) are involved to some extent in the formation of secondary organic aerosol (SOA). We present a stepwise procedure to determine physical properties such as heats of formation, standard entropies, Gibbs free energies of formation, and solvation energies from quantum mechanics (QM), for various short-chain aldehydes and ketones. We show that quantum mechanical gas-phase Gibbs free energies of formation compare reasonably well with the literature values with a root-mean-square (RMS) value of 1.83 kcal/mol for the selected compounds. These QM results are then used to determine the equilibrium constants (reported as log K) of aerosol-phase chemical reactions, including hydration reactions and aldol condensation for formaldehyde, acetaldehyde, acetone, butanal, hexanal, and glyoxal. Results are in qualitatively agreement with previous studies. In addition, the QM results for glyoxal reactions are consistent with experimental observations. To our knowledge, this is the first QM study that supports observations of atmospheric particle-phase reactions. Despite the significant uncertainties in the absolute values from the QM calculations, the results are potentially useful in determining the relative thermodynamic tendency for atmospheric aerosol-phase reactions.", "doi": "10.1021/es0519785", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2006-04-01", "series_number": "7", "volume": "40", "issue": "7", "pages": "2333-2338" }, { "id": "authors:a0dmr-fbb57", "collection": "authors", "collection_id": "a0dmr-fbb57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AMUacp06", "type": "article", "title": "A new inorganic atmospheric aerosol phase equilibrium model (UHAERO)", "author": [ { "family_name": "Amundson", "given_name": "N. R.", "clpid": "Amundson-N-R" }, { "family_name": "Caboussat", "given_name": "A.", "clpid": "Caboussat-A" }, { "family_name": "He", "given_name": "J. W.", "clpid": "He-J-W" }, { "family_name": "Martynenko", "given_name": "A. V.", "clpid": "Martynenko-A-V" }, { "family_name": "Savarin", "given_name": "V. B.", "clpid": "Savarin-V-B" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Yoo", "given_name": "K. Y.", "clpid": "Yoo-K-Y" } ], "abstract": "A variety of thermodynamic models have been developed to predict inorganic gas-aerosol equilibrium. To achieve computational efficiency a number of the models rely on a priori specification of the phases present in certain relative humidity regimes. Presented here is a new computational model, named UHAERO, that is both efficient and rigorously computes phase behavior without any a priori specification. The computational implementation is based on minimization of the Gibbs free energy using a primal-dual method, coupled to a Newton iteration. The mathematical details of the solution are given elsewhere. The model computes deliquescence behavior without any a priori specification of the relative humidities of deliquescence. Also included in the model is a formulation based on classical theory of nucleation kinetics that predicts crystallization behavior. Detailed phase diagrams of the sulfate/nitrate/ammonium/water system are presented as a function of relative humidity at 298.15 K over the complete space of composition.", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2006-04", "series_number": "4", "volume": "6", "issue": "4", "pages": "975-992" }, { "id": "authors:2kxk6-t6a23", "collection": "authors", "collection_id": "2kxk6-t6a23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-165532823", "type": "article", "title": "Use of in situ cloud condensation nuclei, extinction, and aerosol size distribution measurements to test a method for retrieving cloud condensation nuclei profiles from surface measurements", "author": [ { "family_name": "Ghan", "given_name": "Steven J.", "clpid": "Ghan-S-J" }, { "family_name": "Rissman", "given_name": "Tracey A.", "clpid": "Rissman-T-A" }, { "family_name": "Elleman", "given_name": "Robert", "clpid": "Elleman-R-A" }, { "family_name": "Ferrare", "given_name": "Richard A.", "orcid": "0000-0002-1005-9730", "clpid": "Ferrare-R-A" }, { "family_name": "Turner", "given_name": "David", "clpid": "Turner-D" }, { "family_name": "Flynn", "given_name": "Connor", "clpid": "Flynn-C" }, { "family_name": "Wang", "given_name": "Jian", "clpid": "Wang-Jian" }, { "family_name": "Ogren", "given_name": "John", "clpid": "Ogren-J-A" }, { "family_name": "Hudson", "given_name": "James", "clpid": "Hudson-J-G" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "VanReken", "given_name": "Timothy M.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-T-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "If the aerosol composition and size distribution below cloud are uniform, the vertical profile of cloud condensation nuclei concentration can be retrieved entirely from surface measurements of CCN concentration and particle humidification function and surface-based retrievals of relative humidity and aerosol extinction or backscatter. This provides the potential for long-term measurements of CCN concentrations near cloud base. We have used a combination of aircraft, surface in situ, and surface remote sensing measurements to test various aspects of the retrieval scheme. Our analysis leads us to the following conclusions. The retrieval works better for supersaturations of 0.1% than for 1% because CCN concentrations at 0.1% are controlled by the same particles that control extinction and backscatter. If in situ measurements of extinction are used, the retrieval explains a majority of the CCN variance at high supersaturation for at least two and perhaps five of the eight flights examined. The retrieval of the vertical profile of the humidification factor is not the major limitation of the CCN retrieval scheme. Vertical structure in the aerosol size distribution and composition is the dominant source of error in the CCN retrieval, but this vertical structure is difficult to measure from remote sensing at visible wavelengths.", "doi": "10.1029/2004JD005752", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2006-03-16", "series_number": "D5", "volume": "111", "issue": "D5", "pages": "Art. No. D05S10" }, { "id": "authors:mj1vs-h3v21", "collection": "authors", "collection_id": "mj1vs-h3v21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-170119904", "type": "article", "title": "Photoacoustic insight for aerosol light absorption aloft from meteorological aircraft and comparison with particle soot absorption photometer measurements: DOE Southern Great Plains climate research facility and the coastal stratocumulus imposed perturbation experiments", "author": [ { "family_name": "Arnott", "given_name": "W. Patrick", "clpid": "Arnott-W-P" }, { "family_name": "Walker", "given_name": "John W.", "clpid": "Walker-J-W" }, { "family_name": "Moosm\u00fcller", "given_name": "Hans", "clpid": "Moosm\u00fcller-H" }, { "family_name": "Elleman", "given_name": "Robert A.", "clpid": "Elleman-R-A" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Buzorius", "given_name": "Gintautas", "clpid": "Buzorius-G" }, { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-W-C" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aerosol light absorption can be intense close to local sources such as wildland and oil fires, with smoke that disperses into the boundary layer and, with enough lift, into the upper atmosphere where it may be transported around the globe. Filter-based methods such as the Particle Soot Absorption Photometer (PSAP) are most commonly used to quantify aerosol light absorption aloft. This paper reports first measurements of aerosol light absorption aloft with photoacoustic instrumentation (PA). Three examples of aerosol light absorption are presented. The first one illustrates a case of detached layers aloft arising from intercontinental, interoceanic transport of smoke from wildland fires in Siberia to the North American continent and the measurement campaign held at the Department of Energy Atmospheric Radiation Measurement Program Climate Research Facility in north central Oklahoma. Then, two examples of intense local fire smoke light absorption from the Coastal Stratocumulus Imposed Perturbation Experiment near Marina, California, USA, are presented. The first local fire was an oil fire burning in a storage tank near Moss Landing, California, USA, and smoke from this fire was very dark, indicating a low single scattering albedo. By contrast, the second local fire was predominantly burning wood, vegetation, and structures near Fort Ord in Marina, California, USA, and the smoke was very bright, indicating a high single scattering albedo. In all examples, PA measurements at 676 nm were compared with those from a PSAP modified to measure at three wavelengths, including 660 nm.", "doi": "10.1029/2005JD005964", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2006-03-16", "series_number": "D5", "volume": "111", "issue": "D5", "pages": "Art. No. D05S02" }, { "id": "authors:kaqz3-bfb05", "collection": "authors", "collection_id": "kaqz3-bfb05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-170530714", "type": "article", "title": "Characterization of ambient aerosol from measurements of cloud condensation nuclei during the 2003 Atmospheric Radiation Measurement Aerosol Intensive Observational Period at the Southern Great Plains site in Oklahoma", "author": [ { "family_name": "Rissman", "given_name": "T. A.", "clpid": "Rissman-T-A" }, { "family_name": "VanReken", "given_name": "T. M.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-T-M" }, { "family_name": "Wang", "given_name": "J.", "clpid": "Wang-J" }, { "family_name": "Gasparini", "given_name": "R.", "clpid": "Gasparini-R" }, { "family_name": "Collins", "given_name": "D. R.", "clpid": "Collins-D-R" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Brechtel", "given_name": "F. J.", "clpid": "Brechtel-F-J" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Measurements were made by a new cloud condensation nuclei (CCN) instrument (CCNC3) during the Atmospheric Radiation Measurement (ARM) Program's Aerosol Intensive Observational Period (IOP) in May 2003 in Lamont, Oklahoma. An inverse aerosol/CCN closure study is undertaken, in which the predicted number concentration of particles available for activation (N_P) at the CCNC3 operating supersaturations is compared to that observed (N_O). N_P is based on K\u00f6hler Theory, with assumed and inferred aerosol composition and mixing state, and the airborne aerosol size distribution measured by the Caltech Dual Automatic Classified Aerosol Detector (DACAD). An initial comparison of N_O and N_P, assuming the ambient aerosol is pure ammonium sulfate ((NH_4)_2SO_4), results in closure ratios (N_P/N_O) ranging from 1.18 to 3.68 over the duration of the IOP, indicating that the aerosol is less hygroscopic than (NH_4)_2SO_4. N_P and N_O are found to agree when the modeled aerosol population has characteristics of an external mixture of particles, in which insoluble material is preferentially distributed among particles with small diameters (<50 nm) and purely insoluble particles are present over a range of diameters. The classification of sampled air masses by closure ratio and aerosol size distribution is discussed in depth. Inverse aerosol/CCN closure analysis can be a valuable means of inferring aerosol composition and mixing state when direct measurements are not available, especially when surface measurements of aerosol composition and mixing state are not sufficient to predict CCN concentrations at altitude, as was the case under the stratified aerosol layer conditions encountered during the IOP.", "doi": "10.1029/2004JD005695", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2006-03-16", "series_number": "D5", "volume": "111", "issue": "D5", "pages": "Art. No. D05S11" }, { "id": "authors:zwd05-f7h06", "collection": "authors", "collection_id": "zwd05-f7h06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160620-124956898", "type": "article", "title": "Secondary Organic Aerosol Formation from Isoprene Photooxidation", "author": [ { "family_name": "Kroll", "given_name": "Jesse H.", "clpid": "Kroll-J-H" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-S-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recent work has shown that the atmospheric oxidation of isoprene (2-methyl-1,3-butadiene, C_5H_8) leads to the formation of secondary organic aerosol (SOA). In this study, the mechanism of SOA formation by isoprene photooxidation is comprehensively investigated, by measurements of SOA yields over a range of experimental conditions, namely isoprene and NO_x concentrations. Hydrogen peroxide is used as the radical precursor, substantially constraining the observed gas-phase chemistry; all oxidation is dominated by the OH radical, and organic peroxy radicals (RO_2) react only with HO_2 (formed in the OH + H_2O_2 reaction) or NO concentrations, including NO_x-free conditions. At high NO_x, yields are found to decrease substantially with increasing [NOx], indicating the importance of RO2 chemistry in SOA formation. Under low-NOx conditions, SOA mass is observed to decay rapidly, a result of chemical reactions of semivolatile SOA components, most likely organic hydroperoxides.", "doi": "10.1021/es0524301", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2006-03-15", "series_number": "6", "volume": "40", "issue": "6", "pages": "1869-1877" }, { "id": "authors:hxmk9-t9k97", "collection": "authors", "collection_id": "hxmk9-t9k97", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AMUota06.557", "type": "article", "title": "Primal-Dual Active-Set Algorithm for Chemical Equilibrium Problems Related to the Modeling of Atmospheric Inorganic Aerosols", "author": [ { "family_name": "Amundson", "given_name": "N. R.", "clpid": "Amundson-Neal-R" }, { "family_name": "Caboussat", "given_name": "A.", "clpid": "Caboussat-Alexandre" }, { "family_name": "He", "given_name": "J. W.", "clpid": "He-J-W" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Yoo", "given_name": "K. Y.", "clpid": "Yoo-K-Y" } ], "abstract": "A general equilibrium model for multiphase multicomponent inorganic atmospheric aerosols is proposed. The thermodynamic equilibrium is given by the minimum of the Gibbs free energy for a system involving an aqueous phase, a gas phase, and solid salts. A primal-dual algorithm solving the Karush-Kuhn-Tucker conditions is detailed. An active set/Newton method permits to compute the minimum of the energy and tracks the presence or not of solid salts at the equilibrium. Numerical results show the efficiency of our algorithm for the prediction of multiphase multireaction chemical equilibria.", "doi": "10.1007/s10957-006-9030-y", "issn": "0022-3239", "publisher": "Springer", "publication": "Journal of Optimization Theory and Applications", "publication_date": "2006-03", "series_number": "33", "volume": "128", "issue": "33", "pages": "469-498" }, { "id": "authors:zzmfb-geg41", "collection": "authors", "collection_id": "zzmfb-geg41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SHAjas06", "type": "article", "title": "Aerosol and Cloud Microphysical Characteristics of Rifts and Gradients in Maritime Stratocumulus Clouds", "author": [ { "family_name": "Sharon", "given_name": "Tarah M.", "clpid": "Sharon-T-M" }, { "family_name": "Albrecht", "given_name": "Bruce A.", "clpid": "Albrecht-B-A" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Minnis", "given_name": "Patrick", "clpid": "Minnis-P" }, { "family_name": "Khaiyer", "given_name": "Mandana M.", "clpid": "Khaiyer-M-M" }, { "family_name": "van Reken", "given_name": "Timothy M.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-T-M" }, { "family_name": "Seinfeld", "given_name": "John", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Rick", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "A cloud rift is characterized as a large-scale, persistent area of broken, low-reflectivity stratocumulus clouds usually surrounded by a solid deck of stratocumulus. A rift observed off the coast of California was investigated using an instrumented aircraft to compare the aerosol, cloud microphysical, and thermodynamic properties in the rift with those of the surrounding solid stratocumulus deck. The microphysical characteristics in the solid stratocumulus deck differ substantially from those of a broken, cellular rift where cloud droplet concentrations are a factor of 2 lower than those in the solid cloud. Furthermore, cloud condensation nuclei (CCN) concentrations were found to be about 3 times greater in the solid-cloud area compared with those in the rift. Although drizzle was observed near cloud top in parts of the solid stratocumulus cloud, the largest drizzle rates were associated with the broken clouds within the rift area and with extremely large effective droplet sizes retrieved from satellite data. Minimal thermodynamic differences between the rift and solid cloud deck were observed. In addition to marked differences in particle concentrations, evidence of a mesoscale circulation near the solid cloud\u2013rift boundary is presented. This mesoscale circulation may provide a mechanism for maintaining a rift, but further study is required to understand the initiation of a rift and the conditions that may cause it to fill. A review of results from previous studies indicates similar microphysical characteristics in rift features sampled serendipitously. These observations indicate that cloud rifts are depleted of aerosols through the cleansing associated with drizzle and are a manifestation of natural processes occurring in marine stratocumulus.", "doi": "10.1175/JAS3667.1", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2006-03", "series_number": "3", "volume": "63", "issue": "3", "pages": "983-997" }, { "id": "authors:r8zb4-m9a48", "collection": "authors", "collection_id": "r8zb4-m9a48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:VARacpd06", "type": "article", "title": "Hygroscopicity of secondary organic aerosols formed by oxidation of cycloalkenes, monoterpenes, sesquiterpenes, and related compounds", "author": [ { "family_name": "Varutbangkul", "given_name": "V.", "clpid": "Varutbangkul-V" }, { "family_name": "Brechtel", "given_name": "F. J.", "clpid": "Brechtel-F-J" }, { "family_name": "Bahreini", "given_name": "R.", "clpid": "Bahreini-R" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Keywood", "given_name": "M. D.", "clpid": "Keywood-M-D" }, { "family_name": "Kroll", "given_name": "J. H.", "clpid": "Kroll-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Lee", "given_name": "A.", "clpid": "Lee-Anita" }, { "family_name": "Goldstein", "given_name": "A. H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" } ], "abstract": "A series of experiments has been conducted in the Caltech indoor smog chamber facility to investigate the water uptake properties of aerosol formed by oxidation of various organic precursors. Secondary organic aerosol (SOA) from simple and substituted cycloalkenes (C5-C8) is produced in dark ozonolysis experiments in a dry chamber (RH~5%). Biogenic SOA from monoterpenes, sesquiterpenes, and oxygenated terpenes is formed by photooxidation in a humid chamber (~50% RH). Using the hygroscopicity tandem differential mobility analyzer (HTDMA), we measure the diameter-based hygroscopic growth factor (GF) of the SOA as a function of time and relative humidity. All SOA studied is found to be slightly hygroscopic, with smaller water uptake than that of typical inorganic aerosol substances. The aerosol water uptake increases with time early in the experiments for the cycloalkene SOA, but decreases with time for the biogenic SOA. This behavior could indicate competing effects between the formation of more highly oxidized polar compounds (more hygroscopic), and formation of longer-chained oligomers (less hygroscopic). All SOA also exhibit a smooth water uptake with RH with no deliquescence or efflorescence. The water uptake curves are found to be fitted well with an empirical three-parameter functional form. The measured pure organic GF values at 85% RH are between 1.09\u20131.16 for SOA from ozonolysis of cycloalkenes, 1.01\u20131.04 for sesquiterpene photooxidation SOA, and 1.06\u20131.11 for the monoterpene and oxygenated terpene SOA. The GF of pure SOA (GForg) in experiments in which inorganic seed aerosol is used is determined by assuming volume-weighted water uptake (Zdanovskii-Stokes-Robinson or ''ZSR'' approach) and using the size-resolved organic mass fraction measured by the Aerodyne Aerosol Mass Spectrometer. Knowing the water content associated with the inorganic fraction yields GForg values. However, for each precursor, the GForg values computed from different HTDMA-classified diameters agree with each other to varying degrees. Lack of complete agreement may be a result of the non-idealities of the solutions that are not captured by the ZSR method. Comparing growth factors from different precursors, we find that GForg is inversely proportional to the precursor molecular weight and SOA yield, which is likely a result of the fact that higher-molecular weight precursors tend to produce larger and less hygroscopic oxidation products.", "issn": "1680-7375", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2006-02-09", "series_number": "1", "volume": "6", "issue": "1", "pages": "1121-1177" }, { "id": "authors:h62ns-nav98", "collection": "authors", "collection_id": "h62ns-nav98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LUgpr06.293", "type": "article", "title": "Effect of aerosol number concentration on cloud droplet dispersion: A large-eddy simulation study and implications for aerosol indirect forcing", "author": [ { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Through three-dimensional large-eddy simulations of marine stratocumulus we explore the factors that control the cloud spectral relative dispersion ( ratio of cloud droplet spectral width to the mean radius of the distribution) as a function of aerosol number concentration and the extent to which the relative dispersion either enhances or mitigates the Twomey effect. We find that relative dispersion decreases with increasing aerosol number concentration ( for aerosol number concentrations less than about 1000 cm\u207b\u00b3 because smaller droplets resulting from higher aerosol number concentrations inhibit precipitation and lead to (1) less spectral broadening by suppressed collision and coalescence processes and (2) more spectral narrowing by droplet condensational growth at higher updraft velocity because reduced drizzle latent heating at cloud top results in increased boundary layer turbulent kinetic energy production by buoyancy and thereby stronger turbulence. Increased spectral broadening owing to increased cloud-top entrainment mixing, also as a result of increased boundary layer turbulence, is relatively insignificant compared with outcomes 1 and 2. The coefficient k, an important parameter that relates cloud droplet effective radius and volume mean radius in large-scale models, is a function of skewness and relative dispersion of the distribution and is negatively correlated with relative dispersion. Increasing k with increasing aerosol number concentration leads to maximum enhancement of the cloud susceptibility ( the change of cloud optical depth due to change of cloud droplet number concentration) over that attributable to the Twomey effect alone by about 4.2% and 39% for simulated FIRE and ASTEX cases, respectively.", "doi": "10.1029/2005JD006419", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2006-01-27", "series_number": "D2", "volume": "111", "issue": "D2", "pages": "Art. No. D02207" }, { "id": "authors:e6j9r-nx357", "collection": "authors", "collection_id": "e6j9r-nx357", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-163223971", "type": "article", "title": "Gas-phase products and secondary aerosol yields from the ozonolysis of ten different terpenes", "author": [ { "family_name": "Lee", "given_name": "Anita", "clpid": "Lee-Anita" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" }, { "family_name": "Keywood", "given_name": "Melita D.", "clpid": "Keywood-M-D" }, { "family_name": "Gao", "given_name": "Song", "orcid": "0000-0001-7427-6681", "clpid": "Gao-Song" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Bahreini", "given_name": "Roya", "clpid": "Bahreini-R" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The ozonolyses of six monoterpenes (\u03b1-pinene, \u03b2-pinene, 3-carene, terpinolene, \u03b1-terpinene, and myrcene), two sesquiterpenes (\u03b1-humulene and \u03b2-caryophyllene), and two oxygenated terpenes (methyl chavicol and linalool) were conducted individually in Teflon chambers to examine the gas-phase oxidation product and secondary organic aerosol (SOA) yields from these reactions. Particle size distribution and number concentration were monitored and allowed for the calculation of the SOA yield from each experiment, which ranged from 1 to 54%. A proton transfer reaction mass spectrometer (PTR-MS) was used to monitor the evolution of gas-phase products, identified by their mass to charge ratio (m/z). Several gas-phase oxidation products, formaldehyde, acetaldehyde, formic acid, acetone, acetic acid, and nopinone, were identified and calibrated. Aerosol yields, and the yields of these identified and calibrated oxidation products, as well as many higher m/z oxidation products observed with the PTR-MS, varied significantly between the different parent terpene compounds. The sum of measured oxidation products in the gas and particle phase ranged from 33 to 77% of the carbon in the reacted terpenes, suggesting there are still unmeasured products from these reactions. The observations of the higher molecular weight oxidation product ions provide evidence of previously unreported compounds and their temporal evolution in the smog chamber from multistep oxidation processes. Many of the observed ions, including m/z 111 and 113, have also been observed in ambient air above a Ponderosa pine forest canopy, and our results confirm they are consistent with products from terpene + O_3 reactions. Many of these products are stable on the timescale of our experiments and can therefore be monitored in field campaigns as evidence for ozone oxidative chemistry.", "doi": "10.1029/2005JD006437", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2006", "series_number": "D7", "volume": "111", "issue": "D7", "pages": "Art. No. D07302" }, { "id": "authors:0grk8-qf566", "collection": "authors", "collection_id": "0grk8-qf566", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-103824721", "type": "article", "title": "Chamber studies of secondary organic aerosol growth by reactive uptake of simple carbonyl compounds", "author": [ { "family_name": "Kroll", "given_name": "Jesse H.", "clpid": "Kroll-J-H" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-S-M" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recent experimental evidence indicates that heterogeneous chemical reactions play an important role in the gas-particle partitioning of organic compounds, contributing to the formation and growth of secondary organic aerosol in the atmosphere. Here we present laboratory chamber studies of the reactive uptake of simple carbonyl species (formaldehyde, octanal, trans,trans-2,4-hexadienal, glyoxal, methylglyoxal, 2,3-butanedione, 2,4-pentanedione, glutaraldehyde, and hydroxyacetone) onto inorganic aerosol. Gas-phase organic compounds and aqueous seed particles (ammonium sulfate or mixed ammonium sulfate/sulfuric acid) are introduced into the chamber, and particle growth and composition are monitored using a differential mobility analyzer and an Aerodyne Aerosol Mass Spectrometer. No growth is observed for most carbonyls studied, even at high concentrations (500 ppb to 5 ppm), in contrast with the results from previous studies. The single exception is glyoxal (CHOCHO), which partitions into the aqueous aerosol much more efficiently than its Henry's law constant would predict. No major enhancement in particle growth is observed for the acidic seed, suggesting that the large glyoxal uptake is not a result of particle acidity but rather of ionic strength of the seed. This increased partitioning into the particle phase still cannot explain the high levels of glyoxal measured in ambient aerosol, indicating that additional (possibly irreversible) pathways of glyoxal uptake may be important in the atmosphere.", "doi": "10.1029/2005JD006004", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2005-12-16", "series_number": "D23", "volume": "110", "issue": "D23", "pages": "Art. No. D23207" }, { "id": "authors:z5ty5-3js66", "collection": "authors", "collection_id": "z5ty5-3js66", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:VANgrl05.302", "type": "article", "title": "Electron tomography of nanoparticle clusters: Implications for atmospheric lifetimes and radiative forcing of soot", "author": [ { "family_name": "van Poppel", "given_name": "Laura H.", "clpid": "van-Poppel-Laura-H" }, { "family_name": "Friedrich", "given_name": "Heiner", "orcid": "0000-0003-4582-0064", "clpid": "Friedrich-Heiner" }, { "family_name": "Spinsby", "given_name": "Jacob", "clpid": "Spinsby-Jacob" }, { "family_name": "Chung", "given_name": "Serena H.", "orcid": "0000-0001-5030-5871", "clpid": "Chung-Serena-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Buseck", "given_name": "Peter R.", "clpid": "Buseck-Peter-R" } ], "abstract": "Nanoparticles are ubiquitous in nature. Their large surface areas and consequent chemical reactivity typically result in their aggregation into clusters. Their chemical and physical properties depend on cluster shapes, which are commonly complex and unknown. This is the first application of electron tomography with a transmission electron microscope to quantitatively determine the three-dimensional (3D) shapes, volumes, and surface areas of nanoparticle clusters. We use soot (black carbon, BC) nanoparticles as an example because it is a major contributor to environmental degradation and global climate change. To the extent that our samples are representative, we find that quantitative measurements of soot surface areas and volumes derived from electron tomograms differ from geometrically derived values by, respectively, almost one and two orders of magnitude. Global sensitivity studies suggest that the global burden and direct radiative forcing of fractal BC are only about 60% of the value if it is assumed that BC has a spherical shape.", "doi": "10.1029/2005GL024461", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2005-12", "series_number": "24", "volume": "32", "issue": "24", "pages": "Art. No. L24811" }, { "id": "authors:3m4nj-stx59", "collection": "authors", "collection_id": "3m4nj-stx59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LUMjas05", "type": "article", "title": "Study of the Aerosol Indirect Effect by Large-Eddy Simulation of Marine Stratocumulus", "author": [ { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A total of 98 three-dimensional large-eddy simulations (LESs) of marine stratocumulus clouds covering both nighttime and daytime conditions were performed to explore the response of cloud optical depth (\u03c4) to various aerosol number concentrations (Na = 50\u20132500 cm\u22123) and the covarying meteorological conditions (large-scale divergence rate and SST). The idealized First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE) and the Atlantic Stratocumulus Transition Experiment (ASTEX) Lagrangian 1 sounding profiles were used to represent the lightly and heavily drizzling cases, respectively. The first and second aerosol indirect effects are identified. Through statistical analysis, \u03c4 is found be to both positively correlated with Na and cloud liquid water path (LWP) with a higher correlation associated with LWP, which is predominantly regulated by large-scale subsidence and SST. Clouds with high LWP occur under low SST or weak large-scale subsidence. Introduction of a small amount of giant sea salt aerosol into the simulation lowers the number of cloud droplets activated, results in larger cloud droplets, and initiates precipitation for nondrizzling polluted clouds or precedes the precipitation process for drizzling clouds. However, giant sea salt aerosol is found to have a negligible effect on \u03c4 for lightly precipitating cases, while resulting in a relative reduction of \u03c4 of 3%\u201377% (increasing with Na, for Na = 1000\u20132500 cm\u22123) for heavily precipitating cases, suggesting that the impact of giant sea salt is only important for moist and potentially convective clouds. Finally, a regression analysis of the simulations shows that the second indirect effect is more evident in clear than polluted cases. The second indirect effect is found to enhance (reduce) the overall aerosol indirect effect for heavily (lightly) drizzling clouds; that is, \u03c4 is larger (smaller) for the same relative change in Na than considering the Twomey (first indirect) effect alone. The aerosol indirect effect (on \u03c4) is lessened in the daytime afternoon conditions and is dominated by the Twomey effect; however, the effect in the early morning is close but slightly smaller than that in the nocturnal run. Diurnal variations of the aerosol indirect effect should be considered to accurately assess its magnitude.", "doi": "10.1175/JAS3584.1", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2005-11", "series_number": "11", "volume": "62", "issue": "11", "pages": "3909-3932" }, { "id": "authors:ps58d-6rg75", "collection": "authors", "collection_id": "ps58d-6rg75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170315-110055574", "type": "article", "title": "Comment on \"Semiempirical Model for Organic Aerosol Growth by Acid-Catalyzed Heterogeneous Reactions of Carbonyls\"", "author": [ { "family_name": "Barsanti", "given_name": "Kelley C.", "clpid": "Barsanti-K-C" }, { "family_name": "Pankow", "given_name": "James F.", "clpid": "Pankow-J-F" }, { "family_name": "Dabdub", "given_name": "Donald", "clpid": "Dabdub-D" }, { "family_name": "Griffin", "given_name": "Robert J.", "clpid": "Griffin-R-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Jang et al. (1) report measurements of organic particulate\nmatter (OPM) formed in the presence of acidic seed aerosols\nusing both a flow reactor and a Teflon chamber and examine\ntheir data using two modeling approaches. The study is a\ncontinuation of work by Jang et al. (2) on whether acidity in atmospheric PM can promote the formation of OPM by\n\"heterogeneous\" reaction of a variety of relatively volatile\n(C5-C10) aldehydes and ketones. Jang et al. (1) state that (a) \"no predictivity power was achieved\" for their experimental systems when using the absorptive partitioning model of Pankow (3) and (b) \"These results suggest that semiempirical approaches can vastly improve our ability to predict the organic aerosol growth of a variety of different carbonyls in the presence of inorganic acid. For equilibrium conditions in the atmosphere this approach can be applied directly.\" In our view, (a) Jang et al. (1) misapplied the Pankow (3) model and (b) their proposed \"semiempirical model\" is inherently a characterization of the kinetics ofOPMformation (see their\neqs 5-12) under specific conditions and so is not easily\napplicable to the prediction of how much OPM will form\nunder other kinetic conditions and certainly not at equilibrium in the atmosphere.", "doi": "10.1021/es0512529", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2005-10-15", "series_number": "20", "volume": "39", "issue": "20", "pages": "8108-8109" }, { "id": "authors:reyjr-58p79", "collection": "authors", "collection_id": "reyjr-58p79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-104004781", "type": "article", "title": "Secondary organic aerosol formation from isoprene photooxidation under high-NO_x conditions", "author": [ { "family_name": "Kroll", "given_name": "Jesse H.", "clpid": "Kroll-J-H" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Murphy", "given_name": "Shane M.", "orcid": "0000-0002-6415-2607", "clpid": "Murphy-S-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The oxidation of isoprene (2-methyl-1,3-butadiene) is known to play a central role in the photochemistry of the troposphere, but is generally not considered to lead to the formation of secondary organic aerosol (SOA), due to the relatively high volatility of known reaction products. However, in the chamber studies described here, we measure SOA production from isoprene photooxidation under high-NO_x conditions, at significantly lower isoprene concentrations than had been observed previously. Mass yields are low (0.9\u20133.0%), but because of large emissions, isoprene photooxidation may still contribute substantially to global SOA production. Results from photooxidation experiments of compounds structurally similar to isoprene (1,3-butadiene and 2- and 3-methyl-1-butene) suggest that SOA formation from isoprene oxidation proceeds from the further reaction of first-generation oxidation products (i.e., the oxidative attack of both double bonds). The gas-phase chemistry of such oxidation products is in general poorly characterized and warrants further study.", "doi": "10.1029/2005GL023637", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2005-09-28", "series_number": "18", "volume": "32", "issue": "18", "pages": "Art. No. L18808," }, { "id": "authors:3wz9g-ghq34", "collection": "authors", "collection_id": "3wz9g-ghq34", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HEAgrl05.737", "type": "article", "title": "A large organic aerosol source in the free troposphere missing from current models", "author": [ { "family_name": "Heald", "given_name": "Colette L.", "orcid": "0000-0003-2894-5738", "clpid": "Heald-Colette-L" }, { "family_name": "Jacob", "given_name": "Daniel J.", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-Daniel-J" }, { "family_name": "Park", "given_name": "Rokjin J.", "orcid": "0000-0001-8922-0234", "clpid": "Park-Rokjin-J" }, { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Huebert", "given_name": "Barry J.", "orcid": "0000-0001-7711-0468", "clpid": "Huebert-Barry-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Weber", "given_name": "Rodney J.", "orcid": "0000-0003-0765-8035", "clpid": "Weber-Rodney-J" } ], "abstract": "Aircraft measurements of organic carbon (OC) aerosol by two independent methods over the NW Pacific during the ACE-Asia campaign reveal unexpectedly high concentrations in the free troposphere (FT). Concentrations average 4 \u03bcg sm\u207b\u00b3 in the 2\u20136.5 km column with little vertical gradient. These values are 10\u2013100 times higher than computed with a global chemical transport model (CTM) including a standard 2-product simulation of secondary organic aerosol (SOA) formation based on empirical fits to smog chamber data. The same CTM reproduces the observed vertical profiles of sulfate and elemental carbon aerosols, which indicate sharp decreases from the boundary layer to the FT due to wet scavenging. Our results suggest a large, sustained source of SOA in the FT from oxidation of long-lived volatile organic compounds. We find that this SOA is the dominant component of aerosol mass in the FT, with implications for intercontinental pollution transport and radiative forcing of climate.", "doi": "10.1029/2005GL023831", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2005-09-28", "series_number": "18", "volume": "32", "issue": "18", "pages": "Art. No. L18809" }, { "id": "authors:dn4s6-kr045", "collection": "authors", "collection_id": "dn4s6-kr045", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AMUacpd05", "type": "article", "title": "A computationally efficient inorganic atmospheric aerosol phase equilibrium model (UHAERO)", "author": [ { "family_name": "Amundson", "given_name": "N. R.", "clpid": "Amundson-N-R" }, { "family_name": "Caboussat", "given_name": "A.", "clpid": "Caboussat-A" }, { "family_name": "He", "given_name": "J. W.", "clpid": "He-J-W" }, { "family_name": "Martynenko", "given_name": "A. V.", "clpid": "Martynenko-A-V" }, { "family_name": "Savarin", "given_name": "V. B.", "clpid": "Savarin-V-B" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Yoo", "given_name": "K. Y.", "clpid": "Yoo-K-Y" } ], "abstract": "A variety of thermodynamic models have been developed to predict inorganic gas-aerosol equilibrium. To achieve computational efficiency a number of the models rely on a priori specification of the phases present in certain relative humidity regimes. Presented here is a new computational model, named UHAERO, that is both efficient and rigorously computes phase behavior without any a priori specification. The computational implementation is based on minimization of the Gibbs free energy using a primal-dual method, coupled to a Newton iteration. The mathematical details of the solution are given elsewhere. The model also computes deliquescence and crystallization behavior without any a priori specification of the relative humidities of deliquescence or crystallization. Detailed phase diagrams of the sulfate/nitrate/ammonium/water system are presented as a function of relative humidity at 298.15 K over the complete space of composition.", "issn": "1680-7367", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2005-09-28", "series_number": "5", "volume": "5", "issue": "5", "pages": "9291-9324" }, { "id": "authors:nv7gm-5x984", "collection": "authors", "collection_id": "nv7gm-5x984", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIAgpr05.365", "type": "article", "title": "Global impacts of gas-phase chemistry-aerosol interactions on direct radiative forcing by anthropogenic aerosols and ozone", "author": [ { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We present here a first global modeling study on the influence of gas-phase chemistry/aerosol interactions on estimates of anthropogenic forcing by tropospheric O\u2083 and aerosols. Concentrations of gas-phase species and sulfate, nitrate, ammonium, black carbon, primary organic carbon, secondary organic carbon, sea salt, and mineral dust aerosols in the preindustrial, present-day, and year 2100 (IPCC SRES A2) atmospheres are simulated online in the Goddard Institute for Space Studies general circulation model II' (GISS GCM II'). With fully coupled chemistry and aerosols, the preindustrial, present-day, and year 2100 global burdens of tropospheric ozone are predicted to be 190, 319, and 519 Tg, respectively. The burdens of sulfate, nitrate, black carbon, and organic carbon are predicted respectively to be 0.32. 0.18, 0.01, 0.33 Tg in preindustrial time, 1.40, 0.48, 0.23, 1.60 Tg in present-day, and 1.37, 1.97, 0.54, 3.31 Tg in year 2100. Anthropogenic O\u2083 is predicted to have a globally and annually averaged present-day forcing of +0.22 W m\u207b\u00b2 and year 2100 forcing of +0.57 W m\u207b\u00b2 at the top of the atmosphere (TOA). Net anthropogenic TOA forcing by internally mixed sulfate, nitrate, organic carbon, and black carbon aerosols is estimated to be virtually zero in the present-day and +0.34 W m\u207b\u00b2 in year 2100, whereas it is predicted to be \u22120.39 W m\u207b\u00b2 in present-day and \u22120.61 W m\u207b\u00b2 in year 2100 if the aerosols are externally mixed. Heterogeneous reactions are shown to be important in affecting anthropogenic forcing. When reactions of N\u2082O\u2085, NO\u2083, NO\u2082, and HO\u2082 on aerosols are accounted for, TOA anthropogenic O\u2083 forcing is less by 20\u201345% in present-day and by 20\u201332% in year 2100 at mid to high latitudes in the Northern Hemisphere, as compared with values predicted in the absence of heterogeneous gas-aerosol reactions. Mineral dust uptake of HNO\u2083 and O\u2083 is shown to have practically no influence on anthropogenic O\u2083 forcing. Heterogeneous reactions of N\u2082O\u2085, NO\u2083, NO\u2082, and HO\u2082 are predicted to have noticeable impacts on anthropogenic aerosol forcing over industrialized areas, leading to 0\u20132 W m\u207b\u00b2 more anthropogenic aerosol cooling in present-day and 2\u20138 W m\u207b\u00b2 more cooling in year 2100 in these areas as compared with forcings calculated in the absence of heterogeneous reactions. Sea salt uptake of SO\u2082 reduces the magnitude of TOA aerosol cooling by 0.5\u20131 W m\u207b\u00b2 over the oceans around 60\u00b0N in the present-day and year 2100 scenarios. Near dust sources, mineral dust uptake of SO\u2082 and HNO\u2083 leads to less anthropogenic aerosol cooling by 0.5\u20131 W m\u207b\u00b2 in the present-day and 1\u20132 W m\u207b\u00b2 in year 2100.", "doi": "10.1029/2005JD005907", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2005-09-27", "series_number": "D18", "volume": "110", "issue": "D18", "pages": "Art. No. D18208" }, { "id": "authors:bh72c-09f75", "collection": "authors", "collection_id": "bh72c-09f75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MESgpr05.318", "type": "article", "title": "Evaluation of a new cloud droplet activation parameterization with in situ data from CRYSTAL-FACE and CSTRIPE", "author": [ { "family_name": "Meskhidze", "given_name": "Nicholas", "orcid": "0000-0001-5628-8777", "clpid": "Meskhidze-Nicholas" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-William-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The accuracy of the 2003 prognostic, physically based aerosol activation parameterization of A. Nenes and J. H. Seinfeld (NS) with modifications introduced by C. Fountoukis and A. Nenes in 2005 ( modified NS) is evaluated against extensive microphysical data sets collected on board the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft for cumuliform and stratiform clouds of marine and continental origin. The cumuliform cloud data were collected during NASA's Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE, Key West, Florida, July 2002), while the stratiform cloud data were gathered during Coastal Stratocumulus Imposed Perturbation Experiment (CSTRIPE, Monterey, California, July 2003). In situ data sets of aerosol size distribution, chemical composition, and updraft velocities are used as input for the NS parameterization, and the evaluation is carried out by comparing predicted cloud droplet number concentrations (CDNC) with observations. This is the first known study in which a prognostic cloud droplet activation parameterization has been evaluated against a wide range of observations. On average, predicted droplet concentration in adiabatic regions is within similar to 20% of observations at the base of cumuliform clouds and similar to 30% of observations at different altitudes throughout the stratiform clouds, all within experimental uncertainty. Furthermore, CDNC is well parameterized using either a single mean updraft velocity (w) over bar or by weighting droplet nucleation rates with a Gaussian probability density function of w. This study suggests that for nonprecipitating warm clouds of variable microphysics, aerosol composition, and size distribution the modified NS parameterization can accurately predict cloud droplet activation and can be successfully implemented for describing the aerosol activation process in global climate models.", "doi": "10.1029/2004JD005703", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2005-08-27", "series_number": "D16", "volume": "110", "issue": "D16", "pages": "Art. No. D16202" }, { "id": "authors:hrawe-h2305", "collection": "authors", "collection_id": "hrawe-h2305", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-103607449", "type": "article", "title": "Measurements of Secondary Organic Aerosol from Oxidation of Cycloalkenes, Terpenes, and m-Xylene Using an Aerodyne Aerosol Mass Spectrometer", "author": [ { "family_name": "Bahreini", "given_name": "R.", "clpid": "Bahreini-R" }, { "family_name": "Keywood", "given_name": "M. D.", "clpid": "Keywood-M-D" }, { "family_name": "Ng", "given_name": "N. L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Varutbangkul", "given_name": "V.", "clpid": "Varutbangkul-V" }, { "family_name": "Gao", "given_name": "S.", "orcid": "0000-0001-7427-6681", "clpid": "Gao-Song" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Worsnop", "given_name": "D. R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-D-R" }, { "family_name": "Jimenez", "given_name": "J. L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" } ], "abstract": "he Aerodyne aerosol mass spectrometer (AMS) was used to characterize physical and chemical properties of secondary organic aerosol (SOA) formed during ozonolysis of cycloalkenes and biogenic hydrocarbons and photooxidation of m-xylene. Comparison of mass and volume distributions from the AMS and differential mobility analyzers yielded estimates of \"effective\" density of the SOA in the range of 0.64\u22121.45 g/cm^3, depending on the particular system. Increased contribution of the fragment at m/z 44, CO_2^+ ion fragment of oxygenated organics, and higher \"\u0394\" values, based on ion series analysis of the mass spectra, in nucleation experiments of cycloalkenes suggest greater contribution of more oxygenated molecules to the SOA as compared to those formed under seeded experiments. Dominant negative \"\u0394\" values of SOA formed during ozonolysis of biogenics indicates the presence of terpene derivative structures or cyclic or unsaturated oxygenated compounds in the SOA. Evidence of acid-catalyzed heterogeneous chemistry, characterized by greater contribution of higher molecular weight fragments to the SOA and corresponding changes in \"\u0394\" patterns, is observed in the ozonolysis of \u03b1-pinene. Mass spectra of SOA formed during photooxidation of m-xylene exhibit features consistent with the presence of furandione compounds and nitro organics. This study demonstrates that mixtures of SOA compounds produced from similar precursors result in broadly similar AMS mass spectra. Thus, fragmentation patterns observed for biogenic versus anthropogenic SOA may be useful in determining the sources of ambient SOA.", "doi": "10.1021/es048061a", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2005-08-01", "series_number": "15", "volume": "39", "issue": "15", "pages": "5674-5688" }, { "id": "authors:pxt7a-mvf18", "collection": "authors", "collection_id": "pxt7a-mvf18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SANast05.420", "type": "article", "title": "Inverse Modeling of Aerosol Dynamics Using Adjoints: Theoretical and Numerical Considerations", "author": [ { "family_name": "Sandu", "given_name": "A.", "orcid": "0000-0002-5380-0103", "clpid": "Sandu-Adrian" }, { "family_name": "Liao", "given_name": "W.", "clpid": "Liao-W" }, { "family_name": "Carmichael", "given_name": "G. R.", "orcid": "0000-0001-8097-3475", "clpid": "Carmichael-Gregory-R" }, { "family_name": "Henze", "given_name": "D. K.", "orcid": "0000-0001-6431-4963", "clpid": "Henze-Daven-K" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In this paper we develop the algorithmic tools needed for inverse modeling of aerosol dynamics. Continuous and discrete adjoints of the aerosol dynamic equation are derived, as well as sensitivity coefficients with respect to the coagulation kernel, the growth rate, and the emission and deposition coefficients. Numerical tests performed in the twin experiment framework for a single component model problem show that the initial distributions and the dynamic parameters can be recovered from time series of observations of particle size distributions.", "doi": "10.1080/02786820500182289", "issn": "0278-6826", "publisher": "Taylor & Francis", "publication": "Aerosol Science and Technology", "publication_date": "2005-08", "series_number": "8", "volume": "39", "issue": "8", "pages": "677-694" }, { "id": "authors:znnhf-g7773", "collection": "authors", "collection_id": "znnhf-g7773", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:HAKgpr05.86", "type": "article", "title": "Adjoint inverse modeling of black carbon during the Asian Pacific Regional Aerosol Characterization Experiment", "author": [ { "family_name": "Hakami", "given_name": "A.", "orcid": "0000-0003-3122-9548", "clpid": "Hakami-Amir" }, { "family_name": "Henze", "given_name": "D. K.", "orcid": "0000-0001-6431-4963", "clpid": "Henze-Daven-K" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Chai", "given_name": "T.", "clpid": "Chai-T" }, { "family_name": "Tang", "given_name": "Y.", "clpid": "Tang-Y" }, { "family_name": "Carmichael", "given_name": "G", "orcid": "0000-0001-8097-3475", "clpid": "Carmichael-Gregory-R" }, { "family_name": "Sandu", "given_name": "A.", "orcid": "0000-0002-5380-0103", "clpid": "Sandu-Adrian" } ], "abstract": "An adjoint model is used for inverse modeling of black carbon during the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). We use the four-dimensional variational data assimilation (4D-Var) approach to optimally recover spatially resolved anthropogenic and biomass-burning emissions and initial and boundary conditions of black carbon. Boundary conditions and biomass-burning emissions are assigned daily scaling factors. Anthropogenic emissions are scaled by a combination of daily and monthly scaling factors. Simulation results are compared to various observations of black carbon concentrations during the campaign. Measurements at five islands and on board the research vessel Ronald H. Brown are used for inverse modeling. Different levels of constraints are examined for inversion, and a case with 62% reduction in the total square errors is chosen. The assimilated results are compared with the observations on board the Twin Otter aircraft that were not used for assimilation. Among the scaled variables, anthropogenic emissions are the most significant, followed by the boundary conditions. The domain-wide emissions inventory does not change significantly as a result of the assimilation, but sizable changes occur on the subregional level. Most noticeably, anthropogenic emissions over southeastern China are reduced while those in northeast China and Japan are increased.", "doi": "10.1029/2004JD005671", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2005-07-27", "series_number": "D14", "volume": "110", "issue": "D14", "pages": "Art. No. D14301" }, { "id": "authors:11h3b-9z605", "collection": "authors", "collection_id": "11h3b-9z605", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-171117048", "type": "article", "title": "Anvil glaciation in a deep cumulus updraught over Florida simulated with the Explicit Microphysics Model. I: Impact of various nucleation processes", "author": [ { "family_name": "Phillips", "given_name": "Vaughan T. J.", "clpid": "Phillips-V-T-J" }, { "family_name": "Andronache", "given_name": "Constantin", "clpid": "Andronache-C" }, { "family_name": "Sherwood", "given_name": "Steven C.", "clpid": "Sherwood-S-C" }, { "family_name": "Bansemer", "given_name": "Aaron", "clpid": "Bansemer-A" }, { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-W-C" }, { "family_name": "DeMott", "given_name": "Paul J.", "clpid": "DeMott-P-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Heymsfield", "given_name": "Andy", "clpid": "Heymsfield-A" }, { "family_name": "Jonsson", "given_name": "Haflidi", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Poellot", "given_name": "Micheal", "clpid": "Poellot-M" }, { "family_name": "Rissman", "given_name": "Tracey A.", "clpid": "Rissman-T-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "VanReken", "given_name": "Tim", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-T-M" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Wilson", "given_name": "James C.", "clpid": "Wilson-J-C" } ], "abstract": "Simulations of a cumulonimbus cloud observed in the Cirrus Regional Study of Tropical Anvils and Cirrus Layers\u2013Florida Area Cirrus Experiment (CRYSTAL-FACE) with an advanced version of the Explicit Microphysics Model (EMM) are presented. The EMM has size-resolved aerosols and predicts the time evolution of sizes, bulk densities and axial ratios of ice particles. Observations by multiple aircraft in the troposphere provide inputs to the model, including observations of the ice nuclei and of the entire size distribution of condensation nuclei.\n\nHomogeneous droplet freezing is found to be the source of almost all of the ice crystals in the anvil updraught of this particular model cloud. Most of the simulated droplets that freeze to form anvil crystals appear to be nucleated by activation of aerosols far above cloud base in the interior of the cloud ('secondary' or 'in-cloud' droplet nucleation). This is partly because primary droplets formed at cloud base are invariably depleted by accretion before they can reach the anvil base in the updraught, which promotes an increase with height of the average supersaturation in the updraught aloft. More than half of these aerosols, activated far above cloud base, are entrained into the updraught of this model cloud from the lateral environment above about 5 km above mean sea level. This confirms the importance of remote sources of atmospheric aerosol for anvil glaciation.\n\nOther nucleation processes impinge indirectly upon the anvil glaciation by modifying the concentration of supercooled droplets in the upper levels of the mixed-phase region. For instance, the warm-rain process produces a massive indirect impact on the anvil crystal concentration, because it determines the mass of precipitation forming in the updraught. It competes with homogeneous freezing as a sink for cloud droplets. The effects from turbulent enhancement of the warm-rain process and from other nucleation processes on the anvil ice properties are assessed.", "doi": "10.1256/qj.04.85", "issn": "0035-9009", "publisher": "Wiley", "publication": "Quarterly Journal of the Royal Meteorological Society", "publication_date": "2005-07", "series_number": "609", "volume": "131", "issue": "609", "pages": "2019-2046" }, { "id": "authors:t8y6x-3yb52", "collection": "authors", "collection_id": "t8y6x-3yb52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHUgpr05.218", "type": "article", "title": "Climate response of direct radiative forcing of anthropogenic black carbon", "author": [ { "family_name": "Chung", "given_name": "Serena H.", "orcid": "0000-0001-5030-5871", "clpid": "Chung-Serena-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The equilibrium climate effect of direct radiative forcing of anthropogenic black carbon (BC) is examined by 100-year simulations in the Goddard Institute for Space Studies General Circulation Model II-prime coupled to a mixed-layer ocean model. Anthropogenic BC is predicted to raise globally and annually averaged equilibrium surface air temperature by 0.20 K if BC is assumed to be externally mixed. The predicted increase is significantly greater in the Northern Hemisphere (0.29 K) than in the Southern Hemisphere (0.11 K). If BC is assumed to be internally mixed with the present-day level of sulfate aerosol, the predicted annual mean surface temperature increase rises to 0.37 K globally, 0.54 K for the Northern Hemisphere, and 0.20 K for the Southern Hemisphere. The climate sensitivity of BC direct radiative forcing is calculated to be 0.6 K W\u207b\u00b9 m\u00b2, which is about 70% of that of CO\u2082, independent of the assumption of BC mixing state. The largest surface temperature response occurs over the northern high latitudes during winter and early spring. In the tropics and midlatitudes, the largest temperature increase is predicted to occur in the upper troposphere. Direct radiative forcing of anthropogenic BC is also predicted to lead to a change of precipitation patterns in the tropics; precipitation is predicted to increase between 0 and 20\u00b0N and decrease between 0 and 20\u00b0S, shifting the intertropical convergence zone northward. If BC is assumed to be internally mixed with sulfate instead of externally mixed, the change in precipitation pattern is enhanced. The change in precipitation pattern is not predicted to alter the global burden of BC significantly because the change occurs predominantly in regions removed from BC sources.", "doi": "10.1029/2004JD005441", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2005-06-16", "series_number": "D11", "volume": "110", "issue": "D11", "pages": "Art. No. D11102" }, { "id": "authors:xgacb-v7198", "collection": "authors", "collection_id": "xgacb-v7198", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170315-094708638", "type": "article", "title": "Representation of Secondary Organic Aerosol Laboratory Chamber Data for the Interpretation of Mechanisms of Particle Growth", "author": [ { "family_name": "Kroll", "given_name": "Jesse H.", "clpid": "Kroll-J-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Absorptive models of gas-particle partitioning have been shown to be successful in describing the formation and growth of secondary organic aerosol (SOA). Here the expression for particle growth derived by Odum et al. (Odum, J. R.; Hoffmann, T.; Bowman, F.; Collins, D.; Flagan, R. C.; Seinfeld, J. H. Gas/particle partitioning and secondary organic aerosol yields. Environ. Sci. Technol. 1996, 30, 2580\u22122585) is extended to facilitate interpretation of SOA growth data measured in the laboratory in terms of the underlying chemistry, even when details of the reactions are not well-constrained. A simple (one-component) expression for aerosol growth (\u0394M) as a function of the amount of hydrocarbon reacted (\u0394HC) is derived, and the effects of changes to three key parameters, stoichiometric yield of condensable species, gas-particle partitioning coefficient, and concentration of preexisting aerosol, are discussed. Two sets of laboratory chamber data on SOA growth are examined in this context:\u2009 the ozonolysis of \u03b1-pinene and the OH-initiated photooxidation of aromatic compounds. Even though these two systems have a number of significant differences, both are described well within this framework. From the shapes of the \u0394M versus \u0394HC curves in each case, the importance of poorly constrained chemistry such as heterogeneous reactions and gas-phase reactions of oxidation products is examined.", "doi": "10.1021/es048292h", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2005-06-01", "series_number": "11", "volume": "39", "issue": "11", "pages": "4159-4165" }, { "id": "authors:06hfz-n4a07", "collection": "authors", "collection_id": "06hfz-n4a07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-103220235", "type": "article", "title": "Effect of Angle of Attack on the Performance of an Airborne Counterflow Virtual Impactor", "author": [ { "family_name": "Chen", "given_name": "Junhong", "clpid": "Chen-Junhong" }, { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-W-C" }, { "family_name": "Rissman", "given_name": "Tracey A.", "clpid": "Rissman-T-A" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A three-dimensional model has been developed within the framework of the commercial computational fluid dynamics program, FLUENT\u00ae, to investigate the collection efficiency of an airborne counterflow virtual impactor (CVI). The model assumes steady-state, isothermal, compressible, and turbulent flow. Particle trajectories are computed based on the Lagrangian discrete phase model (DPM). In addition to predicting the effects of flight velocity and counterflow rate on the particle collection efficiency, as do prior models, the model quantifies the effect of flight attack angle on the particle collection efficiency. With an angle of attack as small as 5\u00b0, the CVI collection efficiency drastically degrades at large particle sizes, and only particles with intermediate sizes are collected. Smaller particles do not have sufficient inertia to fight the counterflow, and larger particles tend to impact the CVI inner walls and are lost to the CVI walls. The modeling results show that the alignment between the free stream flow and the CVI inlet is critical to the performance of the CVI.", "doi": "10.1080/027868290964838", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2005-06", "series_number": "6", "volume": "39", "issue": "6", "pages": "485-491" }, { "id": "authors:n9wmz-ev887", "collection": "authors", "collection_id": "n9wmz-ev887", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AMUcrm05.122", "type": "article", "title": "An optimization problem related to the modeling of atmospheric organic aerosols", "author": [ { "family_name": "Amundson", "given_name": "Neal R.", "clpid": "Amundson-Neal-R" }, { "family_name": "Caboussat", "given_name": "Alexandre", "clpid": "Caboussat-Alexandre" }, { "family_name": "He", "given_name": "Jiwen", "clpid": "He-Jiwen" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A mathematical model for the computation of the phase equilibrium related to atmospheric organic aerosols is proposed. The equilibrium is Oven by the minimum of the Gibbs free energy and is characterized Using the notion of phase simplex of its convex hull. A primal-dual interior-point method solving the Karush-Kithn-Tucker conditions is detailed. Numerical results show the efficiency of our algorithm.", "doi": "10.1016/j.crma.2005.04.018", "issn": "1631-073X", "publisher": "Elsevier", "publication": "Comptes Rendus Mathematique", "publication_date": "2005-05-15", "series_number": "10", "volume": "340", "issue": "10", "pages": "765-768" }, { "id": "authors:mnkg7-6dp89", "collection": "authors", "collection_id": "mnkg7-6dp89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141125-121113224", "type": "article", "title": "In Search of Balance", "author": [ { "family_name": "Charlson", "given_name": "Robert J.", "clpid": "Charlson-R-J" }, { "family_name": "Valero", "given_name": "Francisco P. J.", "clpid": "Valero-F-P-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The climate of Earth and its global mean surface temperature are the consequence of a balance between the amount of solar radiation absorbed by Earth's surface and atmosphere and the amount of outgoing longwave radiation emitted by the system. The former is governed by the albedo (reflectivity) of the system, whereas the latter depends strongly on the atmospheric content of gases and particles (such as clouds and dust). Although the theory of absorption of infrared radiation by gases in the atmosphere (1) is well accepted and embodied in climate models, the observational and theoretical treatments of albedo, aerosols, and clouds are still under development. One brevium (2) and two reports (3, 4) in this issue report estimates of Earth's albedo and of solar radiation reaching the surface, but the uncertainties remain large. The buildup of CO_2 (5), CH_4, and other greenhouse gases during the past century has led to an increased absorption of infrared radiation in the atmosphere (enhanced greenhouse effect) and a consequent warming (\"positive forcing\") of the climate. But human-made changes in aerosols and clouds can cause enhanced albedo and hence cooling (\"negative forcing\"), and they may already have offset a substantial part of the enhanced greenhouse effect. Present trends suggest that by 2050, the magnitude of the enhanced greenhouse effect will be so large that the net anthropogenic forcing will be unequivocally positive and substantial in magnitude (6).", "doi": "10.1126/science.1108162", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2005-05-06", "series_number": "5723", "volume": "308", "issue": "5723", "pages": "806-807" }, { "id": "authors:5eg7c-bch02", "collection": "authors", "collection_id": "5eg7c-bch02", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:AMUcrm05.121", "type": "article", "title": "An optimization problem related to the modeling of atmospheric inorganic aerosols", "author": [ { "family_name": "Amundson", "given_name": "Neal R.", "clpid": "Amundson-Neal-R" }, { "family_name": "Caboussat", "given_name": "Alexandre", "clpid": "Caboussat-Alexandre" }, { "family_name": "He", "given_name": "Jiwen", "clpid": "He-Jiwen" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Yoo", "given_name": "Kee-Youn", "clpid": "Yoo-Kee-Youn" } ], "abstract": "A mathematical model for the computation of chemical equilibrium of atmospheric inorganic aerosols is proposed. The equilibrium is given by the minimum of the Gibbs free energy for a system involving an aqueous phase, a gas phase and solid salts. A primal-dual method solving the Karush-Kuhn-Tucker conditions is detailed. An active set/Newton method permits the computation of the minimum and track solid salts at the equilibrium.", "doi": "10.1016/j.crma.2005.01.025", "issn": "1631-073X", "publisher": "Elsevier", "publication": "Comptes Rendus Mathematique", "publication_date": "2005-05-01", "series_number": "9", "volume": "340", "issue": "9", "pages": "683-686" }, { "id": "authors:38h1e-h0692", "collection": "authors", "collection_id": "38h1e-h0692", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-125604441", "type": "article", "title": "Cloud condensation nucleus activation properties of biogenic secondary organic aerosol", "author": [ { "family_name": "VanReken", "given_name": "Timothy M.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-T-M" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Organic aerosols in general and secondary organic aerosol (SOA) in particular are known to contribute significantly to the atmospheric population of cloud condensation nuclei (CCN). However, current knowledge is limited with respect to the nature of this contribution. This study presents a series of experiments wherein the potential for biogenically derived SOA to act as CCN is explored. Five compounds were studied: four monoterpenes (\u03b1-pinene, \u03b2-pinene, limonene, and \u0394^3-carene) and one terpenoid alcohol (terpinene-4-ol). In each case the aerosol formation was driven by the reaction of ozone with the biogenic precursor. The SOA produced in each experiment was allowed to age for several hours, during which CCN concentrations were periodically measured at four supersaturations: S = 0.27%, 0.32%, 0.54%, and 0.80%. The calculated relationships between particle dry diameter and critical supersaturation were found to fall in the range of previously reported data for single-component organic aerosols; of the systems studied, \u03b1-pinene SOA was the least CCN active, while limonene SOA exhibited the strongest CCN activity. Interestingly, the inferred critical supersaturation of the SOA products was considerably more sensitive to particle diameter than was found in previous studies. Furthermore, the relationships between particle size and critical supersaturation for the monoterpene SOA shifted considerably over the course of the experiments, with the aerosol becoming less hygroscopic over time. These results are consistent with the progressive oligomerization of the SOA.", "doi": "10.1029/2004JD005465", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2005-04-16", "series_number": "D7", "volume": "110", "issue": "D7", "pages": "Art. No. D07206" }, { "id": "authors:780yj-h5r58", "collection": "authors", "collection_id": "780yj-h5r58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KANacp05", "type": "article", "title": "Organic aerosol and global climate modelling: a review", "author": [ { "family_name": "Kanakidou", "given_name": "M.", "orcid": "0000-0002-1724-9692", "clpid": "Kanakidou-Maria" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pandis", "given_name": "S. N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Barnes", "given_name": "I.", "clpid": "Barnes-I" }, { "family_name": "Dentener", "given_name": "F. J.", "orcid": "0000-0001-7556-3076", "clpid": "Dentener-Frank-J" }, { "family_name": "Facchini", "given_name": "M. C.", "orcid": "0000-0003-4833-9305", "clpid": "Facchini-M-Cristina" }, { "family_name": "Van Dingenen", "given_name": "R.", "clpid": "van-Dingenen-R" }, { "family_name": "Ervens", "given_name": "B.", "orcid": "0000-0002-6223-1635", "clpid": "Ervens-Barbara" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Nielsen", "given_name": "C. J.", "clpid": "Nielsen-C-J" }, { "family_name": "Swietlicki", "given_name": "E.", "clpid": "Swietlicki-E" }, { "family_name": "Putaud", "given_name": "J. P.", "clpid": "Putaud-J-P" }, { "family_name": "Balkanski", "given_name": "Y.", "orcid": "0000-0001-8241-2858", "clpid": "Balkanski-Yves" }, { "family_name": "Fuzzi", "given_name": "S.", "clpid": "Fuzzi-S" }, { "family_name": "Horth", "given_name": "J.", "clpid": "Horth-J" }, { "family_name": "Moortgat", "given_name": "G. K.", "clpid": "Moortgat-Geert-K" }, { "family_name": "Winterhalter", "given_name": "R.", "clpid": "Winterhalter-R" }, { "family_name": "Myhre", "given_name": "C. E. L.", "clpid": "Myhre-C-E-L" }, { "family_name": "Tsigaridis", "given_name": "K.", "orcid": "0000-0001-5328-819X", "clpid": "Tsigaridis-Kostas" }, { "family_name": "Vignati", "given_name": "E.", "clpid": "Vignati-Elisabetta" }, { "family_name": "Stephanou", "given_name": "E. G.", "clpid": "Stephanou-E-G" }, { "family_name": "Wilson", "given_name": "J.", "clpid": "Wilson-J" } ], "abstract": "The present paper reviews existing knowledge with regard to Organic Aerosol (OA) of importance for global climate modelling and defines critical gaps needed to reduce the involved uncertainties. All pieces required for the representation of OA in a global climate model are sketched out with special attention to Secondary Organic Aerosol (SOA): The emission estimates of primary carbonaceous particles and SOA precursor gases are summarized. The up-to-date understanding of the chemical formation and transformation of condensable organic material is outlined. Knowledge on the hygroscopicity of OA and measurements of optical properties of the organic aerosol constituents are summarized. The mechanisms of interactions of OA with clouds and dry and wet removal processes parameterisations in global models are outlined. This information is synthesized to provide a continuous analysis of the flow from the emitted material to the atmosphere up to the point of the climate impact of the produced organic aerosol. The sources of uncertainties at each step of this process are highlighted as areas that require further studies.", "doi": "10.5194/acp-5-1053-2005", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2005-03-30", "series_number": "4", "volume": "5", "issue": "4", "pages": "1053-1123" }, { "id": "authors:tnqw1-xxr32", "collection": "authors", "collection_id": "tnqw1-xxr32", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-124343836", "type": "article", "title": "Development and initial evaluation of a dynamic species-resolved model for gas phase chemistry and size-resolved gas/particle partitioning associated with secondary organic aerosol formation", "author": [ { "family_name": "Griffin", "given_name": "Robert J.", "clpid": "Griffin-R-J" }, { "family_name": "Dabdub", "given_name": "Donald", "clpid": "Dabdub-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A module for predicting the dynamic evolution of the gas phase species and the aerosol size and composition distribution during formation of secondary organic aerosol (SOA) is presented. The module is based on the inorganic gas-aerosol equilibrium model Simulating the Composition of Atmospheric Particles at Equilibrium 2 (SCAPE2) and updated versions of the lumped Caltech Atmospheric Chemistry Mechanism (CACM) and the Model to Predict the Multiphase Partitioning of Organics (MPMPO). The aerosol phase generally consists of an organic phase and an aqueous phase containing dissolved inorganic and organic components. Simulations are presented in which a single salt (either dry or aqueous), a volatile organic compound, and oxides of nitrogen undergo photo-oxidation to form SOA. Predicted SOA mass yields for classes of aromatic and biogenic hydrocarbons exhibit the proper qualitative behavior when compared to laboratory chamber data. Inasmuch as it is currently not possible to represent explicitly aerosol phase chemistry involving condensed products of gas phase oxidation, the present model can be viewed as the most detailed SOA formation model available yet will undergo continued improvement in the future.", "doi": "10.1029/2004JD005219", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2005-03-16", "series_number": "D5", "volume": "110", "issue": "D5", "pages": "Art. No. D05304" }, { "id": "authors:2ktwf-k4n70", "collection": "authors", "collection_id": "2ktwf-k4n70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150319-091150586", "type": "article", "title": "Marine aerosols and iodine emissions - Reply", "author": [ { "family_name": "O'Dowd", "given_name": "Colin D.", "clpid": "O'Dowd-C-D" }, { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Bahreini", "given_name": "Roya", "clpid": "Bahreini-R" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "H\u00e4meri", "given_name": "Kaarle", "clpid": "H\u00e4meri-K" }, { "family_name": "Pirjola", "given_name": "Liisa", "clpid": "Pirjola-L" }, { "family_name": "Kulmala", "given_name": "Markku", "clpid": "Kulmala-M" }, { "family_name": "Jennings", "given_name": "S. Gerard", "clpid": "Jennings-S-G" }, { "family_name": "Hoffmann", "given_name": "Thorsten", "clpid": "Hoffmann-T" } ], "abstract": "O'Dowd et al. reply - McFiggans raises some interesting, but partly speculative, issues about the possibility of additional condensable-iodine-vapour (CIV) precursors being involved in marine aerosol formation from biogenic iodine emissions, and about the relative roles of iodine oxide and sulphuric acid in the marine new-particle formation process.", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2005-02-10", "series_number": "7026", "volume": "433", "issue": "7026", "pages": "E13-E14" }, { "id": "authors:b9k4d-1ss05", "collection": "authors", "collection_id": "b9k4d-1ss05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200127-095651205", "type": "book_section", "title": "Ensemble-Based Data Assimilation for Atmospheric Chemical Transport Models", "book_title": "Computational Science - ICCS 2005", "author": [ { "family_name": "Sandu", "given_name": "Adrian", "clpid": "Sandu-A" }, { "family_name": "Constantinescu", "given_name": "Emil M.", "clpid": "Constantinescu-E-M" }, { "family_name": "Liao", "given_name": "Wenyuan", "clpid": "Liao-Wenyuan" }, { "family_name": "Carmichael", "given_name": "Gregory R.", "clpid": "Carmichael-G-R" }, { "family_name": "Chai", "given_name": "Tianfeng", "clpid": "Chai-Tianfeng" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "D\u0103escu", "given_name": "Dacian", "clpid": "D\u0103escu-D" } ], "contributor": [ { "family_name": "Sunderam", "given_name": "Vaidy S.", "clpid": "Sunderam-V-S" }, { "family_name": "van Albada", "given_name": "Geert Dick", "clpid": "van-Albada-G-D" }, { "family_name": "Sloot", "given_name": "Peter M. A.", "clpid": "Sloot-P-M-A" }, { "family_name": "Dongarra", "given_name": "Jack J.", "clpid": "Dongarra-J-J" } ], "abstract": "The task of providing an optimal analysis of the state of the atmosphere requires the development of dynamic data-driven systems (D\u00b3AS) that efficiently integrate the observational data and the models. In this paper we discuss fundamental aspects of nonlinear ensemble data assimilation applied to atmospheric chemical transport models. We formulate autoregressive models for the background errors and show how these models are capable of capturing flow dependent correlations. Total energy singular vectors describe the directions of maximum errors growth and are used to initialize the ensembles. We highlight the challenges encountered in the computation of singular vectors in the presence of stiff chemistry and propose solutions to overcome them. Results for a large scale simulation of air pollution in East Asia illustrate the potential of nonlinear ensemble techniques to assimilate chemical observations.", "doi": "10.1007/11428848_84", "isbn": "978-3-540-26043-1", "publisher": "Springer", "place_of_publication": "Berlin", "publication_date": "2005", "pages": "648-655" }, { "id": "authors:7vd2g-qjn29", "collection": "authors", "collection_id": "7vd2g-qjn29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-102702345", "type": "article", "title": "Particle Phase Acidity and Oligomer Formation in Secondary Organic Aerosol", "author": [ { "family_name": "Gao", "given_name": "Song", "orcid": "0000-0001-7427-6681", "clpid": "Gao-Song" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Keywood", "given_name": "Melita", "orcid": "0000-0001-9953-6806", "clpid": "Keywood-Melita-D" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-Varuntida" }, { "family_name": "Bahreini", "given_name": "Roya", "orcid": "0000-0001-8292-5338", "clpid": "Bahreini-Roya" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "He", "given_name": "Jiwen", "clpid": "He-Jiwen" }, { "family_name": "Yoo", "given_name": "Kee Y.", "clpid": "Yoo-Kee-Y" }, { "family_name": "Beauchamp", "given_name": "J. L.", "orcid": "0000-0001-8839-4822", "clpid": "Beauchamp-J-L" }, { "family_name": "Hodyss", "given_name": "Robert P.", "orcid": "0000-0002-6523-3660", "clpid": "Hodyss-Robert-P" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A series of controlled laboratory experiments are carried out in dual Teflon chambers to examine the presence of oligomers in secondary organic aerosols (SOA) from hydrocarbon ozonolysis as well as to explore the effect of particle phase acidity on SOA formation. In all seven hydrocarbon systems studied (i.e., \u03b1-pinene, cyclohexene, 1-methyl cyclopentene, cycloheptene, 1-methyl cyclohexene, cyclooctene, and terpinolene), oligomers with MW from 250 to 1600 are present in the SOA formed, both in the absence and presence of seed particles and regardless of the seed particle acidity. These oligomers are comparable to, and in some cases, exceed the low molecular weight species (MW < 250) in ion intensities in the ion trap mass spectra, suggesting they may comprise a substantial fraction of the total aerosol mass. It is possible that oligomers are widely present in atmospheric organic aerosols, formed through acid- or base-catalyzed heterogeneous reactions. In addition, as the seed particle acidity increases, larger oligomers are formed more abundantly in the SOA; consequently, the overall SOA yield also increases. This explicit effect of particle phase acidity on the composition and yield of SOA may have important climatic consequences and need to be considered in relevant models.", "doi": "10.1021/es049125k", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2004-12-15", "series_number": "24", "volume": "38", "issue": "24", "pages": "6582-6589" }, { "id": "authors:ks85h-wnx53", "collection": "authors", "collection_id": "ks85h-wnx53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-102409741", "type": "article", "title": "Low-Molecular-Weight and Oligomeric Components in Secondary Organic Aerosol from the Ozonolysis of Cycloalkenes and \u03b1-Pinene", "author": [ { "family_name": "Gao", "given_name": "Song", "orcid": "0000-0001-7427-6681", "clpid": "Gao-Song" }, { "family_name": "Keywood", "given_name": "Melita", "orcid": "0000-0001-9953-6806", "clpid": "Keywood-Melita-D" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-Varuntida" }, { "family_name": "Bahreini", "given_name": "Roya", "orcid": "0000-0001-8292-5338", "clpid": "Bahreini-Roya" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The composition of secondary organic aerosol (SOA) from the ozonolysis of C_5\u2212C_8 cycloalkenes and \u03b1-pinene, as well as the effects of hydrocarbon precursor structure and particle-phase acidity on SOA formation, have been investigated by a series of controlled laboratory chamber experiments. A liquid chromatography\u2212mass spectrometer and an ion trap mass spectrometer are used concurrently to identify and to quantify SOA components with molecular weights up to 1600 Da. Diacids, carbonyl-containing acids, diacid alkyl esters, and hydroxy diacids are the four major classes of low-molecular-weight (MW < 250 Da) components in the SOA; together they comprise 42\u221283% of the total SOA mass, assuming an aerosol density of 1.4 g/cm^3. In addition, oligomers (MW > 250 Da) are found to be present in all SOA. Using surrogate standards, it is estimated that the mass fraction of oligomers in the total SOA is at least 10% for the cycloalkene systems (with six or more carbons) and well over 50% for the \u03b1-pinene system. Higher seed particle acidity is found to lead to more rapid oligomer formation and, ultimately, to higher SOA yields. Because oligomers are observed to form even in the absence of seed particles, organic acids produced from hydrocarbon oxidation itself may readily promote acid catalysis and oligomer formation. The distinct effects of carbon numbers, substituent groups, and isomeric structures of the precursor hydrocarbons on the composition and yield of SOA formed are also discussed.", "doi": "10.1021/jp047466e", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2004-11-18", "series_number": "46", "volume": "108", "issue": "46", "pages": "10147-10164" }, { "id": "authors:zdb9y-bkk23", "collection": "authors", "collection_id": "zdb9y-bkk23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-123620570", "type": "article", "title": "Environmental snapshots from ACE-Asia", "author": [ { "family_name": "Kahn", "given_name": "Ralph A.", "clpid": "Kahn-R-A" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "On five occasions spanning the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) field campaign in spring 2001, the Multiangle Imaging Spectroradiometer spaceborne instrument took data coincident with high-quality observations by instruments on two or more surface and airborne platforms. The cases capture a range of clean, polluted, and dusty aerosol conditions. With a three-stage optical modeling process, we synthesize the data from over 40 field instruments into layer-by-layer environmental snapshots that summarize what we know about the atmospheric and surface states at key locations during each event. We compare related measurements and discuss the implications of apparent discrepancies, at a level of detail appropriate for satellite retrieval algorithm and aerosol transport model validation. Aerosols within a few kilometers of the surface were composed primarily of pollution and Asian dust mixtures, as expected. Medium- and coarse-mode particle size distributions varied little among the events studied; however, column aerosol optical depth changed by more than a factor of 4, and the near-surface proportion of dust ranged between 25% and 50%. The amount of absorbing material in the submicron fraction was highest when near-surface winds crossed Beijing and the Korean Peninsula and was considerably lower for all other cases. Having simultaneous single-scattering albedo measurements at more than one wavelength would significantly reduce the remaining optical model uncertainties. The consistency of component particle microphysical properties among the five events, even in this relatively complex aerosol environment, suggests that global, satellite-derived maps of aerosol optical depth and aerosol mixture (air-mass-type) extent, combined with targeted in situ component microphysical property measurements, can provide a detailed global picture of aerosol behavior.", "doi": "10.1029/2003JD004339", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2004-10-16", "series_number": "D19", "volume": "109", "issue": "D19", "pages": "Art. No. D19S14" }, { "id": "authors:yqj92-e0w05", "collection": "authors", "collection_id": "yqj92-e0w05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-153457152", "type": "article", "title": "Three-dimensional simulations of inorganic aerosol distributions in east Asia during spring 2001", "author": [ { "family_name": "Tang", "given_name": "Youhua", "orcid": "0000-0001-7089-7915", "clpid": "Tang-Youhua" }, { "family_name": "Carmichael", "given_name": "Gregory R.", "orcid": "0000-0001-8097-3475", "clpid": "Carmichael-Gregory-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Dabdub", "given_name": "Donald", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "Weber", "given_name": "Rodney J.", "orcid": "0000-0003-0765-8035", "clpid": "Weber-Rodney-J" }, { "family_name": "Huebert", "given_name": "Barry", "orcid": "0000-0001-7711-0468", "clpid": "Huebert-Barry-J" }, { "family_name": "Clarke", "given_name": "Antony D.", "clpid": "Clarke-Antony-D" }, { "family_name": "Guazzotti", "given_name": "Sergio A.", "clpid": "Guazzotti-Sergio-A" }, { "family_name": "Sodeman", "given_name": "David A.", "clpid": "Sodeman-David-A" }, { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" }, { "family_name": "Uno", "given_name": "Itsushi", "orcid": "0000-0002-0508-6267", "clpid": "Uno-Itsushi" }, { "family_name": "Woo", "given_name": "Jung-Hun", "orcid": "0000-0002-2515-8467", "clpid": "Woo-Jung-Hun" }, { "family_name": "Yienger", "given_name": "James J.", "clpid": "Yienger-James-J" }, { "family_name": "Streets", "given_name": "David G.", "orcid": "0000-0002-0223-1350", "clpid": "Streets-David-G" }, { "family_name": "Quinn", "given_name": "Patricia K.", "orcid": "0000-0003-0337-4895", "clpid": "Quinn-Patricia-K" }, { "family_name": "Johnson", "given_name": "James E.", "clpid": "Johnson-James-E" }, { "family_name": "Song", "given_name": "Chul-Han", "clpid": "Song-Chul-Han" }, { "family_name": "Grassian", "given_name": "Vicki H.", "clpid": "Grassian-V-H" }, { "family_name": "Sandu", "given_name": "Adrian", "clpid": "Sandu-Adrian" }, { "family_name": "Talbot", "given_name": "Robert W.", "clpid": "Talbot-Robert-W" }, { "family_name": "Dibb", "given_name": "Jack E.", "orcid": "0000-0003-3096-7709", "clpid": "Dibb-Jack-E" } ], "abstract": "In this paper, aerosol composition and size distributions in east Asia are simulated using a comprehensive chemical transport model. Three-dimensional aerosol simulations for the TRACE-P and ACE-Asia periods are performed and used to help interpret actual observations. The regional chemical transport model, STEM-2K3, which includes the on-line gas-aerosol thermodynamic module SCAPE II, and explicitly considers chemical aging of dust, is used in the analysis. The model is found to represent many of the important observed features. The Asian outflow during March and April of 2001 is heavily polluted with high aerosol loadings. Under conditions of low dust loading, SO_2 condensation and gas phase ammonia distribution determine the nitrate size and gas-aerosol distributions along air mass trajectories, a situation that is analyzed in detail for two TRACE-P flights. Dust is predicted to alter the partitioning of the semivolatile components between the gas and aerosol phases as well as the size distributions of the secondary aerosol constituents. Calcium in the dust affects the gas-aerosol equilibrium by shifting the equilibrium balance to an anion-limited status, which benefits the uptake of sulfate and nitrate, but reduces the amount of aerosol ammonium. Surface reactions on dust provide an additional mechanism to produce aerosol nitrate and sulfate. The size distribution of dust is shown to be a critical factor in determining the size distribution of secondary aerosols. As much of the dust mass is found in the supermicron mode (70\u201390%), appreciable amounts of sulfate and nitrate are found in the supermicron particles. For sulfate the observations and the analysis indicate that 10\u201330% of sulfate is in the supermicron fraction during dust events; in the case of nitrate, more than 80% is found in the supermicron fraction.", "doi": "10.1029/2003JD004201", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2004-10-16", "series_number": "D19", "volume": "109", "issue": "D19", "pages": "Art. No. D19S23" }, { "id": "authors:1j17g-ypw88", "collection": "authors", "collection_id": "1j17g-ypw88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:DINams04.523", "type": "article", "title": "PARAGON: An Integrated Approach for Characterizing Aerosol Climate Impacts and Environmental Interactions", "author": [ { "family_name": "Diner", "given_name": "David J.", "orcid": "0000-0001-8102-7616", "clpid": "Diner-David-J" }, { "family_name": "Ackerman", "given_name": "Thomas P.", "orcid": "0000-0001-5259-964X", "clpid": "Ackerman-Thomas-P" }, { "family_name": "Anderson", "given_name": "Theodore L.", "clpid": "Anderson-Theodore-L" }, { "family_name": "B\u00f6senberg", "given_name": "Jens", "clpid": "B\u00f6senberg-Jens" }, { "family_name": "Braverman", "given_name": "Amy J.", "orcid": "0000-0001-5127-9230", "clpid": "Braverman-Amy-J" }, { "family_name": "Charlson", "given_name": "Robert J.", "clpid": "Charlson-Robert-J" }, { "family_name": "Collins", "given_name": "William D.", "orcid": "0000-0002-7419-0850", "clpid": "Collins-William-D" }, { "family_name": "Davies", "given_name": "Roger", "orcid": "0000-0002-2991-0409", "clpid": "Davies-Roger" }, { "family_name": "Holben", "given_name": "Brent N.", "orcid": "0000-0002-1251-9809", "clpid": "Holben-Brent-N" }, { "family_name": "Hostetler", "given_name": "Chris A.", "orcid": "0000-0003-3364-4497", "clpid": "Hostetler-Chris-A" }, { "family_name": "Kahn", "given_name": "Ralph A.", "orcid": "0000-0002-5234-6359", "clpid": "Kahn-Ralph-A" }, { "family_name": "Martonchik", "given_name": "John V.", "clpid": "Martonchik-John-V" }, { "family_name": "Menzies", "given_name": "Robert T.", "clpid": "Menzies-Robert-T" }, { "family_name": "Miller", "given_name": "Mark A.", "clpid": "Miller-Mark-A" }, { "family_name": "Ogren", "given_name": "John A.", "orcid": "0000-0002-7895-9583", "clpid": "Ogren-John-A" }, { "family_name": "Penner", "given_name": "Joyce E.", "orcid": "0000-0001-5577-452X", "clpid": "Penner-Joyce-E" }, { "family_name": "Rasch", "given_name": "Philip J.", "orcid": "0000-0002-5125-2174", "clpid": "Rasch-Philip-J" }, { "family_name": "Schwartz", "given_name": "Stephen E.", "orcid": "0000-0001-6288-310X", "clpid": "Schwartz-Stephen-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Stephens", "given_name": "Graeme L.", "orcid": "0000-0003-1657-3770", "clpid": "Stephens-Graeme-L" }, { "family_name": "Torres", "given_name": "Omar", "orcid": "0000-0003-0917-3429", "clpid": "Torres-Omar" }, { "family_name": "Travis", "given_name": "Larry D.", "clpid": "Travis-Larry-D" }, { "family_name": "Wielicki", "given_name": "Bruce A.", "orcid": "0000-0002-4976-0110", "clpid": "Wielicki-Bruce-A" }, { "family_name": "Yu", "given_name": "Bin", "clpid": "Yu-Bin" } ], "abstract": "Aerosols exert myriad influences on the earth's environment and climate, and on human health. The complexity of aerosol-related processes requires that information gathered to improve our understanding of climate change must originate from multiple sources, and that effective strategies for data integration need to be established. While a vast array of observed and modeled data are becoming available, the aerosol research community currently lacks the necessary tools and infrastructure to reap maximum scientific benefit from these data. Spatial and temporal sampling differences among a diverse set of sensors, nonuniform data qualities, aerosol mesoscale variabilities, and difficulties in separating cloud effects are some of the challenges that need to be addressed. Maximizing the long-term benefit from these data also requires maintaining consistently well-understood accuracies as measurement approaches evolve and improve. Achieving a comprehensive understanding of how aerosol physical, chemical, and radiative processes impact the earth system can be achieved only through a multidisciplinary, inter-agency, and international initiative capable of dealing with these issues. A systematic approach, capitalizing on modern measurement and modeling techniques, geospatial statistics methodologies, and high-performance information technologies, can provide the necessary machinery to support this objective. We outline a framework for integrating and interpreting observations and models, and establishing an accurate, consistent, and cohesive long-term record, following a strategy whereby information and tools of progressively greater sophistication are incorporated as problems of increasing complexity are tackled. This concept is named the Progressive Aerosol Retrieval and Assimilation Global Observing Network (PARAGON). To encompass the breadth of the effort required, we present a set of recommendations dealing with data interoperability; measurement and model integration; multisensor synergy; data summarization and mining; model evaluation; calibration and validation; augmentation of surface and in situ measurements; advances in passive and active remote sensing; and design of satellite missions. Without an initiative of this nature, the scientific and policy communities will continue to struggle with understanding the quantitative impact of complex aerosol processes on regional and global climate change and air quality.", "doi": "10.1175/BAMS-85-10-1491", "issn": "0003-0007", "publisher": "American Meteorological Society", "publication": "Bulletin of the American Meteorological Society", "publication_date": "2004-10", "series_number": "10", "volume": "85", "issue": "10", "pages": "1491-1502" }, { "id": "authors:9m25r-m4762", "collection": "authors", "collection_id": "9m25r-m4762", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KAHbams04", "type": "article", "title": "Aerosol Data Sources and Their Roles within PARAGON", "author": [ { "family_name": "Kahn", "given_name": "Ralph A.", "clpid": "Kahn-R-A" }, { "family_name": "Ogren", "given_name": "John A.", "clpid": "Ogren-J-A" }, { "family_name": "Ackerman", "given_name": "Thomas P.", "clpid": "Ackerman-T-P" }, { "family_name": "B\u00f6senberg", "given_name": "Jens", "clpid": "B\u00f6senberg-J" }, { "family_name": "Charlson", "given_name": "Robert J.", "clpid": "Charlson-R-J" }, { "family_name": "Diner", "given_name": "David J.", "orcid": "0000-0001-8102-7616", "clpid": "Diner-D-J" }, { "family_name": "Holben", "given_name": "Brent N.", "clpid": "Holben-B-N" }, { "family_name": "Menzies", "given_name": "Robert T.", "clpid": "Menzies-R-T" }, { "family_name": "Miller", "given_name": "Mark A.", "orcid": "0000-0002-3964-9312", "clpid": "Miller-M-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We briefly but systematically review major sources of aerosol data, emphasizing suites of measurements that seem most likely to contribute to assessments of global aerosol climate forcing. The strengths and limitations of existing satellite, surface, and aircraft remote sensing systems are described, along with those of direct sampling networks and ship-based stations. It is evident that an enormous number of aerosol-related observations have been made, on a wide range of spatial and temporal sampling scales, and that many of the key gaps in this collection of data could be filled by technologies that either exist or are expected to be available in the near future. Emphasis must be given to combining remote sensing and in situ active and passive observations and integrating them with aerosol chemical transport models, in order to create a more complete environmental picture, having sufficient detail to address current climate forcing questions. The Progressive Aerosol Retrieval and Assimilation Global Observing Network (PARAGON) initiative would provide an organizational framework to meet this goal.", "doi": "10.1175/BAMS-85-10-1511", "issn": "0003-0007", "publisher": "American Meteorological Society", "publication": "Bulletin of the American Meteorological Society", "publication_date": "2004-10", "series_number": "10", "volume": "85", "issue": "10", "pages": "1511-1522" }, { "id": "authors:awp5s-3b513", "collection": "authors", "collection_id": "awp5s-3b513", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111019-092332903", "type": "article", "title": "Scientific Objectives, Measurement Needs, and Challenges Motivating the PARAGON Aerosol Initiative", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Kahn", "given_name": "Ralph A.", "clpid": "Kahn-R-A" }, { "family_name": "Anderson", "given_name": "Theodore L.", "clpid": "Anderson-T-L" }, { "family_name": "Charlson", "given_name": "Robert J.", "clpid": "Charlson-R-J" }, { "family_name": "Davies", "given_name": "Roger", "clpid": "Davies-R" }, { "family_name": "Diner", "given_name": "David J.", "orcid": "0000-0001-8102-7616", "clpid": "Diner-D-J" }, { "family_name": "Ogren", "given_name": "John A.", "clpid": "Ogren-J-A" }, { "family_name": "Schwartz", "given_name": "Stephen E.", "clpid": "Schwartz-S-E" }, { "family_name": "Wielicki", "given_name": "Bruce A.", "clpid": "Wielicki-B-A" } ], "abstract": "Aerosols are involved in a complex set of processes that operate across many spatial and temporal scales. Understanding these processes, and ensuring their accurate representation in models of transport, radiation transfer, and climate, requires knowledge of aerosol physical, chemical, and optical properties and the distributions of these properties in space and time. To derive aerosol climate forcing, aerosol optical and microphysical properties and their spatial and temporal distributions, and aerosol interactions with clouds, need to be understood. Such data are also required in conjunction with size-resolved chemical composition in order to evaluate chemical transport models and to distinguish natural and anthropogenic forcing. Other basic parameters needed for modeling the radiative influences of aerosols are surface reflectivity and three-dimensional cloud fields. This large suite of parameters mandates an integrated observing and modeling system of commensurate scope. The Progressive Aerosol Retrieval and Assimilation Global Observing Network (PARAGON) concept, designed to meet this requirement, is motivated by the need to understand climate system sensitivity to changes in atmospheric constituents, to reduce climate model uncertainties, and to analyze diverse collections of data pertaining to aerosols. This paper highlights several challenges resulting from the complexity of the problem. Approaches for dealing with them are offered in the set of companion papers.", "doi": "10.1175/BAMS-85-10-1503", "issn": "0003-0007", "publisher": "American Meteorological Society", "publication": "Bulletin of the American Meteorological Society", "publication_date": "2004-10", "series_number": "10", "volume": "85", "issue": "10", "pages": "1503-1509" }, { "id": "authors:2x4sf-a3k77", "collection": "authors", "collection_id": "2x4sf-a3k77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110920-114400141", "type": "article", "title": "An Integrated Approach for Characterizing Aerosol Climate Impacts and Environmental Interactions", "author": [ { "family_name": "Diner", "given_name": "David J.", "orcid": "0000-0001-8102-7616", "clpid": "Diner-D-J" }, { "family_name": "Ackerman", "given_name": "Thomas P.", "clpid": "Ackerman-T-P" }, { "family_name": "Anderson", "given_name": "Theodore L.", "clpid": "Anderson-T-L" }, { "family_name": "B\u00f6senberg", "given_name": "Jens", "clpid": "B\u00f6senberg-J" }, { "family_name": "Braverman", "given_name": "Amy J.", "clpid": "Braverman-A-J" }, { "family_name": "Charlson", "given_name": "Robert J.", "clpid": "Charlson-R-J" }, { "family_name": "Collins", "given_name": "Williams D.", "clpid": "Collins-W-D" }, { "family_name": "Davies", "given_name": "Roger", "clpid": "Davies-R" }, { "family_name": "Holben", "given_name": "Brent N.", "clpid": "Holben-B-N" }, { "family_name": "Hostetler", "given_name": "Chris A.", "clpid": "Hostetler-C-A" }, { "family_name": "Kahn", "given_name": "Ralph A.", "clpid": "Kahn-R-A" }, { "family_name": "Martonchik", "given_name": "John V.", "clpid": "Martonchik-J-V" }, { "family_name": "Menzies", "given_name": "Robert T.", "clpid": "Menzies-R-T" }, { "family_name": "Miller", "given_name": "Mark A.", "orcid": "0000-0002-3964-9312", "clpid": "Miller-M-A" }, { "family_name": "Ogren", "given_name": "John A.", "clpid": "Ogren-J-A" }, { "family_name": "Penner", "given_name": "Joyce E.", "clpid": "Penner-J-E" }, { "family_name": "Rasch", "given_name": "Philip J.", "orcid": "0000-0002-5125-2174", "clpid": "Rasch-P-J" }, { "family_name": "Schwartz", "given_name": "Stephen E.", "clpid": "Schwartz-S-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Stephens", "given_name": "Graeme L.", "clpid": "Stephens-G-L" }, { "family_name": "Torres", "given_name": "Omar", "clpid": "Torres-O" }, { "family_name": "Travis", "given_name": "Larry D.", "clpid": "Travis-L-D" }, { "family_name": "Wielicki", "given_name": "Bruce A.", "clpid": "Wielicki-B-A" }, { "family_name": "Yu", "given_name": "Bin", "clpid": "Yu-Bin" } ], "abstract": "Aerosols exert myriad influences on the earth's environment and climate, and on human health. The complexity of aerosol-related processes requires that information gathered to improve our understanding of climate change must originate from multiple sources, and that effective strategies for data integration need to be established. While a vast array of observed and modeled data are becoming available, the aerosol research community currently lacks the necessary tools and infrastructure to reap maximum scientific benefit from these data. Spatial and temporal sampling differences among a diverse set of sensors, nonuniform data qualities, aerosol mesoscale variabilities, and difficulties in separating cloud effects are some of the challenges that need to be addressed. Maximizing the long-term benefit from these data also requires maintaining consistently well-understood accuracies as measurement approaches evolve and improve. Achieving a comprehensive understanding of how aerosol physical, chemical, and radiative processes impact the earth system can be achieved only through a multidisciplinary, inter-agency, and international initiative capable of dealing with these issues. A systematic approach, capitalizing on modern measurement and modeling techniques, geospatial statistics methodologies, and high-performance information technologies, can provide the necessary machinery to support this objective. We outline a framework for integrating and interpreting observations and models, and establishing an accurate, consistent, and cohesive long-term record, following a strategy whereby information and tools of progressively greater sophistication are incorporated as problems of increasing complexity are tackled. This concept is named the Progressive Aerosol Retrieval and Assimilation Global Observing Network (PARAGON). To encompass the breadth of the effort required, we present a set of recommendations dealing with data interoperability; measurement and model integration; multisensor synergy; data summarization and mining; model evaluation; calibration and validation; augmentation of surface and in situ measurements; advances in passive and active remote sensing; and design of satellite missions. Without an initiative of this nature, the scientific and policy communities will continue to struggle with understanding the quantitative impact of complex aerosol processes on regional and global climate change and air quality.", "doi": "10.1175/BAMS-85-10-1491", "issn": "0003-0007", "publisher": "American Metereological Society", "publication": "Bulletin of the American Meteorological Society", "publication_date": "2004-10", "series_number": "10", "volume": "85", "issue": "10", "pages": "1491-1501" }, { "id": "authors:vnee1-g3j33", "collection": "authors", "collection_id": "vnee1-g3j33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KANapcd04", "type": "article", "title": "Organic aerosol and global climate modelling: a review", "author": [ { "family_name": "Kanakidou", "given_name": "M.", "orcid": "0000-0002-1724-9692", "clpid": "Kanakidou-Maria" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pandis", "given_name": "S. N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Barnes", "given_name": "I.", "clpid": "Barnes-I" }, { "family_name": "Dentener", "given_name": "F. J.", "orcid": "0000-0001-7556-3076", "clpid": "Dentener-Frank-J" }, { "family_name": "Facchini", "given_name": "M. C.", "orcid": "0000-0003-4833-9305", "clpid": "Facchini-M-Cristina" }, { "family_name": "van Dingenen", "given_name": "R.", "clpid": "van-Dingenen-R" }, { "family_name": "Ervens", "given_name": "B.", "orcid": "0000-0002-6223-1635", "clpid": "Ervens-Barbara" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Nielsen", "given_name": "C. J.", "clpid": "Nielsen-C-J" }, { "family_name": "Swietlicki", "given_name": "E.", "clpid": "Swietlicki-E" }, { "family_name": "Putaud", "given_name": "J. P.", "clpid": "Putaud-J-P" }, { "family_name": "Balkanski", "given_name": "Y.", "orcid": "0000-0001-8241-2858", "clpid": "Balkanski-Yves" }, { "family_name": "Fuzzi", "given_name": "S.", "clpid": "Fuzzi-S" }, { "family_name": "Horth", "given_name": "J.", "clpid": "Horth-J" }, { "family_name": "Moortgat", "given_name": "G. K.", "clpid": "Moortgat-Geert-K" }, { "family_name": "Winterhalter", "given_name": "R.", "clpid": "Winterhalter-R" }, { "family_name": "Myhre", "given_name": "C. E. L.", "clpid": "Myhre-C-E-L" }, { "family_name": "Tsigaridis", "given_name": "K.", "orcid": "0000-0001-5328-819X", "clpid": "Tsigaridis-Kostas" }, { "family_name": "Vignati", "given_name": "E.", "clpid": "Vignati-Elisabetta" }, { "family_name": "Stephanou", "given_name": "E. G.", "clpid": "Stephanou-E-G" }, { "family_name": "Wilson", "given_name": "J.", "clpid": "Wilson-J" } ], "abstract": "The present paper reviews existing knowledge with regard to Organic Aerosol (OA) of importance for global climate modelling and defines critical gaps needed to reduce the involved uncertainties. All pieces required for the representation of OA in a global climate model are sketched out with special attention to Secondary Organic Aerosol (SOA): The emission estimates of primary carbonaceous particles and SOA precursor gases are summarized. The up-to-date understanding of the chemical formation and transformation of condensable organic material is outlined. Knowledge on the hygroscopicity of OA and measurements of optical properties of the organic aerosol constituents are summarized. The mechanisms of interactions of OA with clouds and dry and wet removal processes parameterisations in global models are outlined. This information is synthesized to provide a continuous analysis of the flow from the emitted material to the atmosphere up to the point of the climate impact of the produced organic aerosol. The sources of uncertainties at each step of this process are highlighted as areas that require further studies.", "doi": "10.5194/acpd-4-5855-2004", "issn": "1680-7375", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics Discussions", "publication_date": "2004-09-28", "series_number": "5", "volume": "4", "issue": "5", "pages": "5855-6024" }, { "id": "authors:0apb0-sjv70", "collection": "authors", "collection_id": "0apb0-sjv70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-094421952", "type": "article", "title": "Global radiative forcing of coupled tropospheric ozone and aerosols in a unified general circulation model", "author": [ { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Adams", "given_name": "Peter J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Mickley", "given_name": "Loretta J.", "orcid": "0000-0002-7859-3470", "clpid": "Mickley-Loretta-J" } ], "abstract": "Global simulations of sea salt and mineral dust aerosols are integrated into a previously developed unified general circulation model (GCM), the Goddard Institute for Space Studies (GISS) GCM II\u2032, that simulates coupled tropospheric ozone-NO_x-hydrocarbon chemistry and sulfate, nitrate, ammonium, black carbon, primary organic carbon, and secondary organic carbon aerosols. The fully coupled gas-aerosol unified GCM allows one to evaluate the extent to which global burdens, radiative forcing, and eventually climate feedbacks of ozone and aerosols are influenced by gas-aerosol chemical interactions. Estimated present-day global burdens of sea salt and mineral dust are 6.93 and 18.1 Tg with lifetimes of 0.4 and 3.9 days, respectively. The GCM is applied to estimate current top of atmosphere (TOA) and surface radiative forcing by tropospheric ozone and all natural and anthropogenic aerosol components. The global annual mean value of the radiative forcing by tropospheric ozone is estimated to be +0.53 W m^(\u22122) at TOA and +0.07 W m^(\u22122) at the Earth's surface. Global, annual average TOA and surface radiative forcing by all aerosols are estimated as \u22120.72 and \u22124.04 W m^(\u22122), respectively. While the predicted highest aerosol cooling and heating at TOA are \u221210 and +12 W m^(\u22122), respectively, surface forcing can reach values as high as \u221230 W m^(\u22122), mainly caused by the absorption by black carbon, mineral dust, and OC. We also estimate the effects of chemistry-aerosol coupling on forcing estimates based on currently available understanding of heterogeneous reactions on aerosols. Through altering the burdens of sulfate, nitrate, and ozone, heterogeneous reactions are predicted to change the global mean TOA forcing of aerosols by 17% and influence global mean TOA forcing of tropospheric ozone by 15%.", "doi": "10.1029/2003JD004456", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2004-08-27", "series_number": "D16", "volume": "109", "issue": "D16", "pages": "Art. No. D16207" }, { "id": "authors:30crc-1q346", "collection": "authors", "collection_id": "30crc-1q346", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160614-163656245", "type": "article", "title": "Secondary Organic Aerosol Formation from the Ozonolysis of Cycloalkenes and Related Compounds", "author": [ { "family_name": "Keywood", "given_name": "M. D.", "clpid": "Keywood-M-D" }, { "family_name": "Varutbangkul", "given_name": "V.", "clpid": "Varutbangkul-V" }, { "family_name": "Bahreini", "given_name": "R.", "clpid": "Bahreini-R" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The secondary organic aerosol (SOA) yields from the laboratory chamber ozonolysis of a series of cycloalkenes and related compounds are reported. The aim of this work is to investigate the effect of the structure of the hydrocarbon parent molecule on SOA formation for a homologous set of compounds. Aspects of the compound structures that are varied include the number of carbon atoms present in the cycloalkene ring (C_5 to C_8), the presence and location of methyl groups, and the presence of an exocyclic or endocyclic double bond. The specific compounds considered here are cyclopentene, cyclohexene, cycloheptene, cyclooctene, 1-methyl-1-cyclopentene, 1-methyl-1-cyclohexene, 1-methyl-1-cycloheptene, 3-methyl-1-cyclohexene, and methylenecyclohexane. The SOA yield is found to be a function of the number of carbons present in the cycloalkene ring, with an increasing number resulting in increased yield. The yield is enhanced by the presence of a methyl group located at a double-bonded site but reduced by the presence of a methyl group at a non-double-bonded site. The presence of an exocyclic double bond also leads to a reduced yield relative to that of the equivalent methylated cycloalkene. On the basis of these observations, the SOA yield for terpinolene relative to the other cyclic alkenes is qualitatively predicted, and this prediction compares well to measurements of the SOA yield from the ozonolysis of terpinolene. This work shows that relative SOA yields from ozonolysis of cyclic alkenes can be qualitatively predicted from properties of the parent hydrocarbons.", "doi": "10.1021/es035363o", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2004-08-01", "series_number": "15", "volume": "38", "issue": "15", "pages": "4157-4164" }, { "id": "authors:7ep7w-5kq86", "collection": "authors", "collection_id": "7ep7w-5kq86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-102011829", "type": "article", "title": "The Scanning DMA Transfer Function", "author": [ { "family_name": "Collins", "given_name": "Don R.", "clpid": "Collins-D-R" }, { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-D-R-III" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The scanning differential mobility analyzer (DMA) has been widely employed for measurement of rapidly evolving aerosol size distributions. Interpretation of data from scanning DMAs is greatly facilitated when an exponential voltage ramp is prescribed, since the shape of the instrumental transfer function remains constant throughout a scan. However, that transfer function may differ significantly from that expected for fixed voltage operation. Because no simple analytical description of the scanning DMA transfer function exists, it has been evaluated numerically by simulating particle trajectories within a TSI 3081 cylindrical DMA. These computations yield transfer functions for the DMA up scan that are roughly triangular but with widths significantly greater than those for fixed voltage operation, and transfer functions for the down scan that are highly asymmetric. The impact of these distortions is most obvious when the size distribution of the measured aerosol is narrow, but errors in recovered size and concentration can be significant even when the aerosol size distribution is much broader than the transfer function. The magnitude of these errors is dependent upon the ratio of the mean gas residence time to the exponential voltage time constant, the sheath-to-aerosol-flow ratio, and the technique used to determine the instrument plumbing time. Experimental results for scans across broad and narrow size distributions compare favorably with predictions based on the simulated transfer functions. Simplified corrections are provided that can be used to adjust the concentration and mobility of size distributions recovered using a fixed voltage transfer function.", "doi": "10.1080/027868290503082", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2004-08", "series_number": "8", "volume": "38", "issue": "8", "pages": "833-850" }, { "id": "authors:1ff8g-wvf43", "collection": "authors", "collection_id": "1ff8g-wvf43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-123025415", "type": "article", "title": "Inverse modeling of aerosol dynamics: Condensational growth", "author": [ { "family_name": "Henze", "given_name": "D. K.", "clpid": "Henze-D-K" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Liao", "given_name": "W.", "clpid": "Liao-W" }, { "family_name": "Sandu", "given_name": "A.", "clpid": "Sandu-A" }, { "family_name": "Carmichael", "given_name": "G. R.", "clpid": "Carmichael-G-R" } ], "abstract": "The feasibility of inverse modeling a multicomponent, size-resolved aerosol evolving by condensation/evaporation is investigated. The adjoint method is applied to the multicomponent aerosol dynamic equation in a box model (zero-dimensional) framework. Both continuous and discrete formulations of the model (the forward equation) and the adjoint are considered. A test example is studied in which the initial aerosol size composition distribution and the pure component vapor concentrations (i.e., vapor pressures) are estimated on the basis of measurements of all species, or a subset of the species, and the entire size distribution, or a portion of the size distribution. It is found that the adjoint method can successfully retrieve the initial size distribution and the pure component vapor concentrations even when only a subset of the species or a portion of the size distribution is observed, although this success is shown to depend upon the form of the initial estimates, the nature of the observations, and the length of the assimilation period. The results presented here provide a basis for the inverse modeling of aerosols in three-dimensional atmospheric chemical transport models.", "doi": "10.1029/2004JD004593", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2004-07-27", "series_number": "D14", "volume": "109", "issue": "D14", "pages": "Art. No. D14201" }, { "id": "authors:3bsb0-kev86", "collection": "authors", "collection_id": "3bsb0-kev86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-093136295", "type": "article", "title": "Aerosol\u2013cloud drop concentration closure in warm cumulus", "author": [ { "family_name": "Conant", "given_name": "W. C.", "clpid": "Conant-William-C" }, { "family_name": "VanReken", "given_name": "T. M.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-Timothy-M" }, { "family_name": "Rissman", "given_name": "T. A.", "clpid": "Rissman-Tracey-A" }, { "family_name": "Varutbangkul", "given_name": "V.", "clpid": "Varutbangkul-Varuntida" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Jimenez", "given_name": "J. L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-Jos\u00e9-L" }, { "family_name": "Delia", "given_name": "A. E.", "clpid": "Delia-A-E" }, { "family_name": "Bahreini", "given_name": "R.", "orcid": "0000-0001-8292-5338", "clpid": "Bahreini-Roya" }, { "family_name": "Roberts", "given_name": "G. C.", "orcid": "0000-0002-3636-8590", "clpid": "Roberts-Greg-C" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Our understanding of the activation of aerosol particles into cloud drops during the formation of warm cumulus clouds presently has a limited observational foundation. Detailed observations of aerosol size and composition, cloud microphysics and dynamics, and atmospheric thermodynamic state were collected in a systematic study of 21 cumulus clouds by the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft during NASA's Cirrus Regional Study of Tropical Anvils and Cirrus Layers\u2013Florida Area Cirrus Experiment (CRYSTAL-FACE). An \"aerosol-cloud\" closure study was carried out in which a detailed cloud activation parcel model, which predicts cloud drop concentration using observed aerosol concentration, size distribution, cloud updraft velocity, and thermodynamic state, is evaluated against observations. On average, measured droplet concentration in adiabatic cloud regions is within 15% of the predictions. This agreement is corroborated by independent measurements of aerosol activation carried out by two cloud condensation nucleus (CCN) counters on the aircraft. Variations in aerosol concentration, which ranged from 300 to 3300 cm^(\u22123), drives large microphysical differences (250\u20132300 cm^(\u22123)) observed among continental and maritime clouds in the South Florida region. This is the first known study in which a cloud parcel model is evaluated in a closure study using a constraining set of data collected from a single platform. Likewise, this is the first known study in which relationships among aerosol size distribution, CCN spectrum, and cloud droplet concentration are all found to be consistent with theory within experimental uncertainties much less than 50%. Vertical profiles of cloud microphysical properties (effective radius, droplet concentration, dispersion) clearly demonstrate the boundary layer aerosol's effect on cloud microphysics throughout the lowest 1 km of cloud depth. Onboard measurements of aerosol hygroscopic growth and the organic to sulfate mass ratio are related to CCN properties. These chemical data are used to quantify the range of uncertainty associated with the simplified treatment of aerosol composition assumed in the closure study.", "doi": "10.1029/2003JD004324", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2004-07-16", "series_number": "D13", "volume": "109", "issue": "D13", "pages": "Art. No. D13204" }, { "id": "authors:dx3jk-nc806", "collection": "authors", "collection_id": "dx3jk-nc806", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170315-111555514", "type": "article", "title": "Thermodynamic Properties of Multifunctional Oxygenates in Atmospheric Aerosols from Quantum Mechanics and Molecular Dynamics: Dicarboxylic Acids", "author": [ { "family_name": "Tong", "given_name": "Chinghang", "clpid": "Tong-Chinghang" }, { "family_name": "Blanco", "given_name": "Mario", "clpid": "Blanco-Mario" }, { "family_name": "Goddard", "given_name": "William A., III", "orcid": "0000-0003-0097-5716", "clpid": "Goddard-W-A-III" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Ambient particulate matter contains polar multifunctional oxygenates that partition between the vapor and aerosol phases. Vapor pressure predictions are required to determine the gas\u2212particle partitioning of such organic compounds. We present here a method based on atomistic simulations combined with the Clausius\u2212Clapeyron equation to predict the liquid vapor pressure, enthalpies of vaporization, and heats of sublimation of atmospheric organic compounds. The resulting temperature-dependent vapor pressure equation is a function of the heat of vaporization at the normal boiling point [\u0394H_(vap)(T_b)], normal boiling point (T_b), and the change in heat capacity (liquid to gas) of the compound upon phase change [\u0394C_p(T_b)]. We show that heats of vaporization can be estimated from calculated cohesive energy densities (CED) of the pure compound obtained from multiple sampling molecular dynamics. The simulation method (CED) uses a generic force field (Dreiding) and molecular models with atomic charges determined from quantum mechanics. The heats of vaporization of five dicarboxylic acids [malonic (C_3), succinic (C_4), glutaric (C_5), adipic (C_6), and pimelic (C_7)] are calculated at 500 K. Results are in agreement with experimental values with an averaged error of about 4%. The corresponding heats of sublimation at 298 K are also predicted using molecular simulations. Vapor pressures of the five dicarboxylic acids are also predicted using the derived Clausius\u2212Clapeyron equation. Predicted liquid vapor pressures agree well with available literature data with an averaged error of 29%, while the predicted solid vapor pressures at ambient temperature differ considerably from a recent study by Bilde et al. (Environ. Sci. Technol. 2003, 37, 1371\u22121378) (an average of 70%). The difference is attributed to the linear dependence assumption that we used in the derived Clausius\u2212Clapeyron equation.", "doi": "10.1021/es0354216", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2004-07-15", "series_number": "14", "volume": "38", "issue": "14", "pages": "3941-3949" }, { "id": "authors:fhmyd-1n797", "collection": "authors", "collection_id": "fhmyd-1n797", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190822-104855825", "type": "article", "title": "Mark Jacobson, Atmospheric Pollution: History, Science, and Regulation [Book Review]", "author": [ { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The Earth's atmosphere is the fluid that blankets human life. Changes to the atmosphere, caused by natural phenomena or human action, can strongly influence life on Earth, either directly through change in the composition of the atmosphere, or indirectly through chemical impacts on climate and the biosphere. The chemistry of the atmosphere plays a role in determining weather and climate, while, in turn, the physics and dynamics of the atmosphere influence chemical processes and composition. In the last three decades, scientific evidence has shown that the chemical composition of the atmosphere is changing on a global scale and that unprecedented changes, such as the depletion of stratospheric ozone, are the result of human activities. Increasing concentrations of long-lived molecules that absorb infrared radiation, such as carbon dioxide, nitrous oxide, and methane, are important factors in global climate.", "doi": "10.1023/B:CLIM.0000037589.60845.51", "issn": "0165-0009", "publisher": "Springer", "publication": "Climatic Change", "publication_date": "2004-07", "series_number": "1-2", "volume": "65", "issue": "1-2", "pages": "251-252" }, { "id": "authors:e8e5x-jsr14", "collection": "authors", "collection_id": "e8e5x-jsr14", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160219-104557808", "type": "article", "title": "Concept for a New Cloud Condensation Nucleus (CCN) Spectrometer", "author": [ { "family_name": "VanReken", "given_name": "Timothy M.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-Timothy-M" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The concept of a new cloud condensation nucleus (CCN) spectrometer based on modifications to the original design of Fukuta and Saxena is presented. The key modifications include introducing a trapezoidal geometry and orienting the chamber vertically. A series of simulations demonstrate the broadening of the effective range of the instrument to include supersaturations lower than those reported for the original instrument, without reducing the maximum resolvable supersaturation. A design criterion is developed to eliminate configurations that would result in secondary flows in the growth chamber resulting from buoyancy effects. Using instrument configurations that satisfy this criterion, the effects of variations in the chamber geometry, the imposed temperature gradient, and the total volumetric flow are evaluated. A new configuration is identified that could produce real-time CCN spectra with an effective range at least including supersaturations between 0.07% and 1.2%.", "doi": "10.1080/02786820490479842", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2004-07", "series_number": "7", "volume": "38", "issue": "7", "pages": "639-654" }, { "id": "authors:ctadc-6by59", "collection": "authors", "collection_id": "ctadc-6by59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160614-162310887", "type": "article", "title": "Secondary Organic Aerosol Formation from Cyclohexene Ozonolysis: Effect of OH Scavenger and the Role of Radical Chemistry", "author": [ { "family_name": "Keywood", "given_name": "M. D.", "clpid": "Keywood-M-D" }, { "family_name": "Kroll", "given_name": "J. H.", "clpid": "Kroll-J-H" }, { "family_name": "Varutbangkul", "given_name": "V.", "clpid": "Varutbangkul-V" }, { "family_name": "Bahreini", "given_name": "R.", "clpid": "Bahreini-R" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "To isolate secondary organic aerosol (SOA) formation in ozone-alkene systems from the additional influence of hydroxyl (OH) radicals formed in the gas-phase ozone-alkene reaction, OH scavengers are employed. The detailed chemistry associated with three different scavengers (cyclohexane, 2-butanol, and CO) is studied in relation to the effects of the scavengers on observed SOA yields in the ozone-cyclohexene system. Our results confirm those of Docherty and Ziemann that the OH scavenger plays a role in SOA formation in alkene ozonolysis. The extent and direction of this influence are shown to be dependent on the specific alkene. The main influence of the scavenger arises from its independent production of HO_2 radicals, with CO producing the most HO_2, 2-butanol an intermediate amount, and cyclohexane the least. This work provides evidence for the central role of acylperoxy radicals in SOA formation from the ozonolysis of alkenes and generally underscores the importance of gas-phase radical chemistry beyond the initial ozone-alkene reaction.", "doi": "10.1021/es049725j", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2004-06-15", "series_number": "12", "volume": "38", "issue": "12", "pages": "3343-3350" }, { "id": "authors:e20ty-em333", "collection": "authors", "collection_id": "e20ty-em333", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KNIate04.230", "type": "article", "title": "Comment on \"Instantaneous secondary organic aerosol yields and their comparison with overall aerosol yields for aromatic and biogenic hydrocarbons\" by Weimin Jiang", "author": [ { "family_name": "Knipping", "given_name": "Eladio M.", "orcid": "0000-0002-9654-9019", "clpid": "Knipping-Eladio-M" }, { "family_name": "Griffin", "given_name": "Robert J.", "orcid": "0000-0001-7682-8769", "clpid": "Griffin-Robert-J" }, { "family_name": "Bowman", "given_name": "Frank M.", "clpid": "Bowman-Frank-M" }, { "family_name": "Pun", "given_name": "Betty", "clpid": "Pun-Betty" }, { "family_name": "Seigneur", "given_name": "Christian", "orcid": "0000-0002-3079-4839", "clpid": "Seigneur-Christian" }, { "family_name": "Dabdub", "given_name": "Donald", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In the introduction to the Technical Note, \"Instantaneous secondary organic aerosol yields and their comparison with overall aerosol yields for aromatic and biogenic hydrocarbons\", Jiang (2003) states that \"[t]o model the formation of secondary organic aerosol, SOA, a concept called aerosol yield (or SOA yield), loosely defined as the SOA mass formed per unit mass of reactive organic gas (ROG) reacted, has been widely used.\" He goes on to suggest an expanded concept called instantaneous aerosol yield (IAY), applied to the case of pre-existing organic aerosol. While this IAY method may at first seem reasonable, there is a major assumption in its derivation that limits its use for atmospheric models. Additionally, aerosol yield approaches in general are inappropriate for describing the reversible partitioning process that occurs in the atmosphere.", "doi": "10.1016/j.atmosenv.2004.02.017", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2004-06", "series_number": "17", "volume": "38", "issue": "17", "pages": "2759-2761" }, { "id": "authors:cehpn-njd17", "collection": "authors", "collection_id": "cehpn-njd17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SEIaic04.108", "type": "article", "title": "Air pollution: A half century of progress", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In the 50 years since the air pollution episodes of Donora, PA and London, U.K., a great deal of progress has been made in understanding the nature and sources of air pollution and the atmospheric transport and transformation of pollutants. Also, many significant technological advances in air pollution control equipment, such as the automobile exhaust gas catalytic converter, have led to effective reduction of emissions from a variety of major pollution sources. Finally, remarkable developments in instrumentation for sampling the trace species in the atmosphere have been and continue to be made. Relatively less progress has been made in understanding the biological mechanisms by which pollutants lead to human injury and mortality. In this review the focus is on the extraordinary progress that has been made over the last half century in understanding the atmospheric nature and behavior of pollutants, both gaseous and particulate. A major breakthrough was the determination of the gas-phase chemistry of both the natural and polluted atmosphere, chemistry that leads to the formation of ozone and a vast array of oxidized molecules. The mechanisms of the oxidation of atmospheric sulfur dioxide, one of the main primary pollutants, were elucidated. Finally, the chemistry, physics, and optics of atmospheric particulate matter (aerosols) have been laid open by many stunning research achievements. Whereas 50 years ago air pollution was thought to be confined to the area around a city, it is now recognized that species emitted on one continent frequently find their way to other continents. Strategies for dealing with a truly global atmospheric backyard now represent a major challenge.", "doi": "10.1002/aic.10102", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "2004-06", "series_number": "6", "volume": "50", "issue": "6", "pages": "1096-1108" }, { "id": "authors:9g512-z8y35", "collection": "authors", "collection_id": "9g512-z8y35", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141120-071526447", "type": "article", "title": "Evidence for the Predominance of Mid-Tropospheric Aerosols as Subtropical Anvil Cloud Nuclei", "author": [ { "family_name": "Fridlind", "given_name": "Ann M.", "clpid": "Fridlind-A-M" }, { "family_name": "Ackerman", "given_name": "Andrew S.", "clpid": "Ackerman-A-S" }, { "family_name": "Jensen", "given_name": "Eric J.", "clpid": "Jensen-E-J" }, { "family_name": "Heymsfield", "given_name": "Andrew J.", "clpid": "Heymsfield-A-J" }, { "family_name": "Poellot", "given_name": "Michael R.", "clpid": "Poellot-M-R" }, { "family_name": "Stevens", "given_name": "David E.", "clpid": "Stevens-D-E" }, { "family_name": "Wang", "given_name": "Donghai", "clpid": "Wang-Donghai" }, { "family_name": "Miloshevich", "given_name": "Larry M.", "clpid": "Miloshevich-L-M" }, { "family_name": "Baumgardner", "given_name": "Darrel", "clpid": "Baumgardner-D" }, { "family_name": "Lawson", "given_name": "R. Paul", "clpid": "Lawson-R-P" }, { "family_name": "Wilson", "given_name": "James C.", "clpid": "Wilson-J-C" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "VanReken", "given_name": "Timothy M.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-T-M" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Rissman", "given_name": "Tracey A.", "clpid": "Rissman-T-A" } ], "abstract": "NASA's recent Cirrus Regional Study of Tropical Anvils and Cirrus Layers\u2013Florida Area Cirrus Experiment focused on anvil cirrus clouds, an important but poorly understood element of our climate system. The data obtained included the first comprehensive measurements of aerosols and cloud particles throughout the atmospheric column during the evolution of multiple deep convective storm systems. Coupling these new measurements with detailed cloud simulations that resolve the size distributions of aerosols and cloud particles, we found several lines of evidence indicating that most anvil crystals form on mid-tropospheric rather than boundary-layer aerosols. This result defies conventional wisdom and suggests that distant pollution sources may have a greater effect on anvil clouds than do local sources.", "doi": "10.1126/science.1094947", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2004-04-30", "series_number": "5671", "volume": "304", "issue": "5671", "pages": "718-722" }, { "id": "authors:2675a-92449", "collection": "authors", "collection_id": "2675a-92449", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:RISjas04", "type": "article", "title": "Chemical amplification (or dampening) of the Twomey effect: Conditions derived from droplet activation theory", "author": [ { "family_name": "Rissman", "given_name": "T. A.", "clpid": "Rissman-Tracey-A" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Cloud droplet number concentrations are controlled by both meteorological and microphysical factors. Microphysical factors include aerosol number concentration and composition. This paper examines the importance of microphysical phenomena compared to the sensitivity with respect to parcel updraft velocity in the activation of aerosols to become cloud droplets. Of the compositional (chemical) factors that can influence droplet number concentration, the effect of organics is examined through their ability to alter droplet surface tension and to contribute solute. A recent parameterization of aerosol activation (by Abdul-Razzak et al.) is extended to obtain analytical expressions for the sensitivity of activation to microphysical factors relative to updraft velocity. It is demonstrated that, under some conditions, the droplet number concentration can be as much as 1.5 times more sensitive to changes in aerosol composition than to updraft velocity. Chemical effects seem to be most influential for size distributions typical of marine conditions and decrease in importance for strongly anthropogenically perturbed conditions. The analysis indicates that the presence of surface-active species can lead to as much uncertainty as results from variations in updraft velocity. The presence of surfactant species also drastically changes the response of the cloud condensation nuclei to changes in the updraft velocity spectrum. Conditions are found under which an increase in dissolved organic compounds can actually lead to a decrease in cloud droplet number, a \"contra-Twomey effect.\" Results presented have more general implications than just for organic compounds and can apply, in principle, for any chemically induced activation effect.", "doi": "10.1175/1520-0469(2004)061<0919:CAODOT>2.0.CO;2", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2004-04-15", "series_number": "8", "volume": "61", "issue": "8", "pages": "919-930" }, { "id": "authors:1fj9c-s4529", "collection": "authors", "collection_id": "1fj9c-s4529", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:JACate04.323", "type": "article", "title": "Evolution of nanoparticle size and mixing state near the point of emission", "author": [ { "family_name": "Jacobson", "given_name": "Mark Z.", "clpid": "Jacobson-Mark-Z" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This study examines the evolution of the size distribution and mixing state of soot and background particles near a point and line source of emission. This evolution occurs invariably at a spatial scale smaller than that of the grid scale of urban through global atmospheric models, and the evolved distribution is that which is properly the source distribution \"emitted\" into such models. A recent set of field data showed that, within minutes of emission, the soot particle size distribution evolved substantially, and it was hypothesized that Brownian coagulation was the main cause of the evolution. Here, it is found that Brownian coagulation, alone, may be insufficient to account for the observed rapid evolution of the size distribution. Enhancement of Brownian coagulation due to van der Waals forces offset by viscous forces and fractal geometry may account for a greater share of the evolution. These coagulation processes are represented together with aerosol emissions, nucleation, condensation, dissolution, hydration, and chemistry among 10 aerosol classes in a high-resolution three-dimensional numerical simulation. Dilution is found to be more important than coagulation at reducing the total number concentration of particles near the source of emission, but the relative importance of dilution versus coagulation varies with concentration. It is also found that heterocoagulation of emitted soot with background particles produces new mixtures in increasing concentration with increasing distance from the emission source. However, self-coagulation of emitted soot reduces particle number concentration by an order of magnitude more than does heterocoagulation of emitted soot with background particles in the first few minutes after emission. Heterocoagulation increases in relative importance as emitted particles age.", "doi": "10.1016/j.atmosenv.2004.01.014", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2004-04", "series_number": "13", "volume": "38", "issue": "13", "pages": "1839-1850" }, { "id": "authors:t42hv-xxv78", "collection": "authors", "collection_id": "t42hv-xxv78", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-152626570", "type": "article", "title": "Molecular composition of the water-soluble fraction of atmospheric carbonaceous aerosols collected during ACE-Asia", "author": [ { "family_name": "Mader", "given_name": "B. T.", "clpid": "Mader-B-T" }, { "family_name": "Yu", "given_name": "J. Z.", "clpid": "Yu-J-Z" }, { "family_name": "Xu", "given_name": "J. H.", "clpid": "Xu-J-H" }, { "family_name": "Li", "given_name": "Q. F.", "clpid": "Li-Q-F" }, { "family_name": "Wu", "given_name": "W. S.", "clpid": "Wu-W-S" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "During the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia), samples of carbonaceous aerosols were collected on board the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) De Havilland DHC-6 Twin Otter aircraft. The samples were analyzed to determine their total carbon (TC) and water-soluble organic compound (WSOC) contents as well as to identify the individual compounds comprising the WSOC fraction of the aerosol. The TC concentrations varied from 3.5 to 14.3 \u03bcg C m^(\u22123); the highest TC levels were observed for samples collected in pollution layers that originated over mainland China. WSOC concentrations ranged from 0.54 to 7.2 \u03bcg C m^(\u22123), with the WSOC fraction contributing from 10 to 50% of the carbon mass. About 50% of the carbonaceous aerosol mass in pollution layers could be attributed to WSOC. For samples collected in dust layers the WSOC fraction of TC was much lower than that observed in pollution layers. The sum of all the detected organic ions accounted for 6.9\u201319% of the WSOC. In the six samples collected by the Twin Otter during ACE-Asia, of the organic ions identified in the WSOC fraction, oxalate had the highest concentration. Samples collected from pollution layers exhibited a slightly higher ratio of formate to oxalate as compared to the other samples. Two samples had a relatively high ratio of lactate to oxalate, which might be a signature of some currently unidentified source of carbonaceous aerosol. The sum of the masses of sulfate and nitrate ions exceeded the sum of the masses of the identified organic ions by a factor of 9 to 17. The chemical levoglucosan, a tracer for biomass burning, comprised from 0.1 to 0.4% of TC mass. Comparing this ratio to the ratio measured directly in wood-burning studies it was determined that biomass burning may have represented from \u22482 to 10% of the carbonaceous aerosol collected during ACE-Asia.", "doi": "10.1029/2003JD004105", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2004-03-27", "series_number": "D6", "volume": "109", "issue": "D6", "pages": "Art. No. D06206" }, { "id": "authors:xj0vx-4bs29", "collection": "authors", "collection_id": "xj0vx-4bs29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SEIbams04a", "type": "article", "title": "ACE-ASIA - Regional climatic and atmospheric chemical effects of Asian dust and pollution", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Carmichael", "given_name": "Gregory R.", "clpid": "Carmichael-G-R" }, { "family_name": "Arimoto", "given_name": "Richard", "clpid": "Arimoto-R" }, { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-W-C" }, { "family_name": "Brechtel", "given_name": "Frederick J.", "clpid": "Brechtel-F-J" }, { "family_name": "Bates", "given_name": "Timothy S.", "clpid": "Bates-T-S" }, { "family_name": "Cahill", "given_name": "Thomas A.", "clpid": "Cahill-T-A" }, { "family_name": "Clarke", "given_name": "Antony D.", "clpid": "Clarke-A-D" }, { "family_name": "Doherty", "given_name": "Sarah J.", "clpid": "Doherty-S-J" }, { "family_name": "Flatau", "given_name": "Piotr J.", "clpid": "Flatau-P-J" }, { "family_name": "Huebert", "given_name": "Barry J.", "orcid": "0000-0001-7711-0468", "clpid": "Huebert-B-J" }, { "family_name": "Kim", "given_name": "Jiyoung", "clpid": "Kim-Jiyoung" }, { "family_name": "Markowicz", "given_name": "Krzysztof M.", "clpid": "Markowicz-K-M" }, { "family_name": "Quinn", "given_name": "Patricia K.", "clpid": "Quinn-P-K" }, { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Russell", "given_name": "Philip B.", "clpid": "Russell-P-B" }, { "family_name": "Shimizu", "given_name": "Atsushi", "clpid": "Shimizu-Atsushi" }, { "family_name": "Shinozuka", "given_name": "Yohei", "clpid": "Shinozuka-Yohei" }, { "family_name": "Song", "given_name": "Chul H.", "clpid": "Song-Chul-H" }, { "family_name": "Tang", "given_name": "Youhua", "clpid": "Tang-Youhua" }, { "family_name": "Uno", "given_name": "Itsushi", "clpid": "Uno-Itsushi" }, { "family_name": "Vogelmann", "given_name": "Andrew M.", "clpid": "Vogelmann-A-M" }, { "family_name": "Weber", "given_name": "Rodney J.", "clpid": "Weber-R-J" }, { "family_name": "Woo", "given_name": "Jung-Hun", "clpid": "Woo-Jung-Hun" }, { "family_name": "Zhang", "given_name": "Xiao Y.", "clpid": "Zhang-Xiao-Y" } ], "abstract": "Although continental-scale plumes of Asian dust and pollution reduce the amount of solar radiation reaching the earth's surface and perturb the chemistry of the atmosphere, our ability to quantify these effects has been limited by a lack of critical observations, particularly of layers above the surface. Comprehensive surface, airborne, shipboard, and satellite measurements of Asian aerosol chemical composition, size, optical properties, and radiative impacts were performed during the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) study. Measurements within a massive Chinese dust storm at numerous widely spaced sampling locations revealed the highly complex structure of the atmosphere, in which layers of dust, urban pollution, and biomass-burning smoke may be transported long distances as distinct entities or mixed together. The data allow a first-time assessment of the regional climatic and atmospheric chemical effects of a continental-scale mixture of dust and pollution. Our results show that radiative flux reductions during such episodes are sufficient to cause regional climate change.", "doi": "10.1175/BAMS-85-3-367", "issn": "0003-0007", "publisher": "American Meteorological Society", "publication": "Bulletin of the American Meteorological Society", "publication_date": "2004-03", "series_number": "3", "volume": "85", "issue": "3", "pages": "367-380" }, { "id": "authors:nfjzz-1pt21", "collection": "authors", "collection_id": "nfjzz-1pt21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170524-071409039", "type": "article", "title": "Improvement of the Zdanovskii\u2212Stokes\u2212Robinson Model for Mixtures Containing Solutes of Different Charge Types", "author": [ { "family_name": "Clegg", "given_name": "Simon L.", "clpid": "Clegg-S-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The Zdanovskii\u2212Stokes\u2212Robinson (ZSR) relationship [Stokes and Robinson (J. Phys. Chem. 1966, 70, 2126\u22122130)] enables the solvent content of a liquid mixture to be estimated, for a specified solvent activity, from data for pure solutions of each of the individual solutes. There is an analogous relationship for the activity coefficients of the solutes. The method has been shown to be exact, in the limit of extreme dilution, only for mixtures containing either all uncharged (neutral) solutes or electrolytes all of the same charge type, and in practice it is found to be most accurate for such mixtures. Here we derive an addition to the ZSR equations which removes this limitation by incorporating simple Debye\u2212H\u00fcckel terms into the equations for solvent mass and solute activity coefficients. This addition, in its simplest form, does not involve any new fitted parameters or require any further thermodynamic information. The relationship is general, and not limited to particular Debye\u2212H\u00fcckel expressions. Application of the revised model to activity and osmotic coefficient data for the system NaCl\u2212Na_2SO_4\u2212H_2O at 298.15 K shows that errors are reduced, compared to predictions of the standard model, by up to a factor of 2. Solubilities of NaCl(cr), Na_2SO_4\u00b710H2O(cr), and Na_2SO_4(cr) in that system are similarly better predicted. Activity coefficients of uncharged solutes in salt solutions calculated using the revised model are now largely consistent with the empirically observed Setchenow relationship.", "doi": "10.1021/jp030827q", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2004-02-12", "series_number": "6", "volume": "108", "issue": "6", "pages": "1008-1017" }, { "id": "authors:bkmjp-vre22", "collection": "authors", "collection_id": "bkmjp-vre22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ZHAgpr04.261", "type": "article", "title": "Development and application of the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID)", "author": [ { "family_name": "Zhang", "given_name": "Yang", "clpid": "Zhang-Yang" }, { "family_name": "Pun", "given_name": "Betty", "clpid": "Pun-Betty" }, { "family_name": "Vijayaraghavan", "given_name": "Krish", "clpid": "Vijayaraghavan-Krish" }, { "family_name": "Wu", "given_name": "Shiang-Yuh", "clpid": "Wu-Shiang-Yuh" }, { "family_name": "Seigneur", "given_name": "Christian", "orcid": "0000-0002-3079-4839", "clpid": "Seigneur-Christian" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Jacobson", "given_name": "Mark Z.", "clpid": "Jacobson-Mark-Z" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new aerosol model, the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) has been developed to simulate atmospheric particulate matter (PM). MADRID and the Carnegie-Mellon University (CMU) bulk aqueous-phase chemistry have been incorporated into the three-dimensional Models-3/Community Multiscale Air Quality model (CMAQ). The resulting model, CMAQ-MADRID, is applied to simulate the August 1987 episode in the Los Angeles basin. Model performance for ozone and PM is consistent with current performance standards. However, organic aerosol was underpredicted at most sites owing to underestimation of primary organic PM emissions and secondary organic aerosol (SOA) formation. Nitrate concentrations were also sometimes underpredicted, mainly owing to overpredictions in vertical mixing, underpredictions in relative humidity, and uncertainties in the emissions of primary pollutants. Including heterogeneous reactions changed hourly O\u2083 by up to 17% and 24-hour average PM_(2.5), sulfate_(2.5), and nitrate_(2.5) concentrations by up to 3, 7, and 19%, respectively. A SOA module with a mechanistic representation provides results that are more consistent with observations than that with an empirical representation. The moving-center scheme for particle growth predicts more accurate size distributions than a typical semi-Lagrangian scheme, which causes an upstream numerical diffusion. A hybrid approach that simulates dynamic mass transfer for coarse PM but assumes equilibrium for fine PM can predict a realistic particle size distribution under most conditions, and the same applies under conditions with insignificant concentrations of reactive coarse particles to a bulk equilibrium approach that allocates transferred mass to different size sections based on condensational growth law. In contrast, a simple bulk equilibrium approach that allocates transferred mass based on a given distribution tends to cause a downstream numerical diffusion in the predicted particle size distribution.", "doi": "10.1029/2003JD003501", "issn": "2169-897X", "publisher": "Wiley", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2004-01-16", "series_number": "D1", "volume": "109", "issue": "D1", "pages": "Art. No. D01202" }, { "id": "authors:426na-rw832", "collection": "authors", "collection_id": "426na-rw832", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-150457940", "type": "article", "title": "The effect on photochemical smog of converting the U.S. fleet of gasoline vehicles to modern diesel vehicles", "author": [ { "family_name": "Jacobson", "given_name": "Mark Z.", "clpid": "Jacobson-M-Z" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Carmichael", "given_name": "Greg R.", "clpid": "Carmichael-G-R" }, { "family_name": "Streets", "given_name": "David G.", "clpid": "Streets-D-G" } ], "abstract": "With the increased use of particle traps and nitrogen oxide (NO_x) control devices to reduce air pollution, \"modern\" diesel vehicles are being encouraged over gasoline vehicles globally as a central method of slowing global warming. Data to date, though, suggest that the NO_2:NO ratio from modern diesel may exceed that of gasoline, and it is difficult to reduce diesel NO_x below gasoline NO_x without increasing particle emissions. Here, it is calculated that, unless the diesel NO_2:NO ratio and total NO_x are reduced to those of gasoline, modern diesel, which should have lower hydrocarbon (HC) and carbon monoxide (CO) emissions than gasoline, may still enhance photochemical smog at the surface and aloft, on average, over the U.S. relative to gasoline. The reason is that vehicle-produced smog in the U.S. depends more on NO_x and the NO_2:NO ratio than on HCs or CO. It is also found that vehicle NO_x controls may be more effective than NO_2:NO ratio controls at reducing ozone.", "doi": "10.1029/2003GL018448", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2004-01", "series_number": "2", "volume": "31", "issue": "2", "pages": "Art. No. L02116" }, { "id": "authors:rcx5z-v0h42", "collection": "authors", "collection_id": "rcx5z-v0h42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-172232846", "type": "article", "title": "Effect of relative humidity on the detection of sulfur dioxide and sulfuric acid using a chemical ionization mass spectrometer", "author": [ { "family_name": "Salcedo", "given_name": "D.", "clpid": "Salcedo-D" }, { "family_name": "Villalta", "given_name": "P. W.", "clpid": "Villalta-P-W" }, { "family_name": "Varutbangkul", "given_name": "V.", "clpid": "Varutbangkul-V" }, { "family_name": "Wormhoudt", "given_name": "J. C.", "clpid": "Wormhoudt-J-C" }, { "family_name": "Miake-Lye", "given_name": "R. C.", "clpid": "Miake-Lye-R-C" }, { "family_name": "Worsnop", "given_name": "D. R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-D-R" }, { "family_name": "Ballenthin", "given_name": "J. O.", "clpid": "Ballenthin-J-O" }, { "family_name": "Thorn", "given_name": "W. F.", "clpid": "Thorn-W-F" }, { "family_name": "Viggiano", "given_name": "A. A.", "clpid": "Viggiano-A-A" }, { "family_name": "Miller", "given_name": "T. M.", "clpid": "Miller-T-M" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Detection of sulfur dioxide and sulfuric acid at high relative humidity was studied using a chemical ionization mass spectrometer (CIMS). The reactant ions used in the experiments are CO_3^\u2212\u00b7nH_2O (n=0\u20135), which react with SO_2 to form SO_5^\u2212\u00b7nH_2O (n=0\u20132). H_2SO_4 reacts with the precursor ions to form HSO_4^\u2212 (m/z=97 amu) and H_2SO_4\u00b7CO_3^\u2212 (m/z=158 amu). We report the first use of the latter ionization scheme to detect sulfuric acid. High RH affects the detection of SO_2 and H_2SO_4 by forming clusters with the reactant and product ions, reducing sensitivity. Increasing the temperature breaks these clusters. For SO_2 at high RH, either SO_5^\u2212 (m/z=112 amu) or SO_5^\u2212\u00b7H_2O (m/z=130 amu) can be used for SO_2 detection without a decrease in sensitivity. For H_2SO_4 at high RH, it is preferred to detect the ion H_2SO_4\u00b7CO_3^\u2212 because the background signal at 158 amu is small, and a better sensitivity can be achieved.", "doi": "10.1016/j.ijms.2003.09.005", "issn": "1387-3806", "publisher": "Elsevier", "publication": "International Journal of Mass Spectrometry", "publication_date": "2004-01", "series_number": "1", "volume": "231", "issue": "1", "pages": "17-30" }, { "id": "authors:x69kg-hcn75", "collection": "authors", "collection_id": "x69kg-hcn75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CONgpr03.57", "type": "article", "title": "A model for the radiative forcing during ACE-Asia derived from CIRPAS Twin Otter and R/V Ronald H. Brown data and comparison with observations", "author": [ { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-William-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wang", "given_name": "Jian", "clpid": "Wang-Jian" }, { "family_name": "Carmichael", "given_name": "George R.", "clpid": "Carmichael-George-R" }, { "family_name": "Tang", "given_name": "Youhua", "orcid": "0000-0001-7089-7915", "clpid": "Tang-Youhua" }, { "family_name": "Uno", "given_name": "Itsushi", "orcid": "0000-0002-0508-6267", "clpid": "Uno-Itsushi" }, { "family_name": "Flatau", "given_name": "Piotr J.", "orcid": "0000-0003-3487-5764", "clpid": "Flatau-Piotr-J" }, { "family_name": "Markowicz", "given_name": "Krzysztof M.", "orcid": "0000-0003-4190-0243", "clpid": "Markowicz-Krzysztof-M" }, { "family_name": "Quinn", "given_name": "Patricia K.", "orcid": "0000-0003-0337-4895", "clpid": "Quinn-Patricia-K" } ], "abstract": "Vertical profiles of aerosol size, composition, and hygroscopic behavior from Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter and National Oceanic and Atmospheric Administration R/V Ronald H. Brown observations are used to construct a generic optical model of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) aerosol. The model accounts for sulfate, black carbon, organic carbon, sea salt, and mineral dust. The effects of relative humidity and mixing assumptions (internal versus external, coating of dust by pollutants) are explicitly accounted for. The aerosol model is integrated with a Monte Carlo radiative transfer model to compute direct radiative forcing in the solar spectrum. The predicted regional average surface aerosol forcing efficiency (change in clear-sky radiative flux per unit aerosol optical depth at 500 nm) during the ACE-Asia intensive period is \u221265 Wm\u207b\u00b2 for pure dust and \u221260 Wm\u207b\u00b2 for pure pollution aerosol (clear skies). A three-dimensional atmospheric chemical transport model (Chemical Weather Forecast System (CFORS)) is used with the radiative transfer model to derive regional radiative forcing during ACE-Asia in clear and cloudy skies. Net regional solar direct radiative forcing during the 5\u201315 April 2001 dust storm period is \u22123 Wm\u207b\u00b2 at the top of the atmosphere and \u221217 W m\u207b\u00b2 at the surface for the region from 20\u00b0N to 50\u00b0N and 100\u00b0E to 150\u00b0E when the effects of clouds on the direct forcing are included. The model fluxes and forcing efficiencies are found to be in good agreement with surface radiometric observations made aboard the R.H. Brown. Mean cloud conditions are found to moderate the top of atmosphere (TOA) radiative forcing by a factor of \u223c3 compared to clear-sky calculations, but atmospheric absorption by aerosol is not strongly affected by clouds in this study. The regional aerosol effect at the TOA (\"climate forcing\") of \u22123 Wm\u207b\u00b2 is comparable in magnitude, but of opposite sign, to present-day anthropogenic greenhouse gas forcing. The forcing observed during ACE-Asia is similar in character to that seen during other major field experiments downwind of industrial and biomass black carbon sources (e.g., the Indian Ocean Experiment (INDOEX)), insofar as the primary effect of aerosol is to redistribute solar heating from the surface to the atmosphere.", "doi": "10.1029/2002JD003260", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2003-12-16", "series_number": "D23", "volume": "108", "issue": "D23", "pages": "Art. No. 8661" }, { "id": "authors:p89pj-ct490", "collection": "authors", "collection_id": "p89pj-ct490", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170408-172222326", "type": "article", "title": "Aircraft-based aerosol size and composition measurements during ACE-Asia using an Aerodyne aerosol mass spectrometer", "author": [ { "family_name": "Bahreini", "given_name": "Roya", "clpid": "Bahreini-R" }, { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Wang", "given_name": "Jian", "clpid": "Wang-Jian" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Jayne", "given_name": "John T.", "clpid": "Jayne-J-T" }, { "family_name": "Worsnop", "given_name": "Douglas R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-D-R" } ], "abstract": "An Aerodyne aerosol mass spectrometer (AMS) was deployed during the Aerosol Characterization Experiment-Asia (ACE-Asia) field campaign on board the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft to measure the size-resolved chemical composition of submicron aerosols in the outflow from eastern Asia. Research flights were carried out from 31 March to 1 May 2001 in an area that covered 127\u00b0E\u2013135\u00b0E and 32\u00b0N\u201338\u00b0N. Valid data from the AMS were obtained during 15 out of a total of 19 research flights. During the mission the AMS measured distinct layers (from the boundary layer to \u223c3700 m) of submicron aerosols composed of sulfate, ammonium, and organics as the major nonrefractory components, separated by layers with much lower aerosol concentrations. Sulfate and organics mass concentrations of up to 10 \u03bcg m^(\u22123) and 13 \u03bcg m^(\u22123), respectively, were measured in some pollution layers. Back-trajectory analysis shows that the polluted layers originated in urban and industrial areas of China and Korea. The mass-weighed size distribution of the submicron sulfate was relatively constant from day to day and layer to layer, with an aerodynamic diameter mode of 400\u2013500 nm and a width (full width half maximum) of about 450 nm in most of the layers. On the days with low influence of dust in the aerosol outflow, as indicated by other instruments aboard the Twin Otter, the total mass of nonrefractory aerosols estimated by the AMS correlated well with total volume of aerosols measured by a differential mobility analyzer.", "doi": "10.1029/2002JD003226", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2003-12-16", "series_number": "D23", "volume": "108", "issue": "D23", "pages": "Art. No. 8645" }, { "id": "authors:zeqpf-b4n95", "collection": "authors", "collection_id": "zeqpf-b4n95", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-987794800.2", "type": "article", "title": "Column closure studies of lower tropospheric aerosol and water vapor during ACE-Asia using airborne Sun photometer and airborne in situ and ship-based lidar measurements", "author": [ { "family_name": "Schmid", "given_name": "B.", "clpid": "Schmid-Benedikt" }, { "family_name": "Hegg", "given_name": "D. A.", "clpid": "Hegg-Dean-A" }, { "family_name": "Wang", "given_name": "J.", "clpid": "Wang-J" }, { "family_name": "Bates", "given_name": "D.", "clpid": "Bates-D" }, { "family_name": "Redemann", "given_name": "J.", "clpid": "Redemann-J" }, { "family_name": "Russell", "given_name": "P. B.", "clpid": "Russell-Philip-B" }, { "family_name": "Livingston", "given_name": "J. M.", "clpid": "Livingston-J" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Welton", "given_name": "E. J.", "orcid": "0000-0003-0208-4861", "clpid": "Welton-Ellsworth-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Covert", "given_name": "D. S.", "clpid": "Covert-D-S" }, { "family_name": "Dubovik", "given_name": "O.", "orcid": "0000-0003-3482-6460", "clpid": "Dubovik-Oleg" }, { "family_name": "Jefferson", "given_name": "A.", "clpid": "Jefferson-A" } ], "abstract": "We assess the consistency (closure) between solar beam attenuation by aerosols and water vapor measured by airborne Sun photometry and derived from airborne in situ and ship-based lidar measurements during the April 2001 Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The airborne data presented here were obtained aboard the Twin Otter aircraft. Comparing aerosol extinction \u03c3_(ep)(550 nm) from four different techniques shows good agreement for the vertical distribution of aerosol layers. However, the level of agreement in absolute magnitude of the derived aerosol extinction varied among the aerosol layers sampled. The \u03c3_(ep)(550 nm) computed from airborne in situ size distribution and composition measurements shows good agreement with airborne Sun photometry in the marine boundary layer but is considerably lower in layers dominated by dust if the particles are assumed to be spherical. The \u03c3_(ep)(550 nm) from airborne in situ scattering and absorption measurements are about \u223c13% lower than those obtained from airborne Sun photometry during 14 vertical profiles. Combining lidar and the airborne Sun photometer measurements reveals the prevalence of dust layers at altitudes up to 10 km with layer aerosol optical depth (from 3.5 to 10 km altitude) of \u223c0.1 to 0.2 (500 nm) and extinction-to-backscatter ratios of 59\u201371 sr (523 nm). The airborne Sun photometer aboard the Twin Otter reveals a relatively dry atmosphere during ACE-Asia with all water vapor columns <1.5 cm and water vapor densities \u03c1_w < 12 g/m\u00b3. Comparing layer water vapor amounts and \u03c1_w from the airborne Sun photometer to the same quantities measured with aircraft in situ sensors leads to a high correlation (r\u00b2 = 0.96), but the Sun photometer tends to underestimate \u03c1_w by 7%.", "doi": "10.1029/2002jd003361", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2003-12-16", "series_number": "D23", "volume": "108", "issue": "D23", "pages": "Art. No. 8656" }, { "id": "authors:81e55-79h30", "collection": "authors", "collection_id": "81e55-79h30", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-987794800.4", "type": "article", "title": "Toward aerosol/cloud condensation nuclei (CCN) closure during CRYSTAL-FACE", "author": [ { "family_name": "VanReken", "given_name": "Timothy M.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-Timothy-M" }, { "family_name": "Rissman", "given_name": "Tracey A.", "clpid": "Rissman-Tracey-A" }, { "family_name": "Roberts", "given_name": "Gregory C.", "clpid": "Roberts-Gregory-C" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-Varuntida" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "During July 2002, measurements of cloud condensation nuclei were made in the vicinity of southwest Florida as part of the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) field campaign. These observations, at supersaturations of 0.2 and 0.85%, are presented here. The performance of each of the two CCN counters was validated through laboratory calibration and an in situ intercomparison. The measurements indicate that the aerosol sampled during the campaign was predominantly marine in character: the median concentrations were 233 cm\u207b\u00b3 (at S = 0.2%) and 371 cm\u207b\u00b3 (at S = 0.85%). Three flights during the experiment differed from this general trend; the aerosol sampled during the two flights on 18 July was more continental in character, and the observations on 28 July indicate high spatial variability and periods of very high aerosol concentrations. This study also includes a simplified aerosol/CCN closure analysis. Aerosol size distributions were measured simultaneously with the CCN observations, and these data are used to predict a CCN concentration using K\u00f6hler theory. For the purpose of this analysis, an idealized composition of pure ammonium sulfate was assumed. The analysis indicates that in this case, there was good general agreement between the predicted and observed CCN concentrations: at S = 0.2%, N_(predicted)/N_(observed) = 1.047 (R\u00b2 = 0.911); at S = 0.85%, N_(predicted)/N_(observed) = 1.201 (R\u00b2 = 0.835). The impacts of the compositional assumption and of including in-cloud data in the analysis are addressed. The effect of removing the data from the 28 July flight is also examined; doing so improves the result of the closure analysis at S = 0.85%. When omitting that atypical flight, N_(predicted)/N_(observed) = 1.085 (R\u00b2 = 0.770) at S = 0.85%.", "doi": "10.1029/2003jd003582", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2003-10-27", "series_number": "D20", "volume": "108", "issue": "D20", "pages": "Art. No. 4633" }, { "id": "authors:wj06e-m0f95", "collection": "authors", "collection_id": "wj06e-m0f95", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SEIarpc03", "type": "article", "title": "Organic atmospheric particulate material", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pankow", "given_name": "John F.", "clpid": "Pankow-J-F" } ], "abstract": "Carbonaceous compounds comprise a substantial fraction of atmospheric particulate matter (PM). Particulate organic material can be emitted directly into the atmosphere or formed in the atmosphere when the oxidation products of certain volatile organic compounds condense. Such products have lower volatilities than their parent molecules as a result of the fact that adding oxygen and/or nitrogen to organic molecules reduces volatility. Formation of secondary organic PM is often described in terms of a fractional mass yield, which relates how much PM is produced when a certain amount of a parent gaseous organic is oxidized. The theory of secondary organic PM formation is outlined, including the role of water, which is ubiquitous in the atmosphere. Available experimental studies on secondary organic PM formation and molecular products are summarized.", "doi": "10.1146/annurev.physchem.54.011002.103756", "issn": "0066-426X", "publisher": "Annual Reviews", "publication": "Annual Review of Physical Chemistry", "publication_date": "2003-10", "volume": "54", "pages": "121-140" }, { "id": "authors:t2r30-kbp43", "collection": "authors", "collection_id": "t2r30-kbp43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-987794800.6", "type": "article", "title": "Aerosol Growth in a Steady-State, Continuous Flow Chamber: Application to Studies of Secondary Aerosol Formation", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Kleindienst", "given_name": "Tadeusz E.", "orcid": "0000-0002-3024-1564", "clpid": "Kleindienst-Tadeusz-E" }, { "family_name": "Edney", "given_name": "Edward O.", "clpid": "Edney-Edward-O" }, { "family_name": "Cohen", "given_name": "Jason B.", "clpid": "Cohen-Jason-B" } ], "abstract": "An analytical solution for the steady-state aerosol size distribution achieved in a steady-state, continuous flow chamber is derived, where particle growth is occurring by gas-to-particle conversion and particle loss is occurring by deposition to the walls of the chamber. The solution is presented in the case of two condensing species. By fitting the predicted steady-state aerosol size distribution to that measured, one may infer information about the nature of the condensing species from the calculated values of the species's molecular weights. The analytical solution is applied to three sets of experiments on secondary organic aerosol formation carried out in the U.S. Environmental Protection Agency irradiated continuous flow reactor, with parent hydrocarbons: toluene, f -pinene, and a mixture of toluene and f -pinene. Fits to the observed size distributions are illustrated by assuming two condensing products for each parent hydrocarbon; this is a highly simplified picture of secondary organic aerosol formation, which is known to involve considerably more than two condensing products. While not based on a molecular-level model of the gas-to-particle conversion process, the model does allow one to evaluate the extent to which the observed size distribution agrees with that based on a simple, two-component picture of condensation, and to study the sensitivity of those size distributions to variation of the essential properties of the condensing compounds, such as molecular weight. An inherent limitation of the steady-state experiment is that it is not possible to calculate the vapor pressures of the condensing species.", "doi": "10.1080/02786820300915", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2003-09", "series_number": "9", "volume": "37", "issue": "9", "pages": "728-734" }, { "id": "authors:zwr9c-5hc90", "collection": "authors", "collection_id": "zwr9c-5hc90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170315-110822084", "type": "article", "title": "Uncertainties in Modeling Secondary Organic Aerosols: Three-Dimensional Modeling Studies in Nashville/Western Tennessee", "author": [ { "family_name": "Pun", "given_name": "Betty K.", "clpid": "Pun-B-K" }, { "family_name": "Wu", "given_name": "Shiang-Yuh", "clpid": "Wu-Shiang-Yuh" }, { "family_name": "Seigneur", "given_name": "Christian", "clpid": "Seigneur-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Griffin", "given_name": "Robert J.", "clpid": "Griffin-R-J" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-S-N" } ], "abstract": "The formation of secondary organic aerosols (SOA) is simulated for the Nashville/western Tennessee domain using three recent SOA modules incorporated into the three-dimensional air quality model, CMAQ. The Odum/Griffin et al. and CMU/STI modules represent SOA absorptive partitioning into a mixture of primary and secondary particulate organic compounds (OC), with some differences in the formulation of the absorption process and the selection of SOA species and their precursors. Empirical representations based on measured laboratory SOA yields are used for condensable organic products in both these modules. The AEC module simulates SOA absorption into organic and aqueous particulate phases, and a representation based on an explicit gas-phase mechanism is used in the AEC module. Predicted SOA concentrations can vary by a factor of 10 or more. In general, the gas-phase mechanistic approach predicts a higher yield of SOA than those based on laboratory yields. There exist some differences in the two empirical modules despite their similar basis on experimental data. All three modules predict a dominance of SOA of biogenic origin as compared to SOA of anthropogenic origin. The causes for differences among the three SOA modules include the representation of terpenes, the mechanistic versus empirical representation of SOA-forming reactions, the identities of SOA, and the parameters used in the gas/particle partitioning calculations. Two sensitivity studies show that formation of water-soluble SOA and temperature dependence may be areas of key uncertainties affecting current models.", "doi": "10.1021/es0341541", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2003-08-15", "series_number": "16", "volume": "37", "issue": "16", "pages": "3647-3661" }, { "id": "authors:6taek-3ze96", "collection": "authors", "collection_id": "6taek-3ze96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-987794800.8", "type": "article", "title": "Parameterization of cloud droplet formation in global climate models", "author": [ { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An aerosol activation parameterization has been developed based on a generalized representation of aerosol size and composition within the framework of an ascending adiabatic parcel; this allows for parameterizing the activation of chemically complex aerosol with an arbitrary size distribution and mixing state. The new parameterization introduces the concept of \"population splitting,\" in which the cloud condensation nuclei (CCN) that form droplets are treated as two separate populations: those that have a size close to their critical diameter and those that do not. Explicit consideration of kinetic limitations on droplet growth is introduced. Our treatment of the activation process unravels much of its complexity. As a result of this, a substantial number of conditions of droplet formation can be treated completely free of empirical information or correlations; there are, however, some conditions of droplet activation for which an empirically derived correlation is utilized. Predictions of the parameterization are compared against extensive cloud parcel model simulations for a variety of aerosol activation conditions that cover a wide range of chemical variability and CCN concentrations. The parameterization tracks the parcel model simulations closely and robustly. The parameterization presented here is intended to allow for a comprehensive assessment of the aerosol indirect effect in general circulation models.", "doi": "10.1029/2002jd002911", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2003-07-27", "series_number": "D14", "volume": "108", "issue": "D14", "pages": "Art. No. 4415" }, { "id": "authors:tvmgc-32t44", "collection": "authors", "collection_id": "tvmgc-32t44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-987794800.10", "type": "article", "title": "Thermodynamic modelling of aqueous aerosols containing electrolytes and dissolved organic compounds. II. An extended Zdanovskii\u2013Stokes\u2013Robinson approach", "author": [ { "family_name": "Clegg", "given_name": "Simon L.", "clpid": "Clegg-Simon-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Edney", "given_name": "Edward O.", "clpid": "Edney-Edward-O" } ], "abstract": "The Zdanovskii\u2013Stokes\u2013Robinson (ZSR) equation, or linear isopiestic relation, can be used to estimate osmotic and activity coefficients of multicomponent mixtures, based on the properties of pure (single solute) solutions. We have generalised an extension to the ZSR equation (for ternary mixtures) to systems containing an indefinite number of solutes, and derived the corresponding equations for solute activity coefficients. The new model is tested by calculating salt solubilities in Na\u207a/NH\u2084\u207a/Cl\u208b/SO\u2084\u00b2\u208b aqueous solutions, liquid\u2013liquid phase equilibrium in the acetone/glycerol/water system, and thermodynamic properties of aqueous NaCl/sucrose solutions (all at 298.15 K). The mixture parameters, up to three for each pair of solutes, significantly increase the accuracy of the method. It is least satisfactory for solutions containing both electrolytes and non-electrolytes, and it was found that the ZSR equation predicts activity coefficients of trace amounts of non-electrolytes in salt solutions that do not conform to the Setchenow relationship.", "doi": "10.1016/s0021-8502(03)00019-3", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "2003-06", "series_number": "6", "volume": "34", "issue": "6", "pages": "667-690" }, { "id": "authors:fb56q-24k97", "collection": "authors", "collection_id": "fb56q-24k97", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-101811885", "type": "article", "title": "New particle formation from photooxidation of diiodomethane (CH_2I_2)", "author": [ { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Bahreini", "given_name": "Roya", "clpid": "Bahreini-R" }, { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-D-R-III" }, { "family_name": "Zhuang", "given_name": "Hong", "clpid": "Zhuang-Hong" }, { "family_name": "Varutbangkul", "given_name": "Varuntida", "clpid": "Varutbangkul-V" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "O'Dowd", "given_name": "Colin D.", "clpid": "O'Dowd-C-D" }, { "family_name": "Hoffmann", "given_name": "Thorsten", "clpid": "Hoffmann-T" } ], "abstract": "Photolysis of CH_2I_2 in the presence of O_3 has been proposed as a mechanism leading to intense new particle formation in coastal areas. We report here a comprehensive laboratory chamber study of this system. Rapid homogeneous nucleation was observed over three orders of magnitude in CH_2I_2 mixing ratio, down to a level of 15 ppt (\u223c4 \u00d7 10^8 molec. cm^(\u22123)) comparable to the directly measured total gas-phase iodine species concentrations in coastal areas. After the nucleation burst, the observed aerosol dynamics in the chamber was dominated by condensation of additional vapors onto existing particles and particle coagulation. Particles formed under dry conditions are fractal agglomerates with mass fractal dimension, D_f \u223c 1.8\u20132.5. Higher relative humidity (65%) does not change the nucleation or growth behavior from that under dry conditions, but results in more compact and dense particles (D_f \u223c 2.7). On the basis of the known gas-phase chemistry, OIO is the most likely gas-phase species to produce the observed nucleation and aerosol growth; however, the current understanding of this chemistry is very likely incomplete. Chemical analysis of the aerosol using an Aerodyne Aerosol Mass Spectrometer reveals that the particles are composed mainly of iodine oxides but also contain water and/or iodine oxyacids. The system studied here can produce nucleation events as intense as those observed in coastal areas. On the basis of comparison between the particle composition, hygroscopicity, and nucleation and growth rates observed in coastal nucleation and in the experiments reported here, it is likely that photooxidation of CH_2I_2, probably aided by other organic iodine compounds, is the mechanism leading to the observed new particle formation in the west coast of Ireland.", "doi": "10.1029/2002JD002452", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2003-05-27", "series_number": "D10", "volume": "108", "issue": "D10", "pages": "Art. No. 4318" }, { "id": "authors:mq3my-ksn38", "collection": "authors", "collection_id": "mq3my-ksn38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141029-145943020", "type": "article", "title": "A comparison of particle mass spectrometers during the 1999 Atlanta Supersite Project", "author": [ { "family_name": "Middlebrook", "given_name": "Ann M.", "orcid": "0000-0002-2984-6304", "clpid": "Middlebrook-Ann-M" }, { "family_name": "Murphy", "given_name": "Daniel M.", "orcid": "0000-0002-8091-7235", "clpid": "Murphy-Daniel-M" }, { "family_name": "Lee", "given_name": "Shan-Hu", "clpid": "Lee-Shan-Hu" }, { "family_name": "Thomson", "given_name": "David S.", "clpid": "Thomson-David-S" }, { "family_name": "Prather", "given_name": "Kimberly A.", "orcid": "0000-0003-3048-9890", "clpid": "Prather-Kimberly-A" }, { "family_name": "Wenzel", "given_name": "Ryan J.", "clpid": "Wenzel-Ryan-J" }, { "family_name": "Liu", "given_name": "Don-Yuan", "clpid": "Liu-Don-Yuan" }, { "family_name": "Phares", "given_name": "Denis J.", "clpid": "Phares-Denis-J" }, { "family_name": "Rhoads", "given_name": "Kevin P.", "clpid": "Rhoads-Kevin-P" }, { "family_name": "Wexler", "given_name": "Anthony S.", "orcid": "0000-0003-1565-814X", "clpid": "Wexler-Anthony-S" }, { "family_name": "Johnston", "given_name": "Murray V.", "orcid": "0000-0001-9529-8660", "clpid": "Johnston-Murray-V" }, { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-Jose-L" }, { "family_name": "Jayne", "given_name": "John T.", "clpid": "Jayne-John-T" }, { "family_name": "Worsnop", "given_name": "Douglas R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-Douglas-R" }, { "family_name": "Yourshaw", "given_name": "Ivan", "clpid": "Yourshaw-Ivan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "During the Atlanta Supersite Project, four particle mass spectrometers were operated together for the first time: NOAA's Particle Analysis by Laser Mass Spectrometer (PALMS), University of California at Riverside's Aerosol Time-of-Flight Mass Spectrometer (ATOFMS), University of Delaware's Rapid Single-Particle Mass Spectrometer II (RSMS-II), and Aerodyne's Aerosol Mass Spectrometer (AMS). Although these mass spectrometers are generally classified as similar instruments, they clearly have different characteristics due to their unique designs. One primary difference is related to the volatilization/ionization method: PALMS, ATOFMS, and RSMS-II utilize laser desorption/ionization, whereas particles in the AMS instrument are volatilized by impaction onto a heated surface with the resulting components ionized by electron impact. Thus mass spectral data from the AMS are representative of the ensemble of particles sampled, and those from the laser-based instruments are representative of individual particles. In addition, the AMS instrument cannot analyze refractory material such as soot, sodium chloride, and crustal elements, and some sulfate or water-rich particles may not always be analyzed with every laser-based instrument. A main difference among the laser-based mass spectrometers is that the RSMS-II instrument can obtain size-resolved single particle composition information for particles with aerodynamic diameters as small as 15 nm. The minimum sizes analyzed by ATOFMS and PALMS are 0.2 and about 0.35 \u03bcm, respectively, in aerodynamic diameter. Furthermore, PALMS, ATOFMS, and RSMS-II use different laser ionization conditions. Despite these differences the laser-based instruments found similar individual particle classifications, and their relative fractions among comparable sized particles from Atlanta were broadly consistent. Finally, the AMS measurements of the nitrate/sulfate mole ratio were highly correlated with composite measurements (r^2 = 0.93). In contrast, the PALMS nitrate/sulfate ion ratios were only moderately correlated (r^2 \u223c 0.7).", "doi": "10.1029/2001JD000660", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2003-04-16", "series_number": "D7", "volume": "108", "issue": "D7", "pages": "Art. No. 8424" }, { "id": "authors:zptpx-zff67", "collection": "authors", "collection_id": "zptpx-zff67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-101640828", "type": "article", "title": "Ambient aerosol sampling using the Aerodyne Aerosol Mass Spectrometer", "author": [ { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Jayne", "given_name": "John T.", "clpid": "Jayne-J-T" }, { "family_name": "Shi", "given_name": "Quan", "clpid": "Shi-Quan" }, { "family_name": "Kolb", "given_name": "Charles E.", "clpid": "Kolb-C-E" }, { "family_name": "Worsnop", "given_name": "Douglas R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-D-R" }, { "family_name": "Yourshaw", "given_name": "Ivan", "clpid": "Yourshaw-I" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Zhang", "given_name": "Xuefeng", "clpid": "Zhang-Xuefeng" }, { "family_name": "Smith", "given_name": "Kenneth A.", "clpid": "Smith-K-A" }, { "family_name": "Morris", "given_name": "James W.", "clpid": "Morris-J-W" }, { "family_name": "Davidovits", "given_name": "Paul", "clpid": "Davidovits-P" } ], "abstract": "The Aerodyne Aerosol Mass Spectrometer (AMS) has been designed to measure size-resolved mass distributions and total mass loadings of volatile and semivolatile chemical species in/on submicron particles. This paper describes the application of this instrument to ambient aerosol sampling. The AMS uses an aerodynamic lens to focus the particles into a narrow beam, a roughened cartridge heater to vaporize them under high vacuum, and a quadrupole mass spectrometer to analyze the vaporized molecules. Particle size is measured via particle time-of-flight. The AMS is operated in two modes: (1) a continuous mass spectrum mode without size information; and (2) a size distribution measurement mode for selected m/z settings of the quadrupole. Single particles can also be detected and sized if they have enough mass of a chemical component. The AMS was deployed at a ground sampling site near downtown Atlanta during August 1999, as part of the Environmental Protection Agency/Southern Oxidant Study Particulate Matter \"Supersite\" experiment, and at a suburban location in the Boston area during September 1999. The major observed components of the aerosol at both sites were sulfate and organics with a minor fraction of nitrate, consistent with prior studies and colocated instruments. Different aerosol chemical components often had different size distributions and time evolutions. More than half of the sulfate mass was contained in 2% of the ambient particles in one of the sampling periods. Trends in mass concentrations of sulfate and nitrate measured with the AMS in Atlanta compare well with those measured with ion chromatography-based instruments. A marked diurnal cycle was observed for aerosol nitrate in Atlanta. A simple model fit is used to illustrate the integration of data from several chemical components measured by the AMS together with data from other particle instruments into a coherent representation of the ambient aerosol.", "doi": "10.1029/2001JD001213", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2003-04-16", "series_number": "D7", "volume": "108", "issue": "D7", "pages": "Art. No. 8425" }, { "id": "authors:h91hj-68p89", "collection": "authors", "collection_id": "h91hj-68p89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-180045100.1", "type": "article", "title": "Modification of aerosol mass and size distribution due to aqueous-phase SO\u2082 oxidation in clouds: Comparisons of several models", "author": [ { "family_name": "Kreidenweis", "given_name": "Sonia M.", "orcid": "0000-0002-2561-2914", "clpid": "Kreidenweis-Sonia-M" }, { "family_name": "Walcek", "given_name": "Chris J.", "clpid": "Walcek-Chris-J" }, { "family_name": "Feingold", "given_name": "Graham", "orcid": "0000-0002-0774-2926", "clpid": "Feingold-Graham" }, { "family_name": "Gong", "given_name": "Wanmin", "orcid": "0000-0003-3635-0857", "clpid": "Gong-Wanmin" }, { "family_name": "Jacobson", "given_name": "Mark Z.", "orcid": "0000-0002-4315-4128", "clpid": "Jacobson-Mark-Z" }, { "family_name": "Kim", "given_name": "Cheol-Hee", "orcid": "0000-0002-2967-4987", "clpid": "Kim-Cheol-Hee" }, { "family_name": "Liu", "given_name": "Xiaohong", "orcid": "0000-0002-3994-5955", "clpid": "Liu-Xiaohong" }, { "family_name": "Penner", "given_name": "Joyce E.", "orcid": "0000-0001-5577-452X", "clpid": "Penner-Joyce-E" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Models of aerosol scavenging and aqueous-phase oxidation of SO\u2082 by H\u2082O\u2082 and O\u2083 in a cloud updraft are compared. Bulk models considering only a single droplet size are compared with size-resolved models that explicitly simulate multiple aerosol and drop sizes. All models simulate growth of cloud drops on a lognormal ammonium bisulfate aerosol distribution, and subsequent aqueous-phase chemistry during adiabatic ascent. In agreement with earlier published studies, it is found that relative to bulk models, the size-resolved cloud chemical models consistently calculate 2\u20133 times more oxidation via the SO\u2082 + O\u2083 pathway, due to calculated variability of cloud water pH among cloud drops. All models calculate high scavenging of the input dry aerosol mass, but the calculated number of cloud drops formed varies from 275\u2013358 drops cm\u207b\u00b3. Differences in the calculated number of cloud drops formed result from the treatment of gaseous species uptake, solution thermodynamics, applied water condensation mass accommodation coefficient, and bin size range definitions over which the input aerosol distribution is numerically approximated. The difference in calculated cloud drop number can under many conditions propagate to appreciable variations in cloud albedo. It is found that the modifications to the aerosol size and mass spectrum are sensitive to the number of cloud drops formed, and differences in the processed aerosol spectra were found to induce up to 13% differences in calculated light extinction properties of the modified particle distributions. These significant discrepancies among cloud aerosol chemistry interaction models, even when used to simulate relatively simple conditions, suggest that parameterizations of these processes used in larger-scale cloud, regional and longer-term climate models can contain high levels of uncertainty.", "doi": "10.1029/2002jd002697", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2003-04-16", "series_number": "D7", "volume": "108", "issue": "D7", "pages": "Art. No. 4213" }, { "id": "authors:c2e3j-p8d31", "collection": "authors", "collection_id": "c2e3j-p8d31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LUMjas03", "type": "article", "title": "Analysis of Humidity Halos around Trade Wind Cumulus Clouds", "author": [ { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "Wang", "given_name": "Jian", "clpid": "Wang-Jian" }, { "family_name": "Freedman", "given_name": "Andrew", "clpid": "Freedman-A" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "McClatchey", "given_name": "Robert A.", "clpid": "McClatchey-R-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Regions of enhanced humidity in the vicinity of cumulus clouds, so-called cloud halos, reflect features of cloud evolution, exert radiative effects, and may serve as a locus for new particle formation. Reported here are the results of an aircraft sampling campaign carried out near Oahu, Hawaii, from 31 July through 10 August 2001, aimed at characterizing the properties of trade wind cumulus cloud halos. An Aerodyne Research, Inc., fast spectroscopic water vapor sensor, flown for the first time in this campaign, allowed characterization of humidity properties at 10-m spatial resolution. Statistical properties of 60 traverses through cloud halos over the campaign were in general agreement with measurements reported by Perry and Hobbs. One particularly long-lived cloud is analyzed in detail, through both airborne measurement and numerical simulation, to track evolution of the cloud halos over the cloud's lifetime. Results of both observation and the simulation show that cloud halos tend to be broad at lower levels and narrow at upper levels, and broader on the downshear side than on the upshear side, broadening with time particularly in the downshear direction. The high correlation of clear-air turbulence distribution with the halo distribution temporally and spatially suggests that the halo forms, in part, due to turbulent mixing at the cloud boundary. Radiative calculations carried out on the simulated cloud and halo field indicate that the halo radiative effect is largest near cloud top during mature and dissipation stages. The halo-enhanced atmospheric shortwave absorption, averaged over this period, is about 1.3% of total solar absorption in the column.", "doi": "10.1175/1520-0469(2003)60<1041:AOHHAT>2.0.CO;2", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2003-04-15", "series_number": "8", "volume": "60", "issue": "8", "pages": "1041-1059" }, { "id": "authors:dhnv5-gk643", "collection": "authors", "collection_id": "dhnv5-gk643", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MADate03.738", "type": "article", "title": "Sampling methods used for the collection of particle-phase organic and elemental carbon during ACE-Asia", "author": [ { "family_name": "Mader", "given_name": "B. T.", "clpid": "Mader-Brian-T" }, { "family_name": "Schauer", "given_name": "J. J.", "orcid": "0000-0002-5405-1511", "clpid": "Schauer-James-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Yu", "given_name": "J. Z.", "clpid": "Yu-J-Z" }, { "family_name": "Yang", "given_name": "H.", "clpid": "Yang-H" }, { "family_name": "Lim", "given_name": "Ho-Jin", "orcid": "0000-0002-3211-8084", "clpid": "Lim-Ho-Jin" }, { "family_name": "Turpin", "given_name": "B. J.", "orcid": "0000-0003-4513-4187", "clpid": "Turpin-Barbara-J" }, { "family_name": "DeMinter", "given_name": "J. T.", "clpid": "DeMinter-J-T" }, { "family_name": "Heidemann", "given_name": "G.", "clpid": "Heidemann-G" }, { "family_name": "Bae", "given_name": "M. S.", "clpid": "Bae-M-S" }, { "family_name": "Quinn", "given_name": "P.", "clpid": "Quinn-P-K" }, { "family_name": "Bates", "given_name": "T.", "clpid": "Bates-T-S" }, { "family_name": "Eatough", "given_name": "D. J.", "clpid": "Eatough-Delbert-J" }, { "family_name": "Huebert", "given_name": "B. J.", "orcid": "0000-0001-7711-0468", "clpid": "Huebert-Barry-J" }, { "family_name": "Bertram", "given_name": "T.", "orcid": "0000-0002-3026-7588", "clpid": "Bertram-Timothy-H" }, { "family_name": "Howell", "given_name": "S.", "clpid": "Howell-S" } ], "abstract": "The semi-volatile nature of carbonaceous aerosols complicates their collection, and for this reason special air sampling configurations must be utilized. ACE-Asia provided a unique opportunity to compare different sampling techniques for collecting carbonaceous aerosols. In this paper detailed comparisons between filter-based carbonaceous aerosol sampling methods are made. The majority of organic carbon (OC) present on a backup quartz fiber filter (QFF) in an undenuded-filter sampler resulted from the adsorption of native gaseous OC rather than OC evaporated from collected particles. The level of OC on a backup QFF placed behind a QFF was lower than the level present on a backup QFF placed behind a Teflon membrane filter (TMF) indicating that gas/filter equilibrium may not be achieved in some QFF front and backup filter pairs. Gas adsorption artifacts can result in a 20\u2013100% overestimation of the ambient particle-phase OC concentration. The gas collection efficiency of XAD-coated and carbon-impregnated filter-lined denuders were not always 100%, but, nonetheless, such denuders minimize gas adsorption artifacts. The median fraction of particle-phase OC that is estimated to evaporate from particles collected by denuder-filter samplers ranged from 0 to 0.2; this value depends on the sampler configuration, chemical composition of the OC, and sampling conditions. After properly correcting for sampling artifacts, the measured OC concentration may differ by 10% between undenuded- and denuder-filter samplers. Uncorrected, such differences can be as large as a factor two, illustrating the importance of sampling configurations in which gas adsorption or evaporation artifacts are reduced or can be corrected.", "doi": "10.1016/S1352-2310(02)01061-0", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2003-04", "series_number": "11", "volume": "37", "issue": "11", "pages": "1435-1449" }, { "id": "authors:hekyh-xdr52", "collection": "authors", "collection_id": "hekyh-xdr52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-101353210", "type": "article", "title": "ACE-Asia Intercomparison of a Thermal-Optical Method for the Determination of Particle-Phase Organic and Elemental Carbon", "author": [ { "family_name": "Schauer", "given_name": "J. J.", "clpid": "Schauer-J-J" }, { "family_name": "Mader", "given_name": "B. T.", "clpid": "Mader-B-T" }, { "family_name": "DeMinter", "given_name": "J. T.", "clpid": "DeMinter-J-T" }, { "family_name": "Heidemann", "given_name": "G.", "clpid": "Heidemann-G" }, { "family_name": "Bae", "given_name": "M. S.", "clpid": "Bae-M-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Cary", "given_name": "R. A.", "clpid": "Cary-R-A" }, { "family_name": "Smith", "given_name": "D.", "clpid": "Smith-D" }, { "family_name": "Huebert", "given_name": "B. J.", "orcid": "0000-0001-7711-0468", "clpid": "Huebert-B-J" }, { "family_name": "Bertram", "given_name": "T.", "orcid": "0000-0002-3026-7588", "clpid": "Bertram-T-H" }, { "family_name": "Howell", "given_name": "S.", "clpid": "Howell-S" }, { "family_name": "Kline", "given_name": "J. T.", "clpid": "Kline-J-T" }, { "family_name": "Quinn", "given_name": "P.", "clpid": "Quinn-P-K" }, { "family_name": "Bates", "given_name": "T.", "clpid": "Bates-T-S" }, { "family_name": "Turpin", "given_name": "B.", "clpid": "Turpin-B" }, { "family_name": "Lim", "given_name": "H. J.", "clpid": "Lim-H-J" }, { "family_name": "Yu", "given_name": "J. Z.", "clpid": "Yu-J-Z" }, { "family_name": "Yang", "given_name": "H.", "clpid": "Yang-H" }, { "family_name": "Keywood", "given_name": "M. D.", "clpid": "Keywood-M-D" } ], "abstract": "A laboratory intercomparison of organic carbon (OC) and elemental carbon (EC) measurements of atmospheric particulate matter samples collected on quartz filters was conducted among eight participants of the ACE-Asia field experiment. The intercomparison took place in two stages:\u2009 the first round of the intercomparison was conducted when filter samples collected during the ACE-Asia experiment were being analyzed for OC and EC, and the second round was conducted after the ACE-Asia experiment and included selected samples from the ACE-Asia experiment. Each participant operated ECOC analyzers from the same manufacturer and utilized the same analysis protocol for their measurements. The precision of OC measurements of quartz fiber filters was a function of the filter's carbon loading but was found to be in the range of 4\u221213% for OC loadings of 1.0\u221225 \u03bcg of C cm^(-2). For measurements of EC, the precision was found to be in the range of 6\u221221% for EC loadings in the range of 0.7\u22128.4 \u03bcg of C cm^(-2). It was demonstrated for three ambient samples, four source samples, and three complex mixtures of organic compounds that the relative amount of total evolved carbon allocated as OC and EC (i.e., the ECOC split) is sensitive to the temperature program used for analysis, and the magnitude of the sensitivity is dependent on the types of aerosol particles collected. The fraction of elemental carbon measured in wood smoke and an extract of organic compounds from a wood smoke sample were sensitive to the temperature program used for the ECOC analysis. The ECOC split for the three ambient samples and a coal fly ash sample showed moderate sensitivity to temperature program, while a carbon black sample and a sample of secondary organic aerosol were measured to have the same split of OC and EC with all temperature programs that were examined.", "doi": "10.1021/es020622f", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2003-03-01", "series_number": "5", "volume": "37", "issue": "5", "pages": "993-1001" }, { "id": "authors:s4gj4-wzp18", "collection": "authors", "collection_id": "s4gj4-wzp18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-68028600.1", "type": "article", "title": "Disproportionate impact of particulate emissions on global cloud condensation nuclei concentrations", "author": [ { "family_name": "Adams", "given_name": "P. J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Estimates of indirect aerosol radiative forcing have focused on increased sulfate aerosol mass concentrations caused by anthropogenic emissions of gas-phase sulfur dioxide, implicitly neglecting the impact of direct particulate emissions. Emissions of primary particles and gas-phase precursors have different effects on cloud condensation nuclei (CCN) concentrations as they impact CCN concentrations via different microphysical pathways. We present a theoretical analysis and evidence from a three-dimensional global model of aerosol microphysics to show that particulate emissions are more efficient per unit mass than gas-phase emissions at increasing CCN concentrations. Both analyses show that the few percent of anthropogenic sulfur emitted as particulate sulfate results in an increase in CCN concentrations comparable to that resulting from much larger emissions of gas-phase sulfur dioxide. Therefore, models should explicitly distinguish between the microphysical impacts of particulate and gas-phase emissions to accurately estimate the magnitude of the indirect effect of aerosols on climate.", "doi": "10.1029/2002gl016303", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2003-03", "series_number": "5", "volume": "30", "issue": "5", "pages": "Art. No. 1239" }, { "id": "authors:39ext-fvm40", "collection": "authors", "collection_id": "39ext-fvm40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-746165600.2", "type": "article", "title": "A Coupled Hydrophobic-Hydrophilic Model for Predicting Secondary Organic Aerosol Formation", "author": [ { "family_name": "Griffin", "given_name": "Robert J.", "orcid": "0000-0001-7682-8769", "clpid": "Griffin-Robert-J" }, { "family_name": "Nguyen", "given_name": "Khoi", "clpid": "Nguyen-Khoi" }, { "family_name": "Dabdub", "given_name": "Donald", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The formation of secondary organic aerosol (SOA) results from the absorption of gas-phase organic oxidation products by airborne aerosol. Historically, modeling the formation of SOA has relied on relatively crude estimates of the capability of given parent hydrocarbons to form SOA. In more recent work, surrogate organic oxidation products have been separated into two groups, hydrophobic and hydrophilic, depending on whether the product is more likely to dissolve into an organic or an aqueous phase, respectively. The surrogates are then allowed to partition only via the dominant mechanism, governed by molecular properties of the surrogate molecules. The distinction between hydrophobic and hydrophilic is based on structural and physical characteristics of the compound. In general, secondary oxidation products, because of low vapor pressures and high polarities, express affinity for both the organic and aqueous aerosol phases. A fully coupled hydrophobic-hydrophilic organic gas-particle partitioning model is presented here. The model concurrently achieves mass conservation, equilibrium between the gas phase and the organic aerosol phase, equilibrium between the gas phase and the aqueous aerosol phase, and equilibrium between molecular and ionic forms of the partitioning species in the aqueous phase. Simulations have been performed using both a zero-dimensional model and the California Institute of Technology three-dimensional atmospheric chemical transport model. Simultaneous partitioning of species by both mechanisms typically leads to a shift in the distribution of products to the organic aerosol phase and an increase in the total amount of SOA predicted as compared to previous work in which partitioning is assumed to occur independently to organic and aqueous phases.", "doi": "10.1023/a:1022436813699", "issn": "0167-7764", "publisher": "Springer", "publication": "Journal of Atmospheric Chemistry", "publication_date": "2003-02", "series_number": "2", "volume": "44", "issue": "2", "pages": "171-190" }, { "id": "authors:5hyyw-1ra49", "collection": "authors", "collection_id": "5hyyw-1ra49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-772548500.1", "type": "article", "title": "Impact of biomass burning on cloud properties in the Amazon Basin", "author": [ { "family_name": "Roberts", "given_name": "G. C.", "orcid": "0000-0002-3636-8590", "clpid": "Roberts-Greg-C" }, { "family_name": "Nenes", "given_name": "A.", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Andreae", "given_name": "M. O.", "orcid": "0000-0003-1968-7925", "clpid": "Andreae-Meinrat-O" } ], "abstract": "We used a one-dimensional (1-D) cloud parcel model to assess the impact of biomass-burning aerosol on cloud properties in the Amazon Basin and to identify the physical and chemical properties of the aerosol that influence droplet growth. Cloud condensation nuclei (CCN) measurements were performed between 0.15% and 1.5% supersaturation at ground-based sites in the states of Amazonas and Rondonia, Brazil during several field campaigns in 1998 and 1999 as part of the Large-Scale Biosphere - Atmosphere (LBA) Experiment in Amazonia. CCN concentrations measured during the wet season were low and resembled concentrations more typical of marine conditions than most continental sites. During the dry season, smoke aerosol from biomass burning dramatically increased CCN concentrations. The modification of cloud properties, such as cloud droplet effective radius and maximum supersaturation, is most sensitive at low CCN concentrations. Hence, we could expect larger interannual variation of cloud properties during the wet season that the dry season. We found that differences between CCN spectra from forested and deforested regions during the wet season are modest and result in modifications of cloud properties that are small compared to those between wet and dry seasons. Our study suggests that the differences in surface albedo, rather than cloud albedo, between forested and deforested regions may dominate the impact of deforestation on the hydrological cycle and convective activity during the wet season. During the dry season, on the other hand, cloud droplet concentrations may increase by up to 7 times, which leads to a model-predicted decrease in cloud effective radius by a factor of 2. This could imply a maximum indirect radiative forcing due to aerosol as high as ca. -27 W m(-2) for a nonabsorbing cloud. Light-absorbing substances in smoke darken the Amazonian clouds and reduce the net radiative forcing, and a comparison of the Advanced Very High Resolution Radiometer (AVHRR) analysis and our modeling studies suggests that absorption of sunlight due to smoke aerosol may compensate for about half of the maximum aerosol effect. Sensitivity tests show that complete characterization of the aerosol is necessary when kinetic growth limitations become important. Subtle differences in the chemical and physical makeup are shown to be particularly influential in the activation and growth behavior of the aerosol. Knowledge of the CCN spectrum alone is not sufficient to fully capture the climatic influence of biomass burning.", "doi": "10.1029/2001jd000985", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2003-01-27", "series_number": "D2", "volume": "108", "issue": "D2", "pages": "Art. No. 4062" }, { "id": "authors:as9jd-mbv22", "collection": "authors", "collection_id": "as9jd-mbv22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-316763000.2", "type": "article", "title": "Interactions between tropospheric chemistry and aerosols in a unified general circulation model", "author": [ { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Adams", "given_name": "Peter J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Chung", "given_name": "Serena H.", "orcid": "0000-0001-5030-5871", "clpid": "Chung-Serena-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Mickley", "given_name": "Loretta J.", "orcid": "0000-0002-7859-3470", "clpid": "Mickley-Loretta-J" }, { "family_name": "Jacob", "given_name": "Daniel J.", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-Daniel-J" } ], "abstract": "A unified tropospheric chemistry-aerosol model has been developed within the Goddard Institute for Space Studies general circulation model (GCM). The model includes a detailed simulation of tropospheric ozone-NO_x-hydrocarbon chemistry as well as aerosols and aerosol precursors. Predicted aerosol species include sulfate, nitrate, ammonium, black carbon, primary organic carbon, and secondary organic carbon. The partitioning of ammonia and nitrate between gas and aerosol phases is determined by on-line thermodynamic equilibrium, and the formation of secondary organic aerosols is based on equilibrium partitioning and experimentally determined parameters. Two-way coupling between aerosols and chemistry provides consistent chemical fields for aerosol dynamics and aerosol mass for heterogeneous processes and calculations of gas-phase photolysis rates. Although the current version of the unified model does not include a prognostic treatment of mineral dust, we include its effects on photolysis and heterogeneous processes by using three-dimensional off-line fields. We also simulate sulfate and nitrate aerosols that are associated with mineral dust based on currently available chemical understanding. Considering both mineral dust uptake of HNO\u2083 and wet scavenging of HNO\u2083 on ice leads to closer agreement between predicted gas-phase HNO\u2083 concentrations and measurements than in previous global chemical transport model simulations, especially in the middle to upper troposphere. As a result of the coupling between chemistry and aerosols, global burdens of both gas-phase and aerosol species are predicted to respond nonlinearly to changing emissions of NO_x, NH\u2083, and sulfur.", "doi": "10.1029/2001jd001260", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2003-01-16", "series_number": "D1", "volume": "108", "issue": "D1", "pages": "Art. No. 4001" }, { "id": "authors:3zvf0-bhh54", "collection": "authors", "collection_id": "3zvf0-bhh54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141104-141215973", "type": "book_section", "title": "Vertically resolved aerosol optical properties over the ARM SGP site", "author": [ { "family_name": "Schmid", "given_name": "B.", "clpid": "Schmid-B" }, { "family_name": "Jonsson", "given_name": "H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Strawa", "given_name": "A.", "clpid": "Strawa-A" }, { "family_name": "Provencal", "given_name": "B.", "clpid": "Provencal-B" }, { "family_name": "Covert", "given_name": "D.", "clpid": "Covert-D" }, { "family_name": "Arnott", "given_name": "W. P.", "clpid": "Arnott-W-P" }, { "family_name": "Bucholtz", "given_name": "A.", "clpid": "Bucholtz-A" }, { "family_name": "Pilewskie", "given_name": "P.", "clpid": "Pilewskie-P" }, { "family_name": "Pommier", "given_name": "J.", "clpid": "Pommier-J" }, { "family_name": "Rissman", "given_name": "T.", "clpid": "Rissman-T-A" }, { "family_name": "VanReken", "given_name": "T.", "orcid": "0000-0002-2645-4911", "clpid": "VanReken-T-M" }, { "family_name": "Wang", "given_name": "J.", "clpid": "Wang-Jian" }, { "family_name": "Seinfeld", "given_name": "J.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Redemann", "given_name": "J.", "clpid": "Redemann-J" }, { "family_name": "Eilers", "given_name": "J.", "clpid": "Eilers-J" } ], "abstract": "We will present an overview of early airborne results obtained aboard the Center for Interdisciplinary Remotely-Piloted\nAircraft Studies (CIRP AS) Twin Otter aircraft during the Atmospheric Radiation Measurement (ARM) program aerosol\nintensive observation period in May 2003.", "publisher": "Institute for Tropospheric Research", "publication_date": "2003" }, { "id": "authors:4amyk-46y84", "collection": "authors", "collection_id": "4amyk-46y84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170408-163738887", "type": "article", "title": "A Differential Mobility Analyzer (DMA) System for Submicron Aerosol Measurements at Ambient Relative Humidity", "author": [ { "family_name": "Wang", "given_name": "Jian", "clpid": "Wang-Jian" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new differential mobility analyzer (DMA) system for measuring submicron aerosol size distribution at ambient relative humidity (RH), with special attention to implementation on aircraft, is described. The system includes an active RH controller, a cylindrical differential mobility analyzer (CDMA), and a condensation particle counter. A cascade controller consisting of 2 Proportional-Integral-Differential (PID) modules maintains the RH inside the CDMA at ambient RH. The flows are controlled with feedback PID controllers, which compensate for the variation of pressure as the aircraft changes altitude. This system was integrated into the CIRPAS Twin Otter aircraft and used to measure ambient size distributions during the ACE-Asia experiment, which was carried out from March to May 2001 in Japan.", "doi": "10.1080/02786820300891", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2003", "series_number": "1", "volume": "37", "issue": "1", "pages": "46-52" }, { "id": "authors:4awyk-p2f70", "collection": "authors", "collection_id": "4awyk-p2f70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-101054502", "type": "article", "title": "Clear-column radiative closure during ACE-Asia: Comparison of multiwavelength extinction derived from particle size and composition with results from Sun photometry", "author": [ { "family_name": "Wang", "given_name": "J.", "clpid": "Wang-Jian" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Collins", "given_name": "D. R.", "clpid": "Collins-D-R" }, { "family_name": "Russell", "given_name": "P. B.", "clpid": "Russell-P-B" }, { "family_name": "Schmid", "given_name": "B.", "clpid": "Schmid-B" }, { "family_name": "Redemann", "given_name": "J.", "clpid": "Redemann-J" }, { "family_name": "Livingston", "given_name": "J. M.", "clpid": "Livingston-J-M" }, { "family_name": "Gao", "given_name": "S.", "orcid": "0000-0001-7427-6681", "clpid": "Gao-Song" }, { "family_name": "Hegg", "given_name": "D. A.", "clpid": "Hegg-D-A" }, { "family_name": "Welton", "given_name": "E. J.", "clpid": "Welton-E-J" }, { "family_name": "Bates", "given_name": "D.", "clpid": "Bates-D" } ], "abstract": "From March to May 2001, aerosol size distributions and chemical compositions were measured using differential mobility analyzers (DMA), an aerodynamic particle sizer (APS), Micro-Orifice Uniform Deposit Impactors (MOUDI), and denuder samplers onboard the Twin Otter aircraft as part of the Aerosol Characterization Experiment (ACE)-Asia campaign. Of the 19 research flights, measurements on four flights that represented different aerosol characteristics are analyzed in detail. Clear-column radiative closure is studied by comparing aerosol extinctions predicted using in situ aerosol size distribution and chemical composition measurements to those derived from the 14-wavelength NASA Ames Airborne Tracking Sun photometer (AATS-14). In the boundary layer, pollution layers, and free troposphere with no significant mineral dust present, aerosol extinction closure was achieved within the estimated uncertainties over the full range of wavelengths of AATS-14. Aerosol extinctions predicted based on measured size distributions also reproduce the wavelength dependence derived from AATS-14 data. Considering all four flights, the best fit lines yield Predicted/Observed ratios in boundary and pollution layers of 0.97 \u00b1 0.24 and 1.07 \u00b1 0.08 at \u03bb = 525 nm and 0.96 \u00b1 0.21 and 1.08 \u00b1 0.08 at \u03bb = 1059 nm, respectively. In free troposphere dust layers, aerosol extinctions predicted from the measured size distributions were generally smaller than those derived from the AATS-14 data, with Predicted/Observed ratios of 0.65 \u00b1 0.06 and 0.66 \u00b1 0.05 at 525 and 1059 nm, respectively. A detailed analysis suggests that the discrepancy is likely a result of the lack of the knowledge of mineral dust shape as well as variations in aerosol extinction derived from AATS-14 data when viewing through horizontally inhomogeneous layers.", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2002-12-16", "series_number": "D23", "volume": "107", "issue": "D23", "pages": "Art. No. 4688" }, { "id": "authors:wnns6-1q938", "collection": "authors", "collection_id": "wnns6-1q938", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-908468500.1", "type": "article", "title": "Airborne measurements of atmospheric carbonaceous aerosols during ACE-Asia", "author": [ { "family_name": "Mader", "given_name": "Brian T.", "clpid": "Mader-Brian-T" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Airborne levels of carbonaceous aerosols were measured using the Twin Otter aircraft during the Aerosol Characterization Experiment (ACE)-Asia. Particles were collected using a newly developed honeycomb denuder sampler and organic carbon (OC), elemental carbon (EC), and carbonate (CC) carbon levels determined using a thermal\u2013optical carbon analyzer. During some flights, atmospheric layers could be identified as marine boundary, pollution dominated, or mineral dust dominated. \u00c5ngstrom exponent (\u00e5) values, calculated based on data from an onboard three-wavelength nephelometer, were used to discern the nature of some individual layers. Values of \u00e5 for individual layers ranged from 0.2 to 2, corresponding to dust- and pollution-dominated layers, respectively. OC and EC concentrations below 3 km ranged from 0.58 to 29 \u03bcg C m\u207b\u00b3 and from 0.20 to 1.8 \u03bcg C m\u207b\u00b3, respectively. In general, for a given type of atmospheric layer, higher levels of total carbon (TC) were observed during ACE-Asia than those observed during ACE-2, Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and Indian Ocean Experiment (INDOEX). Mixed layers of dust and pollution were found on some occasions. CC was detected in samples taken from layers in which \u00e5 = 1.6, indicating that significant amounts of dust can be present even though \u00e5 > 0.2. A linear regression of light absorption coefficient \u03c3_(ap) (Mm\u207b\u00b9) versus EC concentration had an r\u00b2 of only 0.50, indicating that parameters other than the mass of EC significantly affected the value of \u03c3_(ap). The mass absorption coefficient E_(abs) (m\u00b2 g\u207b\u00b9) varied by as much as a factor of 8 between sampling events, and the average value of 11 m\u00b2 g\u207b\u00b9 (\u00b15.0) agrees well with previous published values.", "doi": "10.1029/2002jd002221", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2002-12-16", "series_number": "D23", "volume": "107", "issue": "D23", "pages": "Art. No. 4704" }, { "id": "authors:t9xb4-g7291", "collection": "authors", "collection_id": "t9xb4-g7291", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-549393600.1", "type": "article", "title": "Black carbon radiative heating effects on cloud microphysics and implications for the aerosol indirect effect 1. Extended K\u00f6hler theory", "author": [ { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-William-C" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Black carbon (BC) aerosol absorbs sunlight that might have otherwise been reflected to space and changes the radiative heating of the atmosphere and surface. These effects may alter the dynamical and hydrological processes governing cloud formation. A new, microphysical, effect of BC on climate is identified here, in which solar heating within BC-containing cloud condensation nuclei (CCN) slows or prevents the activation of these CCN into cloud drops. Solar-heated BC-containing droplets are elevated in temperature by fractions of a degree above the ambient, thus raising the droplet vapor pressure and inhibiting activation of the most absorptive CCN. This paper develops the theory describing the alteration of the Kohler curve (i.e., the equilibrium vapor pressure over a droplet as a function of water uptake) as a function of CCN size and BC fraction. The effect is most significant in those CCN that contain volumes of BC larger than a 500 nm diameter sphere. For an aerosol population with 10% BC mass fraction per particle, solar heating can cause a 10% reduction in the CCN concentration at 0.01% critical supersaturation. On the other hand, the effect of heating by BC absorption on CCN activation above similar to0.1% critical supersaturation is negligible.", "doi": "10.1029/2002jd002094", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2002-11-16", "series_number": "D21", "volume": "107", "issue": "D21", "pages": "Art. No. 4604" }, { "id": "authors:h87g7-ewz91", "collection": "authors", "collection_id": "h87g7-ewz91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-699224600.1", "type": "article", "title": "Black carbon radiative heating effects on cloud microphysics and implications for the aerosol indirect effect 2. Cloud microphysics", "author": [ { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Conant", "given_name": "William C.", "clpid": "Conant-William-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This work examines the effect of black carbon (BC) radiative heating on cloud droplet formation. Changes in cloud droplet concentration and cloud albedo due to the presence of black carbon are computed for different cases of aerosol size distributions, meteorological conditions, BC mixing state, and aerosol composition. We examine the effect of three new mechanisms (that result from BC heating) that can affect cloud droplet number and lifetime. Two of these mechanisms act to increase cloud droplet number or lifetime: (1) the ability of BC to decrease the collection efficiency of giant cloud condensation nuclei (CCN) and (2) the delayed growth of low-S_c CCN that allow higher-S_c CCN to form droplets. These two mechanisms complement each other in terms of increasing cloud droplet number, since it is shown that the former is most efficient at strong updrafts and the latter is most efficient at low updraft velocities. A third mechanism identified, gas-phase heating (which is different from the so-called \"semi-direct effect\"), in our simulations acts to decrease LWC, and thus albedo; however, the droplet number concentration does not change significantly due to dynamic readjustments in cloud supersaturation. The simulations indicate that the mixing state of BC with the CCN population can have an important influence on the effect of BC heating on the droplet population. Although additional work is necessary to fully assess the effects of BC heating on cloud microphysics and climate, this work shows that these effects are more complex than currently thought.", "doi": "10.1029/2002jd002101", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2002-11-16", "series_number": "D21", "volume": "107", "issue": "D21", "pages": "Art. No. 4605" }, { "id": "authors:yv0js-j7q52", "collection": "authors", "collection_id": "yv0js-j7q52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-100415884", "type": "article", "title": "Global distribution and climate forcing of carbonaceous aerosols", "author": [ { "family_name": "Chung", "given_name": "Serena H.", "clpid": "Chung-Serena-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The global distribution of carbonaceous aerosols is simulated online in the Goddard Institute for Space Studies General Circulation Model II-prime (GISS GCM II-prime). Prognostic tracers include black carbon (BC), primary organic aerosol (POA), five groups of biogenic volatile organic compounds (BVOCs), and 14 semivolatile products of BVOC oxidation by O_3, OH, and NO_3, which condense to form secondary organic aerosols (SOA) based on an equilibrium partitioning model and experimental observations. Estimated global burdens of BC, organic carbon (OC), and SOA are 0.22, 1.2, and 0.19 Tg with lifetimes of 6.4, 5.3, and 6.2 days, respectively. The predicted global production of SOA is 11.2 Tg yr^(\u22121), with 91% due to O_3 and OH oxidation. Globally averaged, top of the atmosphere (TOA) radiative forcing by anthropogenic BC is predicted as +0.51 to +0.8 W m^(\u22122), the former being for BC in an external mixture and the latter for BC in an internal mixture of sulfate, OC, and BC. Globally averaged, anthropogenic BC, OC, and sulfate are predicted to exert a TOA radiative forcing of \u22120.39 to \u22120.78 W m^(\u22122), depending on the exact assumptions of aerosol mixing and water uptake by OC. Forcing estimates are compared with those published previously.", "doi": "10.1029/2001JD001397", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2002-10-16", "series_number": "D19", "volume": "107", "issue": "D19", "pages": "Art. No. 4407" }, { "id": "authors:sgp1p-19s25", "collection": "authors", "collection_id": "sgp1p-19s25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-623203500.1", "type": "article", "title": "Predicting global aerosol size distributions in general circulation models", "author": [ { "family_name": "Adams", "given_name": "Peter J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "To better represent the indirect effect of aerosols on climate, a size-resolved simulation of aerosol microphysics, size distributions, number and mass concentrations has been incorporated into the GISS general circulation model (GCM). The TwO-Moment Aerosol Sectional (TOMAS) microphysics model used here conserves aerosol number as well as mass. It has high size resolution, 30 bins between 0.01 and 10 mum diameter. As a first application, a size-resolved simulation of sulfate has been performed. The model reproduces important features of the atmospheric aerosol such as number concentrations that increase with altitude and land-sea contrasts in aerosol number concentrations and size distributions. Comparisons with observations show that simulated size distributions are realistic and condensation nuclei (CN) concentrations agree with observations within about 25%. Predicted cloud condensation nuclei (CCN) concentrations are also in reasonable agreement with observations, although there are locations for which agreement would be improved by including other aerosol components such as sea salt and carbonaceous aerosols. Sensitivity scenarios show that uncertainties in nucleation and primary emissions from fossil fuels can have significant effects on predictions of CN and CCN concentrations.", "doi": "10.1029/2001jd001010", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2002-10-16", "series_number": "D19", "volume": "107", "issue": "D19", "pages": "Art. No. 4370" }, { "id": "authors:fm2mp-79n11", "collection": "authors", "collection_id": "fm2mp-79n11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-144227783", "type": "article", "title": "Secondary organic aerosol 2. Thermodynamic model for gas/particle partitioning of molecular constituents", "author": [ { "family_name": "Pun", "given_name": "Betty K.", "clpid": "Pun-Betty-K" }, { "family_name": "Griffin", "given_name": "Robert J.", "clpid": "Griffin-R-J" }, { "family_name": "Seigneur", "given_name": "Christian", "clpid": "Seigneur-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A model that predicts secondary organic aerosol (SOA) formation based on the thermodynamic equilibrium partitioning of secondary organic oxidation products has been developed for implementation into atmospheric models. Hydrophobic secondary products are assumed to partition to an absorbing organic aerosol consisting of primary organic aerosol (POA) and other secondary hydrophobic organics according to an equilibrium partitioning coefficient calculated iteratively for each secondary compound present. The hydrophobic module is evaluated by studying the partitioning of octadecanoic acid to surrogate POA species. As expected, the amount of octadecanoic acid predicted to be present in the aerosol phase increases as the total amount of absorbing material increases or as the total amount of acid present increases. Hydrophilic secondary compounds partition to an aqueous phase via Henry's law; the fraction of each compound's mass that partitions is determined by its Henry's law constant and its acid dissociation constant(s). The available liquid water content (LWC) of the aerosol is determined iteratively between an inorganic aerosol module and the hydrophilic module, which is evaluated by studying the partitioning of glyoxalic and malic acids. While glyoxalic acid tends to remain in the gas phase, malic acid partitions strongly to the aqueous phase, with ions being the dominant form in the aqueous phase. As expected, an increase in relative humidity increases the amount of water associated with the organics (\u0394LWC), and a lower aerosol pH favors molecular solutes over ionized forms. Increasing pH results in higher effective Henry's law constants for the acids, yielding higher organic aerosol concentrations. Results also indicate that increasing \u0394LWC induces additional partitioning of inorganics to the aqueous phase.", "doi": "10.1029/2001JD000542", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2002-09-16", "series_number": "D17", "volume": "107", "issue": "D17", "pages": "Art. No. 4333" }, { "id": "authors:3cxx2-wp366", "collection": "authors", "collection_id": "3cxx2-wp366", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-144829433", "type": "article", "title": "Secondary organic aerosol 3. Urban/regional scale model of size- and composition-resolved aerosols", "author": [ { "family_name": "Griffin", "given_name": "Robert J.", "clpid": "Griffin-R-J" }, { "family_name": "Dabdub", "given_name": "Donald", "clpid": "Dabdub-D" }, { "family_name": "Kleeman", "given_name": "Michael J.", "clpid": "Kleeman-M-J" }, { "family_name": "Fraser", "given_name": "Matthew P.", "clpid": "Fraser-M-P" }, { "family_name": "Cass", "given_name": "Glen R.", "clpid": "Cass-G-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The California Institute of Technology (CIT) three-dimensional urban/regional atmospheric model is used to perform comprehensive gas- and aerosol-phase simulations of the 8 September 1993 smog episode in the South Coast Air Basin of California (SoCAB) using the atmospheric chemical mechanism of part 1 [Griffin et al., 2002] and the thermodynamic module of part 2 [Pun et al., 2002]. This paper focuses primarily on simulations of secondary organic aerosol (SOA) and determination of the species and processes that lead to this SOA. Meteorological data and a gas and particulate emissions inventory for this episode were supplied directly by the South Coast Air Quality Management District. A summer 1993 atmospheric sampling campaign provides data against which the performance of the model is evaluated. Predictions indicate that SOA formation in the SoCAB is dominated by partitioning of hydrophobic secondary products of the oxidation of anthropogenic organics. The biogenic contribution to total SOA increases in the more rural eastern portions of the region, as does the fraction of hydrophilic SOA, the latter reflecting the increasing degree of oxidation of SOA species with atmospheric residence time.", "doi": "10.1029/2001JD000544", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2002-09-16", "series_number": "D17", "volume": "107", "issue": "D17", "pages": "Art. No. 4334" }, { "id": "authors:f4n3r-wqg11", "collection": "authors", "collection_id": "f4n3r-wqg11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-143350672", "type": "article", "title": "Secondary organic aerosol 1. Atmospheric chemical mechanism for production of molecular constituents", "author": [ { "family_name": "Griffin", "given_name": "Robert J.", "clpid": "Griffin-R-J" }, { "family_name": "Dabdub", "given_name": "Donald", "clpid": "Dabdub-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This series of three papers addresses the representation of secondary organic aerosol (SOA) in atmospheric models. SOA forms when gas-phase organic species undergo oxidation, leading to products of sufficiently low vapor pressure that can partition between the gas and aerosol phases. The present paper, part 1, is devoted to the development of a gas-phase atmospheric chemical mechanism designed to represent ozone chemistry as well as formation of individual organic oxidation products that are capable of forming SOA. The ozone chemistry in the mechanism draws upon the recent work of Stockwell et al. [1997] and Jenkin et al. [1997] and SAPRC-97 and SAPRC-99 (available from W.P.L. Carter at http://helium.ucr.edu/~carter/). The mechanism is evaluated in the three-dimensional California Institute of Technology (CIT) model [Meng et al., 1998] by simulating gas-phase concentrations in the South Coast Air Basin (SoCAB) of California over the period 27\u201329 August 1987. Total predicted concentrations of gas-phase SOA compounds are compared with levels of SOA that have been inferred on the basis of ambient organic aerosol measurements during this period. These predicted concentrations indicate that the total gas-phase potential of SOA-forming compounds can account for observed aerosol concentrations. Part 2 develops a thermodynamic gas\u2013aerosol partitioning module, and part 3 presents a full three-dimensional simulation of gas and aerosol levels in the SoCAB during a 1993 episode.", "doi": "10.1029/2001JD000541", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "2002-09-16", "series_number": "D17", "volume": "107", "issue": "D17", "pages": "Art. No. 4332" }, { "id": "authors:fcrzm-hjn85", "collection": "authors", "collection_id": "fcrzm-hjn85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-660660400.1", "type": "article", "title": "Effect of NO\u2082 on Particle Formation in SO\u2082/H\u2082O/Air Mixtures by Ion-Induced and Homogeneous Nucleation", "author": [ { "family_name": "Kim", "given_name": "Chan Soo", "clpid": "Kim-Chan-Soo" }, { "family_name": "Adachi", "given_name": "Motoaki", "clpid": "Adachi-Motoaki" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Effects of NO\u2082 on particle formation in SO\u2082/H\u2082O/Air mixtures by f-ray irradiation as a source of hydroxyl radicals are investigated to evaluate the contribution of homogeneous and ion-induced nucleation in the nanometer-sized aerosol particle generation. The total particle number concentration, the charged-particle fraction, and the electrical mobility distribution of particles and hydrated and solvated ions generated in NO\u2082/SO\u2082/H\u2082O/Air mixtures were measured at NO\u2082 levels of 0-1.98 ppm, SO\u2082 levels of 0-3.87 ppm, and H\u2082O levels of 6480-9889 ppm. Total particle number concentration first tends to increase with increasing NO\u2082 concentration up to a certain NO\u2082 level and then decreases for NO\u2082 concentrations beyond this point. The charged-particle fraction, indicative of particle formation by ion-induced nucleation, tends to decrease with increasing NO\u2082 concentration, reaching a minimum value. The peak intensity of the electrical mobility distribution for particles significantly exceeded that in the absence of NO\u2082 at a relatively low concentration of NO\u2082. The intensity decreased with increasing NO\u2082 concentration and fell below that in the absence of NO\u2082. The results indicate that 2 opposing mechanisms that enhance and suppress the particle formation work simultaneously in NO\u2082/SO\u2082/H\u2082O/Air mixtures, and the dominant mechanism depends on the NO\u2082 concentration.", "doi": "10.1080/02786820290092122", "issn": "0278-6826", "publisher": "Taylor & Francis", "publication": "Aerosol Science and Technology", "publication_date": "2002-09", "series_number": "9", "volume": "36", "issue": "9", "pages": "941-952" }, { "id": "authors:gqw2x-t4y17", "collection": "authors", "collection_id": "gqw2x-t4y17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-145634392", "type": "article", "title": "Can chemical effects on cloud droplet number rival the first indirect effect?", "author": [ { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Charlson", "given_name": "Robert J.", "clpid": "Charlson-Robert-J" }, { "family_name": "Facchini", "given_name": "M. Cristina", "orcid": "0000-0003-4833-9305", "clpid": "Facchini-M-Cristina" }, { "family_name": "Kulmala", "given_name": "Markku", "orcid": "0000-0003-3464-7825", "clpid": "Kulmala-Markku" }, { "family_name": "Laaksonen", "given_name": "Ari", "orcid": "0000-0002-1657-2383", "clpid": "Laaksonen-Ari" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An increase in cloud droplet number concentration resulting from an increase in ambient aerosol (and subsequent albedo increase) is typically identified as the first indirect (or \"Twomey\") climatic effect of aerosols [Twomey, 1974]. A key question is whether chemical effects (dissolution of soluble gases and slightly soluble substances, surface tension depression by organic substances and accommodation coefficient changes) could potentially rival changes in droplet number from changes in aerosol number concentration. We assess the sensitivity of cloud droplet number concentration to such chemical factors, using a cloud parcel model. We find that numerous conditions exist, for which chemical influences on cloud droplet activation can indeed rival the Twomey effect.", "doi": "10.1029/2002GL015295", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2002-09", "series_number": "17", "volume": "29", "issue": "17", "pages": "Art. No. 1848" }, { "id": "authors:2mf45-8h491", "collection": "authors", "collection_id": "2mf45-8h491", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LUMjam02", "type": "article", "title": "Cloud Halos: Numerical Simulation of Dynamical Structure and Radiative Impact", "author": [ { "family_name": "Lu", "given_name": "Miao-Ling", "clpid": "Lu-Miao-Ling" }, { "family_name": "McClatchey", "given_name": "Robert A.", "clpid": "McClatchey-R-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Significant enhancements in humidity around cumulus clouds, that is, the \"cloud halos\" observed in many aircraft penetrations, are simulated using a three-dimensional dynamic model. Five case studies show that humidity halos occur mainly near lateral cloud boundaries and also occur at cloud top and base when the cloud dissipates. The humidity halo broadens as the cloud ages and is also broader in the presence of wind shear than in its absence, especially on the downshear side of the cloud. The broadband calculation over the solar spectrum (0.2\u20134.0 \u03bcm) shows that the shortwave (SW) heating rate in the halo is about 11%\u201318% larger than the ambient environmental heating rate. The strongest halo-induced surface SW radiative forcing for all cases studied is about \u22120.2 W m^\u22122, which is approximately a 0.02% change from the forcing without a halo.", "doi": "10.1175/1520-0450(2002)041<0832:CHNSOD>2.0.CO;2", "issn": "0894-8763", "publisher": "American Meteorological Society", "publication": "Journal of Applied Meteorology", "publication_date": "2002-08", "series_number": "8", "volume": "41", "issue": "8", "pages": "832-848" }, { "id": "authors:cjb4a-3ey42", "collection": "authors", "collection_id": "cjb4a-3ey42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150325-103852382", "type": "article", "title": "Marine aerosol formation from biogenic iodine emissions", "author": [ { "family_name": "O'Dowd", "given_name": "Colin D.", "clpid": "O'Dowd-C-D" }, { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Bahreini", "given_name": "Roya", "clpid": "Bahreini-R" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "H\u00e4meri", "given_name": "Kaarle", "clpid": "H\u00e4meri-K" }, { "family_name": "Pirjola", "given_name": "Liisa", "clpid": "Pirjola-L" }, { "family_name": "Kulmala", "given_name": "Markku", "clpid": "Kulmala-M" }, { "family_name": "Jennings", "given_name": "S. Gerard", "clpid": "Jennings-S-G" }, { "family_name": "Hoffmann", "given_name": "Thorsten", "clpid": "Hoffmann-T" } ], "abstract": "The formation of marine aerosols and cloud condensation nuclei\u2014from which marine clouds originate\u2014depends ultimately on the availability of new, nanometre-scale particles in the marine boundary layer. Because marine aerosols and clouds scatter incoming radiation and contribute a cooling effect to the Earth's radiation budget, new particle production is important in climate regulation. It has been suggested that sulphuric acid\u2014derived from the oxidation of dimethyl sulphide\u2014is responsible for the production of marine aerosols and cloud condensation nuclei. It was accordingly proposed that algae producing dimethyl sulphide play a role in climate regulation, but this has been difficult to prove and, consequently, the processes controlling marine particle formation remains largely undetermined. Here, using smog chamber experiments under coastal atmospheric conditions, we demonstrate that new particles can form from condensable iodine-containing vapours, which are the photolysis products of biogenic iodocarbons emitted from marine algae. Moreover, we illustrate, using aerosol formation models, that concentrations of condensable iodine-containing vapours over the open ocean are sufficient to influence marine particle formation. We suggest therefore that marine iodocarbon emissions have a potentially significant effect on global radiative forcing.", "doi": "10.1038/nature00775", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2002-06-06", "series_number": "6889", "volume": "417", "issue": "6889", "pages": "632-636" }, { "id": "authors:7khhd-h1752", "collection": "authors", "collection_id": "7khhd-h1752", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-101239873", "type": "article", "title": "Diffusional losses in particle sampling systems containing bends and elbows", "author": [ { "family_name": "Wang", "given_name": "Jian", "clpid": "Wang-Jian" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Classical theoretical treatments for diffusional deposition of particles in tube flow describe the losses within straight tubes. The plumbing in many systems of practical interest, notably aerosol instruments, consists of short segments of tubing connected by elbows, bends, and other disturbances. To understand the particle losses in such systems, particle losses in tube flows containing bends and elbows has been studied for Reynolds numbers ranging from 80 to 950. Monodisperse aerosol of 5\u201315 nm diameter particles passed through individual bends or elbows, and through a number of bends or elbows in series. The results show that the effect of bends and elbows on particle diffusion loss is significant. For a flow configuration with four elbows in series, the penetration efficiency drops as much as 44% when compared to a straight tube with the same length. For Reynolds number smaller than 250, the enhancement of diffusion losses due to bends and elbows is sensitive to both the relative orientations of the bends and elbows and the lengths of straight tubing between them. Because of this sensitivity, direct calibration or simulation is required to assess nanoparticle penetration efficiencies for any flow system containing bends or elbows at low Reynolds number. When the Reynolds number exceeds 250, the enhancement is insensitive to the actual flow configurations. Experimental results are presented, which may be useful for design of aerosol flow systems at Reynolds number larger than 250.", "doi": "10.1016/S0021-8502(02)00042-3", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "2002-06", "series_number": "6", "volume": "33", "issue": "6", "pages": "843-857" }, { "id": "authors:fwa8g-d7188", "collection": "authors", "collection_id": "fwa8g-d7188", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ASHae02.310", "type": "article", "title": "Estimating the vapor pressures of multi-functional oxygen-containing organic compounds using group contribution methods", "author": [ { "family_name": "Asher", "given_name": "William E.", "orcid": "0000-0002-1521-0233", "clpid": "Asher-William-E" }, { "family_name": "Pankow", "given_name": "James F.", "orcid": "0000-0002-8602-9159", "clpid": "Pankow-James-F" }, { "family_name": "Erdakos", "given_name": "Garnet B.", "clpid": "Erdakos-Garnet-B" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A UNIFAC-based method for estimating the vapor pressure (pL\u2070) values of oxygen-containing compounds of intermediate-to-low volatility has been developed as an aid in modeling the formation and behavior of organic aerosols. This UNIFAC-pL\u2070 method was constructed using a set of 76 compounds with experimentally determined pL\u2070 values. The compounds chosen are of intermediate-to-low volatility and contain multiple oxygen-containing functionalities. For test and development purposes, the 76 compounds were divided into a basis set of 43 compounds used to generate the coefficients required in the UNIFAC-pL\u2070 method and a second set of 33 compounds that was used to test the coefficients generated using the basis set. Both the basis and test sets contained compounds that possessed similar structures and functionalities. For the 33 compounds in the test set, on average UNIFAC-pL\u2070 predicted the pL\u2070 values to within a factor of 2 over the temperature range 290\u2013320 K. Furthermore, the UNIFAC-pL\u2070 method did not show any correlation in prediction error with pL\u2070 so that it was equally likely to underpredict as overpredict pL\u2070 regardless of volatility. For comparison, three other vapor pressure estimation methods were applied to the test set of compounds. On average, these other methods all predicted the test set pL\u2070 values to within a factor of 3 over the temperature range 290\u2013320 K. In contrast to the UNIFAC-pL\u2070 method, the prediction errors from the methods were found to be correlated with pL\u2070 so that the other methods overpredicted pL\u2070 as volatility decreased.", "doi": "10.1016/S1352-2310(01)00564-7", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2002-03", "series_number": "9", "volume": "36", "issue": "9", "pages": "1483-1498" }, { "id": "authors:z68ra-xj271", "collection": "authors", "collection_id": "z68ra-xj271", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-154256500.2", "type": "article", "title": "A numerical model of the cloud-topped marine boundary layer with explicit treatment of supersaturation\u2013number concentration correlations", "author": [ { "family_name": "Svensson", "given_name": "Gunilla", "orcid": "0000-0001-9074-7623", "clpid": "Svensson-Gunilla" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A numerical model of the cloud-topped marine boundary layer is presented. The model, based on ensemble-averaged conservation equations and containing detailed aerosol microphysics, differs from previous models in one major respect: the mean supersaturation-cloud drop number concentration correlation term, generally neglected in previous numerical mean cloud models, is parametrized using a traditional boundary-layer flux-gradient relationship. The present work highlights the importance of this correlation term and shows how a simple representation of this correlation can lead to dramatically different, and improved, simulations of cloud behaviour. Simulations are presented for a well-studied marine boundary-layer stratocumulus case. Inclusion of the supersaturation-cloud drop number concentration correlation leads to more physically realistic cloud drop spectra and cloud drop concentrations throughout the height of the cloud. Although the parametrization presented must be viewed as a first approximation, the crudeness of the approach should be seen as a justification and starting point for future work.", "doi": "10.1256/003590002321042081", "issn": "1477-870X", "publisher": "Wiley", "publication": "Quarterly Journal of the Royal Meteorological Society", "publication_date": "2002-01", "series_number": "580", "volume": "128", "issue": "580", "pages": "535-558" }, { "id": "authors:mz2sy-q9x14", "collection": "authors", "collection_id": "mz2sy-q9x14", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-100220265", "type": "article", "title": "Improved Inversion of Scanning DMA Data", "author": [ { "family_name": "Collins", "given_name": "Don R.", "clpid": "Collins-D-R" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recovery of aerosol size distributions from either stepping or scanning mode differential mobility analyzer (DMA) measurements requires an accurate description of the characteristics of the DMA itself, as well as certain properties of the aerosol. Inversion of scanning DMA data is further complicated by the nonunique relationship between the time a particle exits the DMA and the time it is ultimately detected. Without an accurate description of this relationship, and an appropriate method of accounting for it, inverted distributions will be broadened and skewed relative to the true distribution. A simplified approach to inversion of scanning DMA data is described here in which adjustment of the raw data to account for the delay time distribution associated with the instrument is accomplished prior to final inversion. This provides the flexibility to utilize more accurate descriptions of the delay time distribution and the DMA transfer function than is feasible if the inversion is to be accomplished in one step as described by Russell et al. (1995). The accuracy of this procedure has been demonstrated through analysis of actual as well as test-case data.", "doi": "10.1080/027868202753339032", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "2002-01", "series_number": "1", "volume": "36", "issue": "1", "pages": "1-9" }, { "id": "authors:205x9-1ca75", "collection": "authors", "collection_id": "205x9-1ca75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141104-142254124", "type": "book_section", "title": "Overview of ACE-Asia spring 2001 investigations on aerosol-radiation interactions", "author": [ { "family_name": "Russell", "given_name": "P. B.", "clpid": "Russell-P-B" }, { "family_name": "Flatau", "given_name": "P. J.", "clpid": "Flatau-P-J" }, { "family_name": "Valero", "given_name": "F. P. J.", "clpid": "Valero-F-P-J" }, { "family_name": "Nakajima", "given_name": "T.", "clpid": "Nakajima-T" }, { "family_name": "Holben", "given_name": "B.", "clpid": "Holben-B-N" }, { "family_name": "Pilewskie", "given_name": "P.", "clpid": "Pilewskie-P" }, { "family_name": "Bergin", "given_name": "M.", "clpid": "Bergin-M" }, { "family_name": "Schmid", "given_name": "B.", "clpid": "Schmid-B" }, { "family_name": "Bergstrom", "given_name": "R. W.", "clpid": "Bergstrom-R-W" }, { "family_name": "Vogelmann", "given_name": "A.", "clpid": "Vogelmann-A-M" }, { "family_name": "Bush", "given_name": "B.", "clpid": "Bush-B" }, { "family_name": "Redemann", "given_name": "J.", "clpid": "Redemann-J" }, { "family_name": "Pope", "given_name": "S.", "clpid": "Pope-S" }, { "family_name": "Livingston", "given_name": "J.", "clpid": "Livingston-J" }, { "family_name": "Leitner", "given_name": "S.", "clpid": "Leitner-S" }, { "family_name": "Hsu", "given_name": "N. C.", "clpid": "Hsu-N-C" }, { "family_name": "Wang", "given_name": "J.", "clpid": "Wang-J" }, { "family_name": "Seinfeld", "given_name": "J.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Hegg", "given_name": "D.", "clpid": "Hegg-D-A" }, { "family_name": "Quinn", "given_name": "P.", "clpid": "Quinn-P-K" }, { "family_name": "Covert", "given_name": "D.", "clpid": "Covert-D" } ], "abstract": "In spring 2001 the Asian Pacific Regional Aerosol\nCharacterization Experiment (ACE-Asia) made\nextensive measurements from land, ocean, air and\nspace platforms. A primary objective was to\nquantify the interactions between aerosols and\nradiation. This talk presents illustrative results from\neach type of platform, with initial assessments of\nregional aerosol radiative forcing obtained by\ncombining satellite and suborbital results.", "publisher": "American Meteorological Society", "publication_date": "2002" }, { "id": "authors:fwa02-30e80", "collection": "authors", "collection_id": "fwa02-30e80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150818-100012364", "type": "article", "title": "Sampling Atmospheric Carbonaceous Aerosols Using a Particle Trap Impactor/Denuder Sampler", "author": [ { "family_name": "Mader", "given_name": "Brian T.", "clpid": "Mader-B-T" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A particle trap impactor/denuder system has been developed and tested for the sampling of ambient carbonaceous aerosols. Use of a particle trap impactor allows for a reduction of particle bounce and re-entrainment at high particle loadings, and operation at high volumetric flow rates is achieved without the use of oiled impaction substrates, thus facilitating the chemical and physical analysis of the organic compounds comprising the collected gas (G) and particle (P) phases. Honeycomb denuders have a greater density of channels for a given denuder cross-sectional area than parallel plate or annular denuders; for a given sampling flow rate, honeycomb denuders can be fabricated in more compact shapes and will have a greater amount of surface area for the collection of gases. Field testing of the sampler was conducted primarily at night to minimize the evaporation of organic carbon (OC) from collected particles, which can result from the heating of collected particles as ambient temperatures rise during the day. In side-by-side testing with an open-face filter pack sampler, the denuder system was found to minimize positive gas adsorption artifacts caused by the adsorption of gaseous OC to quartz filter fiber (QFF) surfaces. In the denuder sampler, negligible amounts of OC were observed on a QFF placed downstream of a particle-loaded QFF, suggesting that OC detected on the backup QFF in the filter pack sampler resulted primarily from the adsorption of ambient G-phase OC rather than OC evaporated from particles collected on the front filter. Equations are presented for the evaluation of the magnitude of positive and negative sampling artifacts. Analysis of these equations indicates that the mass of OC evaporated from filter-bound particles present downstream of a denuder depends on (i) the volume of OC-free gas passed through the filter, (ii) the P-phase concentration and the P/G partition coefficients (K_p) of the compounds comprising the P-phase OC, (iii) the temperature (T) (values of K_p are inversely proportional to T), and (iv) the mass fraction of carbon in the compounds comprising P-phase OC. For these reasons, the magnitude of evaporative losses of OC in denuder samplers may vary among different sampling events. In addition, a method utilizing gas chromatography/mass spectrometry has been developed for determination of inertial impactor collection efficiency and denuder particle transmission efficiency. Using this method, only a single extraction of the sampler components is necessary, thereby reducing the number of extractions and analyses over conventional approaches by at least a factor of 2.", "doi": "10.1021/es011059o", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2001-12-15", "series_number": "24", "volume": "35", "issue": "24", "pages": "4857-4867" }, { "id": "authors:5kg4h-qkt98", "collection": "authors", "collection_id": "5kg4h-qkt98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150806-171813438", "type": "article", "title": "The effect of water on gas\u2013particle partitioning of secondary organic aerosol. Part I: \u03b1-pinene/ozone system", "author": [ { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-D-R-III" }, { "family_name": "Clegg", "given_name": "Simon L.", "clpid": "Clegg-S-L" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The effect of relative humidity (RH) on aerosol formation by the semi-volatile oxidation products of the \u03b1-pinene/O_3 system has been comprehensively studied. Experiments were performed in the presence of ammonium sulfate (aqueous, dry), ammonium bisulfate seed (aqueous, dry), and aqueous calcium chloride seed aerosols to ascertain their effect on the partitioning of the oxidation products. The yield of organic aerosol varies little with RH, and is not affected by the presence of dry inorganic salt aerosols. Aqueous salt aerosols reduce the yield of organic aerosol compared to that under seed-free or dry seed conditions. The degree of reduction is electrolyte dependent, with aqueous ammonium sulfate leading to the largest reduction and aqueous calcium chloride the smallest. Hygroscopic growth of the organic aerosol from <2% to 85% RH was also monitored, and could be satisfactorily represented as the sum of the individual contributions of the organic and inorganic fractions. The implications of the growth factor measurements for concentration/activity relationships of the condensed phase organic material (assuming a liquid solution) was explored. The formation of the organic aerosol was investigated using a simple two component model, and also one including the 12 product compounds identified in a previous study. The experimental results for <2% and 50% RH (without salt seed aerosols) could be satisfactorily predicted. However, the aqueous salt seed aerosols are predicted to increase the overall yield due to the dissolution of the organic compounds into the water associated with the seed aerosol\u2014the opposite effect to that observed. The implications of two distinct phases existing the aerosol phase were investigated.", "doi": "10.1016/S1352-2310(01)00404-6", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2001-12", "series_number": "35", "volume": "35", "issue": "35", "pages": "6049-6072" }, { "id": "authors:h59r9-prh76", "collection": "authors", "collection_id": "h59r9-prh76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-332296900.2", "type": "article", "title": "The effect of water on gas\u2013particle partitioning of secondary organic aerosol: II. m-xylene and 1,3,5-trimethylbenzene photooxidation systems", "author": [ { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-David-R-III" }, { "family_name": "Mader", "given_name": "Brian T.", "clpid": "Mader-Brian-T" }, { "family_name": "Kalberer", "given_name": "Markus", "orcid": "0000-0001-8885-6556", "clpid": "Kalberer-Markus" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An investigation of the effect of relative humidity on aerosol formation from in-xylene and 1,3,5-trimethylbenzene photooxidation is reported, Experiments were performed in the presence and absence of ammonium sulfate seed particles (both aqueous and dry) to ascertain the effect of partitioning of oxidation products into a strong electrolytic solution or onto dry crystalline seed particles, In marked contrast to the alpha -pinene/ozone system, the final measured secondary organic aerosol yield was unaffected by the presence of gas-phase or liquid-phase water at relative humidities (RH) up to 50%. The hygroscopic nature of the aerosol generated upon photooxidation of m-xylene and 1,3,5-trimethylbenzene was examined; the hygroscopicity of the aerosol at 85% RH for both parent organics increased with the extent of the reaction, indicating that the first-generation oxidation products undergo further oxidation. Limited identification of the gas- and aerosol-phase products of in-xylene and 1,3,5-trimethylbenzene photooxidation is reported, It is evident that a more complete molecular identification of aromatic photooxidation aerosol awaits analytical techniques not yet brought to bear on this problem.", "doi": "10.1016/s1352-2310(01)00405-8", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2001-12", "series_number": "35", "volume": "35", "issue": "35", "pages": "6073-6085" }, { "id": "authors:n8kxs-s2482", "collection": "authors", "collection_id": "n8kxs-s2482", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170419-131851671", "type": "article", "title": "On the Hygroscopic Behavior of Atmospheric Organic Aerosols", "author": [ { "family_name": "Hemming", "given_name": "Brooke L.", "clpid": "Hemming-B-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The vapor\u2212liquid equilibrium of organic species and water determines the partitioning of volatile organic species between the gas and aerosol phases in the atmosphere. Essential properties that govern this partitioning are the compounds' vapor pressures and the liquid-phase activity coefficients of the organic species. Key issues include (1) the amount of water absorbed by organic particles, both single-component and multicomponent, as a function of relative humidity and (2) how organic and water partitioning is altered as the relative humidity changes, for a fixed total (gas plus particle) quantity of each organic component. We present here calculations relating to each of these issues for organic molecules that are characteristic of those that have been identified in ambient aerosols. Uncertainties exist in knowledge of vapor pressures of atmospheric organics and in activity coefficients, which are calculated by the UNIFAC method. These uncertainties, the level of which is difficult to estimate because of a lack of appropriate thermodynamic data, can lead to significant uncertainty in predicted gas\u2212aerosol partitioning. Current theories for estimating both vapor pressures and activity coefficients are likely to be improved eventually, but the methods discussed here will probably remain the procedures of choice for the immediate future.", "doi": "10.1021/ie000790l", "issn": "0888-5885", "publisher": "American Chemical Society", "publication": "Industrial & Engineering Chemistry Research", "publication_date": "2001-10-03", "series_number": "20", "volume": "40", "issue": "20", "pages": "4162-4171" }, { "id": "authors:px7j0-qz475", "collection": "authors", "collection_id": "px7j0-qz475", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-287269600.2", "type": "article", "title": "Hygroscopic Properties of Pasadena, California Aerosol", "author": [ { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-David-R-III" }, { "family_name": "Whitlock", "given_name": "Nathan E.", "clpid": "Whitlock-Nathan-E" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The hygroscopic behavior of Pasadena, CA aerosol was continuously measured from August 15 to September 15, 1999 using a tandem differential mobility analyzer. Two dry particle sizes were sampled, 50 nm and 150 nm in diameter; humidification of the dry aerosol was carried out at 89% relative humidity. Complex growth patterns were observed for both size modes, with aerosol distributions splitting from a single mode at times to more than 6 modes. Diurnal profiles for the observed multiple peaks were noted, with the greatest number of measurable growth modes being found during the late night and predawn hours for 50 mn particles. For 150 nm particles, more modes were present during the afternoon hours, with the humidified aerosol becoming bimodal during the late night/early morning hours. Growth factors, defined as the ratio of humidified particle diameter (at 89%) to dry diameter, were determined for modes with significant number concentrations. Average growth factors over the sampling period for the 2 particle sizes ranged from 1.0 to 1.6. Hygroscopic growth increased in the latter half of the sampling period when forest fires were present. In short, treating this complex urban aerosol as a combination of \"less\" and \"more\" hygroscopic fractions is an oversimplification.", "doi": "10.1080/02786820120653", "issn": "0278-6826", "publisher": "Taylor & Francis", "publication": "Aerosol Science and Technology", "publication_date": "2001-08", "series_number": "2", "volume": "35", "issue": "2", "pages": "637-647" }, { "id": "authors:cfqn1-85n88", "collection": "authors", "collection_id": "cfqn1-85n88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141118-093852759", "type": "article", "title": "Atmospheric science - Reshaping the Theory of Cloud Formation", "author": [ { "family_name": "Charlson", "given_name": "Robert J.", "clpid": "Charlson-Robert-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Kulmala", "given_name": "Markku", "orcid": "0000-0003-3464-7825", "clpid": "Kulmala-Markku" }, { "family_name": "Laaksonen", "given_name": "Ari", "orcid": "0000-0002-1657-2383", "clpid": "Laaksonen-Ari" }, { "family_name": "Facchini", "given_name": "M. Cristina", "orcid": "0000-0003-4833-9305", "clpid": "Facchini-M-Cristina" } ], "abstract": "Man-made aerosols are believed to have a strong influence on cloud optical properties and albedo, with a radiative forcing opposite in sign to that exerted by greenhouse gases. The uncertainties associated with this indirect aerosol forcing are, however, very large. In their Perspective, Charlson et al. discuss recent insights into cloud formation. The results indicate that current estimates of both the magnitude and the uncertainty of indirect aerosol forcing may be too low.", "doi": "10.1126/science.1060096", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2001-06-15", "series_number": "5524", "volume": "292", "issue": "5524", "pages": "2025-2026" }, { "id": "authors:yma2c-23p72", "collection": "authors", "collection_id": "yma2c-23p72", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170315-135131216", "type": "article", "title": "State-of-the-Art Chamber Facility for Studying Atmospheric Aerosol Chemistry", "author": [ { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-D-R-III" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A state-of-the-art chamber facility is described for investigation of atmospheric aerosol chemistry. Dual 28 m^3 FEP Teflon film chambers are used to simulate atmospheric conditions in which aerosol formation may occur. This facility provides the flexibility to investigate dark, single oxidant reactions as well as full photochemical simulations. This paper discusses the environmental control implemented as well as the gas-phase and aerosol-phase instrumentation used to monitor atmospheric aerosol formation and growth. Physical processes occurring in the chamber and procedures for estimating secondary organic aerosol formation during reaction are described. Aerosol formation and evolution protocols at varying relative humidity conditions are presented.", "doi": "10.1021/es0019169", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2001-06-15", "series_number": "12", "volume": "35", "issue": "12", "pages": "2594-2601" }, { "id": "authors:vcx5v-nm968", "collection": "authors", "collection_id": "vcx5v-nm968", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-514738200.1", "type": "article", "title": "Thermodynamic modelling of aqueous aerosols containing electrolytes and dissolved organic compounds", "author": [ { "family_name": "Clegg", "given_name": "Simon L.", "clpid": "Clegg-Simon-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Brimblecombe", "given_name": "Peter", "orcid": "0000-0002-2233-8761", "clpid": "Brimblecombe-Peter" } ], "abstract": "A method for calculating the thermodynamic properties of soluble mixed inorganic/organic aerosols is proposed. It is based upon the use of existing models of inorganic (electrolyte) multicomponent solutions and water/organic mixtures in combination, together with simple thermodynamically consistent terms that express the effects of interactions between ions and organic molecules on the activities of all mixture components. The method is used to calculate the deliquescence properties of the following systems at 298.15 K: sodium chloride/sucrose/water, letovicite/2-butenedioic acid/water, and sodium chloride/butanoic acid/water. The effects of approximations in the ion\u2013organic interaction terms are explored, and it is shown that the method can be used to model liquid/liquid phase separation in sodium chloride/butanoic acid/water mixtures. In this example, it is found that the phase separation results in total water uptake that differs little from that of pure sodium chloride.", "doi": "10.1016/s0021-8502(00)00105-1", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "2001-06", "series_number": "6", "volume": "32", "issue": "6", "pages": "713-738" }, { "id": "authors:z4vet-6zf83", "collection": "authors", "collection_id": "z4vet-6zf83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-153603324", "type": "article", "title": "Iodine oxide homogeneous nucleation: An explanation for coastal new particle production", "author": [ { "family_name": "Hoffmann", "given_name": "Thorsten", "clpid": "Hoffmann-T" }, { "family_name": "O'Dowd", "given_name": "Colin D.", "clpid": "O'Dowd-C-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A series of laboratory experiments on the chemical composition of aerosol particles formed after photodissociation of CH_2I_2, a major volatile alkyl halide released from macroalgae, have been performed in a laboratory scale reaction chamber using on-line atmospheric pressure chemical ionization mass spectrometry (APCI/MS). Based on the mass spectrometric results and the molecular properties of iodine oxides, we suggest that the self-nucleation of iodine oxides provides an efficient source of natural condensable material in coastal environments and discuss this concept focusing on OIO as one potential key species for new particle formation. The presented hypothesis not only fits the measured enrichment of iodine species in submicrometer particles, but also can explain the frequently observed nucleation bursts in the coastal boundary layer.", "doi": "10.1029/2000GL012399", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2001-05-15", "series_number": "10", "volume": "28", "issue": "10", "pages": "1949-1952" }, { "id": "authors:baskq-2c403", "collection": "authors", "collection_id": "baskq-2c403", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170316-101312849", "type": "article", "title": "Modeling the Formation of Secondary Organic Aerosol (SOA). 2. The Predicted Effects of Relative Humidity on Aerosol Formation in the \u03b1-Pinene-, \u03b2-Pinene-, Sabinene-, \u0394^(3-)Carene-, and Cyclohexene-Ozone Systems", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Erdakos", "given_name": "Garnet B.", "clpid": "Erdakos-G-B" }, { "family_name": "Asher", "given_name": "William E.", "clpid": "Asher-W-E" }, { "family_name": "Pankow", "given_name": "James F.", "clpid": "Pankow-J-F" } ], "abstract": "Atmospheric oxidation of volatile organic compounds can lead to the formation of secondary organic aerosol (SOA) through the gas/particle (G/P) partitioning of the oxidation products. Since water is ubiquitous in the atmosphere, the extent of the partitioning for any individual organic product depends not only on the amounts and properties of the partitioning organic compounds, but also on the amount of water present. Predicting the effects of water on the atmospheric G/P distributions of organic compounds is, therefore, central to understanding SOA formation. The goals of the current work are to gain understanding of how increases in RH affect (1) overall SOA yields, (2) water uptake by SOA, (3) the behaviors of individual oxidation products, and (4) the fundamental physical properties of the SOA phase that govern the G/P distribution of each of the oxidation products. Part 1 of this series considered SOA formation from five parent hydrocarbons in the absence of water. This paper predicts how adding RH to those systems uniformly increases both the amount of condensed organic mass and the amount of liquid water in the SOA phase. The presence of inorganic components is not considered. The effect of increasing RH is predicted to be stronger for SOA produced from cyclohexene as compared to SOA produced from four monoterpenes. This is likely a result of the greater general degree of oxidation (and hydrophilicity) of the cyclohexene products. Good agreement was obtained between predicted SOA yields and laboratory SOA yield data actually obtained in the presence of water. As RH increases, the compounds that play the largest roles in changing both the organic and water masses in the SOA phase are those with vapor pressures that are intermediate between those of essentially nonvolatile and highly volatile species. RH-driven changes in the compound-dependent G/P partitioning coefficient K_p result from changes in both the average molecular weight MW_(om) of the absorbing organic/water phase, and the compound-dependent activity coefficient \u03b6 values. Adding water to the SOA phase by increasing the RH drives down MW_(om) and thereby uniformly favors SOA condensation. The effect of RH on \u03b6 values is compound specific and depends on the hydrophilicity of the specific compound of interest; the more hydrophilic a compound, the more increasing RH will favor its condensation into the SOA phase. The results also indicate that it may be a useful first approximation to assume that \u03b6 = 1 for many compounds making up SOA mixtures.", "doi": "10.1021/es001765+", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2001-05-01", "series_number": "9", "volume": "35", "issue": "9", "pages": "1806-1817" }, { "id": "authors:b70hy-8xd67", "collection": "authors", "collection_id": "b70hy-8xd67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-9191700.1", "type": "article", "title": "Kinetic limitations on cloud droplet formation and impact on cloud albedo", "author": [ { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Ghan", "given_name": "Steven", "orcid": "0000-0001-8355-8699", "clpid": "Ghan-Steven" }, { "family_name": "Abdul-Razzak", "given_name": "Hayder", "clpid": "Abdul-Razzak-Hayder" }, { "family_name": "Chuang", "given_name": "Patrick Y.", "orcid": "0000-0003-2290-8346", "clpid": "Chuang-Patrick-Y" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Under certain conditions mass transfer limitations on the growth of cloud condensation nuclei (CCN) may have a significant impact on the number of droplets that can form in a cloud. The assumption that particles remain in equilibrium until activated may therefore not always be appropriate for aerosol populations existing in the atmosphere. This work identifies three mechanisms that lead to kinetic limitations, the effect of which on activated cloud droplet number and cloud albedo is assessed using a one-dimensional cloud parcel model with detailed microphysics for a variety of aerosol size distributions and updraft velocities. In assessing the effect of kinetic limitations, we have assumed as cloud droplets not only those that are strictly activated (as dictated by classical K\u00f6hler theory), but also unactivated drops large enough to have an impact on cloud optical properties. Aerosol number concentration is found to be the key parameter that controls the significance of kinetic effects. Simulations indicate that the equilibrium assumption leads to an overprediction of droplet number by less than 10% for marine aerosol; this overprediction can exceed 40% for urban type aerosol. Overall, the effect of kinetic limitations on cloud albedo can be considered important when equilibrium activation theory consistently overpredicts droplet number by more than 10%. The maximum change in cloud albedo as a result of kinetic limitations is less than 0.005 for cases such as marine aerosol; however albedo differences can exceed 0.1 under more polluted conditions. Kinetic limitations are thus not expected to be climatically significant on a global scale, but can regionally have a large impact on cloud albedo.", "doi": "10.3402/tellusb.v53i2.16569", "issn": "1600-0889", "publisher": "Stockholm University Press", "publication": "Tellus B: Chemical and Physical Meteorology", "publication_date": "2001-04", "series_number": "2", "volume": "53", "issue": "2", "pages": "133-149" }, { "id": "authors:d48cp-4ze07", "collection": "authors", "collection_id": "d48cp-4ze07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170316-090119069", "type": "article", "title": "Modeling the Formation of Secondary Organic Aerosol. 1. Application of Theoretical Principles to Measurements Obtained in the \u03b1-Pinene/, \u03b2-Pinene/, Sabinene/, \u0394^3-Carene/, and Cyclohexene/Ozone Systems", "author": [ { "family_name": "Pankow", "given_name": "James F.", "clpid": "Pankow-J-F" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Asher", "given_name": "William E.", "clpid": "Asher-W-E" }, { "family_name": "Erdakos", "given_name": "Garnet B.", "clpid": "Erdakos-G-B" } ], "abstract": "Secondary organic aerosol (SOA) forms in the atmosphere when volatile parent compounds are oxidized to form low-volatility products that condense to yield organic particulate matter (PM). Under conditions of intense photochemical smog, from 40 to 80% of the particulate organic carbon can be secondary in origin. Because describing multicomponent condensation requires a compound-by-compound identification and quantification of the condensable compounds, the complexity of ambient SOA has made it difficult to test the ability of existing gas/particle (G/P) partitioning theory to predict SOA formation in urban air. This paper examines that ability using G/P data from past laboratory chamber experiments carried out with five parent hydrocarbons (HCs) (four monoterpenes at 308 K and cyclohexene at 298 K) in which significant fractions (61\u2212100%) of the total mass of SOA formed from those HCs were identified and quantified by compound. The model calculations were based on a matrix representation of the multicomponent, SOA G/P distribution process. The governing equations were solved by an iterative method. Input data for the model included (i) \u0394HC (\u03bcg m^(-3)), the amount of reacted parent hydrocarbon; (ii) the \u03b1 values that give the total concentration T (gas + particle phase, ng m^(-3)) values for each product i according to Ti = 10^3 \u03b1i\u0394HC; (iii) estimates of the pure compound liquid vapor pressure P^o_L values (at the reaction temperature) for the products; and (iv) UNIFAC parameters for estimating activity coefficients in the SOA phase for the products as a function of SOA composition. The model predicts the total amount M_o (\u03bcg m^(-3)) of organic aerosol that will form from the reaction of \u0394HC, the total aerosol yield Y (= M_o/\u0394HC), and the compound-by-compound yield values Y_i. An impediment in applying the model is the lack of literature data on P^o_L values for the compounds of interest or even on P^o_L values for other, similarly low-volatility compounds. This was overcome in part by using the G/P data from the \u03b1-pinene and cyclohexene experiments to determine P^o_L values for use (along with a set of 14 other independent polar compounds) in calculating UNIFAC vapor pressure parameters that were, in turn, used to estimate all of the needed P^o_L values. The significant degree of resultant circularity in the calculations for \u03b1-pinene and cyclohexene helped lead to the good agreement that was found between the Y_i values predicted by the model, and those measured experimentally for those two compounds. However, the model was also able to predict the aerosol yield values from \u03b2-pinene, sabinene, and \u0394^3-carene, for which there was significatly less circularity in the calculations, thereby providing evidence supporting the idea that given the correct input information, SOA formation can in fact be accurately modeled as a multicomponent condensation process.", "doi": "10.1021/es001321d", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2001-03-15", "series_number": "6", "volume": "35", "issue": "6", "pages": "1164-1172" }, { "id": "authors:kt52p-vzv50", "collection": "authors", "collection_id": "kt52p-vzv50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:65", "type": "article", "title": "A theoretical analysis of cloud condensation nucleus (CCN) instruments", "author": [ { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Chuang", "given_name": "Patrick Y.", "orcid": "0000-0003-2290-8346", "clpid": "Chuang-Patrick-Y" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The behavior and performance of four cloud condensation nucleus instruments are theoretically analyzed. They include the static diffusion cloud chamber (SDCC), the Fukuta continuous flow spectrometer (FCNS), the Hudson continuous flow spectrometer (HCNS), and the California Institute of Technology continuous flow spectrometer (CCNS). A numerical model of each instrument is constructed on the basis of a general fluid dynamics code coupled to an aerosol growth/activation model. Instrument performance is explored by simulating instrument response when sampling a monodisperse ammonium sulfate aerosol. The uncertainty in the wall temperature boundary condition is estimated for all the instruments and is found to be appreciable only for the CCNS. The CCNS and HCNS models reasonably reproduced experimental data, while reported limits were also verified by the FCNS model. Regarding the performance of each instrument, simulations show that the SDCC produces droplets that are monodisperse to within 10% of the particle diameter (for particles of a constant critical supersaturation). The FCNS can potentially activate particles over a wide range of critical supersaturations, but the prevailing design exhibits low sensitivity to particles with critical supersaturations below 0.1% as a result of the short time available for droplet growth under low supersaturations. The resolution capability of both HCNS and CCNS with respect to critical supersaturation is shown to be particularly sensitive to operational parameters. This is a consequence of the strongly nonlinear nature of droplet growth; droplet size cannot always be used to distinguish particles with different critical supersaturation because of the growing droplets' trend toward monodispersity. Of the two instruments, the HCNS generally displays higher resolution capability. This is attributed to the smoother and monotonic supersaturation profiles established in the HCNS. While different design parameters or operating conditions may lead to modest shifts in the performance from that predicted here for any of the four instruments, the essential features described in this paper are inherent to their designs.", "doi": "10.1029/2000JD900614", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2001-02-27", "series_number": "D4", "volume": "106", "issue": "D4", "pages": "3449-3474" }, { "id": "authors:57hkj-k6z47", "collection": "authors", "collection_id": "57hkj-k6z47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-948910900.1", "type": "article", "title": "General circulation model assessment of direct radiative forcing by the sulfate-nitrate-ammonium-water inorganic aerosol system", "author": [ { "family_name": "Adams", "given_name": "Peter J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Koch", "given_name": "Dorothy", "clpid": "Koch-Dorothy-M" }, { "family_name": "Mickley", "given_name": "Loretta", "orcid": "0000-0002-7859-3470", "clpid": "Mickley-Loretta-J" }, { "family_name": "Jacob", "given_name": "Daniel", "orcid": "0000-0002-6373-3100", "clpid": "Jacob-Daniel-J" } ], "abstract": "An on-line simulation of aerosol sulfate, nitrate, ammonium, and water in the Goddard Institute for Space Studies general circulation model (GCM II-prime) has been used to estimate direct aerosol radiative forcing for the years 1800, 2000, and 2100. This is the first direct forcing estimate based on the equilibrium water content of a changing SO\u2084\u00b2\u207b-NO\u2083\u207b-NH\u2084\u207a mixture and the first estimate of nitrate forcing based on a global model of nitrate aerosol. Present-day global and annual average anthropogenic direct forcing is estimated to be \u22120.95 and \u22120.19 W/m\u00b2 for sulfate and nitrate, respectively. Simulations with a future emissions scenario indicate that nitrate forcing could increase to \u22121.28 W/m\u00b2 by 2100, while sulfate forcing declines to \u22120.85 W/m\u00b2. This result shows that future estimates of aerosol forcing based solely on predicted sulfate concentrations may be misleading and that the potential for significant concentrations of ammonium nitrate needs to be considered in estimates of future climate change. Calculated direct aerosol forcing is highly sensitive to the model treatment of water uptake. By calculating the equilibrium water content of a SO\u2084\u00b2\u207b-NH\u2084\u207a aerosol mixture and the optical properties of the wet aerosol, we estimate a forcing that is almost 35% greater than that derived from correcting a low relative humidity scattering coefficient with an empirical f(RH) factor. The discrepancy stems from the failure of the empirical parameterization to adequately account for water uptake above about 90% relative humidity. These results suggest that water uptake above 90% RH may make a substantial contribution to average direct forcing, although subgrid-scale variability makes it difficult to represent humid areas in a GCM.", "doi": "10.1029/2000jd900512", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2001-01-16", "series_number": "D1", "volume": "106", "issue": "D1", "pages": "1097-1111" }, { "id": "authors:fmd52-gaz11", "collection": "authors", "collection_id": "fmd52-gaz11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160610-153822008", "type": "article", "title": "Aerosol Formation in the Cyclohexene-Ozone System", "author": [ { "family_name": "Kalberer", "given_name": "M.", "clpid": "Kalberer-M" }, { "family_name": "Yu", "given_name": "J.", "clpid": "Yu-J" }, { "family_name": "Cocker", "given_name": "D. R.", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-D-R-III" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric oxidation of certain volatile organic compounds can lead to products of sufficiently low vapor pressure that the products partition into the aerosol phase, producing what is termed secondary organic aerosol. Cyclohexene has long been known to produce aerosol upon photooxidation. In this study, we obtain molecular product information especially for those species that partition between the gas and particle phases. Compounds identified in the aerosol phase include hydroxyglutaric acid, adipic acid, and hydroxyadipic acid. In accord with previous studies, pentanal is found to be the predominant identified gas-phase products, at a molar yield of 17%. Possible explanations for the presence of relatively high vapor pressure compounds in the aerosol phase are advanced.", "doi": "10.1021/es001180f", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2000-12-01", "series_number": "23", "volume": "34", "issue": "23", "pages": "4894-4901" }, { "id": "authors:m3a87-azk79", "collection": "authors", "collection_id": "m3a87-azk79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200427-152233637", "type": "article", "title": "The Use of Ambient Measurements To Identify which Precursor Species Limit Aerosol Nitrate Formation", "author": [ { "family_name": "Blanchard", "given_name": "Charles L.", "clpid": "Blanchard-C-L" }, { "family_name": "Roth", "given_name": "Philip M.", "clpid": "Roth-P-M" }, { "family_name": "Tanenbaum", "given_name": "Shelley J.", "clpid": "Tanenbaum-S-J" }, { "family_name": "Ziman", "given_name": "Steve D.", "clpid": "Ziman-S-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A thermodynamic equilibrium model was used to investigate the response of aerosol NO\u2083 to changes in concentrations of HNO\u2083, NH\u2083, and H\u2082SO\u2084. Over a range of temperatures and relative humidities (RHs), two parameters provided sufficient information for indicating the qualitative response of aerosol NO\u2083. The first was the excess of aerosol NH\u2084\u207a plus gas-phase NH\u2083 over the sum of HNO\u2083, particulate NO\u2083, and particulate SO\u2084\u00b2\u207b concentrations. The second was the ratio of particulate to total NO\u2083 concentrations. Computation of these quantities from ambient measurements provides a means to rapidly analyze large numbers of samples and identify cases in which inorganic aerosol NO\u2083 formation is limited by the availability of NH\u2083. Example calculations are presented using data from three field studies. The predictions of the indicator variables and the equilibrium model are compared.", "doi": "10.1080/10473289.2000.10464239", "issn": "1096-2247", "publisher": "Taylor & Francis", "publication": "Journal of the Air & Waste Management Association", "publication_date": "2000-12", "series_number": "12", "volume": "50", "issue": "12", "pages": "2073-2084" }, { "id": "authors:f1vzj-k2k71", "collection": "authors", "collection_id": "f1vzj-k2k71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150806-170014061", "type": "article", "title": "The scanning flow DMA", "author": [ { "family_name": "Collins", "given_name": "Don R.", "clpid": "Collins-Donald-R" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new method of DMA operation has been implemented in which the flow rates are continuously changed in conjunction with the applied voltage. By optimizing the flow and voltage ramps, improvements can be made in the DMA's measurable size range, counting statistics, resolution, or a partial combination of each of these. Detailed modeling of this technique suggests that errors on the order of 2 to 5% result from incorrect assumptions concerning the flow profile within the DMA. The experimental system enabled accurate control of flows that were varied by an order of magnitude in as little as 30 s. Excellent agreement was obtained between mobility distributions recovered from a voltage ramp, a flow ramp, and a combined voltage and flow ramp. Slight deviations were apparent in the recovered data as the flow scan time was reduced from 60 to 30 s.", "doi": "10.1016/S0021-8502(99)00576-5", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "2000-10", "series_number": "10", "volume": "31", "issue": "10", "pages": "1129-1144" }, { "id": "authors:48dmn-2h759", "collection": "authors", "collection_id": "48dmn-2h759", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141103-133304101", "type": "article", "title": "A comparison of scavenging and deposition processes in global models: results from the WCRP Cambridge Workshop of 1995", "author": [ { "family_name": "Rasch", "given_name": "P. J.", "orcid": "0000-0002-5125-2174", "clpid": "Rasch-P-J" }, { "family_name": "Seinfeld", "given_name": "J.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We report on results from a World Climate Research Program workshop on representations of scavenging and deposition processes in global transport models of the atmosphere. 15 models were evaluated by comparing simulations of radon, lead, sulfur dioxide, and sulfate against each other, and against observations of these constituents. This paper provides a survey on the simulation differences between models. It identifies circumstances where models are consistent with observations or with each other, and where they differ from observations or with each other. The comparison shows that most models are able to simulate seasonal species concentrations near the surface over continental sites to within a factor of 2 over many regions of the globe. Models tend to agree more closely over source (continental) regions than for remote (polar and oceanic) regions. Model simulations differ most strongly in the upper troposphere for species undergoing wet scavenging processes. There are not a sufficient number of observations to characterize the climatology (long-term average) of species undergoing wet scavenging in the upper troposphere. This highlights the need for either a different strategy for model evaluation (e.g., comparisons on an event by event basis) or many more observations of a few carefully chosen constituents.", "doi": "10.1034/j.1600-0889.2000.00980.x", "issn": "0280-6509", "publisher": "Munskgaard", "publication": "Tellus B", "publication_date": "2000-09", "series_number": "4", "volume": "52", "issue": "4", "pages": "1025-1056" }, { "id": "authors:48ztw-mcx69", "collection": "authors", "collection_id": "48ztw-mcx69", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111128-081450625", "type": "article", "title": "The Impact of Ship-Produced Aerosols on the Microstructure and Albedo of Warm Marine Stratocumulus Clouds: A Test of MAST Hypotheses 1i and 1ii", "author": [ { "family_name": "Durkee", "given_name": "P. A.", "clpid": "Durkee-P-A" }, { "family_name": "Noone", "given_name": "K. J.", "clpid": "Noone-K-J" }, { "family_name": "Ferek", "given_name": "R. J.", "clpid": "Ferek-R-J" }, { "family_name": "Johnson", "given_name": "D. W.", "clpid": "Johnson-D-W" }, { "family_name": "Taylor", "given_name": "J. P.", "clpid": "Taylor-J-P" }, { "family_name": "Garrett", "given_name": "T. J.", "clpid": "Garrett-T-J" }, { "family_name": "Hobbs", "given_name": "P. V.", "clpid": "Hobbs-P-V" }, { "family_name": "Hudson", "given_name": "J. G.", "clpid": "Hudson-J-G" }, { "family_name": "Bretherson", "given_name": "C. S.", "clpid": "Bretherson-C-S" }, { "family_name": "Innis", "given_name": "G.", "clpid": "Innis-G" }, { "family_name": "Frick", "given_name": "G. M.", "clpid": "Frick-G-M" }, { "family_name": "Hoppel", "given_name": "W. A.", "clpid": "Hoppel-W-A" }, { "family_name": "O'Dowd", "given_name": "C. D.", "clpid": "O'Dowd-C-D" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Gasparovic", "given_name": "R.", "clpid": "Gasparovic-R" }, { "family_name": "Nielsen", "given_name": "K. E.", "clpid": "Nielsen-K-E" }, { "family_name": "Tessmer", "given_name": "S. A.", "clpid": "Tessmer-S-A" }, { "family_name": "\u00d6str\u00f6m", "given_name": "E.", "clpid": "\u00d6str\u00f6m-E" }, { "family_name": "Osborne", "given_name": "S. R.", "clpid": "Osborne-S-R" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Rand", "given_name": "H.", "clpid": "Rand-H" } ], "abstract": "Anomalously high reflectivity tracks in stratus and stratocumulus sheets associated with ships (known as ship tracks) are commonly seen in visible and near-infrared satellite imagery. Until now there have been only a limited number of in situ measurements made in ship tracks. The Monterey Area Ship Track (MAST) experiment, which was conducted off the coast of California in June 1994, provided a substantial dataset on ship emissions and their effects on boundary layer clouds. Several platforms, including the University of Washington C-131A aircraft, the Meteorological Research Flight C-130 aircraft, the National Aeronautics and Space Administration ER-2 aircraft, the Naval Research Laboratory airship, the Research Vessel Glorita, and dedicated U.S. Navy ships, participated in MAST in order to study processes governing the formation and maintenance of ship tracks.\nThis paper tests the hypotheses that the cloud microphysical changes that produce ship tracks are due to (a) particulate emission from the ship's stack and/or (b) sea-salt particles from the ship's wake. It was found that ships powered by diesel propulsion units that emitted high concentrations of aerosols in the accumulation mode produced ship tracks. Ships that produced few particles (such as nuclear ships), or ships that produced high concentrations of particles but at sizes too small to be activated as cloud drops in typical stratocumulus (such as gas turbine and some steam-powered ships), did not produce ship tracks. Statistics and case studies, combined with model simulations, show that provided a cloud layer is susceptible to an aerosol perturbation, and the atmospheric stability enables aerosol to be mixed throughout the boundary layer, the direct emissions of cloud condensation nuclei from the stack of a diesel-powered ship is the most likely, if not the only, cause of the formation of ship tracks. There was no evidence that salt particles from ship wakes cause ship tracks.", "doi": "10.1175/1520-0469(2000)057<2554:TIOSPA>2.0.CO;2", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2000-08-15", "series_number": "16", "volume": "57", "issue": "16", "pages": "2554-2569" }, { "id": "authors:dec1y-zqp18", "collection": "authors", "collection_id": "dec1y-zqp18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NOOjas00a", "type": "article", "title": "A Case Study of Ship Track Formation in a Polluted Marine Boundary Layer", "author": [ { "family_name": "Noone", "given_name": "Kevin J.", "clpid": "Noone-Kevin-J" }, { "family_name": "Johnson", "given_name": "Doug W.", "clpid": "Johnson-Doug-W" }, { "family_name": "Taylor", "given_name": "Jonathan P.", "clpid": "Taylor-Jonathan-P" }, { "family_name": "Ferek", "given_name": "Ronald J.", "clpid": "Ferek-Ronald-J" }, { "family_name": "Garrett", "given_name": "Tim", "clpid": "Garrett-Timothy-J" }, { "family_name": "Hobbs", "given_name": "Peter V.", "clpid": "Hobbs-Peter-V" }, { "family_name": "Durkee", "given_name": "Philip A.", "clpid": "Durkee-Philip-A" }, { "family_name": "Nielsen", "given_name": "Kurt", "clpid": "Nielsen-Kurt-E" }, { "family_name": "\u00d6str\u00f6m", "given_name": "Elisabeth", "clpid": "\u00d6str\u00f6m-Elisabeth" }, { "family_name": "O'Dowd", "given_name": "Colin D.", "clpid": "O'Dowd-C-D" }, { "family_name": "Smith", "given_name": "Michael H.", "clpid": "Smith-Michael-H" }, { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "De Bock", "given_name": "Lieve", "clpid": "De-Bock-Lieve" }, { "family_name": "Van Grieken", "given_name": "Ren\u00e9 E.", "clpid": "Van-Grieken-Ren\u00e9-E" }, { "family_name": "Hudson", "given_name": "James G.", "clpid": "Hudson-James-G" }, { "family_name": "Brooks", "given_name": "Ian", "clpid": "Brooks-Ian" }, { "family_name": "Gasparovic", "given_name": "Richard F.", "clpid": "Gasparovic-Richard-F" }, { "family_name": "Pockalny", "given_name": "Robert A.", "clpid": "Pockalny-Robert-A" } ], "abstract": "A case study of the effects of ship emissions on the microphysical, radiative, and chemical properties of polluted marine boundary layer clouds is presented. Two ship tracks are discussed in detail. In situ measurements of cloud drop size distributions, liquid water content, and cloud radiative properties, as well as aerosol size distributions (outside-cloud, interstitial, and cloud droplet residual particles) and aerosol chemistry, are presented. These are related to remotely sensed measurements of cloud radiative properties. \n\nThe authors examine the processes behind ship track formation in a polluted marine boundary layer as an example of the effects of anthropogenic particulate pollution on the albedo of marine stratiform clouds.", "doi": "10.1175/1520-0469(2000)057<2748:ACSOST>2.0.CO;2", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2000-08-15", "series_number": "16", "volume": "57", "issue": "16", "pages": "2748-2764" }, { "id": "authors:8e4wr-wz234", "collection": "authors", "collection_id": "8e4wr-wz234", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:RUSjas00", "type": "article", "title": "Combustion organic aerosol as cloud condensation nuclei in ship tracks", "author": [ { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Noone", "given_name": "Kevin J.", "clpid": "Noone-K-J" }, { "family_name": "Ferek", "given_name": "Ronald J.", "clpid": "Ferek-R-J" }, { "family_name": "Pockalny", "given_name": "Robert A.", "clpid": "Pockalny-R-A" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Polycyclic aromatic hydrocarbons (PAHs) have been sampled in marine stratiform clouds to identify the contribution of anthropogenic combustion emissions in activation of aerosol to cloud droplets. The Monterey Area Ship Track experiment provided an opportunity to acquire data on the role of organic compounds in ambient clouds and in ship tracks identified in satellite images. Identification of PAHs in cloud droplet residual samples indicates that several PAHs are present in cloud condensation nuclei in anthropogenically influenced air and do result in activated droplets in cloud. These results establish the presence of combustion products, such as PAHs, in submicrometer aerosols in anthropogenically influenced marine air, with enhanced concentrations in air polluted by ship effluent. The presence of PAHs in droplet residuals in anthropogenically influenced air masses indicates that some fraction of those combustion products is present in the cloud condensation nuclei that activate in cloud. Although a sufficient mass of droplet residuals was not collected to establish a similar role for organics from measurements in satellite-identified ship tracks, the available evidence from the fraction of organics present in the interstitial aerosol is consistent with part of the organic fraction partitioning to the droplet population. In addition, the probability that a compound will be found in cloud droplets rather than in the unactivated aerosol and the compound's water solubility are compared. The PAHs studied are only weakly soluble in water, but most of the sparse data collected support more soluble compounds having a higher probability of activation.", "doi": "10.1175/1520-0469(2000)057<2591:COAACC>2.0.CO;2", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2000-08-15", "series_number": "16", "volume": "57", "issue": "16", "pages": "2591-2606" }, { "id": "authors:c7zgx-d2y41", "collection": "authors", "collection_id": "c7zgx-d2y41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NOOjas00b", "type": "article", "title": "A case study of ships forming and not forming tracks in moderately polluted clouds", "author": [ { "family_name": "Noone", "given_name": "Kevin J.", "clpid": "Noone-Kevin-J" }, { "family_name": "\u00d6str\u00f6m", "given_name": "Elisabeth", "clpid": "\u00d6str\u00f6m-Elisabeth" }, { "family_name": "Ferek", "given_name": "Ronald J.", "clpid": "Ferek-Ronald-J" }, { "family_name": "Garrett", "given_name": "Tim", "clpid": "Garrett-Tim" }, { "family_name": "Hobbs", "given_name": "Peter V.", "clpid": "Hobbs-Peter-V" }, { "family_name": "Johnson", "given_name": "Doug W.", "clpid": "Johnson-Doug-W" }, { "family_name": "Taylor", "given_name": "Jonathan P.", "clpid": "Taylor-Jonathan-P" }, { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "O'Dowd", "given_name": "Colin D.", "clpid": "O'Dowd-Colin-D" }, { "family_name": "Smith", "given_name": "Michael H.", "clpid": "Smith-Michael-H" }, { "family_name": "Durkee", "given_name": "Philip A.", "clpid": "Durkee-Philip-A" }, { "family_name": "Nielsen", "given_name": "Kurt", "clpid": "Nielsen-Kurt" }, { "family_name": "Hudson", "given_name": "James G.", "clpid": "Hudson-James-G" }, { "family_name": "Pockalny", "given_name": "Robert A.", "clpid": "Pockalny-Robert-A" }, { "family_name": "De Bock", "given_name": "Lieve", "clpid": "De-Bock-Lieve" }, { "family_name": "Van Grieken", "given_name": "Ren\u00e9 E.", "clpid": "Van-Grieken-Ren\u00e9-E" }, { "family_name": "Gasparovic", "given_name": "Richard F.", "clpid": "Gasparovic-Richard-F" }, { "family_name": "Brooks", "given_name": "Ian", "clpid": "Brooks-Ian" } ], "abstract": "The effects of anthropogenic particulate emissions from ships on the radiative, microphysical, and chemical properties of moderately polluted marine stratiform clouds are examined. A case study of two ships in the same air mass is presented where one of the vessels caused a discernible ship track while the other did not. In situ measurements of cloud droplet size distributions, liquid water content, and cloud radiative properties, as well as aerosol size distributions (outside cloud, interstitial, and cloud droplet residual particles) and aerosol chemistry, are presented. These are related to measurements of cloud radiative properties. The differences between the aerosol in the two ship plumes are discussed;these indicate that combustion-derived particles in the size range of about 0.03\u20130.3-\u03bcm radius were those that caused the microphysical changes in the clouds that were responsible for the ship track. \n\nThe authors examine the processes behind ship track formation in a moderately polluted marine boundary layer as an example of the effects that anthropogenic particulate pollution can have in the albedo of marine stratiform clouds.", "doi": "10.1175/1520-0469(2000)057<2729:ACSOSF>2.0.CO;2", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "2000-08-15", "series_number": "16", "volume": "57", "issue": "16", "pages": "2729-2747" }, { "id": "authors:zk7m0-z9311", "collection": "authors", "collection_id": "zk7m0-z9311", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:NENaipcp00", "type": "book_section", "title": "Aerosol-cloud interactions in global models of indirect aerosol radiative forcing", "book_title": "NUCLEATION AND ATMOSPHERIC AEROSOLS 2000: 15th International Conference", "author": [ { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Hale", "given_name": "Barbara N." }, { "family_name": "Kulmala", "given_name": "Markku" } ], "abstract": "The sensitivity of cloud optical properties with respect to parameters that affect aerosol activation is examined. Of particular interest are the effect of volatile gases (such as HNO3), slightly soluble and surfactant species. An adiabatic parcel model is used to simulate cloud droplet formation. Cloud optical properties are calculated from these simulations.", "doi": "10.1063/1.1361930", "isbn": "1-56396-958-0", "publisher": "American Institute of Physics", "place_of_publication": "Melville, NY", "publication_date": "2000-08-02", "pages": "565-568" }, { "id": "authors:3xj4x-5n661", "collection": "authors", "collection_id": "3xj4x-5n661", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KULaipcp00a", "type": "book_section", "title": "Ternary nucleation of H_2SO_4, NH_3 and H_2O", "book_title": "Nucleation and atmospheric aerosols 2000 : 15th International Conference, Rolla, Missouri, 6-11 August 2000", "author": [ { "family_name": "Kulmala", "given_name": "M.", "clpid": "Kulmala-M" }, { "family_name": "Korhonen", "given_name": "P.", "clpid": "Korhonen-P" }, { "family_name": "Laaksonen", "given_name": "A.", "clpid": "Laaksonen-A" }, { "family_name": "Viisanen", "given_name": "Y.", "clpid": "Viisanen-Y" }, { "family_name": "McGraw", "given_name": "R.", "clpid": "McGraw-R" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Hale", "given_name": "Barbara N.", "clpid": "Hale-B-N" }, { "family_name": "Kulmala", "given_name": "Markku", "clpid": "Kulmala-M" } ], "abstract": "A classical theory of the ternary homogeneous nucleation of sulfuric acid\u2014ammonia\u2014water is presented. For NH3 mixing ratios exceeding 1 ppt, the presence of ammonia enhances the binary (sulfuric acid\u2014water) nucleation rate by several orders of magnitude. However, the limiting component for ternary nucleation\u2014as for binary nucleation\u2014is sulfuric acid. The sulfuric acid concentration needed for significant ternary nucleation is several orders of magnitude below that required in binary case.", "doi": "10.1063/1.1361826", "isbn": "1-56396-958-0", "publisher": "American Institute of Physics", "place_of_publication": "Melville, NY", "publication_date": "2000-08-02", "pages": "111-114" }, { "id": "authors:g7ypv-xk473", "collection": "authors", "collection_id": "g7ypv-xk473", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHUjaot00", "type": "article", "title": "Design of a CCN instrument for airborne measurement", "author": [ { "family_name": "Chuang", "given_name": "Patrick Y.", "orcid": "0000-0003-2290-8346", "clpid": "Chuang-Patrick-Y" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Smith", "given_name": "James N.", "orcid": "0000-0003-4677-8224", "clpid": "Smith-James-N" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new instrument for measuring cloud condensation nuclei (CCN) on board small aircraft is described. Small aircraft are attractive mainly because they are less costly, but they require instruments that are designed for minimum weight, volume, and power consumption; that are robust; and that are capable of autonomous operation and making measurements at a frequency appropriate for aircraft speeds. The instrument design combines the streamwise gradient technique previously reported by J. G. Hudson, and the alternating gradient condensation nuclei counter described by W. A. Hoppel et al. Field and laboratory measurements, and modeling studies show that this combination exhibits poor sensitivity for the measurement of CCN spectra; for the climatically important range of critical supersaturations, 0.03%\u20131%, the measured variable, droplet diameter, varies only by 30%. The ability to resolve CCN spectra using this method is therefore in question. Studies of this instrument in a fixed supersaturation mode show that it can measure CCN at a single supersaturation in the range of 0.1%\u20132%. Calibration and testing of the instrument in this mode is described. The instrument is capable of making accurate, high-frequency (>0.1 Hz) measurements of CCN at a fixed supersaturation, while satisfying the constraints for small aircraft.", "doi": "10.1175/1520-0426(2000)017<1005:DOACIF>2.0.CO;2", "issn": "0739-0572", "publisher": "American Meteorological Society", "publication": "Journal of Atmospheric and Oceanic Technology", "publication_date": "2000-08", "series_number": "8", "volume": "17", "issue": "8", "pages": "1005-1019" }, { "id": "authors:4k5hf-0n456", "collection": "authors", "collection_id": "4k5hf-0n456", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-299599000.1", "type": "article", "title": "Formation and cycling of aerosols in the global troposphere", "author": [ { "family_name": "Raes", "given_name": "Frank", "clpid": "Raes-Frank" }, { "family_name": "Van Dingenen", "given_name": "Rita", "orcid": "0000-0003-2521-4972", "clpid": "Van-Dingenen-Rita" }, { "family_name": "Vignati", "given_name": "Elisabetta", "clpid": "Vignati-Elisabetta" }, { "family_name": "Wilson", "given_name": "Julian", "clpid": "Wilson-Julian" }, { "family_name": "Putaud", "given_name": "Jean-Philippe", "clpid": "Putaud-Jean-Philippe" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Adams", "given_name": "Peter", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" } ], "abstract": "Aerosols are formed, evolve, and are eventually removed within the general circulation of the atmosphere. The characteristic time of many of the microphysical aerosol processes is days up to several weeks, hence longer than the residence time of the aerosol within a typical atmospheric compartment (e.g. the marine boundary layer, the free troposphere, etc.). Hence, to understand aerosol properties, one cannot confine the discussion to such compartments, but one needs to view aerosol microphysical phenomena within the context of atmospheric dynamics that connects those compartments. This paper attempts to present an integrated microphysical and dynamical picture of the global tropospheric aerosol system. It does so by reviewing the microphysical processes and those elements of the general circulation that determine the size distribution and chemical composition of the aerosol, and by implementing both types of processes in a diagnostic model, in a 3-D global Chemical Transport Model, and in a General Circulation Model. Initial results are presented regarding the formation, transformation, and cycling of aerosols within the global troposphere.", "doi": "10.1016/s1352-2310(00)00239-9", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2000-07-26", "series_number": "25", "volume": "34", "issue": "25", "pages": "4215-4240" }, { "id": "authors:y20jd-5a662", "collection": "authors", "collection_id": "y20jd-5a662", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-963039800.1", "type": "article", "title": "Airborne analysis of the Los Angeles aerosol", "author": [ { "family_name": "Collins", "given_name": "D. R.", "clpid": "Collins-Donald-R" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Liao", "given_name": "H.", "clpid": "Liao-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Noone", "given_name": "K. J.", "orcid": "0000-0001-7095-7412", "clpid": "Noone-Kevin-J" }, { "family_name": "Hering", "given_name": "S. V.", "orcid": "0000-0001-6536-310X", "clpid": "Hering-Susanne-V" } ], "abstract": "As part of the Southern California ozone study (SCOS), a research aircraft was employed during August and September of 1997 to characterize the physical and chemical properties of the aerosol present over the Los Angeles Basin. Aerosol size distributions measured using a differential mobility analyzer and two optical particle counters were combined with filter-based composition measurements to derive a physicochemical description of the aerosol sampled. The accuracy of this description was evaluated through comparison of derived and directly measured aerosol properties including mass, absorption coefficient, hemispherical backscattering coefficient, and total scattering coefficient at two different relative humidities. The sampled aerosol exhibited a complex vertical structure possessing multiple elevated aerosol layers. The most pronounced of these layers were observed to form by injection of aerosol above the ground-level mixed layer along the southern edge of the San Gabriel Mountains, which form the northern boundary of much of the Los Angeles Basin. Over multiple inland areas, additional layers were observed at about 2500 m above sea level (asl), while off the coast of Santa Monica, thin but concentrated layers were detected about 500 m asl. In addition to the sharp vertical gradients in aerosol concentration observed, horizontal gradients at multiple locations were found to be sufficient to result in more than 50% variability within a 5\u00d75 km computational grid cell commonly used in atmospheric models. Vertically resolved aerosol measurements made over one location during several flights, as well as over several locations during a morning and afternoon flight on the same day, were used to investigate the temporally and spatially resolved impact the aerosol had on gas-phase photolysis rates. These calculations predict that for a 10\u00b0 zenith angle the sampled aerosol enhanced photolysis rates by up to about 5%, although a slight decrease was often observed near ground level.", "doi": "10.1016/s1352-2310(00)00225-9", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2000-07-11", "series_number": "24", "volume": "34", "issue": "24", "pages": "4155-4173" }, { "id": "authors:je4zk-dcp63", "collection": "authors", "collection_id": "je4zk-dcp63", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141103-131053475", "type": "book_section", "title": "Airborne sunphotometer, airborne in-situ, space-borne, and ground-based measurements of tropospheric aerosol in ACE-2", "book_title": "IEEE 2000 International Geoscience and Remote Sensing Symposium (IGARSS 2000)", "author": [ { "family_name": "Schmid", "given_name": "B.", "clpid": "Schmid-B" }, { "family_name": "Collins", "given_name": "D.", "clpid": "Collins-D-J" }, { "family_name": "Gass\u00f3", "given_name": "S.", "clpid": "Gass\u00f3-S" }, { "family_name": "\u00d6str\u00f6m", "given_name": "E.", "clpid": "\u00d6str\u00f6m-E" }, { "family_name": "Powell", "given_name": "D.", "clpid": "Powell-D" }, { "family_name": "Welton", "given_name": "E.", "clpid": "Welton-E" }, { "family_name": "Durkee", "given_name": "P.", "clpid": "Durkee-P-A" }, { "family_name": "Livingston", "given_name": "J.", "clpid": "Livingston-J" }, { "family_name": "Russell", "given_name": "P.", "clpid": "Russell-P" }, { "family_name": "Flagan", "given_name": "R.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Hegg", "given_name": "D.", "clpid": "Hegg-D-A" }, { "family_name": "Noone", "given_name": "K.", "clpid": "Noone-K-J" }, { "family_name": "Voss", "given_name": "K.", "clpid": "Voss-K" }, { "family_name": "Reagan", "given_name": "J.", "clpid": "Reagan-J" }, { "family_name": "Spinhirne", "given_name": "J.", "clpid": "Spinhirne-J" }, { "family_name": "McIntosh", "given_name": "D. M.", "clpid": "McIntosh-D-M" } ], "contributor": [ { "family_name": "Stein", "given_name": "Tammy I.", "clpid": "Stein-T-I" } ], "abstract": "The North Atlantic Regional Aerosol Characterization\nExperiment (ACE-2) of the International Global Atmospheric\nChemistry Project (IGAC) ran from 16 June to 25 July 1997.\nThe results presented in this study are part of the \"Clear-sky\ncolumn closure experiment\" (CLEARCOLUMN) activity,\none of 6 ACE-2 activities [1]. Clear-sky column closure\nexperiments call for characterization of aerosol layers by\nsimultaneous measurements using different techniques that\ncan be related using models [2]. \n\nA wide range of aerosol types was encountered throughout\nthe ACE-2 area, including background Atlantic marine,\nEuropean pollution-derived and African mineral dust. In a\nseries of papers, we reported on ACE-2 CLEARCOLUMN\nresults obtained by combining airborne sunphotometer and\nin-situ measurements taken aboard the Pelican aircraft, spaceborne\nNOAA/VHRR data and ground-based lidar and\nsunphotometer measurements [3]-[10]. Those and other\nCLEARCOLUMN results have been summarized in [11]. \n\nIn this paper we only report on results not shown in this\nform in [3]-[11].", "doi": "10.1109/IGARSS.2000.857288", "isbn": "0-7803-6360-4", "publisher": "IEEE", "place_of_publication": "Piscataway, NJ", "publication_date": "2000-07", "pages": "1613-1615" }, { "id": "authors:xa2ch-6r704", "collection": "authors", "collection_id": "xa2ch-6r704", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141117-085016512", "type": "article", "title": "Meeting at the Interface", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Reactions on or within particles are an important aspect of atmospheric chemistry, but relatively little is known about such processes in the lower parts of the atmosphere. In this Perspective, Seinfeld discusses results by Knipping et al. that shed light on one of the key heterogeneous reactions in the troposphere, that of chlorine release from sea salt particles. It turns out that the surfaces of these particles may play a larger role in their reaction chemistry than previously believed.", "doi": "10.1126/science.288.5464.285", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2000-04-14", "series_number": "5464", "volume": "288", "issue": "5464", "pages": "285" }, { "id": "authors:v4w5d-x0s92", "collection": "authors", "collection_id": "v4w5d-x0s92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-160865500.3", "type": "article", "title": "Shipboard sunphotometer measurements of aerosol optical depth spectra and columnar water vapor during ACE-2, and comparison with selected land, ship, aircraft, and satellite measurements", "author": [ { "family_name": "Livingston", "given_name": "John M.", "clpid": "Livingston-John-M" }, { "family_name": "Kapustin", "given_name": "Vladimir N.", "clpid": "Kapustin-Vladimir-N" }, { "family_name": "Schmid", "given_name": "Beat", "orcid": "0000-0002-4705-8715", "clpid": "Schmid-Beat" }, { "family_name": "Russell", "given_name": "Philip B.", "clpid": "Russell-Philip-B" }, { "family_name": "Quinn", "given_name": "Patricia K.", "orcid": "0000-0003-0337-4895", "clpid": "Quinn-Patricia-K" }, { "family_name": "Bates", "given_name": "Timothy S.", "clpid": "Bates-Timothy-S" }, { "family_name": "Durkee", "given_name": "Philip A.", "clpid": "Durkee-Philip-A" }, { "family_name": "Smith", "given_name": "Peter J.", "clpid": "Smith-Peter-J" }, { "family_name": "Freudenthaler", "given_name": "Volker", "clpid": "Freudenthaler-Volker" }, { "family_name": "Wiegner", "given_name": "Matthias", "clpid": "Wiegner-Matthias" }, { "family_name": "Covert", "given_name": "Dave S.", "clpid": "Covert-Dave-S" }, { "family_name": "Gass\u00f3", "given_name": "Santiago", "clpid": "Gass\u00f3-Santiago" }, { "family_name": "Hegg", "given_name": "Dean", "clpid": "Hegg-Dean" }, { "family_name": "Collins", "given_name": "Donald R.", "clpid": "Collins-Donald-R" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Vitale", "given_name": "Vito", "orcid": "0000-0003-0978-8976", "clpid": "Vitale-Vito" }, { "family_name": "Tomasi", "given_name": "Claudio", "clpid": "Tomasi-Claudio" } ], "abstract": "Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements acquired with NASA Ames Research Center's 6-channel Airborne Tracking Sunphotometer (AATS-6) operated aboard the R/V Professor Vodyanitskiy during the 2nd Aerosol Characterization Experiment (ACE-2) are discussed. Data are compared with various in situ and remote measurements for selected cases. The focus is on 10 July, when the Pelican airplane flew within 70 km of the ship near the time of a NOAA-14/AVHRR satellite overpass and AOD measurements with the 14\u2013channel Ames Airborne Tracking Sunphotometer (AATS-14) above the marine boundary layer (MBL) permitted calculation of AOD within the MBL from the AATS-6 measurements. A detailed column closure test is performed for MBL AOD on 10 July by comparing the AATS-6 MBL AODs with corresponding values calculated by combining shipboard particle size distribution measurements with models of hygroscopic growth and radiosonde humidity profiles (plus assumptions on the vertical profile of the dry particle size distribution and composition). Large differences (30\u201380% in the mid-visible) between measured and reconstructed AODs are obtained, in large part because of the high sensitivity of the closure methodology to hygroscopic growth models, which vary considerably and have not been validated over the necessary range of particle size/composition distributions. The wavelength dependence of AATS-6 AODs is compared with the corresponding dependence of aerosol extinction calculated from shipboard measurements of aerosol size distribution and of total scattering measured by a shipboard integrating nephelometer for several days. Results are highly variable, illustrating further the great difficulty of deriving column values from point measurements. AATS-6 CWV values are shown to agree well with corresponding values derived from radiosonde measurements during 8 soundings on 7 days and also with values calculated from measurements taken on 10 July with the AATS-14 and the University of Washington Passive Humidigraph aboard the Pelican.", "doi": "10.1034/j.1600-0889.2000.00045.x", "issn": "0280-6509", "publisher": "Wiley", "publication": "Tellus B", "publication_date": "2000-04", "series_number": "2", "volume": "52", "issue": "2", "pages": "594-619" }, { "id": "authors:a3sdh-swc11", "collection": "authors", "collection_id": "a3sdh-swc11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150806-170600160", "type": "article", "title": "In situ aerosol-size distributions and clear-column radiative closure during ACE-2", "author": [ { "family_name": "Collins", "given_name": "D. R.", "clpid": "Collins-D-R" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Gass\u00f3", "given_name": "S.", "clpid": "Gass\u00f3-S" }, { "family_name": "Hegg", "given_name": "D. A.", "clpid": "Hegg-D-A" }, { "family_name": "Russell", "given_name": "P. B.", "clpid": "Russell-P-B" }, { "family_name": "Schmid", "given_name": "B.", "clpid": "Schmid-B" }, { "family_name": "Livingston", "given_name": "J. M.", "clpid": "Livingston-J-M" }, { "family_name": "\u00d6str\u00f6m", "given_name": "E.", "clpid": "\u00d6str\u00f6m-E" }, { "family_name": "Noone", "given_name": "K. J.", "clpid": "Noone-K-J" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Putaud", "given_name": "J. P.", "clpid": "Putaud-J-P" } ], "abstract": "As part of the second Aerosol Characterization Experiment (ACE-2) during June and July of 1997, aerosol-size distributions were measured on board the CIRPAS Pelican aircraft through the use of a DMA and 2 OPCs. During the campaign, the boundary-layer aerosol typically possessed characteristics representative of a background marine aerosol or a continentally influenced aerosol, while the free-tropospheric aerosol was characterized by the presence or absence of a Saharan dust layer. A range of radiative closure comparisons were made using the data obtained during vertical profiles flown on 4 missions. Of particular interest here are the comparisons made between the optical properties as determined through the use of measured aerosol-size distributions and those measured directly by an airborne 14-wavelength sunphotometer and 3 nephelometers. Variations in the relative humidity associated with each of the direct measurements required consideration of the hygroscopic properties of the aerosol for size-distribution-based calculations. Simultaneous comparison with such a wide range of directly-measured optical parameters not only offers evidence of the validity of the physicochemical description of the aerosol when closure is achieved, but also provides insight into potential sources of error when some or all of the comparisons result in disagreement. Agreement between the derived and directly-measured optical properties varied for different measurements and for different cases. Averaged over the 4 case studies, the derived extinction coefficient at 525 nm exceeded that measured by the sunphotometer by 2.5% in the clean boundary layer, but underestimated measurements by 13% during pollution events. For measurements within the free troposphere, the mean derived extinction coefficient was 3.3% and 17% less than that measured by the sunphotometer during dusty and non-dusty conditions, respectively. Likewise, averaged discrepancies between the derived and measured scattering coefficient were \u22129.6%, +4.7%, +17%, and \u221241% for measurements within the clean boundary layer, polluted boundary layer, free troposphere with a dust layer, and free troposphere without a dust layer, respectively. Each of these quantities, as well as the majority of the >100 individual comparisons from which they were averaged, were within estimated uncertainties.", "doi": "10.1034/j.1600-0889.2000.00008.x", "issn": "0280-6509", "publisher": "Co-Action Publishing", "publication": "Tellus B", "publication_date": "2000-04", "series_number": "2", "volume": "52", "issue": "2", "pages": "498-525" }, { "id": "authors:vnzyn-e0m78", "collection": "authors", "collection_id": "vnzyn-e0m78", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150806-170820449", "type": "article", "title": "Clear-sky closure studies of lower tropospheric aerosol and water vapor during ACE-2 using airborne sunphotometer, airborne in-situ, space-borne, and ground-based measurements", "author": [ { "family_name": "Schmid", "given_name": "Beat", "clpid": "Schmid-B" }, { "family_name": "Livingston", "given_name": "John M.", "clpid": "Livingston-J-M" }, { "family_name": "Russell", "given_name": "Philip B.", "clpid": "Russell-P-B" }, { "family_name": "Durkee", "given_name": "Philip A.", "clpid": "Durkee-P-A" }, { "family_name": "Jonsson", "given_name": "Haflidi H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-H-H" }, { "family_name": "Collins", "given_name": "Donald R.", "clpid": "Collins-D-R" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Gass\u00f3", "given_name": "Santiago", "clpid": "Gass\u00f3-S" }, { "family_name": "Hegg", "given_name": "Dean A.", "clpid": "Hegg-D-A" }, { "family_name": "\u00d6str\u00f6m", "given_name": "Elisabeth", "clpid": "\u00d6str\u00f6m-E" }, { "family_name": "Noone", "given_name": "Kevin J.", "clpid": "Noone-K-J" }, { "family_name": "Welton", "given_name": "Ellsworth J.", "clpid": "Welton-E-J" }, { "family_name": "Voss", "given_name": "Kenneth J.", "clpid": "Voss-K-J" }, { "family_name": "Gordon", "given_name": "Howard R.", "clpid": "Gordon-H-R" }, { "family_name": "Formenti", "given_name": "Paola", "clpid": "Formenti-P" }, { "family_name": "Andreae", "given_name": "Meinrat O.", "orcid": "0000-0003-1968-7925", "clpid": "Andreae-M-O" } ], "abstract": "We report on clear-sky column closure experiments (CLEARCOLUMN) performed in the Canary Islands during the second Aerosol Characterization Experiment (ACE-2) in June/July 1997. We present CLEARCOLUMN results obtained by combining airborne sunphotometer and in-situ (optical particle counter, nephelometer, and absorption photometer) measurements taken aboard the Pelican aircraft, space-borne NOAA/AVHRR data and ground-based lidar and sunphotometer measurements. During both days discussed here, vertical profiles flown in cloud-free air masses revealed 3 distinctly different layers: a marine boundary layer (MBL) with varying pollution levels, an elevated dust layer, and a very clean layer between the MBL and the dust layer. A key result of this study is the achievement of closure between extinction or layer aerosol optical depth (AOD) computed from continuous in-situ aerosol size-distributions and composition and those measured with the airborne sunphotometer. In the dust, the agreement in layer AOD (\u03bb=380\u20131060 nm) is 3\u20138%. In the MBL there is a tendency for the in-situ results to be slightly lower than the sunphotometer measurements (10\u201317% at \u03bb=525 nm), but these differences are within the combined error bars of the measurements and computations.", "doi": "10.1034/j.1600-0889.2000.00009.x", "issn": "0280-6509", "publisher": "Co-Action Publishing", "publication": "Tellus B", "publication_date": "2000-04", "series_number": "2", "volume": "52", "issue": "2", "pages": "568-593" }, { "id": "authors:3q89k-z5411", "collection": "authors", "collection_id": "3q89k-z5411", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-160865500.2", "type": "article", "title": "Regional aerosol optical depth characteristics from satellite observations: ACE-1, TARFOX and ACE-2 results", "author": [ { "family_name": "Durkee", "given_name": "P. A.", "clpid": "Durkee-Philip-A" }, { "family_name": "Nielsen", "given_name": "K. E.", "clpid": "Nielsen-K-E" }, { "family_name": "Smith", "given_name": "P. J.", "clpid": "Smith-Peter-J" }, { "family_name": "Russell", "given_name": "P. B.", "clpid": "Russell-Philip-B" }, { "family_name": "Schmid", "given_name": "B.", "orcid": "0000-0002-4705-8715", "clpid": "Schmid-Beat" }, { "family_name": "Livingston", "given_name": "J. M.", "clpid": "Livingston-John-M" }, { "family_name": "Holben", "given_name": "B. N.", "orcid": "0000-0002-1251-9809", "clpid": "Holben-Brent-N" }, { "family_name": "Tomasi", "given_name": "C.", "clpid": "Tomasi-Claudio" }, { "family_name": "Vitale", "given_name": "V.", "orcid": "0000-0003-0978-8976", "clpid": "Vitale-Vito" }, { "family_name": "Collins", "given_name": "D.", "clpid": "Collins-Donald-R" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Noone", "given_name": "K. J.", "orcid": "0000-0001-7095-7412", "clpid": "Noone-Kevin-J" }, { "family_name": "\u00d6str\u00f6m", "given_name": "E.", "clpid": "\u00d6str\u00f6m-Elisabeth" }, { "family_name": "Gass\u00f3", "given_name": "S.", "clpid": "Gass\u00f3-Santiago" }, { "family_name": "Hegg", "given_name": "D. A.", "clpid": "Hegg-Dean-A" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Bates", "given_name": "T. S.", "clpid": "Bates-Timothy-S" }, { "family_name": "Quinn", "given_name": "P. K.", "orcid": "0000-0003-0337-4895", "clpid": "Quinn-Patricia-K" } ], "abstract": "Analysis of the aerosol properties during 3 recent international field campaigns (ACE-1, TARFOX and ACE-2) are described using satellite retrievals from NOAA AVHRR data. Validation of the satellite retrieval procedure is performed with airborne, shipboard, and land-based sunphotometry during ACE-2. The intercomparison between satellite and surface optical depths has a correlation coefficient of 0.93 for 630 nm wavelength and 0.92 for 860 nm wavelength. The standard error of estimate is 0.025 for 630 nm wavelength and 0.023 for 860 nm wavelength. Regional aerosol properties are examined in composite analysis of aerosol optical properties from the ACE-1, TARFOX and ACE-2 regions. ACE-1 and ACE-2 regions have strong modes in the distribution of optical depth around 0.1, but the ACE-2 tails toward higher values yielding an average of 0.16 consistent with pollution and dust aerosol intrusions. The TARFOX region has a noticeable mode of 0.2, but has significant spread of aerosol optical depth values consistent with the varied continental aerosol constituents off the eastern North American Coast.", "doi": "10.1034/j.1600-0889.2000.00040.x", "issn": "0280-6509", "publisher": "Wiley", "publication": "Tellus B", "publication_date": "2000-04", "series_number": "2", "volume": "52", "issue": "2", "pages": "484-497" }, { "id": "authors:5y42w-xgm65", "collection": "authors", "collection_id": "5y42w-xgm65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230221-326436600.2", "type": "article", "title": "CCN measurements during ACE-2 and their relationship to cloud microphysical properties", "author": [ { "family_name": "Chuang", "given_name": "P. Y.", "orcid": "0000-0003-2290-8346", "clpid": "Chuang-Patrick-Y" }, { "family_name": "Collins", "given_name": "D. R.", "clpid": "Collins-Donald-R" }, { "family_name": "Pawlowska", "given_name": "H.", "clpid": "Pawlowska-H" }, { "family_name": "Snider", "given_name": "J. R.", "clpid": "Snider-J-R" }, { "family_name": "Jonsson", "given_name": "H. H.", "orcid": "0000-0003-3043-1074", "clpid": "Jonsson-Haflidi-H" }, { "family_name": "Brenguier", "given_name": "J. L.", "clpid": "Brenguier-J-L" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Measurements of cloud condensation nuclei (CCN) concentration at 0.1% supersaturation were made onboard the CIRPAS Pelican over the northeast Atlantic during June and July, 1997, in the vicinity of Tenerife, Spain, as part of the second Aerosol Characterization Experiment (ACE-2). The average CCN concentration (N_(ccn)) in the marine boundary layer for clean air masses was 27\u00b18 and 42\u00b114 cm\u207b\u00b3 for cloudy and clear conditions, respectively, consistent with measurements made near the British Isles and close to Tasmania, Australia, during ACE-1 for similar conditions. A local CCN closure experiment was conducted. Measured N_(ccn) is compared with predictions based on aerosol number size distributions and size-resolved chemical composition profiles determined from measurements and the literature. A sublinear relationship between measured and predicted N_(ccn), N_(ccn)\u223cN^(0.51)_(ccn,predicted), was found. This result is consistent with some previous studies, but others have obtained results much closer to the expected 1 : 1 relationship between measured and predicted N_(ccn). A large variability between measured and predicted N_(ccn) was also observed, leading to the conclusion that, for 95% of the data, the predictions agree with measurements to within a factor of 11. Relationships between below-cloud N_(ccn) and aerosol accumulation mode concentration, and in-cloud cloud droplet number concentration, measured onboard the Pelican and the M\u00e9t\u00e9o-France Merlin-IV, respectively, are calculated for periods while the 2 aircraft were in close proximity at approximately the same time. Measured relationships are reproduced by an adiabatic parcel model, and are also consistent with some previous studies. However, the shape of the CCN spectrum, or the aerosol size distribution, and the updraft velocity are predicted by the model to affect these relationships to a significant extent. Therefore, parameterizations of cloud microphysical properties need to include these variables to accurately predict cloud droplet number concentration. A relationship between N_(ccn) and cloud droplet effective diameter is also calculated and shown to be consistent both with the literature and with the parameterization of effective diameter proposed by Martin et al.", "doi": "10.1034/j.1600-0889.2000.00018.x", "issn": "0280-6509", "publisher": "Wiley", "publication": "Tellus B", "publication_date": "2000-04", "series_number": "2", "volume": "52", "issue": "2", "pages": "843-867" }, { "id": "authors:h9dwx-8r024", "collection": "authors", "collection_id": "h9dwx-8r024", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SEIaiche00.223", "type": "article", "title": "Clouds and climate: Unravelling a key piece of global warming", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Anthropogenic emissions have altered the composition of the\nglobal atmosphere during the 20th century. Evidence that\nthese changes have led to a discernable influence on global\nclimate is mounting. Yet, the global climate system is complex, replete with intricate feedbacks, and it has proved challenging to attribute observed climate changes unambiguously to anthropogenic emissions.", "doi": "10.1002/aic.690460202", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "2000-02", "series_number": "2", "volume": "46", "issue": "2", "pages": "226-228" }, { "id": "authors:nxmmc-v1z70", "collection": "authors", "collection_id": "nxmmc-v1z70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-172931100.1", "type": "article", "title": "A comparative review of inorganic aerosol thermodynamic equilibrium modules: similarities, differences, and their likely causes", "author": [ { "family_name": "Zhang", "given_name": "Yang", "clpid": "Zhang-Yang-ENV" }, { "family_name": "Seigneur", "given_name": "Christian", "orcid": "0000-0002-3079-4839", "clpid": "Seigneur-Christian" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Jacobson", "given_name": "Mark", "orcid": "0000-0002-4315-4128", "clpid": "Jacobson-Mark-Z" }, { "family_name": "Clegg", "given_name": "Simon L.", "clpid": "Clegg-Simon-L" }, { "family_name": "Binkowski", "given_name": "Francis S.", "orcid": "0000-0002-2701-1258", "clpid": "Binkowski-Francis-S" } ], "abstract": "A comprehensive comparison of five inorganic aerosol thermodynamic equilibrium modules, MARS-A, SEQUILIB, SCAPE2, EQUISOLV II, and AIM2, was conducted for a variety of atmospheric concentrations of particulate matter (PM) constituents, relative humidities (RHs), and temperatures. Our results show that although the PM compositions and concentrations predicted by these modules are generally comparable under most conditions, significant discrepancies exist under some conditions, especially at high nitrate/chloride concentrations and low/medium RHs. As a consequence, the absolute differences in total PM concentrations predicted by these modules under all simulation conditions are 7.7\u201312.3% on average and as much as 68% for specific cases. The PM predictions are highly sensitive to changes in the molar ratios of ammonium to sulfate, nitrate to sulfate, and sodium chloride to sulfate, relative humidity, and temperature. The similarities and differences in simulation results predicted by the five modules are analyzed and the likely causes for these differences are discussed in detail. Recommendations are provided regarding the relative advantages of these modules, possible improvements of their performance, and applications in three-dimensional PM modeling studies.", "doi": "10.1016/s1352-2310(99)00236-8", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2000-01", "series_number": "1", "volume": "34", "issue": "1", "pages": "117-137" }, { "id": "authors:mjryb-z7v92", "collection": "authors", "collection_id": "mjryb-z7v92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-175085400.3", "type": "article", "title": "Aerosol dynamics in ship tracks", "author": [ { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Ferek", "given_name": "Ronald J.", "clpid": "Ferek-Ronald-J" }, { "family_name": "Hegg", "given_name": "Dean A.", "clpid": "Hegg-Dean-A" }, { "family_name": "Hobbs", "given_name": "Peter V.", "clpid": "Hobbs-Peter-V" }, { "family_name": "Wobrock", "given_name": "Wolfram", "orcid": "0000-0002-4681-5171", "clpid": "Wobrock-Wolfram" }, { "family_name": "Flossmann", "given_name": "Andrea I.", "orcid": "0000-0002-4484-6425", "clpid": "Flossmann-Andrea-I" }, { "family_name": "O'Dowd", "given_name": "Colin D.", "orcid": "0000-0002-3068-2212", "clpid": "O'Dowd-Colin-D" }, { "family_name": "Nielsen", "given_name": "Kurt E.", "clpid": "Nielsen-Kurt-E" }, { "family_name": "Durkee", "given_name": "Phillip A.", "clpid": "Durkee-Phillip-A" } ], "abstract": "Ship tracks are a natural laboratory to isolate the effect of anthropogenic aerosol emissions on cloud properties. The Monterey Area Ship Tracks (MAST) experiment in the Pacific Ocean west of Monterey, California, in June 1994, provides an unprecedented data set for evaluating our understanding of the formation and persistence of the anomalous cloud features that characterize ship tracks. The data set includes conditions in which the marine boundary layer is both clean and continentally influenced. Two case studies during the MAST experiment are examined with a detailed aerosol microphysical model that considers an external mixture of independent particle populations. The model allows tracking individual particles through condensational and coagulational growth to identify the source of cloud condensation nuclei (CCN). In addition, a cloud microphysics model was employed to study specific effects of precipitation. Predictions and observations reveal important differences between clean (particle concentrations below 150 cm\u207b\u00b3) and continentally influenced (particle concentrations above 400 cm\u207b\u00b3) background conditions: in the continentally influenced conditions there is a smaller change in the cloud effective radius, drop number and liquid water content in the ship track relative to the background than in the clean marine case. Predictions of changes in cloud droplet number concentrations and effective radii are consistent with observations although there is significant uncertainty in the absolute concentrations due to a lack of measurements of the plume dilution. Gas-to-particle conversion of sulfur species produced by the combustion of ship fuel is predicted to be important in supplying soluble aerosol mass to combustion-generated particles, so as to render them available as CCN. Studies of the impact of these changes on the cloud's potential to precipitate concluded that more complex dynamical processes must be represented to allow sufficiently long drop activations for drizzle droplets to form.", "doi": "10.1029/1999jd900985", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1999-12-27", "series_number": "D24", "volume": "104", "issue": "D24", "pages": "31077-31095" }, { "id": "authors:vvvgc-tzx02", "collection": "authors", "collection_id": "vvvgc-tzx02", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-175085400.5", "type": "article", "title": "Simulation of Aerosol Dynamics: A Comparative Review of Algorithms Used in Air Quality Models", "author": [ { "family_name": "Zhang", "given_name": "Yang", "clpid": "Zhang-Yang-ENV" }, { "family_name": "Seigneur", "given_name": "Christian", "orcid": "0000-0002-3079-4839", "clpid": "Seigneur-Christian" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Jacobson", "given_name": "Mark Z.", "orcid": "0000-0002-4315-4128", "clpid": "Jacobson-Mark-Z" }, { "family_name": "Binkowski", "given_name": "Francis S.", "orcid": "0000-0002-2701-1258", "clpid": "Binkowski-Francis-S" } ], "abstract": "A comparative review of algorithms currently used in air quality models to simulate aerosol dynamics is presented. This review addresses coagula tion, condensational growth, nucleation, and gas particle mass transfer. Two major approaches are used in air quality models to represent the particle size distribution: (1) the sectional approach in which the size distribution is discretized into sections and particle properties are assumed to be constant over particle size sections and (2) the modal approach in which the size distribution is approxi mated by several modes and particle properties are assumed to be uniform in each mode. The sectional approach is accurate for coagulation and can reproduce the major characteristics of the evolution of the particle size distribution for condensa tional growth with the moving-center and hybrid algorithms. For coagulation and condensational growth, the modal approach provides more accurate results when the standard deviations of the modes are allowed to vary than it does when they are fixed. Predictions of H\u2082SO\u2084 nucleation rates are highly sensitive to environ mental variables and simulation of relative rates of condensation on existing particles and nucleation is a preferable approach. Explicit treatment of mass transfer is recommended for cases where volatile species undergo different equilib rium reactions in different particle size ranges (e.g., in the presence of coarse salt particles). The results of this study provide useful information for use in selecting algorithms to simulate aerosol dynamics in air quality models and for improving the accuracy of existing algorithms.", "doi": "10.1080/027868299304039", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1999-12", "series_number": "6", "volume": "31", "issue": "6", "pages": "487-514" }, { "id": "authors:3jqr5-hw806", "collection": "authors", "collection_id": "3jqr5-hw806", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-175085400.7", "type": "article", "title": "Ternary nucleation of H\u2082SO\u2084, NH\u2083, and H\u2082O in the atmosphere", "author": [ { "family_name": "Korhonen", "given_name": "P.", "clpid": "Korhonen-P" }, { "family_name": "Kulmala", "given_name": "M.", "orcid": "0000-0003-3464-7825", "clpid": "Kulmala-Markku" }, { "family_name": "Laaksonen", "given_name": "Ari", "orcid": "0000-0002-1657-2383", "clpid": "Laaksonen-Ari" }, { "family_name": "Viisanen", "given_name": "Y.", "orcid": "0000-0002-9660-3281", "clpid": "Viisanen-Yrj\u00f6" }, { "family_name": "McGraw", "given_name": "R.", "clpid": "McGraw-R" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Classical theory of binary homogeneous nucleation is extended to the ternary system H\u2082SO\u2084-NH\u2083-H\u2082O. For NH\u2083 mixing ratios exceeding about 1 ppt, the presence of NH\u2083 enhances the binary H\u2082SO\u2084-H\u2082O nucleation rate by several orders of magnitude. The Gibbs free energies of formation of the critical H\u2082SO\u2084-NH\u2083-H\u2082O cluster, as calculated by two independent approaches, are in substantial agreement. The finding that the H\u2082SO\u2084-NH\u2083-H\u2082O ternary nucleation rate is independent of relative humidity over a large range of H\u2082SO\u2084 concentrations has wide atmospheric consequences. The limiting component for ternary H\u2082SO\u2084-NH\u2083-H\u2082O nucleation is, as in the binary H\u2082SO\u2084-H\u2082O case, H\u2082SO\u2084; however, the H\u2082SO\u2084 concentration needed to achieve significant nucleation rates is several orders of magnitude below that required in the binary case.", "doi": "10.1029/1999jd900784", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1999-11-20", "series_number": "D21", "volume": "104", "issue": "D21", "pages": "26349-26353" }, { "id": "authors:ymref-8sb58", "collection": "authors", "collection_id": "ymref-8sb58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-111107356", "type": "article", "title": "Effects of aerosols on tropospheric photolysis rates in clear and cloudy atmospheres", "author": [ { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Yung", "given_name": "Yuk L.", "orcid": "0000-0002-4263-2562", "clpid": "Yung-Y-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The effect of aerosols on 14 tropospheric photolysis reactions is examined under noncloudy and cloudy sky conditions by using a detailed one-dimensional radiative transfer model. Pure (NH_4)_2SO_4, pure soot, and internal and external mixtures of the two aerosols, as well as mineral dust aerosol, are considered. Nonabsorbing aerosol generally enhances photolysis rates above and in the upper part of the aerosol layer in both noncloudy and cloudy atmospheres, with the enhancement effect reduced in the presence of clouds. In contrast, soot aerosol reduces photolysis rates under both noncloudy and cloudy sky conditions, with the reduction accentuated by a cloud layer. Mixtures of absorbing and nonabsorbing aerosols may produce enhancement or reduction in photolysis rates under clear sky conditions, whereas they generally reduce rates when a cloud is present. In the absence of cloud, sulfate aerosol at urban levels enhances tropospheric average photolysis rates from 11 to 18% for the 14 reactions studied; soot aerosol decreases tropospheric average rates from 6 to 11%. In the presence of a 500-m-thick stratus cloud, sulfate aerosol enhances each of 14 tropospheric average photolysis rates by about 5%; soot aerosol decreases tropospheric average photolysis rates from 9 to 19%.", "doi": "10.1029/1999JD900409", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "1999-10-20", "series_number": "D19", "volume": "104", "issue": "D19", "pages": "23697-23707" }, { "id": "authors:jtahn-mn734", "collection": "authors", "collection_id": "jtahn-mn734", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150806-165631636", "type": "article", "title": "Gas-phase Ozone Oxidation of Monoterpenes: Gaseous and Particulate Products", "author": [ { "family_name": "Yu", "given_name": "Jianzhen", "clpid": "Yu-Jianzhen" }, { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-David-R-III" }, { "family_name": "Griffin", "given_name": "Robert J.", "orcid": "0000-0001-7682-8769", "clpid": "Griffin-Robert-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric oxidation of monoterpenes contributes to formation of tropospheric ozone and secondary organic aerosol, but their products are poorly characterized. In this work, we report a series of outdoor smog chamber experiments to investigate both gaseous and particulate products in the ozone oxidation of four monoterpenes: \u03b1-pinene, \u03b2-pinene, \u0394^3-carene, and sabinene. More than ten oxygenated products are detected and identified in each monoterpene/O_3 reaction by coupling derivatization techniques and GC/MS detection. A denuder/filter pack sampling system is used to separate and simultaneously collect gas and aerosol samples. The identified products, consisting of compounds containing carbonyl, hydroxyl, and carboxyl functional groups, are estimated to account for about 34\u201350%, 57%, 29\u201367%, and 24% of the reacted carbon mass for \u03b2-pinene, sabinene, \u03b1-pinene, and \u0394^3-carene, respectively. The identified individual products account for >83%, \u223c100%, >90%, and 61% of the aerosol mass produced in the ozone reaction of \u03b2-pinene, sabinene, \u03b1-pinene, and \u0394^3-carene. The uncertainty in the yield data is estimated to be \u223c \u00b150%. Many of the products partition between gas and aerosol phases, and their gas-aerosol partitioning coefficients are determined and reported here. Reaction schemes are suggested to account for the products observed.", "doi": "10.1023/A:1006254930583", "issn": "0167-7764", "publisher": "Springer", "publication": "Journal of Atmospheric Chemistry", "publication_date": "1999-10", "series_number": "2", "volume": "34", "issue": "2", "pages": "207-258" }, { "id": "authors:4arjr-8sp86", "collection": "authors", "collection_id": "4arjr-8sp86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141029-124953551", "type": "article", "title": "Estimate of global atmospheric organic aerosol from oxidation of biogenic hydrocarbons", "author": [ { "family_name": "Griffin", "given_name": "Robert J.", "clpid": "Griffin-R-J" }, { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-D-R-III" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Dabdub", "given_name": "Donald", "clpid": "Dabdub-D" } ], "abstract": "The results from a series of outdoor chamber experiments establishing the atmospheric aerosol-forming potential of fourteen terpenoid hydrocarbons have been used to estimate the annual amount of secondary organic aerosol formed globally from compounds emitted by vegetation. Hydroxyl radical, ozone, and nitrate radical oxidation each contribute to aerosol formation in full-photooxidation experiments; because oxidation by nitrate radical under ambient, remote conditions is likely to be negligible, parameters describing aerosol formation from hydroxyl radical and ozone reaction only are developed. Chamber results, temporally and spatially resolved, compound-specific estimates of biogenic hydrocarbon emissions, and hydroxyl radical and ozone fields are combined to lead to an estimate for atmospheric secondary organic aerosol formed annually from biogenic precursors of 18.5 Tg, a number smaller than the previously published estimate of 30\u2013270 Tg [Andreae and Crutzen, 1997].", "doi": "10.1029/1999GL900476", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "1999-09-01", "series_number": "17", "volume": "26", "issue": "17", "pages": "2721-2724" }, { "id": "authors:sc9cd-85z55", "collection": "authors", "collection_id": "sc9cd-85z55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170408-163228813", "type": "article", "title": "Incremental Aerosol Reactivity: Application to Aromatic and Biogenic Hydrocarbons", "author": [ { "family_name": "Griffin", "given_name": "Robert J.", "clpid": "Griffin-R-J" }, { "family_name": "Cocker", "given_name": "David R.", "clpid": "Cocker-D-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The concept of incremental aerosol reactivity is introduced, and the incremental aerosol reactivities of a number of important anthropogenic and biogenic hydrocarbons are investigated for four ambient scenarios. The incremental aerosol reactivity, defined as a change in the secondary organic aerosol mass produced (in \u03bcg m^(-3)) per unit change of parent organic reacted (in ppb), is a measure of the aerosol-forming capability of a given parent organic in a prescribed mixture of other organic compounds. The base-case scenario is a mixture of both aromatic and biogenic organics. Reactivity values depend on the choice of the initial organic mixture, so cases are also examined in which all biogenic hydrocarbon concentrations are set to zero and all aromatic concentrations are set to zero. The influence of additional organic aerosol is also investigated. For the compounds studied, incremental aerosol reactivities range from 0.228 \u03bcg m^(-3) ppb^(-1) (m-xylene) to 10.352 \u03bcg m^(-3) ppb^(-1) (\u03b1-humulene) for the base case, from 0.234 \u03bcg m^(-3) ppb^(-1) (m-xylene) to 9.446 \u03bcg m^(-3) ppb^(-1) (\u03b1-humulene) for the base case in the presence of initial organic aerosol, from 0.133 \u03bcg m^(-3) ppb^(-1) (m-xylene) to 0.801 \u03bcg m^(-3) ppb^(-1) (diethylbenzene) for the zero-biogenic case, and from 0.456 \u03bcg m^(-3) ppb^(-1) (linalool) to 6.923 \u03bcg m^(-3) ppb^(-1) (\u03b1-humulene) for the zero-aromatic case. Using m-xylene as a basis, relative incremental aerosol reactivities range from 1.153 (low-yield aromatics) to 3.338 (diethylbenzene) for aromatics in the base case and from 1.349 (low-yield aromatics) to 6.032 (diethylbenzene) in the zero-biogenic case. Using \u03b1-pinene as a basis, relative incremental aerosol reactivities range from 0.569 (terpinolene) to 12.843 (\u03b1-humulene) for biogenics in the base case and from 0.882 (linalool) to 13.385 (\u03b1-humulene) in the zero-aromatic case.", "doi": "10.1021/es981330a", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1999-07-15", "series_number": "14", "volume": "33", "issue": "14", "pages": "2403-2408" }, { "id": "authors:2tcp0-yzj46", "collection": "authors", "collection_id": "2tcp0-yzj46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-175085400.9", "type": "article", "title": "Analysis of ozone in the San Joaquin Valley of California", "author": [ { "family_name": "Dabdub", "given_name": "Donald", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "DeHaan", "given_name": "Laurel L.", "orcid": "0000-0002-0842-8760", "clpid": "DeHaan-Laurel-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The dynamics of ozone in the San Joaquin Valley of central California are studied by systematic diagnostic runs of the three-dimensional SARMAP Air Quality Model. Air quality in the San Joaquin Valley is the result of a complex combination of local and transported emissions. Simulations show that relatively brisk winds at points of inflow to the Valley produce a strong dependence of ozone in the Valley on upwind conditions. Furthermore, NO\u2093 influx from boundaries and local emissions has significantly greater impact on ozone production than ROG influx and emissions.", "doi": "10.1016/s1352-2310(98)00256-8", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1999-07", "series_number": "16", "volume": "33", "issue": "16", "pages": "2501-2514" }, { "id": "authors:eb2gc-94135", "collection": "authors", "collection_id": "eb2gc-94135", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-300212700.1", "type": "article", "title": "Global concentrations of tropospheric sulfate, nitrate, and ammonium aerosol simulated in a general circulation model", "author": [ { "family_name": "Adams", "given_name": "Peter J.", "orcid": "0000-0003-0041-058X", "clpid": "Adams-Peter-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Koch", "given_name": "Dorothy M.", "clpid": "Koch-Dorothy-M" } ], "abstract": "Global sulfate aerosol composition is simulated online in the Goddard Institute for Space Studies general circulation model II\u2032 (GISS GCM II-prime). Four sulfur species, hydrogen peroxide, gas phase ammonia, and particulate ammonium are the prognostic tracer species, the emissions, transport, and deposition of which are explicitly simulated. Nitric acid fields are prescribed based on a global chemical transport model. An online thermodynamic equilibrium calculation determines the partitioning of ammonia and nitrate between gas and aerosol phases, and the quantity of aerosol water based on the temperature, relative humidity, and sulfate concentration in each GCM grid cell. The total global burden of sulfate, nitrate, ammonium, and aerosol water is 7.5 Tg and is most sensitive to changes in sulfur emissions. Tropospheric lifetimes for ammonium and ammonia are 4.2 and 0.9 days, respectively; the tropospheric ammonium burden is 0.30 Tg N, compared with 0.14 Tg N for ammonia. Simulated ammonium concentrations are generally within a factor of 2 of observations. Subgrid variability in measured concentrations hinders comparison of observations to predictions. Ammonium nitrate aerosol plays an important role in determining total aerosol mass in polluted continental areas. In the upper troposphere and near the poles, cold temperatures allow unneutralized nitric acid to condense into the aerosol phase. Acidic aerosol species tend to be neutralized by ammonia to a greater degree over continents than over oceans. The aerosol is most basic and gas phase ammonia concentrations are highest over India. Water uptake per mole of sulfate aerosol varies by two orders of magnitude because of changes in relative humidity and aerosol composition. Spatial variations in aerosol composition and water uptake have implications for direct and indirect aerosol radiative forcing.", "doi": "10.1029/1999jd900083", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1999-06-20", "series_number": "D11", "volume": "104", "issue": "D11", "pages": "13791-13823" }, { "id": "authors:k5s34-bq335", "collection": "authors", "collection_id": "k5s34-bq335", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141029-142350840", "type": "article", "title": "Observation of gaseous and particulate products of monoterpene oxidation in forest atmospheres", "author": [ { "family_name": "Yu", "given_name": "Jianzhen", "clpid": "Yu-Jianzhen" }, { "family_name": "Griffin", "given_name": "Robert J.", "orcid": "0000-0001-7682-8769", "clpid": "Griffin-Robert-J" }, { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-David-R-III" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Blanchard", "given_name": "Pierrette", "clpid": "Blanchard-Pierrette" } ], "abstract": "Atmospheric oxidation of biogenic hydrocarbons, such as monoterpenes, is estimated to be a significant source of global aerosol. Whereas laboratory studies have established that photochemical oxidation of monoterpenes leads to aerosol formation, there are limited field studies detecting such oxidation products in ambient aerosols. Drawing on prior results of monoterpene product analysis under controlled smog chamber conditions, we have identified organic aerosol components attributable to monoterpene oxidation in two forest atmospheres, Kejimkujik National Park, Nova Scotia, Canada, and Big Bear, San Bernardino National Forest, California, U.S.A. The major identified aerosol products derived from \u03b1-pinene and \u03b2-pinene oxidation include pinic acid, pinonic acid, norpinonic acid and its isomers, hydroxy pinonaldehydes, and pinonaldehyde, concentrations of which in the aerosol phase are in the sub ng m^(\u22123) range. Identification of oxidation products in atmospheric aerosol samples serves as direct evidence for aerosol formation from monoterpenes under ambient conditions.", "doi": "10.1029/1999GL900169", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "1999-04-15", "series_number": "8", "volume": "26", "issue": "8", "pages": "1145-1148" }, { "id": "authors:g8955-nhe36", "collection": "authors", "collection_id": "g8955-nhe36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-989990300.1", "type": "article", "title": "A study of processes that govern the maintenance of aerosols in the marine boundary layer", "author": [ { "family_name": "Katoshevski", "given_name": "David", "orcid": "0000-0003-4740-4275", "clpid": "Katoshevski-David" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We systematically evaluate the relative influence of sources and sinks of particles in the remote marine boundary layer (MBL) to elucidate the principal factors that govern MBL aerosol behavior. Processes considered include: (1) surface flux of dimethyl sulfide (DMS); (2) gas-phase oxidation of DMS to SO\u2082; (3) gas-phase oxidation of SO\u2082 to H\u2082SO\u2084; (4) mass transfer of SO\u2082 and H\u2082SO\u2084 to pre-existing particles; (5) homogenous nucleation of H\u2082SO\u2084/H\u2082O; (6) entrainment of air from the free troposphere; (7) deposition to the sea surface; (8) cycling of air through clouds and rain scavenging; (9) oxidation of SO\u2082 in sea salt aerosols and cloud droplets; and (10) sea-salt particle production at sea surface. The average aerosol number concentration is found to be quite sensitive to the rate of entrainment of aerosol-containing air from the free troposphere. The path that leads to the greatest accumulation of non-sea-salt (nss) sulfate involves SO\u2082 (rather than H\u2082SO\u2084) absorption into existing particles. Because of scavenging of SO\u2082 and H\u2082SO\u2084 by sea-salt aerosol, a considerable fraction of nss-sulfate is internally mixed with sea-salt aerosol. Under the conditions assumed in this study, MBL aerosol number concentration is dominated by free tropospheric aerosol under virtually all conditions, 89% in the base case, and even 69% at a 17 m s\u207b\u00b9 wind speed. Aerosol mass, on the other hand, is dominated by sea-salt particles, 62% in the base case and 98% at a wind speed of 17 m s\u207b\u00b9. Evaporation of cloud droplets provides 4.6% of the particle number in the base case, but 28% of the particle mass. At the high nucleation rate case considered here, there is notably little change in the overall contributions to aerosol number and mass from the base case; only about 5% of the total particle number is provided by nucleation events. Variation in precipitation frequency also has only a minor effect on the overall contributions. One concludes that the MBL aerosol is remarkably robust in the face of ever-changing conditions. Free tropospheric aerosol entrainment tends to sustain particle number concentrations, and sea-salt emissions maintain most of the aerosol mass. Cloud processing, while not a major contributor to aerosol number, does provide, except under high wind conditions, the order of 20% of the aerosol mass. Although nucleation occurs only infrequently and does not contribute appreciably to long-term average aerosol number or mass, nucleation is, nonetheless, the mechanism that replenishes aerosol number in brief, intense episodes when aerosol surface area levels are substantially reduced by precipitation.", "doi": "10.1016/s0021-8502(98)00740-x", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "1999-04", "series_number": "4", "volume": "30", "issue": "4", "pages": "503-532" }, { "id": "authors:s619y-pgd49", "collection": "authors", "collection_id": "s619y-pgd49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150806-165845978", "type": "article", "title": "Organic aerosol formation from the oxidation of biogenic hydrocarbons", "author": [ { "family_name": "Griffin", "given_name": "Robert J.", "orcid": "0000-0001-7682-8769", "clpid": "Griffin-Robert-J" }, { "family_name": "Cocker", "given_name": "David R., III", "orcid": "0000-0002-0586-0769", "clpid": "Cocker-David-R-III" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A series of outdoor chamber experiments has been used to establish and characterize the significant atmospheric aerosol-forming potentials of the most prevalent biogenic hydrocarbons emitted by vegetation. These compounds were also studied to elucidate the effect of structure on aerosol yield for these types of compounds. Because oxidation products partition between the gas and aerosol phases, the aerosol yields of the parent biogenic hydrocarbons depend on the concentration of organic aerosol into which these products can be absorbed. For organic mass concentrations between 5 and 40 \u00b5g m^(-3), mass-based yields in photooxidation experiments range from 17 to 67% for sesquiterpenes, from 2 to 23% for cyclic diolefins, from 2 to 15% for bicyclic olefins, and from 2 to 6% for the acyclic triolefin ocimene. In these photooxidation experiments, hydroxyl and nitrate radicals and ozone can contribute to consumption of the parent hydrocarbon. For bicyclic olefins (\u03b1-pinene, \u03b2-pinene, \u0394^3-carene, and sabinene), experiments were also carried out at daytime temperatures in a dark system in the presence of ozone or nitrate radicals alone. For ozonolysis experiments, resulting aerosol yields are less dependent on organic mass concentration, when compared to full, sunlight-driven photooxidation. Nitrate radical experiments exhibit extremely high conversion to aerosol for \u03b2-pinene, sabinene, and \u0394^3-carene. The relative importance of aerosol formation from each type of reaction for bicyclic olefin photooxidation is elucidated.", "doi": "10.1029/1998JD100049", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "1999-02-20", "series_number": "D3", "volume": "104", "issue": "D3", "pages": "3555-3567" }, { "id": "authors:atf0t-rgf87", "collection": "authors", "collection_id": "atf0t-rgf87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-104818400.1", "type": "article", "title": "Radiative forcing by mineral dust aerosols: Sensitivity to key variables", "author": [ { "family_name": "Liao", "given_name": "H.", "clpid": "Liao-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We examine diurnally averaged radiative forcing by mineral dust aerosols in shortwave and longwave spectral regions using a one-dimensional column radiation model. At the top of the atmosphere (TOA), net (shortwave plus longwave) dust radiative forcing can be positive (heating) or negative (cooling) depending on values of key variables. We derive an analytical expression for the critical single-scattering albedo at which forcing changes sign for an atmosphere containing both cloud and aerosol layers. At the surface, net dust forcing can be positive or negative under clear-sky conditions, whereas it is always cooling in the presence of a low-level stratus cloud. Longwave radiative forcing is essentially zero when clouds are present. We also study the sensitivity of dust diurnally averaged forcing to the imaginary part of refractive index (k), height of the dust layer, dust particle size, and dust optical depth. These variables play different roles as follows: (1) under both clear- and cloudy sky conditions, net TOA forcing is more sensitive to k than net surface forcing; (2) clear-sky longwave forcing and cloudy-sky TOA shortwave forcing are very sensitive to the altitude of the dust layer; although clear-sky shortwave forcing is not sensitive to it; (3) clear-sky shortwave forcing is much more sensitive to particle size than cloudy-sky shortwave forcing; longwave forcing is not sensitive to particle size; and (4) all forcings are sensitive to optical depth except cloudy-sky longwave forcing.", "doi": "10.1029/1998jd200036", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1998-12-27", "series_number": "D24", "volume": "103", "issue": "D24", "pages": "31637-31645" }, { "id": "authors:ykay5-0cs98", "collection": "authors", "collection_id": "ykay5-0cs98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150806-164934482", "type": "article", "title": "Identification of Products Containing \u2212COOH, \u2212OH, and \u2212C=O in Atmospheric Oxidation of Hydrocarbons", "author": [ { "family_name": "Yu", "given_name": "Jianzhen", "clpid": "Yu-Jianzhen" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric oxidation of hydrocarbons by hydroxyl radicals and ozone leads to products containing \u2212COOH, \u2212OH, and \u2212C=O functional groups. The high polarity of such compounds precludes direct GC\u2212MS analysis. In addition, many such compounds often exist in a single sample at trace levels. An analytical method has been developed to identify compounds containing one or more functional groups of carbonyl, carboxy, and hydroxy in atmospheric samples. In the method, \u2212C=O groups are derivatized using O-(2,3,4,5,6-pentafluorobenzyl) hydroxy amine (PFBHA), and \u2212COOH and \u2212OH groups are derivatized using a silylation reagent N,O-bis(trimethylsilyl)-trifluoroacetamide (BSTFA). The derivatives are easily resolved by a GC column. The chemical ionization mass spectra of these derivatives exhibit several pseudomolecular ions, allowing unambiguous determination of molecular weights. Functional group identification is accomplished by monitoring the ions in the electron ionization mass spectra that are characteristic of each functional group derivative:\u2009 m/z 181 for carbonyl and m/z 73 and 75 for carboxyl and hydroxy groups. The method is used to identify products in laboratory studies of ozone oxidation of \u03b1-pinene and \u0394^3-carene. Among products from ozone oxidation of \u03b1-pinene, we have detected pinonaldehyde, norpinonaldehyde, pinonic acid, norpinonic acid, C_(10) hydroxy dicarbonyls, pinic acid, 2,2-dimethyl-3-(formylmethyl)-cyclobutane-formic acid, and a product that has a molecular weight of 156 and contains a CO and a COOH/OH group. The latter two products have not been reported previously. \u0394^3-Carene is structurally analogous to \u03b1-pinene in that both have an internal unsaturated bond where ozone oxidation takes place. We have also identified the corresponding analogous products, of which all but caronaldehyde are reported for the first time.", "doi": "10.1021/es980129x", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1998-08-15", "series_number": "16", "volume": "32", "issue": "16", "pages": "2357-2370" }, { "id": "authors:gcxm5-c2s27", "collection": "authors", "collection_id": "gcxm5-c2s27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp98b", "type": "article", "title": "Binary nucleation of sulfuric acid-water: Monte Carlo simulation", "author": [ { "family_name": "Kusaka", "given_name": "I.", "clpid": "Kusaka-Isamu" }, { "family_name": "Wang", "given_name": "Z.-G.", "orcid": "0000-0002-3361-6114", "clpid": "Wang-Zhen-Gang" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We have developed a classical mechanical model for the H2SO4/H2O binary system. Monte Carlo simulation was performed in a mixed ensemble, in which the number of sulfuric acid molecules is fixed while that of water molecules is allowed to fluctuate. Simulation in this ensemble is computationally efficient compared to conventional canonical simulation, both in sampling very different configurations of clusters relevant in nucleation and in evaluating the free energy of cluster formation. The simulation yields molecular level information, such as the shape of the clusters and the dissociation behavior of the acid molecule in the cluster. Our results indicate that the clusters are highly nonspherical as a result of the anisotropic intermolecular interactions and that a cluster with a given number of acid molecules has several very different conformations, which are close in free energy and hence equally relevant in nucleation. The dissociation behavior of H2SO4 in a cluster differs markedly from that in bulk solution and depends sensitively on the assumed value of the free energy f(hb) of the dissociation reaction H2SO4+H2O-HSO4-. H3O+. In a small cluster, no dissociation is observed. As the cluster size becomes larger, the probability of having an HSO4-. H3O+ ion pair increases. However, in clusters relevant in nucleation, the resulting ion pairs remain in contact; about 240 water molecules are required to observe behavior that resembles that in bulk solution. If a larger value of f(hb) is assumed to reflect its uncertainty, the probability of dissociation becomes negligible. A reversible work surface obtained for a condition typical of vapor to liquid nucleation suggests that the rate-limiting step of new particle formation is a binary collision of two hydrated sulfuric acid molecules. The ion pairs formed by dissociation play a key role in stabilizing the resulting cluster. The reversible work surface is sensitive to the assumed value of f(hb), thus pointing to the need for an accurate estimate of the quantity either by ab initio calculations or experiments.", "doi": "10.1063/1.476097", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1998-04-22", "series_number": "16", "volume": "108", "issue": "16", "pages": "6829-6848" }, { "id": "authors:yw0xe-1t936", "collection": "authors", "collection_id": "yw0xe-1t936", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp98a", "type": "article", "title": "Direct evaluation of the equilibrium distribution of physical clusters by a grand canonical Monte Carlo simulation", "author": [ { "family_name": "Kusaka", "given_name": "I.", "clpid": "Kusaka-Isamu" }, { "family_name": "Wang", "given_name": "Z.-G.", "orcid": "0000-0002-3361-6114", "clpid": "Wang-Zhen-Gang" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new approach to cluster simulation is developed in the context of nucleation theory. This approach is free of any arbitrariness involved in the definition of a cluster. Instead, it preferentially and automatically generates the physical clusters, defined as the density fluctuations that lead to nucleation, and determines their equilibrium distribution in a single simulation, thereby completely bypassing the computationally expensive free energy evaluation that is necessary in a conventional approach. The validity of the method is demonstrated for a single component system using a model potential for water under several values of supersaturation.", "doi": "10.1063/1.475741", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1998-03-01", "series_number": "9", "volume": "108", "issue": "9", "pages": "3416-3423" }, { "id": "authors:jy2kc-xsx70", "collection": "authors", "collection_id": "jy2kc-xsx70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-480771600.4", "type": "article", "title": "In Situ Study of Single Aqueous Droplet Solidification of Ceramic Precursors Used for Spray Pyrolysis", "author": [ { "family_name": "Chan", "given_name": "Chak K.", "orcid": "0000-0001-9687-8771", "clpid": "Chan-Chak-Keung" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The electrodynamic balance (EDB) is demonstrated to be useful for the in situ study of aqueous droplet solidification. We have used an EDB to study the solidification of solution droplets used for ceramic powder synthesis by spray pyrolysis. The mass change and the elastic light scattering of the drying 20 \u03bcm solution droplets were monitored. We found that aqueous MgCl\u2082 droplets crystallize but Mg(COOCH\u2083)\u2082, MgSO\u2084, ZrO(OH)Cl, and Zr(COOCH\u2083)\u2084 droplets appear to form gels at high concentrations. As a result of the gel formation, the rate of loss of water from the droplets can be reduced by approximately 150 times and drying is limited by solute diffusion in the gel.", "doi": "10.1111/j.1151-2916.1998.tb02384.x", "issn": "0002-7820", "publisher": "Wiley", "publication": "Journal of the American Ceramic Society", "publication_date": "1998-03", "series_number": "3", "volume": "81", "issue": "3", "pages": "646-648" }, { "id": "authors:mcggp-pb893", "collection": "authors", "collection_id": "mcggp-pb893", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141029-124402302", "type": "article", "title": "Effect of clouds on direct aerosol radiative forcing of climate", "author": [ { "family_name": "Liao", "given_name": "Hong", "clpid": "Liao-Hong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The effect of a cloud layer on top-of-atmosphere (TOA) aerosol radiative forcing is examined by means of a one-dimensional vertical column simulation. To span the range between nonabsorbing and strongly absorbing particles, (NH_4)_2SO_4 and soot aerosols are considered individually and in internal and external mixtures. For a cloud layer embedded within an aerosol layer it is shown that direct aerosol radiative forcing still occurs. For a nonabsorbing aerosol a maximum in (negative) forcing actually occurs for a thin cloud layer (100 m thickness for the set of parameters considered). The presence of an embedded cloud layer enhances the heating effect of soot aerosol, producing, for thick clouds, forcing values as much as a factor of 3 over those under cloud-free conditions. An absorbing aerosol layer can lead to an increase of in-cloud solar heating rates by up to 3% for the parameter values considered here. A cirrus cloud layer above an aerosol layer leads to only modest changes of TOA aerosol forcing from those in the absence of the cloud layer; thus aerosol forcing in the presence of typical cirrus clouds cannot be neglected.", "doi": "10.1029/97JD03455", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "1998-02-27", "series_number": "D4", "volume": "103", "issue": "D4", "pages": "3781-3788" }, { "id": "authors:jwt9m-2yy65", "collection": "authors", "collection_id": "jwt9m-2yy65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150605-102510514", "type": "article", "title": "Clouds, contrails and climate", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Cirrus clouds warm the Earth. Their formation is incompletely understood, but recent studies hint that they can evolve from jet contrails. This is an unsuspected, but possibly important, effect of human activity on climate \u2014 offering a new way to study the processes involved.", "doi": "10.1038/35974", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "1998-02-26", "series_number": "6670", "volume": "391", "issue": "6670", "pages": "837-838" }, { "id": "authors:g53nj-56k76", "collection": "authors", "collection_id": "g53nj-56k76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-242167600.2", "type": "article", "title": "Size-resolved and chemically resolved model of atmospheric aerosol dynamics", "author": [ { "family_name": "Meng", "given_name": "Zhaoyue", "clpid": "Meng-Zhaoyue" }, { "family_name": "Dabdub", "given_name": "Donald", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A three-dimensional, size-resolved and chemically resolved aerosol model is developed. Gas-to-particle conversion is represented by dynamic mass transfer between the gas and aerosol phases. Particle-phase thermodynamics is computed by a new thermodynamic model, Simulating Composition of Atmospheric Particles at Equilibrium 2. The aerosol model is applied to simulate gas and aerosol behavior in the August 27\u201329, 1987, episode in the South Coast Air Basin of California. The assumption that volatile inorganic species such as NH\u2084NO\u2083 are at instantaneous, local equilibrium is examined.", "doi": "10.1029/97jd02796", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1998-02-20", "series_number": "D3", "volume": "103", "issue": "D3", "pages": "3419-3435" }, { "id": "authors:f7ksz-gfj62", "collection": "authors", "collection_id": "f7ksz-gfj62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-478708400.1", "type": "article", "title": "Nanometer-Sized Particle Formation from NH\u2083/SO\u2082/H\u2082O/Air Mixtures by Ionizing Irradiation", "author": [ { "family_name": "Kim", "given_name": "Tae Oh", "clpid": "Kim-Tae-Oh" }, { "family_name": "Ishida", "given_name": "Takashi", "clpid": "Ishida-Takashi" }, { "family_name": "Adachi", "given_name": "Motoaki", "clpid": "Adachi-Motoaki" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Formation of nanometer-sized particles in NH\u2083/SO\u2082/H\u2082O/Air mixtures by \u03b1-ray irradiation was studied experimentally to evaluate the effect of NH3 gas on the gas-to-particle conversion process. The total particle number concentration, the charged-particle fraction, and the electrical mobility distribution of particles generated in the ionization chamber were measured at various NH\u2083, SO\u2082, and H\u2082O vapor concentrations and residence times of the gas mixture. Particle generation was enhanced in the presence of NH\u2083, but the enhancement depends greatly on the SO\u2082, NH\u2083, and H\u2082O concentrations; particle number concentrations at NH\u2083 mixing ratios of 0.71\u20133.6 ppm were 2\u20134 times higher than those in the absence of NH\u2083, but were constant in this range of NH\u2083 concentration. The charged-particle fraction decreased with the addition of NH\u2083, which indicated that ion-induced nucleation was decreased and homogeneous nucleation was enhanced. To evaluate the number concentrations of gaseous products, kinetic equations for the vapor species were solved on the basis of chain reactions initiated by OH radicals. From comparisons between experimental and predicted behavior, it is strongly suggested that the NH\u2083SO\u2083 species is the principal route to nanometer-sized particles in the NH\u2083/SO\u2082/H\u2082O/Air mixture.", "doi": "10.1080/02786829808965556", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1998-01", "series_number": "2", "volume": "29", "issue": "2", "pages": "111-125" }, { "id": "authors:e1z2p-dec59", "collection": "authors", "collection_id": "e1z2p-dec59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-480771600.2", "type": "article", "title": "Size- and Composition-Resolved Externally Mixed Aerosol Model", "author": [ { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The need for a numerical algorithm to predict the growth of external mixtures of aerosol populations is common to several current areas of study, including aerosol radiative effects, particle production processes, and pollution source apportionment. This work describes a model that solves this problem for explicit external and internal mixtures for the processes of coagulation, condensation, deposition, activation, and nucleation. The solution is numerically accurate for both particulate mass and number conservation by virtue of a dual-moment sectional method for solute growth. In addition, evaporable components are calculated in moving sections to retain information during particle activation in supersaturated conditions. The model is illustrated by application to the problem of cloud processing in a marine boundary layer capped with a layer of stratus clouds. The aerosol population is tracked in an air parcel circulating within the boundary layer and through the cloud layer. Boundary layer structure and cloud supersaturation profiles are predicted from gradients of observed thermodynamic variables. The model shows the differential growth of particles during cloud processing in two different types of particle populations, one of sea-salt origin and the other of sulfate origin.", "doi": "10.1080/02786829808965534", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1998-01", "series_number": "5", "volume": "28", "issue": "5", "pages": "403-416" }, { "id": "authors:gb2yr-cbp52", "collection": "authors", "collection_id": "gb2yr-cbp52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150609-080501350", "type": "article", "title": "Kinetic limitations on droplet formation in clouds", "author": [ { "family_name": "Chuang", "given_name": "P. Y.", "clpid": "Chuang-P-Y" }, { "family_name": "Charlson", "given_name": "Robert J.", "clpid": "Charlson-R-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The 'indirect' radiative cooling of climate due to the role of anthropogenic aerosols in cloud droplet formation processes (which affect cloud albedo) is potentially large, up to -1.5 W m^(-2) (ref. 1). It is important to be able to determine the number concentration of cloud droplets to within a few per cent, as radiative forcing as a result of clouds is very sensitive to changes in this quantity, but empirical approaches are problematic. The initial growth of a subset of particles known as cloud condensation nuclei and their subsequent 'activation' to form droplets are generally calculated with the assumption that cloud droplet activation occurs as an equilibrium process described by classical K\u00f6hler theory. Here we show that this assumption can be invalid under certain realistic conditions. We conclude that the poor empirical correlation between cloud droplet and cloud condensation nuclei concentrations is partly a result of kinetically limited growth before droplet activation occurs. Ignoring these considerations in calculations of total cloud radiative forcing based on cloud condensation nuclei concentrations could lead to errors that are of the same order of magnitude as the total anthropogenic greenhouse-gas radiative forcing.", "doi": "10.1038/37576", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "1997-12-11", "series_number": "6660", "volume": "390", "issue": "6660", "pages": "594-596" }, { "id": "authors:krxxv-e5x19", "collection": "authors", "collection_id": "krxxv-e5x19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-242167600.4", "type": "article", "title": "Mathematical model for gas-particle partitioning of secondary organic aerosols", "author": [ { "family_name": "Bowman", "given_name": "Frank M.", "clpid": "Bowman-Frank-M" }, { "family_name": "Odum", "given_name": "Jay R.", "clpid": "Odum-Jay-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" } ], "abstract": "A dynamic model is developed for gas-particle absorptive partitioning of semi-volatile organic aerosols. The model is applied to simulate a pair of m-xylene/NO\u2093 outdoor smog chamber experiments. In the presence of an inorganic seed aerosol a threshold for aerosol formation is predicted. An examination of characteristic times suggests conditions where an assumption of instantaneous gas-particle equilibrium is justified. Semi-volatile products that are second-generation, rather than first-generation, products of a parent hydrocarbon cause a delay in aerosol formation due to the delayed rate at which the second-generation products are formed. The gas-particle accommodation coefficient is the principal transport parameter and is estimated to have a value between 1.0 and 0.1 for the m-xylene aerosol.", "doi": "10.1016/s1352-2310(97)00245-8", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1997-12", "series_number": "23", "volume": "31", "issue": "23", "pages": "3921-3931" }, { "id": "authors:3mqdy-hzt44", "collection": "authors", "collection_id": "3mqdy-hzt44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180510-160557448", "type": "article", "title": "Gas/Particle Partitioning of Semivolatile Organic Compounds To Model Inorganic, Organic, and Ambient Smog Aerosols", "author": [ { "family_name": "Liang", "given_name": "Cikui", "clpid": "Liang-Cikui" }, { "family_name": "Pankow", "given_name": "James F.", "clpid": "Pankow-J-F" }, { "family_name": "Odum", "given_name": "Jay R.", "clpid": "Odum-J-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Gas/particle (G/P) partitioning is an important process that affects the deposition, chemical reactions, long-range transport, and impact on human and ecosystem health of atmospheric semivolatile organic compounds (SOCs). Gas/particle partitioning coefficients (K_p) were measured in an outdoor chamber for a group of polynuclear aromatic hydrocarbons (PAHs) and n-alkanes sorbing to three types of model aerosol materials:\u2009 solid ammonium sulfate, liquid dioctyl phthalate (DOP), and secondary organic aerosol (SOA) generated from the photooxidation of whole gasoline vapor. K_p values were also measured for ambient n-alkanes sorbing to urban particulate material (UPM) during summer smog episodes in the Los Angeles metropolitan area. Based on the K_p values obtained for the aerosols studied here, for environmental tobacco smoke (ETS), and for a quartz surface, we conclude that G/P partitioning of SOCs to UPM during summer smog episodes is dominated by absorption into the organic fraction in the aerosol. Comparisons of the partitioning of SOCs to three different types of aerosols demonstrate that (1) DOP aerosol may be a good surrogate for ambient aerosol that consists mainly of organic compounds from primary emissions; (2) ETS particles may be a good surrogate for SOA; and (3) the sorption properties of ambient smog aerosol and the chamber-generated SOA from gasoline are very similar. The similarities observed between ambient smog aerosol and chamber-generated SOA from gasoline support the use of literature SOA yield data from smog chamber studies to predict the extent of SOA formation during summer midday smog episodes.", "doi": "10.1021/es9702529", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1997-11", "series_number": "11", "volume": "31", "issue": "11", "pages": "3086-3092" }, { "id": "authors:wbx07-tym26", "collection": "authors", "collection_id": "wbx07-tym26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-980742900.4", "type": "article", "title": "Benchmarking stiff ode solvers for atmospheric chemistry problems-I. implicit vs explicit", "author": [ { "family_name": "Sandu", "given_name": "A.", "orcid": "0000-0002-5380-0103", "clpid": "Sandu-Adrian" }, { "family_name": "Verwer", "given_name": "J. G.", "clpid": "Verwer-Jan-G" }, { "family_name": "Van Loon", "given_name": "M.", "clpid": "Van-Loon-Maarten" }, { "family_name": "Carmichael", "given_name": "G. R.", "orcid": "0000-0001-8097-3475", "clpid": "Carmichael-Gregory-R" }, { "family_name": "Potra", "given_name": "F. A.", "clpid": "Potra-Florian-A" }, { "family_name": "Dabdub", "given_name": "D.", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In many applications of atmospheric transport-chemistry problems, a major task is the numerical integration of the stiff systems of ordinary differential equations describing the chemical transformations. This paper presents a comprehensive numerical comparison between five dedicated explicit and four implicit solvers for a set of seven benchmark problems from actual applications. The implicit solvers use sparse matrix techniques to economize on the numerical linear algebra overhead. As a result they are often more efficient than the dedicated explicit ones, particularly when approximately two or more figures of accuracy are required. In most test cases, sparse RODAs, a Rosenbrock solver, came out as most competitive in the 1% error region. Of the dedicated explicit solvers, TWOSTEP came out as best. When less than 1% accuracy is aimed at, this solver performs very efficiently for tropospheric gas-phase problems. However, like all other dedicated explicit solvers, it cannot efficiently deal with gas-liquid phase chemistry. The results presented may constitute a guide for atmospheric modelers to select a suitable integrator based on the type and dimension of their chemical mechanism and on the desired level of accuracy. Furthermore, we would like to consider this paper an open invitation for other groups to add new representative test problems to those described here and to benchmark their numerical algorithms in our standard computational environment.", "doi": "10.1016/s1352-2310(97)00059-9", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1997-10", "series_number": "19", "volume": "31", "issue": "19", "pages": "3151-3166" }, { "id": "authors:6xykz-32490", "collection": "authors", "collection_id": "6xykz-32490", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-980742900.6", "type": "article", "title": "Modelling urban and regional aerosols\u2014II. Application to California's South Coast Air Basin", "author": [ { "family_name": "Lurmann", "given_name": "F. W.", "orcid": "0000-0001-9943-4172", "clpid": "Lurmann-Fred-W" }, { "family_name": "Wexler", "given_name": "A. S.", "orcid": "0000-0003-1565-814X", "clpid": "Wexler-Anthony-S" }, { "family_name": "Pandis", "given_name": "S. N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Musarra", "given_name": "S.", "clpid": "Musarra-S" }, { "family_name": "Kumar", "given_name": "N.", "clpid": "Kumar-N" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A three-dimensional gas/aerosol atmospheric model is presented that predicts the size-resolved concentrations of all major primary and secondary components of atmospheric particulate matter (PM), including sulfate, nitrate, ammonium, chloride, sodium, elemental carbon, organic carbon, water, and crustal material. Aerosol size resolution is based on a sectional representation, typically extending from 0.01 to 10 \u03bc for aerosols and from 0.01 to 30 \u03bc when fog is present. The model is based on an internally mixed aerosol, wherein all particles in a specific size range are assumed to have the same chemical composition. Gas/aerosol equilibrium is computed based on the SEQUILIB algorithm of Pilinis and Seinfeld. An empirical fog model is included that approximates the effect of fogs on gas-phase photolysis rates, on aqueous-phase chemical reactions of sulfate and nitrate, and on the growth and shrinkage of the aerosol/fog droplet size distribution. The model is applied to simulate atmospheric conditions in the South Coast Air Basin of California during the 24\u201325 June 1987 episode of the Southern California Air Quality Study (SCAQS). The sensitivity of predicted aerosol levels to changes in source emissions is investigated.", "doi": "10.1016/s1352-2310(97)00100-3", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1997-09", "series_number": "17", "volume": "31", "issue": "17", "pages": "2695-2715" }, { "id": "authors:1h5g2-m4e64", "collection": "authors", "collection_id": "1h5g2-m4e64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:JUNjcp97", "type": "article", "title": "Prediction of bond dissociation energies and transition state barriers by a modified complete basis set model chemistry", "author": [ { "family_name": "Jungkamp", "given_name": "Tim P. W.", "clpid": "Jungkamp-T-P-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The complete basis set model chemistries CBS-4 and CBS-q were modified using density functional theory for the geometry optimization step of these methods. The accuracy of predicted bond dissociation energies and transition state barrier heights was investigated based on geometry optimizations using the B3LYP functional with basis set sizes ranging from 3-21G(d,p) to 6-311G(d,p). Transition state barrier heights can be obtained at CBS-q with B3LYP/6-31G(d,p) geometries with rms error of 1.7 kcal/mol within a test set of ten transition state species. The method should be applicable to molecules with up to eight or more heavy atoms. Use of B3LYP/6-311G(d,p) for geometry optimizations leads to further improvement of CBS-q barrier heights with a rms error of 1.4 kcal/mol. For reference, the CBS-QCI/APNO model chemistry was evaluated and is shown to provide very reliable predictions of barrier heights (rms error=1.0 kcal/mol).", "doi": "10.1063/1.474504", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1997-08-01", "series_number": "5", "volume": "107", "issue": "5", "pages": "1513-1521" }, { "id": "authors:jwxv8-pk024", "collection": "authors", "collection_id": "jwxv8-pk024", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141124-111417458", "type": "article", "title": "Chemical Coupling Between Atmospheric Ozone and Particulate Matter", "author": [ { "family_name": "Meng", "given_name": "Z.", "clpid": "Meng-Z" }, { "family_name": "Dabdub", "given_name": "D.", "clpid": "Dabdub-D" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A major fraction of ambient particulate matter arises from atmospheric gas-to-particle conversion. Attempts to reduce particulate matter levels require control of the same organic and nitrogen oxide (NO_x) emissions that are precursors to urban and regional ozone formation. Modeling of the gas-aerosol chemical interactions that govern levels of particulate components showed that control of gas-phase organic and NO_x precursors does not lead to proportionate reductions of the gas-phase\u2013derived components of atmospheric particles. The chemical coupling between ozone and particulate matter has implications for strategies to achieve the new ozone and particulate matter standards proposed by the U.S. Environmental Protection Agency.", "doi": "10.1126/science.277.5322.116", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1997-07-04", "series_number": "5322", "volume": "277", "issue": "5322", "pages": "116-119" }, { "id": "authors:4j23a-prj08", "collection": "authors", "collection_id": "4j23a-prj08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-980742900.7", "type": "article", "title": "Molecular speciation of secondary organic aerosol from photooxidation of the higher alkenes: 1-octene and 1-decene", "author": [ { "family_name": "Forstner", "given_name": "Hali J. L.", "clpid": "Forstner-Hali-J-L" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Outdoor smog chamber photooxidations to determine the molecular composition of secondary organic aerosol (SOA) from 1-octene and 1-decene in sunlight-irradiated hydrocarbon-NO_x mixtures are reported. The observed products are consistent with the current understanding of alkene reactions with OH and O\u2083. Gas-phase mechanisms leading to the observed products are outlined. Heptanal, heptanoic acid, and dihydro-5-propyl-2(3H)-furanone were the dominant organics identified in 1-octene aerosol. The corresponding species in 1-decene aerosol were nonanal, nonanoic acid, and dihydro-5-pentyl-2(3H)-furanone. Measured aerosol yields from 1-octene and 1-decene experiments are also reported, and are found to correlate with organic mass concentration according to semi-volatile gas/particle partitioning theory. A new organic aerosol extraction procedure utilizing supercritical CO\u2082 extraction is outlined.", "doi": "10.1016/s1352-2310(96)00356-1", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1997-07", "series_number": "13", "volume": "31", "issue": "13", "pages": "1953-1964" }, { "id": "authors:q4sw9-1pq93", "collection": "authors", "collection_id": "q4sw9-1pq93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-182702433", "type": "article", "title": "Rate constants for the gas-phase reaction of the hydroxyl radical with a series of dimethylbenzaldehydes and trimethylphenols at atmospheric pressure", "author": [ { "family_name": "Tse", "given_name": "Cecilia W.", "clpid": "Tse-Cecilia-W" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Rate constants for three dimethylbenzaldehydes and two trimethylphenols have been determined for the OH reactions at 298\u00b12 K and atmospheric pressure using a relative rate method. The OH reaction rate constants were placed on an absolute basis using the literature rate constant for 1,2,4-trimethylbenzene of (3.25\u00b10.5)\u00d710\u207b\u00b9\u00b9 cm\u00b3 molecule\u207b\u00b9s\u207b\u00b9). The measured rate constants were (in units of cm\u00b3 molecule\u207b\u00b9 s\u207b\u00b9) 2,4-dimethyl-benzaldehyde, (4.32\u00b10.67)\u00d710\u207b\u00b9\u00b9; 2,5-dimethylbenzaldehyde, (4.37\u00b10.68)\u00d710\u207b\u00b9\u00b9; 3,4-dimethylbenzaldehyde, (2.14\u00b10.34)\u00d710\u207b\u00b9\u00b9; and 2,3,5- trimethylphenol, (12.5\u00b11.9)\u00d710\u207b\u00b9\u00b9, 2,3,6-trimethylphenol, (11.8\u00b11.8)\u00d710\u207b\u00b9\u00b9. Using an average OH concentration of 8.7\u00d710\u2075 molecule cm\u207b\u00b3, the estimated atmospheric lifetimes are ca. 7.5 h for 2,4- and 2,5-dimethylbenzaldehydes, ca. 15 h for 3,4-dimethylbenzaldehyde, ca. 2.5 h for 2,3,5- and 2,3,6-trimethylphenols. The reactivities of the trimethylphenols exceed those of the dimethyl-benzaldehydes by more than a factor of 3.", "doi": "10.1002/(SICI)1097-4601(1997)29:7%3C523::AID-KIN6%3E3.0.CO;2-W", "issn": "0538-8066", "publisher": "Wiley", "publication": "International Journal of Chemical Kinetics", "publication_date": "1997-07", "series_number": "7", "volume": "29", "issue": "7", "pages": "523-525" }, { "id": "authors:p8vqm-6ad53", "collection": "authors", "collection_id": "p8vqm-6ad53", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150806-164227268", "type": "article", "title": "Aromatics, Reformulated Gasoline, and Atmospheric Organic Aerosol Formation", "author": [ { "family_name": "Odum", "given_name": "J. R.", "clpid": "Odum-Jay-R" }, { "family_name": "Jungkamp", "given_name": "T. P. W.", "clpid": "Jungkamp-Tim-P-W" }, { "family_name": "Griffin", "given_name": "R. J.", "orcid": "0000-0001-7682-8769", "clpid": "Griffin-Robert-J" }, { "family_name": "Forstner", "given_name": "H. J. L.", "clpid": "Forstner-Hali-J-L" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) yield curves have been obtained for 17 individual aromatic species from an extensive series of sunlight-irradiated smog chamber experiments. These yield curves, interpreted within the framework of a gas/aerosol absorption model, are used to quantitatively account for the SOA that is formed in a series of smog chamber experiments performed with the whole vapor of 12 different reformulated gasolines. The total amount of secondary organic aerosol produced from the atmospheric oxidation of whole gasoline vapor can be represented as the sum of the contributions of the individual aromatic molecular constituents of the fuel.", "doi": "10.1021/es960535l", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1997-06-30", "series_number": "7", "volume": "31", "issue": "7", "pages": "1890-1897" }, { "id": "authors:fmd2m-8pt32", "collection": "authors", "collection_id": "fmd2m-8pt32", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-340483300.2", "type": "article", "title": "Atmospheric Oxidation Mechanism of n-Butane:\u2009 The Fate of Alkoxy Radicals", "author": [ { "family_name": "Jungkamp", "given_name": "Tim P. W.", "clpid": "Jungkamp-Tim-P-W" }, { "family_name": "Smith", "given_name": "James N.", "clpid": "Smith-James-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The atmospheric oxidation mechanism of n-butane is investigated by means of density functional theory and ab initio calculations. Calculation of energies of reactants, transition states, and stable intermediates predicts the detailed pathways leading to experimentally observed products of n-butane oxidation. Also serving as a model system for the oxidation of larger alkanes, quantitative information is obtained for elementary reaction steps that heretofore have been subject to speculation. Complete basis set model chemistries CBS-4 and CBS-q were used with B3LYP/6-31G(d,p) optimized geometries to calculate energies of over 70 stable species and transition states. Energies based on density functional theory were obtained at the B3LYP/6-311+G(3df,2p)//B3LYP/6-31G(d,p) level of theory. The principal pathway following formation of the 1-butyl radical from hydroxyl (OH) attack on n-butane is found to be 1,5-H shift of the 1-butoxy radical. After conversion to the \u03b4-hydroxy-1-butoxy radical, another 1,5-H shift is expected to be the primary route to 4-hydroxy-1-butanal. 4-Hydroperoxy-1-butanal can be formed after 1,6-H shift in chemically activated 4-hydroxy-1-butylperoxy radicals. Whereas \u03b2-scission in 1-butoxy is an endothermic process, fragmentation of 2-butoxy into C\u2082H\u2085 and CH\u2083CHO is predicted to be the major degradation pathway of the secondary butyl radicals.", "doi": "10.1021/jp970212r", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "1997-06-12", "series_number": "24", "volume": "101", "issue": "24", "pages": "4392-4401" }, { "id": "authors:naf3p-zgb60", "collection": "authors", "collection_id": "naf3p-zgb60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150806-163950869", "type": "article", "title": "Secondary Organic Aerosol from the Photooxidation of Aromatic Hydrocarbons: Molecular Composition", "author": [ { "family_name": "Forstner", "given_name": "Hali J. L.", "clpid": "Forstner-Hali-J-L" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Outdoor smog chamber photooxidations to determine the molecular composition of secondary organic aerosol (SOA) from toluene, m-xylene, p-xylene, ethylbenzene, m-ethyltoluene, p-ethyltoluene, and 1,2,4-trimethylbenzene in sunlight-irradiated hydrocarbon\u2212NO\u2093 mixtures are reported. Gas-phase mechanisms leading to the observed products are proposed. Unsaturated anhydrides (2,5-furandione, 3-methyl-2,5-furandione, 3-ethyl-2,5-furandione) are predominant components of aerosol from all the aromatics, an observation that is consistent with gas-phase aromatic mechanisms involving ring fragmentation. Saturated anhydrides were also detected in significant quantities, which could result from the hydrogenation of the furandiones in sunlight in the particle phase.", "doi": "10.1021/es9605376", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1997-04-29", "series_number": "5", "volume": "31", "issue": "5", "pages": "1345-1358" }, { "id": "authors:ths42-0r356", "collection": "authors", "collection_id": "ths42-0r356", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141126-125811492", "type": "article", "title": "The Atmospheric Aerosol-Forming Potential of Whole Gasoline Vapor", "author": [ { "family_name": "Odum", "given_name": "Jay R.", "clpid": "Odum-Jay-R" }, { "family_name": "Jungkamp", "given_name": "T. P. W.", "clpid": "Jungkamp-Tim-P-W" }, { "family_name": "Griffin", "given_name": "R. J.", "orcid": "0000-0001-7682-8769", "clpid": "Griffin-Robert-J" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A series of sunlight-irradiated, smog-chamber experiments confirmed that the atmospheric organic aerosol formation potential of whole gasoline vapor can be accounted for solely in terms of the aromatic fraction of the fuel. The total amount of secondary organic aerosol produced from the atmospheric oxidation of whole gasoline vapor can be represented as the sum of the contributions of the individual aromatic molecular constituents of the fuel. The urban atmospheric, anthropogenic hydrocarbon profile is approximated well by evaporated whole gasoline, and thus these results suggest that it is possible to model atmospheric secondary organic aerosol formation.", "doi": "10.1126/science.276.5309.96", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1997-04-04", "series_number": "5309", "volume": "276", "issue": "5309", "pages": "96-99" }, { "id": "authors:8a2q9-qze84", "collection": "authors", "collection_id": "8a2q9-qze84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-115101473", "type": "article", "title": "Formation of Organic Aerosols from the Oxidation of Biogenic Hydrocarbons", "author": [ { "family_name": "Hoffmann", "given_name": "Thorsten", "orcid": "0000-0003-0939-271X", "clpid": "Hoffmann-Thorsten" }, { "family_name": "Odum", "given_name": "Jay R.", "clpid": "Odum-Jay-R" }, { "family_name": "Bowman", "given_name": "Frank", "clpid": "Bowman-Frank-M" }, { "family_name": "Collins", "given_name": "Donald", "clpid": "Collins-Donald-R" }, { "family_name": "Klockow", "given_name": "Dieter", "clpid": "Klockow-Dieter" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Measurements of aerosol formation during thephotooxidation of \u03b1-pinene, \u03b2-pinene,d-3-carene, d-limonene, ocimene, linalool, terpinene-4-ol, andtrans-caryophyllene were conducted in an outdoor smog chamber. Daylight experiments in the presence of NO\u2093 and dark experiments with elevated ozone concentrations were performed. The evolution of the aerosol was simulated by the application of a gas/particle absorption model in connection with a chemical reaction mechanism. The fractional aerosol yield is shown to be a function of the organic aerosol mass concentration and temperature. Ozone and, for selected hydrocarbons, the NO\u2083 reaction of the compounds were found to represent efficient routes to the formation of condensable products. For initial hydrocarbon mixing ratios of about 100 ppb, the fractional aerosol yields from daylight runs have been estimated to be \u223c5% for open-chain hydrocarbons, such as ocimene and linalool, 5\u201325% for monounsaturated cyclic monoterpenes, such as \u03b1-pinene, d-3-carene, or terpinene-4-ol, and \u223c40% for a cyclic monoterpene with two double bonds like d-limonene. For the only sesquiterpene investigated, trans-caryophyllene, a fractional aerosol yield of close to 100% was observed. The majority of the compounds studied showed an even higher aerosol yield during dark experiments in the presence of ozone.", "doi": "10.1023/A:1005734301837", "issn": "0167-7764", "publisher": "Springer", "publication": "Journal of Atmospheric Chemistry", "publication_date": "1997-02", "series_number": "2", "volume": "26", "issue": "2", "pages": "189-222" }, { "id": "authors:qasgy-ah813", "collection": "authors", "collection_id": "qasgy-ah813", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-62428000.2", "type": "article", "title": "Bimodal character of accumulation mode aerosol mass distributions in Southern California", "author": [ { "family_name": "Hering", "given_name": "Susanne", "orcid": "0000-0001-6536-310X", "clpid": "Hering-Susanne" }, { "family_name": "Eldering", "given_name": "AnnMarie", "orcid": "0000-0003-1080-9922", "clpid": "Eldering-AnnMarie" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Size-resolved measurements of fine particle chemical composition and physical measurements of fine particle size distributions obtained during the Southern California Air Quality Study (SCAQS) are compared. Number distributions of the ambient aerosols were measured using optical particle counters and electrical aerosol analyzers. Optical counter data are reduced using an ambient-based calibration. Mass size distributions are inferred from the sum of size-resolved chemical composition as measured by impactors. Optical counter data reduced with an ambient-based calibration compare well to impactor measurements. Both sets of data show that the accumulation mode of the total mass size distribution may be bimodal. Condensation and droplet modes previously identified in chemical species size distributions are frequently apparent in the total mass size distribution.", "doi": "10.1016/s1352-2310(96)00175-6", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1997-01", "series_number": "1", "volume": "31", "issue": "1", "pages": "1-11" }, { "id": "authors:n5ep6-5tp40", "collection": "authors", "collection_id": "n5ep6-5tp40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-281718300.1", "type": "article", "title": "Experimental Measurement of Competitive Ion-Induced and Binary Homogeneous Nucleation in SO\u2082/H\u2082O/N\u2082 Mixtures", "author": [ { "family_name": "Kim", "given_name": "Tae Oh", "clpid": "Kim-Tae-Oh" }, { "family_name": "Adachi", "given_name": "Motoaki", "clpid": "Adachi-Motoaki" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Alpha-ray radiolysis of SO\u2082/H\u2082O/N\u2082 gas mixtures is carried out to investigate the competitive processes of ion-induced and binary homogeneous nucleation in this system. Charged particles in the system are indicative of ion-induced nucleation and most likely involve water clusters. Charged particle neutralization was prevented by application of a dc electric field, therefore, uncharged particles in the system result from homogeneous nucleation. Hydroxyl (OH) radicals are generated by the a-ray radiolysis. Oxidation of SO\u2082 by OH radicals leads to sulfuric acid (H\u2082SO\u2084) vapor molecules and to subsequent binary homogeneous nucleation of H\u2082SO\u2084/H\u2082O. At increased SO\u2082 concentrations the contribution of binary homogeneous nucleation increases relative to that of ion-induced nucleation. Electrical mobility distributions of bipolar ions and nanometer-sized charged particles were measured with a cluster-differential mobility analyzer combined with a Faraday cup electrometer. In this system, ion-induced nucleation occurred preferentially on negative rather than positive ions.", "doi": "10.1080/02786829708965451", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1997-01", "series_number": "6", "volume": "26", "issue": "6", "pages": "527-543" }, { "id": "authors:rajcx-4dp75", "collection": "authors", "collection_id": "rajcx-4dp75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-980742900.2", "type": "article", "title": "Analytical\u2013Numerical Solution of the Multicomponent Aerosol General Dynamic Equation\u2014with Coagulation", "author": [ { "family_name": "Katoshevski", "given_name": "David", "orcid": "0000-0003-4740-4275", "clpid": "Katoshevski-David" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A numerical procedure based on an analytical solution is presented for solution of the full multicomponent aerosol general dynamic equation. The analytical solution for the equation, accounting for growth, removal, and particle sources, is employed in an iterative procedure to account for coagulation. The iterative process is shown to be rapidly convergent, and its performance is validated by comparison with the exact solution for pure coagulation of a single-component aerosol. A simulation is presented of the evolution of a multicomponent coagulating aerosol, where each component grows-evaporates at a different rate.", "doi": "10.1080/02786829708965494", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1997-01", "series_number": "4", "volume": "27", "issue": "4", "pages": "550-556" }, { "id": "authors:c71dy-s4251", "collection": "authors", "collection_id": "c71dy-s4251", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-242167600.6", "type": "article", "title": "Analytical Solution of the Multicomponent Aerosol General Dynamic Equation\u2014without Coagulation", "author": [ { "family_name": "Katoshevski", "given_name": "David", "orcid": "0000-0003-4740-4275", "clpid": "Katoshevski-David" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An analytical analysis of multicomponent aerosol dynamics is presented. The analysis is applicable for linear as well as nonlinear condensation\u2014evaporation rates and for any type of initial size\u2014mass distribution. The effects of growth and removal are described, while the influence of particle coagulation is not considered. The analytical solution can be of use for describing the evolution of an initial mass distribution representing a multicomponent aerosol where each species grows-evaporates at a different rate.", "doi": "10.1080/02786829708965493", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1997-01", "series_number": "4", "volume": "27", "issue": "4", "pages": "541-549" }, { "id": "authors:ccp7w-rng13", "collection": "authors", "collection_id": "ccp7w-rng13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-923022000.1", "type": "article", "title": "The mechanism of methoxy radical oxidation: hydrogen abstraction versus trioxy radical formation", "author": [ { "family_name": "Jungkamp", "given_name": "Tim P. W.", "clpid": "Jungkamp-Tim-P-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The energetic profiles of the two possible pathways of formaldehyde and HO\u2082 radical formation in the oxidation of the methoxy radical CH\u2083O, i.e. (a) via H-abstraction or (b) as addition/elimination involving methyl trioxy radicals CH\u2083OOO as intermediates, were calculated using G2M(RCC) and CBS-QCI/APNO model chemistries. The 298 K barrier height for path (a) is found to be 11.5 (14.8) kcal/mol at G2M(RCC) level (CBS-QCI/APNO value in parentheses). Along path (b), the HO\u2082 elimination from cis-CH\u2083OOO is found to have a barrier of 1.3 (8.5) kcal/mol. Therefore, oxidation of CH\u2083O is likely to occur by forming the CH\u2083OOO intermediate rather than by H-abstraction.", "doi": "10.1016/s0009-2614(96)01197-9", "issn": "0009-2614", "publisher": "Elsevier", "publication": "Chemical Physics Letters", "publication_date": "1996-12-13", "series_number": "3-4", "volume": "263", "issue": "3-4", "pages": "371-378" }, { "id": "authors:vd5ty-kge11", "collection": "authors", "collection_id": "vd5ty-kge11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120712-083815675", "type": "article", "title": "Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS)", "author": [ { "family_name": "Bluth", "given_name": "R. T.", "clpid": "Bluth-R-T" }, { "family_name": "Durkee", "given_name": "P. A.", "clpid": "Durkee-Philip-A" }, { "family_name": "Finn", "given_name": "P.", "clpid": "Finn-P" }, { "family_name": "Russell", "given_name": "L. M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Crowley", "given_name": "P. A.", "clpid": "Crowley-P-A" } ], "abstract": "A remotely piloted aircraft research facility is described that will provide new capabilities for atmospheric and oceanographic measurements. The aircraft can fly up to 24 h over remote ocean regions, at low or high altitude, and in various other challenging mission scenarios. The aircraft will fly research missions at speeds of 40 m s^(\u22121) and provide high spatial resolution measurements. Data will be transmitted in real time to a ground station for analysis and decision-making purposes. The facility will expand the opportunities for universities to participate in field measurement programs.", "doi": "10.1175/1520-0477(1996)077<2691:CFIRPA>2.0.CO;2", "issn": "0003-0007", "publisher": "American Meteorological Society", "publication": "Bulletin of the American Meteorological Society", "publication_date": "1996-11", "series_number": "11", "volume": "77", "issue": "11", "pages": "2691-2699" }, { "id": "authors:wfwy3-j6r31", "collection": "authors", "collection_id": "wfwy3-j6r31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-924021800.2", "type": "article", "title": "Time scales to achieve atmospheric gas-aerosol equilibrium for volatile species", "author": [ { "family_name": "Meng", "given_name": "Zhaoyue", "clpid": "Meng-Zhaoyue" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Time scales to achieve gas-aerosol equilibrium for volatile atmospheric species are systematically studied. It is found that equilibration between submicron aerosol and the gas phase is attainable on a time scale comparable to that of typical ambient gas and aerosol dynamics. However, the time required for the coarse aerosol to reach equilibrium is predicted to be sufficiently long that volatile species in atmospheric coarse aerosol particles may generally exist in nonequilibrium transition states. Variation of the gas-phase concentrations of volatile compounds is generally controlled by equilibration with the fine-mode particles. Volatile compounds in the gas phase can approach the equilibrium state on a much shorter time scale than that of the gas-aerosol system. Sensitivity analysis is performed to study how the equilibration times depend on relative humidity, initial gas-phase concentrations, aerosol mass concentration, aerosol size, temperature, accommodation coefficient, and different chemical compositions. The equilibration time increases with increasing particle size, or decreasing accommodation coefficient or temperature. Transport calculations performed for typical ambient aerosols confirm the results obtained from hypothetical cases. Equilibrium for ammonia between the gas phase and submicron marine aerosol is also examined.", "doi": "10.1016/1352-2310(95)00493-9", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1996-08", "series_number": "16", "volume": "30", "issue": "16", "pages": "2889-2900" }, { "id": "authors:qwyvs-kjf98", "collection": "authors", "collection_id": "qwyvs-kjf98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-113921105", "type": "article", "title": "Gas/Particle Partitioning and Secondary Organic Aerosol Yields", "author": [ { "family_name": "Odum", "given_name": "Jay R.", "clpid": "Odum-Jay-R" }, { "family_name": "Hoffmann", "given_name": "Thorsten", "orcid": "0000-0003-0939-271X", "clpid": "Hoffmann-Thorsten" }, { "family_name": "Bowman", "given_name": "Frank", "clpid": "Bowman-Frank-M" }, { "family_name": "Collins", "given_name": "Don", "clpid": "Collins-Donald-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Secondary organic aerosol (SOA) formation is considered in the framework of the gas/particle partitioning absorption model outlined by Pankow. Expressions for the fractional SOA yield (Y) are developed within this framework and shown to be a function of the organic aerosol mass concentration, M\u2092. These expressions are applied to over 30 individual reactive organic gas (ROG) photooxidation smog chamber experiments. Analysis of the data from these experiments clearly shows that Y is a strong function of M\u2092 and that secondary organic aerosol formation is best described by a gas/particle partitioning absorption model. In addition to the 30 individual ROG experiments, three experiments were performed with ROG mixtures. The expressions developed for Y in terms of M\u2092, used in conjunction with the overall yield data from the individual ROG experiments, are able to account for the M\u2092 generated in the ROG mixture experiments. This observation not only suggests that SOA yields for individual ROGs are additive but that smog chamber SOA yield data may be confidently extrapolated to the atmosphere in order to determine the important ambient sources of SOA in the environment.", "doi": "10.1021/es950943+", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1996-07-25", "series_number": "8", "volume": "30", "issue": "8", "pages": "2580-2585" }, { "id": "authors:gtnks-fte38", "collection": "authors", "collection_id": "gtnks-fte38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230222-499820700.2", "type": "article", "title": "The enthalpy of formation of trioxy radicals ROOO (R = H, CH\u2083, C\u2082H\u2085). An ab initio study", "author": [ { "family_name": "Jungkamp", "given_name": "Tim P. W.", "clpid": "Jungkamp-Tim-P-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Enthalpies of formation of trioxy radicals, ROOO, with R = H, CH\u2083, and C\u2082H\u2085, are calculated, along with values for the corresponding species R, RO, RO\u2082, RO\u2082H, and RO\u2083H using the G2M(RCC) approach, a modified Gaussian-2 model extrapolating the RCCSD(T)/6-311 + G(3df,2p) level of theory. Where applicable, CBS-QCI/APNO calculations were performed. The enthalpy of formation \u0394H_f\u2070 (298K) of cis-HOOO (\u00b2A\u2033) was determined to be 6.1 kcal/mol using the CBS-QCI/APNO model. The HO-OO bond dissociation energy was calculated using the G2M(RCC) formalism to be +1.31 kcal/mol for 0K which is very close to the result of +1.15 kcal/mol using the CBS-QCI/APNO model. The CH\u2083O-OO and C\u2082H\u2085O-OO bond energies were calculated to be \u22120.87 (G2M(RCC)) and \u22120.5 kcal/mol (G2M(RCC,MP2)).", "doi": "10.1016/0009-2614(96)00520-9", "issn": "0009-2614", "publisher": "Elsevier", "publication": "Chemical Physics Letters", "publication_date": "1996-07-19", "series_number": "1-2", "volume": "257", "issue": "1-2", "pages": "15-22" }, { "id": "authors:cqkgy-q5x26", "collection": "authors", "collection_id": "cqkgy-q5x26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160607-114130563", "type": "article", "title": "Mechanism of Atmospheric Photooxidation of Aromatics: A Theoretical Study", "author": [ { "family_name": "Andino", "given_name": "Jean M.", "clpid": "Andino-Jean-M" }, { "family_name": "Smith", "given_name": "James N.", "orcid": "0000-0003-4677-8224", "clpid": "Smith-James-N" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Goddard", "given_name": "William A., III", "orcid": "0000-0003-0097-5716", "clpid": "Goddard-W-A-III" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The mechanisms of atmospheric photooxidation of aromatic compounds are of seminal importance in the chemistry of the urban and regional atmosphere. It has been difficult to experimentally account for the full spectrum of oxidation products in laboratory studies. In an effort to fully elucidate the atmospheric reaction pathways for the aromatic\u2212OH reaction, we have conducted theoretical calculations on aromatic intermediates. Energies have been determined for these intermediates by using semiempirical UHF/PM3 geometry optimizations combined with ab initio calculations using density functional theory (DFT). A hybrid DFT model, the Becke3 parameter function with the nonlocal correlation function of Lee, Yang, and Parr, was used in conjunction with the 6-31G(d,p) basis set to study the intermediate structures. Full mechanisms for the OH-initiated photooxidation of toluene, m-xylene, p-xylene, 1,2,4-trimethylbenzene, and m-ethyltoluene are developed. The lowest energy intermediates have been determined, and predicted products from these structures are compared to available experimental product data. These studies serve to refine proposed mechanisms currently available for toluene, m-xylene, and p-xylene, while providing new information on the 1,2,4-trimethylbenzene and m-ethyltoluene reaction pathways.", "doi": "10.1021/jp952935l", "issn": "0022-3654", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry", "publication_date": "1996-06-27", "series_number": "26", "volume": "100", "issue": "26", "pages": "10967-10980" }, { "id": "authors:fhjs1-te535", "collection": "authors", "collection_id": "fhjs1-te535", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:RUSjaot96", "type": "article", "title": "Radially Classified Aerosol Detector for Aircraft-Based Submicron Aerosol Measurements", "author": [ { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Zhang", "given_name": "Shou-Hua", "clpid": "Zhang-Shou-Hua" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Stolzenburg", "given_name": "Mark R.", "orcid": "0000-0002-5528-6646", "clpid": "Stolzenburg-Mark-R" }, { "family_name": "Caldow", "given_name": "Robert", "clpid": "Caldow-Robert" } ], "abstract": "A radially classified aerosol detector (RCAD) for fast characterization of fine particle size distributions aboard aircraft has been designed and implemented. The measurement system includes a radial differential mobility analyzer and a high-flow, high-efficiency condensation nuclei counter based on modifications to a commercial model (TST, model 3010). Variations in pressure encountered during changes in altitude in flight are compensated by feedback control of volumetric flow rates with a damped proportional control algorithm. Sampling resolution is optimized with the use of an automated dual-bag sampling system. This new system has been tested aboard the University of Washington Cl31a research aircraft to demonstrate its in-flight performance capabilities. The system was used to make measurements of aerosol, providing observations of the spatial variability within the cloud-topped boundary layer off the coast of Monterey, California.", "doi": "10.1175/1520-0426(1996)013<0598:RCADFA>2.0.CO;2", "issn": "0739-0572", "publisher": "American Meteorological Society", "publication": "Journal of Atmospheric and Oceanic Technology", "publication_date": "1996-06", "series_number": "3", "volume": "13", "issue": "3", "pages": "598-609" }, { "id": "authors:dd533-2mt63", "collection": "authors", "collection_id": "dd533-2mt63", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180720-152513589", "type": "article", "title": "Atmospheric Photochemical Oxidation of Benzene:\u2009 Benzene + OH and the Benzene\u2212OH Adduct (Hydroxyl-2,4-cyclohexadienyl) + O_2", "author": [ { "family_name": "Lay", "given_name": "Tsan H.", "clpid": "Lay-Tsan-H" }, { "family_name": "Bozzelli", "given_name": "Joseph W.", "clpid": "Bozzelli-J-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The addition of hydroxyl radical to benzene leading to the formation of the hydroxyl-2,4-cyclohexadienyl radical (benzene\u2212OH adduct, BOH) initiates the atmospheric oxidation of benzene. This reaction and subsequent reactions of the BOH adduct with O_2 are chemically activated reactions. Rate constants of these chemically activated bimolecular reactions and unimolecular decompositions are analyzed using a quantum version of Rice\u2212Ramsperger\u2212Kassel theory (QRRK) for k(E) and a modified strong collision approach for falloff. Results of QRRK analyses show that stabilization channels of energized BOH and benzene\u2212OH\u2212O_2 (BOHO_2) adducts are dominant in chemically activated reaction systems under atmospheric condition. Unimolecular reactions of stabilized adducts to products are also important. Thermodynamic parameters (\u0394H_f^\u00b0_(298), S^\u00b0_(298), and C_p(T)s) are calculated using group additivity techniques with evaluated bond energies (for \u0394H_f^\u00b0_(298)) and semiempirical PM3 molecular orbital calculations (for S6\u00b0_(298) and C_p(T)s). A limited elementary reaction mechanism that includes 29 reactions and 26 species is developed with reverse reaction rates determined from species thermodynamic parameters and microscopic reversibility for each step. Simulation results of three reaction systems indicate that pseudo-equilibrium is attained and that equilibrium levels of the important BOH and BOHO_2 adducts are controlled by thermodynamic properties. The most important bicyclic intermediate leading to ring cleavage products is adduct III. Rate constants of important bimolecular reactions are (k = A(T/K)^n exp(\u2212E_a/RT), A in cm^3/(mol s), Ea in kcal/mol): k^4, (4.65 \u00d7 10^(15))(T/K)^(-1.18) e^(-1.23/RT) for C)6H)6 + OH \u21d2 BOH; k_7, (3.55 \u00d7 10^(36))(T/K)^(-8.86) e^(-3.79/RT) for BOH + O_2 \u21d2 BOHO_2; k_8, (1.73 \u00d7 10^(10))(T/K)^(-0.26) e^(-8.28/RT) for BOH + O_2 \u21d2 hexadienedial + OH; k_9, (7.06 \u00d7 10^(14))(T/K)^(-1.83) e^(-5.36/RT) for BOH + O_2 \u21d2 phenol + HO_2; k_(10), (2.14 \u00d7 10^(15))(T/K)^(-2.05) e^(-4.69/RT) for BOH + O_2 \u21d2 adduct III. Rate constants of important unimolecular reactions are (A in s^(-1)): k_6, (2.04 \u00d7 10^(25))(T/K)^(-4.2) e^(-24.5/RT) for BOH \u21d2 phenol + H; k_(15), (6.30 \u00d7 10^(40))(T/K)^(-10.86) e^(-19.4/RT) for BOHO)2 \u21d2 phenol + HO)2; k_(16), (1.43 \u00d7 10^(42))(T/K)^(-11.34) e^(-18.8/RT) for BOHO_2 \u21d2 adduct III.", "doi": "10.1021/jp951726y", "issn": "0022-3654", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry", "publication_date": "1996-04-18", "series_number": "16", "volume": "100", "issue": "16", "pages": "6543-6554" }, { "id": "authors:1mkmr-2vh17", "collection": "authors", "collection_id": "1mkmr-2vh17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180510-152204183", "type": "article", "title": "Atmospheric Chemistry of 1-Octene, 1-Decene, and Cyclohexene: Gas-Phase Carbonyl and Peroxyacyl Nitrate Products", "author": [ { "family_name": "Grosjean", "given_name": "Eric", "clpid": "Grosjean-E" }, { "family_name": "Grosjean", "given_name": "Daniel", "clpid": "Grosjean-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric reactions of 1-octene, 1-decene, and cyclohexene have been studied in laboratory experiments involving alkene\u2212ozone mixtures in the dark and alkene\u2212NO and aldehyde\u2212NO mixtures in sunlight. Major carbonyl products of the alkene\u2212ozone reaction (with sufficient cyclohexane added to scavenge OH) were heptanal from 1-octene, nonanal from 1-decene, formaldehyde from both, and pentanal from cyclohexene. For 1-octene and 1-decene, carbonyl formation yields were consistent with the simple mechanism:\u2009 RCH = CH_2 + O_3 \u2192 0.5(HCHO + RCHOO) + 0.5(RCHO + H_2COO). Other carbonyls were formed and accounted for ca. 0.10\u22120.20 of the subsequent reactions of the RCHOO biradical. Pentanal accounted for ca. 0.16 of the cyclohexene\u2212O_3 reaction. Sunlight irradiation of alkene\u2212NO and aldehyde\u2212NO mixtures leads to carbonyls, alkyl nitrates, and peroxyacyl nitrates. Major carbonyl products of the OH\u2212alkene reaction were heptanal from 1-octene, nonanal from 1-decene, and formaldehyde from both. Experimental data indicated that addition is an important pathway of the overall OH\u22121-alkene reaction, decomposition is important for the \u03b2-hydroxyalkoxy radicals that form following OH addition, and reaction with O2 is of some importance for the alkoxy radicals that form in several pathways in the alkene\u2212NO (sunlight), aldehyde\u2212NO (sunlight), and peroxyacyl nitrate\u2212NO (dark) systems. The extent of isomerization of alkoxy and \u03b2-hydroxyalkoxy radicals could not be assessed. Several peroxyacyl nitrates [RC(O)OONO_2] were formed including those with R = n-C_4H_9 from cyclohexene, R = n-C_5H_(11) from hexanal, and R = n-C_6H_(13) from heptanal and from 1-octene. The thermal decomposition rates of n-C_5H_(11)C(O)OONO_2 and n-C_6H_(13)C(O)OONO_2, which were synthesized in the liquid phase and were characterized in a number of tests using electron capture gas chromatography, were (in units of 10^(-4) s^(-1)) 0.72\u22122.02 (T = 291\u2212299 K) and 0.61\u22121.19 (T = 291\u2212295 K), respectively, at p = 1 atm of air. Comparison with data for lower molecular weight homologues including PAN (R = CH_3) suggests that the thermal stability of peroxyacyl nitrates may increase with the size of the n-alkyl substituent. The atmospheric persistence of the atmospheric oxidation products of 1-octene, 1-decene, and cyclohexene is briefly discussed.", "doi": "10.1021/es950592z", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1996-02-26", "series_number": "3", "volume": "30", "issue": "3", "pages": "1038-1047" }, { "id": "authors:2qyk2-b9e92", "collection": "authors", "collection_id": "2qyk2-b9e92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230223-180952000.1", "type": "article", "title": "Characterization of submicron aerosol size distributions from time-resolved measurements in the Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange", "author": [ { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Huebert", "given_name": "Barry J.", "orcid": "0000-0001-7711-0468", "clpid": "Huebert-Barry-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "As part of the Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange (ASTEX/MAGE), ship-based aerosol size distribution measurements have been carried out with a scanning electrical mobility spectrometer (SEMS) aboard the R/V Oceanus. The fast time resolution of these measurements illustrates some of the short-timescale variability of both the marine background aerosol and the anthropogenically influenced continental air masses. The resulting total number concentrations are largely in agreement with those from a collocated condensation nucleus counter (CNC). The aerosol size distributions provide characteristic signatures for different atmospheric conditions, showing low-concentration bimodal distributions in cleaner air masses and higher-concentration single-mode distributions in air masses with apparent recent continental influence.", "doi": "10.1029/95jd01372", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1996-02-20", "series_number": "D2", "volume": "101", "issue": "D2", "pages": "4469-4478" }, { "id": "authors:8f345-k7387", "collection": "authors", "collection_id": "8f345-k7387", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230226-660977600.2", "type": "article", "title": "Parallel computation in atmospheric chemical modeling", "author": [ { "family_name": "Dabdub", "given_name": "Donald", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The porting of atmospheric chemical dynamic models to massively parallel computers presents interesting computational challenges. Strategies for the parallelization of the transport and chemistry operators of atmospheric models are outlined. The use of parallel buffers to perform input/output operations is described. Results are given for implementation of the CIT urban air pollution model on distributed memory multiple instruction/multiple data (MIMD) machines ranging from a cluster of workstations to a 512 node Intel Paragon. A speed-up factor of 94.9 is achieved when the I/O, transport, and chemistry portions of the model are performed in parallel using 256 nodes of the Intel Paragon.", "doi": "10.1016/0167-8191(95)00063-1", "issn": "0167-8191", "publisher": "Elsevier", "publication": "Parallel Computing", "publication_date": "1996-01", "series_number": "1", "volume": "22", "issue": "1", "pages": "111-130" }, { "id": "authors:2hn96-37618", "collection": "authors", "collection_id": "2hn96-37618", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp95b", "type": "article", "title": "Ion-induced nucleation. II. Polarizable multipolar molecules", "author": [ { "family_name": "Kusaka", "given_name": "I.", "clpid": "Kusaka-Isamu" }, { "family_name": "Wang", "given_name": "Z.-G.", "orcid": "0000-0002-3361-6114", "clpid": "Wang-Zhen-Gang" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Density functional theory is applied to ion-induced nucleation of polarizable multipolar molecules. The asymmetric nature of the ion-molecule interaction is shown to cause the sign preference in ion-induced nucleation. When the ion-molecule interaction is weak, the observed sign preference is consistent with that of the bare ion-molecule interaction potential and decreases with increasing supersaturation. However, as the ion-molecule interaction becomes stronger, the sign preference in the reversible work exhibits some nontrivial behavior. For molecular parameters applicable for CS2 and CH4, the predicted values of the reversible work of nucleation depend on the sign of the ion charge, yielding a difference in the nucleation rate by factors of 10 to 10^(2) and 10 to 10^(5), respectively.", "doi": "10.1063/1.470089", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1995-11-22", "series_number": "20", "volume": "103", "issue": "20", "pages": "8993-9009" }, { "id": "authors:8w2v6-t9803", "collection": "authors", "collection_id": "8w2v6-t9803", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230226-660977600.3", "type": "article", "title": "Emission Reductions Needed to Meet the Standard for Ozone in Southern California: Effect of Boundary Conditions", "author": [ { "family_name": "Kuklin", "given_name": "Aleksandr", "clpid": "Kuklin-Aleksandr" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Combinations of total reactive organic gas (ROG) and nitrogen oxide (NO\u2093) emissions that do not exceed the National Ambient Air Quality Standard (NAAQS) for ozone for the meteorological conditions of the August 26-28, 1987 SCAQS episode, have been determined using the California Institute of Technology (CIT) photochemical air quality model. The sensitivity of these combinations to pollutant boundary conditions is examined.", "doi": "10.1080/10473289.1995.10467421", "issn": "1096-2247", "publisher": "Taylor & Francis", "publication": "Journal of the Air & Waste Management Association", "publication_date": "1995-11", "series_number": "11", "volume": "45", "issue": "11", "pages": "899-901" }, { "id": "authors:v8v6c-3pt66", "collection": "authors", "collection_id": "v8v6c-3pt66", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230226-660977600.8", "type": "article", "title": "Sensitivity of direct climate forcing by atmospheric aerosols to aerosol size and composition", "author": [ { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We evaluate, using a box model, the sensitivity of direct climate forcing by atmospheric aerosols for a \"global mean\" aerosol that consists of fine and coarse modes to aerosol composition, aerosol size distribution, relative humidity (RH), aerosol mixing state (internal versus external mixture), deliquescence/crystallization hysteresis, and solar zenith angle. We also examine the dependence of aerosol upscatter fraction on aerosol size, solar zenith angle, and wavelength and the dependence of single scatter albedo on wavelength and aerosol composition. The single most important parameter in determining direct aerosol forcing is relative humidity, and the most important process is the increase of the aerosol mass as a result of water uptake. An increase of the relative humidity from 40 to 80% is estimated for the global mean aerosol considered to result in an increase of the radiative forcing by a factor of 2.1. Forcing is relatively insensitive to the fine mode diameter increase due to hygroscopic growth, as long as this mode remains inside the efficient scattering size region. The hysteresis/deliquescence region introduces additional uncertainty but, in general, errors less than 20% result by the use of the average of the two curves to predict forcing. For fine aerosol mode mean diameters in the 0.2\u20130.5 \u03bcm range direct aerosol forcing is relatively insensitive (errors less than 20%) to variations of the mean diameter. Estimation of the coarse mode diameter within a factor of 2 is generally sufficient for the estimation of the total aerosol radiative forcing within 20%. Moreover, the coarse mode, which represents the nonanthropogenic fraction of the aerosol, is estimated to contribute less than 10% of the total radiative forcing for all RHs of interest. Aerosol chemical composition is important to direct radiative forcing as it determines (1) water uptake with RH, and (2) optical properties. The effect of absorption by aerosol components on forcing is found to be significant even for single scatter albedo values of \u03c9=0.93\u20130.97. The absorbing aerosol component reduces the aerosol forcing from that in its absence by roughly 30% at 60% RH and 20% at 90% RH. The mixing state of the aerosol (internal versus external) for the particular aerosol considered here is found to be of secondary importance. While sulfate mass scattering efficiency (m\u00b2 (g SO\u2084\u00b2\u207b)\u207b\u00b9) and the normalized sulfate forcing (W (g SO\u2084\u00b2\u207b)\u207b\u00b9) increase strongly with RH, total mass scattering efficiency (m\u00b2 g\u207b\u00b9) and normalized forcing (W g\u207b\u00b9) are relatively insensitive to RH, wherein the mass of all species, including water, are accounted for. Following S. Nemesure et al. (Direct shortwave forcing of climate by anthropogenic sulfate aerosol: sensitivity to particle size, composition, and relative humidity, submitted to Journal of Geophysical Research, 1995), we find that aerosol feeing achieves a maximum at a particular solar zenith angle, reflecting a balance between increasing upscatter fraction with increasing solar zenith angle and decreasing solar flux (from Rayleigh scattering) with increasing solar zenith angle.", "doi": "10.1029/95jd02119", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1995-09-20", "series_number": "D9", "volume": "100", "issue": "D9", "pages": "18739-18754" }, { "id": "authors:4p2mb-mdy25", "collection": "authors", "collection_id": "4p2mb-mdy25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230226-708566600.1", "type": "article", "title": "Organics alter hygroscopic behavior of atmospheric particles", "author": [ { "family_name": "Saxena", "given_name": "Pradeep", "clpid": "Saxena-Pradeep" }, { "family_name": "Hildemann", "given_name": "Lynn M.", "orcid": "0000-0003-4772-915X", "clpid": "Hildemann-Lynn-M" }, { "family_name": "McMurry", "given_name": "Peter H.", "clpid": "McMurry-Peter-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The optical and chemical properties of atmospheric particles and their ability to act as cloud condensation nuclei (CCN) depend strongly upon their affinity for water. Laboratory experiments have shown that water soluble substances such as ammonium sulfate, ammonium nitrate, and sodium chloride, which are major inorganic components of atmospheric particles, absorb water in an amount proportional to water vapor pressure. Analogous information about the interactions between water and organics, which are another major component of atmospheric particles, is lacking. Here we analyze concurrent observations of particle chemical composition and water content from a continental nonurban (Grand Canyon) and an urban (Los Angeles) location to determine whether the water content of atmospheric particles is influenced by the presence of organics. By comparing the observed water content with the water content expected to be associated with the inorganic fraction, we find that the aggregate hygroscopic properties of inorganic particles are altered substantially when organics are also present. Furthermore, the alterations can be positive or negative. For the nonurban location, organics enhance water absorption by inorganics. In the relative humidity (RH) range of 80\u201388% organics account for 25\u201340% of the total water uptake, on average. For the urban location, on the other hand, the net effect of organics is to diminish water absorption of the inorganics by 25\u201335% in the RH range of 83\u201393%.", "doi": "10.1029/95jd01835", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1995-09-20", "series_number": "D9", "volume": "100", "issue": "D9", "pages": "18755-18770" }, { "id": "authors:rym2x-z8n22", "collection": "authors", "collection_id": "rym2x-z8n22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-19495300.3", "type": "article", "title": "Atmospheric chemistry of alternate fuels and reformulated gasoline components", "author": [ { "family_name": "Bowman", "given_name": "Frank M.", "clpid": "Bowman-Frank-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Recent air quality regulations have mandated the use of reformulated gasoline and alternate fuels in motor vehicles. Reformulated fuels are intended to reduce both ozone-forming volatile organic compound (VOC) emissions and air toxic emissions from vehicles. A method that allows the determination of the individual contributions of a single VOC to the ozone formation in a complex VOC/NO_x mixture is outlined and applied to eight potential reformulated fuel components. In calculations using a current comprehensive atmospheric chemical reaction mechanism a wide variety of organics are shown to be responsible for ozone production. The incremental reactivities of the fuel components, which are defined as the additional amount of ozone formed per amount of organic compound added to a base mixture, include both the direct production of ozone by the oxygenate itself and additional ozone produced by the VOC mixture when the oxygenate is added. The enhancement of ozone production attributable to the organic mixture upon adding the oxygenates is shown to be a result of changes to the organic free radical pool. Most of the fuel oxygenates have relatively low incremental reactivities due to their slow reaction rates and to the formation of relatively unreactive formate and acetate products. The more reactive fuel oxygenates are those containing ethyl groups, which react faster than their counterparts containing only methyl and tert-butyl groups.", "doi": "10.1016/0360-1285(95)00008-9", "issn": "0360-1285", "publisher": "Elsevier", "publication": "Progress in Energy and Combustion Science", "publication_date": "1995-08", "series_number": "5", "volume": "21", "issue": "5", "pages": "387-417" }, { "id": "authors:ej9c2-pjf80", "collection": "authors", "collection_id": "ej9c2-pjf80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180313-095811793", "type": "article", "title": "Dynamics of Tropospheric Aerosols", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-S-N" }, { "family_name": "Wexler", "given_name": "Anthony S.", "clpid": "Wexler-A-S" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Anthropogenic emissions leading to atmospheric aerosols have increased dramatically over the past century. Airborne particles have been implicated in human health effects, visibility reduction in urban and regional areas, acidic deposition, and altering the earth's radiation balance. The atmosphere subjects aerosol particles to an array of transport and transformation processes that alter their size, number, and composition; the transformation processes include condensation and evaporation, homogeneous nucleation, coagulation, and chemical reactions. A major goal of our research has been to use first principles to gain a predictive understanding of the physical and chemical processes that govern the dynamics, size, and chemical composition of atmospheric aerosols. We review here the current state of our ability to model this atmospheric aerosol behavior.", "doi": "10.1021/j100024a003", "issn": "0022-3654", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry", "publication_date": "1995-06-01", "series_number": "24", "volume": "99", "issue": "24", "pages": "9646-9659" }, { "id": "authors:ka09r-pb226", "collection": "authors", "collection_id": "ka09r-pb226", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230226-710568100.4", "type": "article", "title": "Ozone and aerosol productivity of reactive organics", "author": [ { "family_name": "Bowman", "given_name": "Frank M.", "clpid": "Bowman-Frank-M" }, { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A technique developed to determine the amount of ozone and secondary photochemical species generated by the individual organic components of a complex atmospheric organic/NO\u2093 mixture (Bowman and Seinfeld, J. geophys. Res. 99, 5309\u20135324 (1994a)) is used to study the individual contributions of carbonyl, aromatic, alkane, and alkene emissions to ozone and secondary organic and inorganic aerosol species in the South Coast Air Basin of California for the Southern California Air Quality Study (SCAQS) air pollution episode of 27\u201328 August 1987. Aldehydes exhibit the highest ozone productivity followed by alkenes, and lumped reactive aromatics. The aromatic species and formaldehyde enhance the production of secondary organic and secondary sulfate aerosol, because they are effectively OH sources. The same species, through their effect on both OH and O\u2083 production, are also significant precursors of HNO\u2083, and consequently, of nitrate aerosol. This methodology can be used in conjunction with urban airshed models to investigate alternative emission control scenarios.", "doi": "10.1016/1352-2310(94)00283-q", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1995-04", "series_number": "5", "volume": "29", "issue": "5", "pages": "579-589" }, { "id": "authors:cc8a6-zdv34", "collection": "authors", "collection_id": "cc8a6-zdv34", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-113503042", "type": "article", "title": "Asymmetric Instrument Response Resulting from Mixing Effects in Accelerated DMA-CPC Measurements", "author": [ { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Several method have been proposed to accelerate the measurements made with differential mobility analyzers (DMA), including the Scanning Electrical Mobility Spectrometer (SEMS) and the Scanning Mobility Particle Sizer (SMPS). Wang and Flagan (1990) developed a data analysis procedure that accounts for the migration of the particles through a time-varying electric field and the delay associated with transport from the analyzer column outlet to the detection point. Experience using a variety of detectors and scan rates has indicated that the instrument response depends on the plumbing configuration if a condensation particle counter (CPC) is used as a detector. When a sharply peaked distribution is analyzed, the apparent breadth of the measured distribution depends on the detector used and on the scan rate. Size distributions measured with an increasing voltage scan exhibit a tail toward large particle sizes, while decreasing voltage scans produce a more pronounced tail on the small particle end of the distribution. The reduction in peak height with increasing scan rate can be attributed to particle retention in the plumbing between the outlet of the DMA analyzer column and the point in the CPC where the particles are detected optically. This paper examines the smearing of the transfer function of the SEMS as a result of flow non-idealities in the system. A model has been developed to predict the distortion of the transfer function in terms of the particle residence time distribution within the instrument. Results of this model are compared with calibration data as a function of the detector employed and the scan rate. We include laboratory observations of the phenomenon and examine the use of data inversion techniques to retrieve the true size distribution.", "doi": "10.1080/02786829508965332", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1995-04", "series_number": "4", "volume": "23", "issue": "4", "pages": "491-509" }, { "id": "authors:9r51g-ave73", "collection": "authors", "collection_id": "9r51g-ave73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-112913411", "type": "article", "title": "Radial Differential Mobility Analyzer", "author": [ { "family_name": "Zhang", "given_name": "Shou-Hua", "clpid": "Zhang-Shou-Hua" }, { "family_name": "Akutsu", "given_name": "Yoshiaki", "clpid": "Akutsu-Yoshiaki" }, { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A differential mobility analyzer in which particles are classified in a radial flow toward the center of parallel disk electrodes, termed the Radial Differential Mobility Analyzer (RDMA), has been developed. Its classifying characteristics have been determined experimentally using both standard polystyrene latex spheres and mobility-classified aerosol particles over the size range of 3\u2013200 nm. The idealized transfer function for the RDMA differs from that of the conventional cylindrical DMA only by a group of geometrical constants. The RDMA is designed specifically for the measurement of ultrafine aerosol particles, achieving a transmission efficiency of 0.85 to 0.90 in the 3\u201310-nm size range and having a short residence time to limit diffusional broadening of the transfer function. The simple design of the RDMA reduces the number of precision parts that must be fabricated below that for cylindrical DMAs, resulting in a compact, relatively lightweight, and low-cost instrument.", "doi": "10.1080/02786829508965320", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1995-03", "series_number": "3", "volume": "23", "issue": "3", "pages": "357-372" }, { "id": "authors:8e1x2-kka38", "collection": "authors", "collection_id": "8e1x2-kka38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-569576900.2", "type": "article", "title": "Inverse air pollution modelling of urban-scale carbon monoxide emissions", "author": [ { "family_name": "Mulholland", "given_name": "Michael", "clpid": "Mulholland-Michael" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new recursive least-squares technique is developed to give spatial and temporal definition to the adjustments necessary in an emission inventory, to fit ambient concentration observations optimally. The CIT Photochemical Airshed Model is used to compute CO concentration distributions arising from 29 separate source domains in the South Coast Air Basin of California. A Kalman filter integrated within the model matches predictions with CO observations at 27 locations by superposing the computed distributions with optimal weighting factors. The filter structure allows control of the extent to which adjusted emission inventories are allowed to deviate from a base-case, which already has high spatial and temporal definition. Applied to the Southern California Air Quality Study, 27\u201329 August 1987, strong temporal dependence was noted in the necessary adjustment to the available CO emission inventory, with a peak factor of 3.0 at midday on weekdays. The spatial resolution of the technique revealed new high-emission zones for CO in a corridor between Pasadena and San Bernardino, in the Riverside-Corona area, and along the Pacific coast on Saturday. In this first such application to an urban environment, some success was also achieved in correcting the phasing of emissions for errors arising from the neglect of source-receptor lags in the inverse modelling technique.", "doi": "10.1016/1352-2310(94)00245-g", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1995-03", "series_number": "4", "volume": "29", "issue": "4", "pages": "497-516" }, { "id": "authors:kn0mb-15275", "collection": "authors", "collection_id": "kn0mb-15275", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-569576900.3", "type": "article", "title": "Extrapolation techniques used in the solution of stiff odes associated with chemical kinetics of air quality models", "author": [ { "family_name": "Dabdub", "given_name": "Donald", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The solution of chemical kinetics is generally the most computationally intensive step in atmospheric air quality models. The incorporation of ever more complex chemical mechanisms and physicochemical phenomena into these models stimulates the search for more accurate and efficient numerical ODE integration methods. We report here on a new method based on Richardson extrapolation to solve the chemical kinetics in air quality models. The extrapolation method presents high accuracy consistently for wide ranges of ROG/NO\u2093 ratios. The method is robust during sunrise and sunset transitions, when the rate of change of concentrations of a number of photochemically driven species is the greatest. In addition, the extrapolation algorithm is one of the most efficient computationally tested.", "doi": "10.1016/1352-2310(94)00282-p", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1995-02", "series_number": "3", "volume": "29", "issue": "3", "pages": "403-410" }, { "id": "authors:9sv90-ejf87", "collection": "authors", "collection_id": "9sv90-ejf87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp95a", "type": "article", "title": "Ion-induced nucleation: A density functional approach", "author": [ { "family_name": "Kusaka", "given_name": "I.", "clpid": "Kusaka-Isamu" }, { "family_name": "Wang", "given_name": "Z.-G.", "orcid": "0000-0002-3361-6114", "clpid": "Wang-Zhen-Gang" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Density functional theory is applied to ion-induced nucleation of dipolar molecules. The predicted reversible work shows a sign preference, resulting in a difference in the nucleation rate by a factor of 10\u201310^2, for realistic values of model parameters. The sign effect is found to decrease systematically as the supersaturation is increased. The asymmetry of a molecule is shown to be directly responsible for the sign preference in ion-induced nucleation.", "doi": "10.1063/1.469158", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1995-01-08", "series_number": "2", "volume": "102", "issue": "2", "pages": "913-924" }, { "id": "authors:tcp5v-hb659", "collection": "authors", "collection_id": "tcp5v-hb659", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230226-660977600.5", "type": "article", "title": "Gas/Aerosol Distribution of Formic and Acetic Acids", "author": [ { "family_name": "Meng", "given_name": "Zhaoyue", "clpid": "Meng-Zhaoyue" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Saxena", "given_name": "Pradeep", "clpid": "Saxena-Pradeep" } ], "abstract": "Data and correlations for evaluating the gas/aerosol equilibrium of formic and acetic acids are developed. The species considered include HCOOH(g), CH\u2083COOH(g), HCOOH(aq), CH\u2083COOH(aq), HCOO\u207b, CH\u2083COO\u207b, HCOONa(s), CH\u2083COONa(s), HCOOK(s), (HCOO)\u2082Ca(s), and (CH\u2083COO)\u2082Ca(s). Based on available thermodynamic data, we show that the gas /aerosol distribution of formic and acetic acids is strongly on the gas-phase side for typical sulfate/ nitrate / ammonium / sodium / chloride / water aerosols and that dissolved formate and acetate have negligible effect on the gas/aerosol equilibrium of the other components.", "doi": "10.1080/02786829508965338", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1995-01", "series_number": "4", "volume": "23", "issue": "4", "pages": "561-578" }, { "id": "authors:1f3z9-mxk77", "collection": "authors", "collection_id": "1f3z9-mxk77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-19495300.2", "type": "article", "title": "Contribution of Water to Particulate Mass in the South Coast Air Basin", "author": [ { "family_name": "Meng", "given_name": "Zhaoyue", "clpid": "Meng-Zhaoyue" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Saxena", "given_name": "Pradeep", "clpid": "Saxena-Pradeep" }, { "family_name": "Kim", "given_name": "Yong Pyo", "clpid": "Kim-Yong-Pyo" } ], "abstract": "Water content associated with the inorganic fraction of PM_(2.5) and PM\u2081\u2080 mass at San Nicolas Island, Long Beach, Burbank, and Riverside, CA has been estimated by using a thermodynamic gas/aerosol equilibrium model (SCAPE) and the measured aerosol composition data from the 1987 Southern California Air Quality Study (SCAQS). From midnight to the early morning, when the temperature is low and relative humidity is high, water is usually the predominant aerosol substance. Particulate water in the winter is estimated to be considerably larger than in the summer at each of the four sites. The estimated mass of aerosol water at high relative humidities is generally larger than that required to account for the total measured gravimetric aerosol mass, suggesting a loss of water in the measurement of total PM_(2.5) and PM\u2081\u2080 mass. Aerosol acidity was also estimated on the basis of the SCAQS data. Generally pH is estimated to be low for all the sampling sites, with the highest pH values at Riverside (2\u20134.5) and lowest at Long Beach and San Nicolas Island (-0.8\u20133.3) in the summer. Wintertime particles are estimated to be less acidic than those in the summer.", "doi": "10.1080/02786829408959731", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1995-01", "series_number": "1", "volume": "22", "issue": "1", "pages": "111-123" }, { "id": "authors:20qz7-dft87", "collection": "authors", "collection_id": "20qz7-dft87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230226-710568100.3", "type": "article", "title": "Atmospheric Gas-Aerosol Equilibrium: IV. Thermodynamics of Carbonates", "author": [ { "family_name": "Meng", "given_name": "Zhaoyue", "clpid": "Meng-Zhaoyue" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Saxena", "given_name": "Pradeep", "clpid": "Saxena-Pradeep" }, { "family_name": "Kim", "given_name": "Yong Pyo", "clpid": "Kim-Yong-Pyo" } ], "abstract": "Data and correlations for incorporating carbonate and bicarbonate salts into a gas/aerosol equilibrium model are developed. The species considered include CO\u2082(g), CO\u2082(aq), HCO\u2083\u207b, CO\u2082\u00b2\u207b, NH\u2082CO\u2082\u207b, Na\u2082CO\u2083(s), NaHCO\u2083(s), K\u2082CO\u2083 (s), KHCO\u2083(s), CaCO\u2083(s), MgCO\u2083(s), NH\u2084HCO\u2083(s), and NH\u2082COONH\u2084(s). Three activity coefficient estimation methods (Bromley, K-M, and Pitzer) are examined. Necessary parameters for these three methods are obtained. It is found that, in general, the Pitzer method performs better than the other two, and is selected as the multicomponent activity coefficient estimation method of choice. Water activity correlations for binary carbonate solutions are obtained by polynomial fitting of available data. Deliquescence points for the important atmospheric carbonate salts and their temperature dependence are given.", "doi": "10.1080/02786829508965300", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1995-01", "series_number": "2", "volume": "23", "issue": "2", "pages": "131-154" }, { "id": "authors:xyfsc-xy107", "collection": "authors", "collection_id": "xyfsc-xy107", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-16027800.1", "type": "article", "title": "Atmospheric Gas\u2013Aerosol Equilibrium: III. Thermodynamics of Crustal Elements Ca\u00b2\u207a, K\u207a, and Mg\u00b2\u207a", "author": [ { "family_name": "Kim", "given_name": "Yong Pyo", "clpid": "Kim-Yong-Pyo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Thermodynamics of the water-soluble crustal ionic species Ca\u00b2\u207a, K\u207a, and Mg\u00b2\u207a are added to that of those species already included (Na\u207a, NH\u2084\u207a, Cl\u207b, NO\u2083\u207b, and SO\u2084\u00b2\u207b) in the gas-particle equilibrium model SCAPE (Kim et al., 1993ab) which estimates the state and composition of atmospheric inorganic species between the gas and aerosol phases. Thermodynamic properties for the aerosol species that include the above ions, equilibrium constants, ionic activity coefficients, water activity, and deliquescence points, are estimated. Various methods for activity coefficient estimation are compared.", "doi": "10.1080/02786829408959730", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1995-01", "series_number": "1", "volume": "22", "issue": "1", "pages": "93-110" }, { "id": "authors:vmndf-12036", "collection": "authors", "collection_id": "vmndf-12036", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-40523600.1", "type": "article", "title": "Fundamental basis of incremental reactivities of organics in ozone formation in VOC/NO\u2093 mixtures", "author": [ { "family_name": "Bowman", "given_name": "Frank M.", "clpid": "Bowman-Frank-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The incremental reactivity of a particular organic species refers to the change in the ozone generated upon addition of a small amount of the organic to a complex organic/NO\u2093, mixture undergoing photooxidation. It is known that the values of the incremental reactivities of organic species depend on the composition of the particular organic/NO\u2093, mixture, the hydrocarbon-to-NO\u2093, ratio, and other environmental conditions. Using a method that enables the assignment of the ozone produced in the photo-oxidation of a complex organic/NO\u2093, mixture to each of the individual organics present, we show how the incremental ozone reactivity of any one organic species results from changes in the ozone generated by each of the organics present. Thus, we demonstrate explicitly the dependence of the incremental reactivity of each organic present on the nature of the organic/NO\u2093, mixture. Calculations are presented using the SAPRC 90 chemical mechanism to explain the origin of the variation of incremental reactivities with initial hydrocarbon-to-NO\u2093 ratio.", "doi": "10.1016/1352-2310(94)00165-h", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1994-11", "series_number": "20", "volume": "28", "issue": "20", "pages": "3359-3368" }, { "id": "authors:v0e74-e2352", "collection": "authors", "collection_id": "v0e74-e2352", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-41543800.2", "type": "article", "title": "Numerical advective schemes used in air quality models\u2014sequential and parallel implementation", "author": [ { "family_name": "Dabdub", "given_name": "Donald", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Six algorithms for solving the advection equation are compared to determine their suitability for use in photochemical air quality models. The algorithms tested are the Smolarkiewicz method, the Galerkin finite element method, the numerical method of lines, the accurate space derivative method (ASD), Bott method, and Emde method. Four algorithms for filtering the numerical noise produced when solving the advection equation are also compared. The algorithms are evaluated both on two test problems and in the CIT model. The Galerkin finite element and the ASD methods are implemented in the CIT in parallel computation. Results indicate that the ASD method, coupled with the Forester filter, produces the most accurate results. When the ASD transport solver is implemented in parallel, a speed-up of about 88 is achieved using, 256 processors. Furthermore, a new set of optimized Forester filter parameters for grid-based air quality models is determined.", "doi": "10.1016/1352-2310(94)00124-4", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1994-11", "series_number": "20", "volume": "28", "issue": "20", "pages": "3369-3385" }, { "id": "authors:bqzyg-nq844", "collection": "authors", "collection_id": "bqzyg-nq844", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141031-124906819", "type": "article", "title": "Aerosol production and growth in the marine boundary layer", "author": [ { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-S-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The dependence of cloud condensation nuclei (CCN) production on the marine dimethylsulfide (DMS) flux is modeled with a dynamic description of the gas, aerosol, and aqueous phase processes in a closed air parcel. The results support the conclusion reached in previous work with a steady state model that an approximately linear dependence exists between CCN concentration and DMS flux under typical remote marine conditions. This linearity does not hold for low DMS fluxes (the threshold is typically near 2.5 \u03bcmol m^(\u22122) day^(\u22121)) because the seasalt particles heterogeneously convert the available SO_2 to sulfate inhibiting the creation of new particles. The conditions under which this linear relationship holds are investigated by a series of sensitivity studies, focusing particular attention on the impact of the timing and frequency of cloud events. We consider the regimes of the model's semiempirical parameters, showing that the uncertainty associated with two such parameters, namely, the nucleation rate scaling factor and the sulfuric acid accommodation coefficient, is sufficient to change the predicted CCN production due to DMS from over 300 cm^(\u22123) day^(\u22121) to none. This sensitivity accounts for most of the range of results predicted by previous models of the DMS-CCN system.", "doi": "10.1029/94JD01932", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "1994-10-20", "series_number": "D10", "volume": "99", "issue": "D10", "pages": "20989-21003" }, { "id": "authors:8egbm-9mf23", "collection": "authors", "collection_id": "8egbm-9mf23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-152832227", "type": "article", "title": "The relationship between DMS flux and CCN concentration in remote marine regions", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-S-N" }, { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-L-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The relationship between the steady state cloud condensation nuclei (CCN) concentration and the dimethylsulfide (DMS) emission flux in remote marine regions is investigated by modeling the principal gas-, aerosol-, and aqueous-phase processes in the marine boundary layer (MBL). Results are in reasonable quantitative agreement with the available measurements of DMS, SO_2, H_2SO_4, CCN, and condensation nuclei (CN) concentrations in remote marine regions of the globe and suggest that indeed DMS plays a major role in the particle dynamics of the MBL. For sufficiently low DMS fluxes practically all the SO_2 produced by DMS photooxidation is predicted to be heterogeneously converted to sulfate in sea-salt aerosol particles. For DMS fluxes higher than approximately 2.5 \u03bcmole m^(\u22122)d^(\u22121) a linear relationship is found to exist between the CCN number concentration and the DMS flux.", "doi": "10.1029/94JD01119", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1994-08-20", "series_number": "D8", "volume": "99", "issue": "D8", "pages": "16945-16957" }, { "id": "authors:62j34-5cq83", "collection": "authors", "collection_id": "62j34-5cq83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-41543800.6", "type": "article", "title": "Air quality modeling on massively parallel computers", "author": [ { "family_name": "Dabdub", "given_name": "Donald", "orcid": "0000-0002-5130-4122", "clpid": "Dabdub-Donald" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The use of massively parallel computers provides an avenue to overcome the computational requirements of air quality modeling. General considerations on parallel implementation of air quality models are outlined including domain decomposition. The implementation of the CIT urban photochemical model on the Intel Touchstone Delta, a distributed memory multiple instruction/multiple data (MIMD) machine is described. When both the transport and chemistry portions of the model are parallelized, a speed-up of about 30 is achieved using 256 processors.", "doi": "10.1016/1352-2310(94)90313-1", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1994-05", "series_number": "9", "volume": "28", "issue": "9", "pages": "1679-1687" }, { "id": "authors:jnjyy-bb067", "collection": "authors", "collection_id": "jnjyy-bb067", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-41543800.3", "type": "article", "title": "Ozone productivity of atmospheric organics", "author": [ { "family_name": "Bowman", "given_name": "Frank M.", "clpid": "Bowman-Frank-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A technique is developed to determine the amount of ozone and other products, such as nitric acid and peroxyacetylnitrate (PAN), generated by the individual organic components of a complex atmospheric organic/NO\u2093 mixture. The technique is applied to the SAPRC 90 photochemical mechanism to study the individual contributions of carbonyls, aromatics, alkanes, alkenes, and carbon monoxide to ozone, nitric acid, PAN, and free radical production at varying organic to NO\u2093 ratios typical of atmospheric conditions.", "doi": "10.1029/93jd03400", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1994-03-20", "series_number": "D3", "volume": "99", "issue": "D3", "pages": "5309-5324" }, { "id": "authors:zp14b-0wb48", "collection": "authors", "collection_id": "zp14b-0wb48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-784283400.4", "type": "article", "title": "Modelling urban and regional aerosols\u2014I. model development", "author": [ { "family_name": "Wexler", "given_name": "Anthony S.", "orcid": "0000-0003-1565-814X", "clpid": "Wexler-Anthony-S" }, { "family_name": "Lurmann", "given_name": "Fredrick W.", "orcid": "0000-0001-9943-4172", "clpid": "Lurmann-Fredrick-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The partial differential equation that describes the size and composition distribution of atmospheric particles is stated. The equation describes the processes that may influence the particulate size and composition, namely emissions, deposition, advection, turbulent, diffusion, condensation, evaporation, coagulation, nucleation, settling and heterogeneous chemical reactions. Each term in the equation is analysed to estimate its influence on the overall distributions under typical urban conditions. Numerical methods are developed to solve the equation in conjunction with an Eulerian gas-phase model.", "doi": "10.1016/1352-2310(94)90129-5", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1994-02", "series_number": "3", "volume": "28", "issue": "3", "pages": "531-546" }, { "id": "authors:jce87-j7017", "collection": "authors", "collection_id": "jce87-j7017", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SHImcp94", "type": "article", "title": "Nucleation in the pre-coalescence stages: universal kinetic laws", "author": [ { "family_name": "Shi", "given_name": "Frank G.", "clpid": "Shi-Frank-Guojun" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This article is devoted to a detailed summary of recent results on the dynamic scaling of the cluster size distribution (CSD) and other universal kinetic laws in the pre-coalescence stages of nucleation and growth. A comprehensive presentation is given to the systematic approaches developed for elucidating the dynamic evolution of the CSD for sizes within the nucleation barrier layer (NBL) and beyond. In the pre-coalescence stages of nucleation and before the complete depletion of the monomer, the CSD for sizes within and beyond the NBL obey dynamic scaling relations. The dynamic scaling relations and their asymptotic limits are invariant to the size dependence of the cluster formation energy. For sizes beyond the NBL, the scaling relation of the CSD exhibits an asymptotic universal power law, the exponent of which depends only on the interphase interfacial atom transport mechanism. Comparison with limited available experimental data for sizes beyond the NBL confirms the predictions. The physical reasons behind the universal kinetic laws in the pre-coalescence stages of nucleation are outlined. The universal kinetic laws open a doorway to the systematic study of nucleation in condensed materials by providing a general novel foundation to guide the design of nucleation experiments and to elucidate fundamental mechanisms based on macroscopic observations of the duster size distribution in the pre-coalescence stages of nucleation and growth.", "doi": "10.1016/0254-0584(94)90064-7", "issn": "0254-0584", "publisher": "Elsevier", "publication": "Materials Chemistry and Physics", "publication_date": "1994-02", "series_number": "1", "volume": "37", "issue": "1", "pages": "1-15" }, { "id": "authors:vr1s1-xej81", "collection": "authors", "collection_id": "vr1s1-xej81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-784283400.3", "type": "article", "title": "On the Source of the Submicrometer Droplet Mode of Urban and Regional Aerosols", "author": [ { "family_name": "Meng", "given_name": "Zhaoyue", "clpid": "Meng-Zhaoyue" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "While atmospheric aerosols are typically described as consisting of three modes, the nucleation mode (0.01\u20130.1 \u03bcm in diameter), the accumulation mode (0.1\u20131.0 \u03bcm in diameter), and the coarse mode (> 1 \u03bcm in diameter), ambient measurements have shown that two distinct modes can exist in the 0.1\u20131.0-\u03bcm diameter range. These modes are referred to as the condensation mode (approximate aerodynamic diameter of 0.2 \u03bcm) and the droplet mode (approximate aerodynamic diameter of 0.7 \u03bcm). It has been postulated that the droplet mode results from aqueous-phase chemistry (Hering and Friedlander, 1982; John et al., 1990). In this work we examine the mechanisms of formation of the droplet mode. It is shown that growth of condensation mode particles by accretion of water vapor or by gas-phase or aerosol-phase sulfate production cannot explain the existence of the droplet mode. Activation of condensation mode particles to form fog or cloud drops followed by aqueous-phase chemistry and fog evaporation is shown to be a plausible mechanism for formation of the droplet mode.", "doi": "10.1080/02786829408959681", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1994-01", "series_number": "3", "volume": "20", "issue": "3", "pages": "253-265" }, { "id": "authors:vx5yg-1hh22", "collection": "authors", "collection_id": "vx5yg-1hh22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-778223000.1", "type": "article", "title": "Determination of Water Activity in Ammonium Sulfate and Sulfuric Acid Mixtures Using Levitated Single Particles", "author": [ { "family_name": "Kim", "given_name": "Yong Pyo", "clpid": "Kim-Yong-Pyo" }, { "family_name": "Pun", "given_name": "Betty K.-L.", "clpid": "Pun-Betty-K-L" }, { "family_name": "Chan", "given_name": "Chak K.", "orcid": "0000-0001-9687-8771", "clpid": "Chan-Chak-Keung" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Water activities of ammonium sulfate-sulfuric acid mixtures with ammonium to sulfate molar ratios between 0 and 2 were measured by a spherical void electrodynamic levitator at relative humidities (RH) of 0.18\u20130.90. Since the composition of the solid particles is subject to uncertainty, solution properties were determined relative to the known properties at RH about 0.75\u20130.90. The data were compared with other measurements and the estimates from the Zdanovskii-Stokes-Robinson (ZSR) method and SCAPE, a newly developed gas-particle equilibrium model, and generally were found to be in good agreement.", "doi": "10.1080/02786829408959683", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1994-01", "series_number": "3", "volume": "20", "issue": "3", "pages": "275-284" }, { "id": "authors:1k175-gzx20", "collection": "authors", "collection_id": "1k175-gzx20", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-41543800.4", "type": "article", "title": "Dynamic scaling of the cluster-size distribul nucleation: Precoalescence stages", "author": [ { "family_name": "Shi", "given_name": "Frank G.", "clpid": "Shi-Frank-Guojun" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The dynamic evolution of the cluster-size distribution (CSD) in the precoalescence stages of nucleation and growth for sizes within and beyond the nucleation barrier layer (NBL) has been obtained. The existence of several universal kinetic laws of nucleation is predicted. In the precoalescence stages of nucleation, the CSD for sizes within and beyond the NBL obeys dynamic scaling relations. In a range of sizes beyond the NBL, the CSD exhibits a universal power law behavior, the exponent of which depends only on the interphase monomer transfer mechanism. Based on the results for the CSD, a general foundation is developed for nucleation kinetic measurements including the determination of the nucleation barrier and the inter-facial monomer transport rate by measuring the CSD. A preliminary comparison with an experimental study confirms the predicted dynamic scaling and the power law behavior of the CSD in the early stages of nucleation and growth.", "doi": "10.1002/aic.690400104", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1994-01", "series_number": "1", "volume": "40", "issue": "1", "pages": "11-18" }, { "id": "authors:0kfwz-6nx88", "collection": "authors", "collection_id": "0kfwz-6nx88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180510-152205259", "type": "article", "title": "Atmospheric oxidation of biogenic hydrocarbons: reaction of ozone with \u03b2-pinene, D-limonene and trans-caryophyllene", "author": [ { "family_name": "Grosjean", "given_name": "Daniel", "clpid": "Grosjean-D" }, { "family_name": "Williams", "given_name": "Edwin L., II", "clpid": "Williams-E-L-II" }, { "family_name": "Grosjean", "given_name": "Eric", "clpid": "Grosjean-E" }, { "family_name": "Andino", "given_name": "Jean M.", "clpid": "Andino-J-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Several gas-phase carbonyl products of two terpenes, \u03b2-pinene and D-limonene, and of the sesquiterpene, transcaryophyllene, have been identified and their concentrations measured in experiments involving the reaction of these unsaturated biogenic hydrocarbons with ozone in the dark. Cyclohexane was added as a scavenger for the hydroxyl radical to minimize interferences from OH, which forms as a product of the ozone-hydrocarbon reaction. Carbonyl products were formaldehyde (yield = 0.42) and nopinone (yield = 0.22) from \u03b2-pinene, formaldehyde (yield = 0.10) and 4-acetyl-1-methylcyclohexene from D-limonene, and formaldehyde (yield 0.08) from transcaryophyllene. The nature and yields of these products are discussed in terms of the ozone-olefin reaction mechanism. The ozone-\u03b2-pinene reaction rate constant, measured in the presence of cyclohexane, is 12.2 \u00b1 1.3 x 10^(-18) cm^3 molecule^(-1) s^(-1) at 22 \u00b1 1 \u00b0C. Carbonyl products have also been identified in exploratory experiments with trans-caryophyllene and NO in sunlight.", "doi": "10.1021/es00049a014", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1993-12", "series_number": "13", "volume": "27", "issue": "13", "pages": "2754-2758" }, { "id": "authors:q7vw6-k3951", "collection": "authors", "collection_id": "q7vw6-k3951", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-744929300.4", "type": "article", "title": "Secondary organic aerosol formation and transport \u2014 II. Predicting the ambient secondary organic aerosol size distribution", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Wexler", "given_name": "Anthony S.", "orcid": "0000-0003-1565-814X", "clpid": "Wexler-Anthony-S" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The size distribution of atmospheric secondary organic aerosol is simulated by a Lagrangian trajectory model that includes descriptions of gas-phase chemistry, inorganic and organic aerosol thermodynamics, condensation/evaporation of aerosol species, dry deposition and emission of primary gaseous and particulate pollutants. The model is applied to simulate the dynamics of aerosol size and composition along trajectories on 27\u201328 August 1987 during the Southern California Air Quality Study (SCAQS). The secondary organic aerosol material is predicted to condense almost exclusively on the submicron aerosol in agreement with the available measurements, and its size distribution for Claremont, CA, is predicted to be unimodal with a mass mean diameter of roughly 0.2 \u03bcm. The distributions of the various secondary organic aerosol species are predicted to be essentially the same. The secondary organic aerosol (SOA) size distribution is found to depend crucially on the mass and size distribution of primary aerosol on which the secondary species condense and on the surface accomodation coefficient of the condensable species. The SOA size distribution is predicted not to be significantly affected by diffusional dry deposition, sources and sinks of ammonia, emissions of VOC, and secondary aerosol yields from precursor hydrocarbons. A bimodal secondary organic aerosol size distribution is predicted only if the submicron primary dust particles reside mainly in the 0.5\u20131.0 \u03bcm diameter size range, or if the condensable species have a strong preference (an accomodation coefficient difference of two orders of magnitude) for the 0.5\u20131.0 \u03bcm diameter particles. The secondary organic aerosol distribution in Claremont is predicted to shift slightly towards the larger aerosol particles during the nighttime hours with it mass mean diameter peaking around midnight at 0.21 \u03bcm and having its minimum in early afternoon at 0.18 \u03bcm. In coastal locations of the Los Angeles basin, secondary organic material exists in relatively smaller particles (mass mean diameter 0.16 \u03bcm) but in far inland locations it condenses on the available larger particles (mass mean diameter 0.23 \u03bcm).", "doi": "10.1016/0960-1686(93)90408-q", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1993-10", "series_number": "15", "volume": "27", "issue": "15", "pages": "2403-2416" }, { "id": "authors:qnn00-z4p28", "collection": "authors", "collection_id": "qnn00-z4p28", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150127-104936932", "type": "article", "title": "Achieving Acceptable Air Quality: Some Reflections on Controlling Vehicle Emissions", "author": [ { "family_name": "Calvert", "given_name": "J. G.", "clpid": "Calvert-J-G" }, { "family_name": "Heywood", "given_name": "J. B.", "clpid": "Heywood-J-B" }, { "family_name": "Sawyer", "given_name": "R. F.", "clpid": "Sawyer-R-F" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Motor vehicle emissions have been and are being controlled in an effort to abate urban air pollution. This article addresses the question: Will the vehicle exhaust emission control and fuel requirements in the 1990 Clean Air Act Amendments and the California Air Resources Board regulations on vehicles and fuels have a significant impact? The effective control of in-use vehicle emissions is the key to a solution to the motor vehicle part of the urban air pollution problem for the next decade or so. It is not necessary, except perhaps in Southern California, to implement extremely low new car emission standards before the end of the 20th century. Some of the proposed gasoline volatility and composition changes in reformulated gasoline will produce significant reductions in vehicle emissions (for example, reduced vapor pressure, sulfur, and light olefin and improved high end volatility), whereas others (such as substantial oxygenate addition and aromatics reduction) will not.", "doi": "10.1126/science.261.5117.37", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1993-07-02", "series_number": "5117", "volume": "261", "issue": "5117", "pages": "37-45" }, { "id": "authors:te4m3-bb341", "collection": "authors", "collection_id": "te4m3-bb341", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230419-953290000.15", "type": "article", "title": "Fourier transform infrared analysis of aerosol formed in the photooxidation of 1-octene", "author": [ { "family_name": "Palen", "given_name": "Edward J.", "clpid": "Palen-Edward-J" }, { "family_name": "Allen", "given_name": "David T.", "clpid": "Allen-David-T" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Paulson", "given_name": "Suzanne", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-Suzanne-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "The chemical composition of aerosol generated in the photooxidation of 1-octene was examined using infrared microscopy interfaced with a low pressure impactor. The low pressure impactor segregated the aerosol into eight size fractions and deposited the aerosol onto ZnSe impaction substrates. The ZnSe surfaces were transparent in the mid-infrared region and therefore allowed direct analysis of the aerosol, with no extraction, using infrared microscopy. Infrared spectra of the size segregated aerosol showed strong absorbances due to ketone, alcohol, carboxylic acid and organonitrate functional groups. Absorbance features were relatively independent of particle size, with the exception of the carboxylic acid absorbances, which were found only in the largest aerosol size fractions. Molar loadings for each of the groups were estimated, based on model compound calibration standards. The molar loadings indicate that most aerosol species are multifunctional, with an average of one ketone group per molecule, an alcohol group in two of every three molecules and an organonitrate group in one of every three molecules.", "doi": "10.1016/0960-1686(93)90133-j", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1993-06", "series_number": "9", "volume": "27", "issue": "9", "pages": "1471-1477" }, { "id": "authors:yhg5e-kn796", "collection": "authors", "collection_id": "yhg5e-kn796", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-181970000.1", "type": "article", "title": "Reply to Comment of V. A. Shneidman", "author": [ { "family_name": "Shi", "given_name": "Frank G.", "clpid": "Shi-Frank-Guojun" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We show that the assertions of Shneidman made in the previous Comment are incorrect.", "doi": "10.1557/jmr.1993.1191", "issn": "0884-2914", "publisher": "Materials Research Society", "publication": "Journal of Materials Research", "publication_date": "1993-05", "series_number": "5", "volume": "8", "issue": "5", "pages": "1191-1193" }, { "id": "authors:943he-yjc51", "collection": "authors", "collection_id": "943he-yjc51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160629-113939210", "type": "article", "title": "Photochemical modeling of the Southern California air quality study", "author": [ { "family_name": "Harley", "given_name": "Robert A.", "clpid": "Harley-R-A" }, { "family_name": "Russell", "given_name": "Armistead G.", "clpid": "Russell-A-G" }, { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-G-J" }, { "family_name": "Cass", "given_name": "Glen R.", "clpid": "Cass-G-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The Southern California Air Quality Study (SCAQS)\nprovides detailed experimental observations that can be\nused to explore the causes of the Los Angeles smog problem.\nIn the present study, the CIT photochemical airshed\nmodel is updated and then applied to the August 27-29,\n1987, SCAQS intensive monitoring period. Using measured\nmeteorological parameters, measured initial and boundary conditions, and the official emission inventory prepared by the government, ozone concentrations are underpredicted by 23% on average. Recent field experiments suggest that emissions of organic gases and carbon monoxide are understated in the official emission inventory. When the organic gas emissions from on-road vehicle engine exhaust are increased as suggested by emission rate measurements made in a Los Angeles area roadway tunnel during SCAQS, ozone predictions match the observed concentrations more closely (the mean normalized bias in ozone predictions for this case is +1%). Reactive hydrocarbon concentrations are underpredicted by 35% in the base case calculation, but are underpredicted by only 12% in the increased emission case. Results of this study thus support prior estimates that the organic gas emissions in Los Angeles have been understated in recent years.", "doi": "10.1021/es00039a019", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1993-02", "series_number": "2", "volume": "27", "issue": "2", "pages": "378-388" }, { "id": "authors:4k5v0-vby36", "collection": "authors", "collection_id": "4k5v0-vby36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170408-151109627", "type": "article", "title": "Atmospheric Gas-Aerosol Equilibrium II. Analysis of Common Approximations and Activity Coefficient Calculation Methods", "author": [ { "family_name": "Kim", "given_name": "Yong Pyo", "clpid": "Kim-Yong-Pyo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Saxena", "given_name": "Pradeep", "clpid": "Saxena-P" } ], "abstract": "The gas-aerosol equilibrium model, SCAPE, presented in Part I is used to evaluate the sensitivity of thermodynamic calculations of aerosol composition to common approximations and the choice of activity coefficient estimation method. The treatment of weak electrolytes, associated ammonia, NH_3(aq), and bisulfate ion, HSO_4^\u2212, is analyzed. Comparisons of the three multi-component activity coefficient estimation methods are carried out with a variety of data. On the basis of the sensitivity analysis results, recommendations are provided for treating these electrolytes and for selecting an activity coefficient estimation method in atmospheric gas-aerosol equilibrium calculations. The two gas-aerosol equilibrium models, SCAPE and AIM, are compared. Remaining questions in gas-aerosol equilibrium are highlighted.", "doi": "10.1080/02786829308959629", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1993-02", "series_number": "2", "volume": "19", "issue": "2", "pages": "182-198" }, { "id": "authors:vzr8v-3jn11", "collection": "authors", "collection_id": "vzr8v-3jn11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-140914000.1", "type": "article", "title": "Determination of Particle Vapor Pressures Using the Tandem Differential Mobility Analyzer", "author": [ { "family_name": "Zhang", "given_name": "Shou-Hua", "clpid": "Zhang-Shou-Hua" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "The application of the tandem differential mobility analyzer (TDMA) as a means of measuring vapor pressures of aerosol species is extended to include vapor saturation effects in the particle evaporator. To verify the analysis experiments were conducted with the controlled evaporation of dioctyl phthalate (DOP) particles with initial sizes ranging from 60 to 95 nm in diameter in a laminar flow evaporator. Vapor pressures of DOP determined with the TDMA were found to agree within 14% of those available in the literature. The results presented enable the use of the TDMA as a means to determine particle vapor pressure for substantially higher particle number concentrations than previously reported.", "doi": "10.1080/02786829308959616", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1993-01", "series_number": "1", "volume": "19", "issue": "1", "pages": "3-14" }, { "id": "authors:cwgj5-14x41", "collection": "authors", "collection_id": "cwgj5-14x41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-744929300.3", "type": "article", "title": "Atmospheric Gas-Aerosol Equilibrium I. Thermodynamic Model", "author": [ { "family_name": "Kim", "given_name": "Yong Pyo", "clpid": "Kim-Yong-Pyo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Saxena", "given_name": "Pradeep", "clpid": "Saxena-Pradeep" } ], "abstract": "A rigorous and computationally efficient thermodynamic model that estimates the state and composition of atmospheric inorganic species between the gas and aerosol phases is presented. The estimation of important thermodynamic properties, equilibrium constants, ionic activity coefficients, water activity, and deliquescence points is described. Various sources and estimation methods for inorganic gas-liquid-solid equilibrium properties are compared and optimal approaches for the new equilibrium routine are incorporated.", "doi": "10.1080/02786829308959628", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1993-01", "series_number": "2", "volume": "19", "issue": "2", "pages": "157-181" }, { "id": "authors:3nrrs-hdt47", "collection": "authors", "collection_id": "3nrrs-hdt47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230228-744929300.6", "type": "article", "title": "Coupling Thermodynamic Theory with Measurements to Characterize Acidity of Atmospheric Particles", "author": [ { "family_name": "Saxena", "given_name": "Pradeep", "clpid": "Saxena-Pradeep" }, { "family_name": "Mueller", "given_name": "Peter K.", "clpid": "Mueller-Peter-K" }, { "family_name": "Kim", "given_name": "Yong P.", "clpid": "Kim-Yong-P" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Koutrakis", "given_name": "Petros", "orcid": "0000-0003-4118-6473", "clpid": "Koutrakis-Petros" } ], "abstract": "The reference method currently being used in community health studies to characterize the acidity of atmospheric particles is based upon measuring the pH of aqueous extracts of atmospheric particles collected on filter media. These measurements represent total extractable acidity, i.e., hydrogen ion concentration at sufficient dilution of the sample, rather than the actual acidity of airborne particles. In contrast, models based upon chemical equilibrium theory can be used to estimate the hydrogen ion concentration and water content of atmospheric particles from the observed concentration of major solutes (sulfate, nitrate, chloride, ammonium, and sodium). Using about 100 data points from an intensive measurement study in Uniontown, Pennsylvania during 1990, we examined the nature and the causes of the deviations between measured and estimated hydrogen ion concentrations. We found that the measured hydrogen ion concentrations were substantially higher than the estimated concentrations because dilution of the sample during extraction promoted dissociation of bisulfate ions and hence increased the hydrogen ion concentration. Because total extractable acidity as measured by the pH method only partially characterizes particles, our results demonstrate that models should be used to augment and improve the information derived from these measurements, particularly to estimate the actual acidity of airborne particles.", "doi": "10.1080/02786829308959636", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1993-01", "series_number": "3", "volume": "19", "issue": "3", "pages": "279-293" }, { "id": "authors:b3fb8-33a72", "collection": "authors", "collection_id": "b3fb8-33a72", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-144673600.2", "type": "article", "title": "Development and evaluation of a photooxidation mechanism for isoprene", "author": [ { "family_name": "Paulson", "given_name": "Suzanne E.", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-Suzanne-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A detailed mechanism for isoprene photooxidation is developed that includes the recent developments on each of isoprene's atmospherically important reactions: O\u2083, OH, O(\u00b3P), and NO\u2083 as well as the OH reactions of methacrolein and methyl vinyl ketone. The mechanism also attempts to account for the gaps in the product distributions for a few reactions. The CO yield from isoprene oxidation in the presence of NO\u2093, more than about 50 ppt, is calculated as about 3.4. The mechanism is tested against chamber data that include a range of mixtures of the primary oxidants, isoprene concentrations, and hydrocarbon/NO\u2093 ratios. It performs well under conditions where the OH and O(\u00b3P) reactions dominate and predicts peak O\u2083 concentrations within about 25% under all conditions. The mechanism underpredicts methyl vinyl ketone yields as well as O\u2083 levels under conditions of low available NO\u2093. Sensitivity of the mechanism to assumptions about the NO\u2083 and O\u2083 reactions are examined, and possible sources of the discrepancies are discussed. A condensed mechanism is developed and compared to the explicit mechanism.", "doi": "10.1029/92jd01914", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1992-12-20", "series_number": "D18", "volume": "97", "issue": "D18", "pages": "20703-20715" }, { "id": "authors:v24hf-vdx72", "collection": "authors", "collection_id": "v24hf-vdx72", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141028-091812090", "type": "article", "title": "Photochemical aerosol formation from \u03b1-pinene- and \u03b2-pinene", "author": [ { "family_name": "Zhang", "given_name": "Shou-Hua", "clpid": "Zhang-Shou-Hua" }, { "family_name": "Shaw", "given_name": "Martha", "clpid": "Shaw-Martha" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "Aerosol formation from \u03b1-pinene and \u03b2-pinene was studied in a series of outdoor smog chamber experiments. Since a previous study focused on \u03b2-pinene (Pandis et al., 1991), more attention was given here to \u03b1-pinene. The initial hydrocarbon and NO\u2093 concentrations ranged from 37 to 582 ppb and 31 to 380 ppb, respectively. The aerosol carbon yield, the fraction of the carbon initially present that is converted to aerosol, varied from 0 to 5.3% for \u03b1-pinene, depending on the initial hydrocarbon-to-NO\u2093 ratio. Dual-bag experiments demonstrate that \u03b1-pinene is more rapidly photooxidized, and produces higher yields of both aerosol and ozone in a given period of time than \u03b2-pinene, although given sufficient time \u03b2-pinene can produce equivalent aerosol yields. Although aerosol formation solely from isoprene photooxidation was found in a previous study to be negligible under ambient conditions, the addition of isoprene to the \u03b1-pinene/NO\u2093 system leads to an increased aerosol yield through the enhanced photochemical activity generated.", "doi": "10.1029/92JD02156", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1992-12-20", "series_number": "D18", "volume": "97", "issue": "D18", "pages": "20717-20729" }, { "id": "authors:1s5dv-zw512", "collection": "authors", "collection_id": "1s5dv-zw512", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-110344300.2", "type": "article", "title": "Heterogeneous sulfate production in an urban fog", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" } ], "abstract": "Heterogeneous production of sulfate in an urban fog has been investigated using data collected during the SCAQS program in the Los Angeles area, for the period of 10\u201311 December 1987. Fog was observed during the night of 10 December and the early morning hours of 11 December near the coast of southern California. Measurements at several sites (Hawthorne, downtown Los Angeles, etc.) indicated a significant increase in sulfate concentration during the afternoon of 11 December. Trajectory analysis suggests that these high sulfate concentrations were associated with the arrival at the receptor sites of air parcels that passed through the fog layer the previous night. To quantify the contribution of aqueous-phase processes to the above sulfate levels, a detailed trajectory model was employed to simulate the gas-phase processes during that episode. The model, using the available information about SO\u2082 and sulfate emissions, initial conditions and meteorology, successfully explained the sulfate levels in air parcels that did not pass through the fog layer, but underestimated by as much as 2.5 the sulfate levels of the trajectories through the fog. Sensitivity/uncertainty analysis indicated that the presence of sulfate beyond that attributable to gasphase chemistry (around 10\u03bcg\u207b\u00b3) cannot be attributed to uncertainties in the model parameters (e.g. initial conditions, emissions, mixing heights, deposition velocities). The episode was then simulated using a full gas- and aqueous-phase chemistry model and the analysis indicated that heterogeneous sulfate formation in fog droplets under the conditions of the episode can indeed explain the observed sulfate.", "doi": "10.1016/0960-1686(92)90103-r", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1992-10", "series_number": "14", "volume": "26", "issue": "14", "pages": "2509-2522" }, { "id": "authors:q2hk0-03228", "collection": "authors", "collection_id": "q2hk0-03228", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160614-164345648", "type": "article", "title": "Secondary organic aerosol formation and transport", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-S-N" }, { "family_name": "Harley", "given_name": "Robert A.", "clpid": "Harley-R-A" }, { "family_name": "Cass", "given_name": "Glen R.", "clpid": "Cass-G-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A Lagrangian trajectory model simulating the formation, transport and deposition of secondary organic aerosol is developed and applied to the Los Angeles area, for the air pollution episode of 27\u201328 August 1987. The predicted secondary organic aerosol on 28 August 1987 represents 15\u201322% of the measured particulate organic carbon at inland locations in the base case simulations, and 5\u20138% of that at coastal locations. A maximum secondary organic aerosol concentration of 6.8 \u03bcg m^(\u22123) is predicted for Claremont, CA, during this episode. On a daily average basis at Claremont about 46% of this secondary organic aerosol is predicted to be a result of the oxidation of non-toluene aromatics (xylenes, alkylbenzenes, etc.), 19% from toluene, 16% from biogenic hydrocarbons (\u03b1-pinene, \u03b2-pinene, etc.), 15% from alkanes and 4% from alkenes. The major uncertainties in predicting secondary organic aerosol concentrations are the reactive organic gas emissions, the aerosol yields and the partitioning of the condensable gases between the two phases. Doubling the reactive organic gas (ROG) emissions results in an increase of the secondary organic aerosol predicted at Claremont by a factor of 2.3. Predicted secondary organic aerosol levels are less sensitive to changes in secondary organic aerosol deposition and NO_x emissions than to ROG emissions.", "doi": "10.1016/0960-1686(92)90358-R", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1992-09", "series_number": "13", "volume": "26", "issue": "13", "pages": "2269-2282" }, { "id": "authors:ctt7r-qg483", "collection": "authors", "collection_id": "ctt7r-qg483", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WYSjcp92", "type": "article", "title": "Nonisothermal homogeneous nucleation", "author": [ { "family_name": "Wyslouzil", "given_name": "B. E.", "orcid": "0000-0001-9763-5990", "clpid": "Wyslouzil-Barbara-E" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Classical homogeneous nucleation theory is extended to nonisothermal conditions through simultaneous cluster mass and energy balances. The transient nucleation of water vapor following a sudden increase in saturation ratio is studied by numerically solving the coupled mass and energy balance equations. The ultimate steady state nucleation rate, considering nonisothermal effects, is found to be lower than the corresponding isothermal rate, with the discrepancy increasing as the pressure of the background gas decreases. After the decay of the initial temperature transients, subcritical clusters in the vicinity of the critical cluster are found to have temperatures elevated with respect to that of the background gas.", "doi": "10.1063/1.463055", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1992-08-15", "series_number": "4", "volume": "97", "issue": "4", "pages": "2661-2670" }, { "id": "authors:0y46e-x3962", "collection": "authors", "collection_id": "0y46e-x3962", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180510-152205768", "type": "article", "title": "Atmospheric oxidation of selected terpenes and related carbonyls: gas-phase carbonyl products", "author": [ { "family_name": "Grosjean", "given_name": "Daniel", "clpid": "Grosjean-D" }, { "family_name": "Williams", "given_name": "Edwin L., II", "clpid": "Williams-E-L-II" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The gas-phase carbonyl products of \u03b1-pinene, \u03b2-pinene, and d-limonene have been identified and their concentrations measured in experiments involving sunlight irradiations of mixtures of terpene (1-2 ppm) and NO (0.25 ppm) in air. In turn, sunlight irradiations of carbonyl-NO_x mixtures have been carried out for the major high molecular weight carbonyl products of \u03b2-pinene (6,6-dimethylbicyclo[3.1.1] heptan-2-one) and d-limonene (4-acetyl-1-methylcyclohexene), and the corresponding carbonyl products have been identified. The nature and yields of these carbonyl products are discussed in terms of oxidation mechanisms involving the OH-terpene, ozone-terpene, OH-carbonyl, and ozone-carbonyl reactions.", "doi": "10.1021/es00032a005", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1992-08", "series_number": "8", "volume": "26", "issue": "8", "pages": "1526-1533" }, { "id": "authors:ye0e4-vye33", "collection": "authors", "collection_id": "ye0e4-vye33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-144673600.3", "type": "article", "title": "Selective nucleation of silicon clusters in CVD", "author": [ { "family_name": "Shi", "given_name": "Frank G.", "clpid": "Shi-Frank-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A nucleation model is developed that includes chemical etching of atoms as an additional loss process besides thermal dissociation that competes with the process of atom addition in forming a cluster. The model has the proper qualitative features to describe observations of the evolution of cluster formation on amorphous silicon substrates in the low pressure CVD of a mixture of SiH\u2082Cl\u2082/HCl/H\u2082.", "doi": "10.1557/jmr.1992.1809", "issn": "0884-2914", "publisher": "Materials Research Society", "publication": "Journal of Materials Research", "publication_date": "1992-07", "series_number": "7", "volume": "7", "issue": "7", "pages": "1809-1815" }, { "id": "authors:d7wc3-tj798", "collection": "authors", "collection_id": "d7wc3-tj798", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-144673600.4", "type": "article", "title": "Prediction of homogeneous nucleation free-energy change from the cell model of liquids", "author": [ { "family_name": "Huang", "given_name": "David D.", "clpid": "Huang-David-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The free-energy change of cluster formation in gas-phase homogeneous nucleation and the cluster partition functions are studied based on the cell model of liquids. We provide a new molecular-level theory that is applicable in the larger cluster size range where liquid-like properties begin to emerge and a cluster surface is present. The microcluster surface tension can be appropriately defined. A microscopic expression for the surface tension variation with cluster size is obtained and the calculated result is compared with that predicted from the Tolman approach. The cluster rotational contribution to the free-energy change is shown to become insignificant for liquid-like clusters. The energy changes of cluster formation from the classical capillary approximation, the Lothe-Pound theory, and the atomistic theory are compared with that of the present theory.", "doi": "10.1016/0021-9797(92)90256-l", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1992-06", "series_number": "1", "volume": "151", "issue": "1", "pages": "258-287" }, { "id": "authors:bxsr0-p6s77", "collection": "authors", "collection_id": "bxsr0-p6s77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180510-152204703", "type": "article", "title": "Atmospheric Photochemical Oxidation of 1-Octene: OH, O_3, and O(^3P) Reactions", "author": [ { "family_name": "Paulson", "given_name": "Suzanne E.", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-S-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The photooxidation chemistry of 1-octene is examined in detail. Formation of OH from the O_3 reaction was examined with the use of methylcyclohexane as an OH radical tracer. The O_3,-1-octene reaction is found to produce, apparently directly, significant quantities of OH, 0.45 \u00b1 0.2 on a per molecule of reacted 1-octene basis. Almost 100% of the reacted 1-octene could be accounted for as 80 \u00b1 10% heptanal, 10 \u00b1 6% thermally stabilized Criegee biradical, and ~ 1 % hexane. The OH-1-octene reaction was found to produce only 15 \u00b1 5% heptanal. The remainder is assumed to result in the formation of alkyl nitrates, and possibly multisubstituted products. A separate experiment examining the O(^3P)-1-octene reaction showed that the sum of hexyloxirane and octanal accounted for ~75% of the reacted 1-octene. A photochemical model was developed for 1-octene oxidation and compared favorably with smog chamber results from NO-NO_2-1-octene experiments, predicting ozone maxima within \u00b125%.", "doi": "10.1021/es50002a604", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1992-06", "series_number": "6", "volume": "26", "issue": "6", "pages": "1165-1173" }, { "id": "authors:5g6k9-nf613", "collection": "authors", "collection_id": "5g6k9-nf613", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-507743900.2", "type": "article", "title": "Experimental studies of ion-induced nucleation", "author": [ { "family_name": "Adachi", "given_name": "Motoaki", "clpid": "Adachi-Motoaki" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new system for experimental investigation of ion-induced nucleation, based on a continuous flow-mixing type device, is introduced. Measurements of the ion-induced nucleation of dibutylphthalate (DBP) vapor in the presence of unipolar ions are presented. When an ionized water vapor/N\u2082 mixture comes into contact with DBP vapor, nucleation of DBP particles is significantly enhanced relative to that in the absence of ions for both positive and negative ions. The number concentration of DBP particles activated by ions increases with increasing ion number concentration and DBP supersaturation ratio. A definite ion polarity effect is observed; at equal saturation ratios, positive ions induce larger number concentrations than negative ions. In the absence of water vapor, an ionized N\u2082 stream produces nucleation rates higher than those for pure homogeneous nucleation but well below those in the presence of water vapor. The present data set should be valuable in future assessments of ion-induced nucleation theories.", "doi": "10.1016/0021-8502(92)90002-d", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "1992-06", "series_number": "4", "volume": "23", "issue": "4", "pages": "327-337" }, { "id": "authors:sxfvp-6rx40", "collection": "authors", "collection_id": "sxfvp-6rx40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-111952094", "type": "article", "title": "Water activities of NH\u2084NO\u2083/(NH\u2084)\u2082SO\u2084 solutions", "author": [ { "family_name": "Chan", "given_name": "Chak K.", "orcid": "0000-0001-9687-8771", "clpid": "Chan-Chak-Keung" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Water activities for mixed ammonium nitrate/ammonium sulfate solutions at relative humidities of 0.35\u20130.75 were measured using a spherical void electrodynamic balance. The concentrations of singly levitated droplets of nitrate to sulfate mole ratio of n = 1/5, 1/3, 1/2, 1, 2 and 4 in equilibrium with an ambient environment of prescribed relative humidity were measured. To avoid uncertainty in determining the composition of the solid particles, solution properties were determined relative to the known properties at about 80% relative humidity. The concentration of this reference state was estimated by three models of mixed electrolyte solutions, the Zdanovskii-Stokes-Robinson (ZSR), the Kusik and Meissner (KM) and the Pitzer models. The measured total mass fraction of solute of the mixed solutions differed by less than 0.5% when different models were used to calculate the reference state concentration. The water activity data were obtained at ionic strengths as high as 108 molal and used to evaluate predictions from these three models. For n = 1/5 and 1/3, deviations of model predictions from experimental data are within 2%. Generally, predictions of the ZSR model are most consistent with our data. Maximum deviations occur at n=2; 6% for ZSR, 8% for KM and 5% for Pitzer. The deviations can be attributed to binary and ternary solute-solute interactions that the ZSR, KM and elementary version of the Pitzer models do not consider. However, no simple characterization of the interaction parameters is possible; they seem to be strong functions of the fractional ionic strength of the solute and the total ionic strength of the solutions.", "doi": "10.1016/0960-1686(92)90065-S", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1992-06", "series_number": "9", "volume": "26", "issue": "9", "pages": "1661-1673" }, { "id": "authors:mesf9-mb971", "collection": "authors", "collection_id": "mesf9-mb971", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-108334100.1", "type": "article", "title": "Fourier transform infrared analysis of aerosol formed in the photo-oxidation of isoprene and \u03b2-pinene", "author": [ { "family_name": "Palen", "given_name": "Edward J.", "clpid": "Palen-Edward-J" }, { "family_name": "Allen", "given_name": "David T.", "clpid": "Allen-David-T" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Paulson", "given_name": "Suzanne E.", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-Suzanne-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "The chemical composition of smog-chamber aerosol generated during the photo-oxidation of isoprene and \u03b2-pinene was probed using infrared (i.r.) microscopy interfaced with a low pressure impactor. The low-pressure impactor employed ZnSe impaction surfaces which allowed direct analysis, with no extraction, using i.r. microscopy. The low detection limits of this technique, coupled with direct sample analysis, permitted the chemical analysis of aerosol generated at low to moderate hydrocarbon and ozone loadings. The quantitative analysis of the i.r. spectra is limited, in part, by the absence of calibration standards, however, it is clear that the biogenic aerosols generated in this work were liquid mixtures containing ketone, aldehyde, alcohol and organonitrate functional groups. Molar loadings of each of these functional groups were estimated for nine smog-chamber experiments. For aerosol formed in isoprene photo-oxidation, aldehyde and ketone groups dominated (1.8 groups per average molecule) while for aerosol formed in \u03b2-pinene photo-oxidation, alcohols and ketones dominated (a combined 2.7 groups per average molecule).", "doi": "10.1016/0960-1686(92)90385-x", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1992-05", "series_number": "7", "volume": "26", "issue": "7", "pages": "1239-1251" }, { "id": "authors:hc3cy-bs979", "collection": "authors", "collection_id": "hc3cy-bs979", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-144673600.5", "type": "article", "title": "Reply [to \"Comment [on \"Should bulk cloudwater or fogwater samples obey Henry's law?\" by S. N. Pandis and J. H. Seinfeld]\"]", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The assumption of Henry's law equilibrium is routinely used to describe the partitioning of a species between the gas and the aqueous phases (fog, cloud, rain) in the atmosphere. Several experimental studies have attempted to evaluate the validity of this assumption for the atmosphere and in the majority of them significant deviations have been reported.", "doi": "10.1029/92jd00112", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1992-04-20", "series_number": "D5", "volume": "97", "issue": "D5", "pages": "6079-6081" }, { "id": "authors:fxmea-jrz92", "collection": "authors", "collection_id": "fxmea-jrz92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-355864900.1", "type": "article", "title": "Simulation of multicomponent aerosol dynamics", "author": [ { "family_name": "Kim", "given_name": "Yong Pyo", "clpid": "Kim-Yong-Pyo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A technique for numerical solution of the multicomponent aerosol general dynamic equation is developed and tested. The method is intended to obtain directly the multivariable size-composition distribution without any a priori assumptions about the nature of the distribution. In selecting the numerical method particular attention is paid to simulating simultaneous coagulation and condensation processes, although if condensation is the dominant process a scheme more suitable for pure condensation can be chosen. Numerical solutions are compared with analytical solutions for model problems of pure condensation, pure coagulation, and simultaneous condensation and coagulation.", "doi": "10.1016/0021-9797(92)90432-l", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1992-03-15", "series_number": "2", "volume": "149", "issue": "2", "pages": "425-449" }, { "id": "authors:3gmvy-2yf13", "collection": "authors", "collection_id": "3gmvy-2yf13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230302-782069800.2", "type": "article", "title": "Analysis of aerosol ammonium nitrate: Departures from equilibrium during SCAQS", "author": [ { "family_name": "Wexler", "given_name": "Anthony S.", "orcid": "0000-0003-1565-814X", "clpid": "Wexler-Anthony-S" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The size distribution of the inorganic components of atmospheric aerosols measured during the 1987 Southern California Air Quality Study (SCAQS) are used to investigate the hypothesis that transport limits equilibration of gas- and aerosol-phase ammonium nitrate and influences their size distribution. Estimates of the equilibration time constants at four sites in southern California show a wide range of values; at small values equilibrium is expected whereas at large values departures from equilibrium are expected. An equilibrium indicator is proposed based on the size distributions of aerosol ammonium and nitrate that shows when particles of different size are in mutual equilibrium with respect to ammonium nitrate. Values of the indicator range from unity, demonstrating equilibrium, to less than 0.5, demonstrating that different size particles are not in mutual equilibrium. Comparison of the time constant values to the equilibrium indicator values show a significant correlation, so it is concluded that different size aerosol particles are often not in mutual equilibrium due to transport limitations, supporting the hypothesis. It is concluded that both thermodynamics and mass transport must be considered to predict accurately the size distribution of the volatile inorganics in atmospheric aerosol.", "doi": "10.1016/0960-1686(92)90171-g", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1992-03", "series_number": "4", "volume": "26", "issue": "4", "pages": "579-591" }, { "id": "authors:0ska2-g3w36", "collection": "authors", "collection_id": "0ska2-g3w36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-357560100.2", "type": "article", "title": "Gas-Phase Nucleation in GaAs Thin Film Preparation by Metal Organic Chemical Vapor Deposition", "author": [ { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Huang", "given_name": "David D.", "clpid": "Huang-David-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Tani", "given_name": "Naoyuki", "clpid": "Tani-Naoyuki" }, { "family_name": "Matsui", "given_name": "Isao", "orcid": "0000-0002-1569-5189", "clpid": "Matsui-Isao" } ], "abstract": "GaAs epitaxial film growth in the metal organic chemical vapor deposition (MOCVD) horizontal reactor was analyzed by a mathematical model, which takes into consideration of vapor phase hydrodynamic and kinetic phenomena including decomposition reactions of reactants, Ga or GaAs nucleation and subsequent particle growth. The position dependent changes in mass concentrations of Ga or GaAs monomers and homogeneously nucleated Ga or GaAs particles are predicted under various substrate temperatures. The appearance of particles in the gas phase is found to be enhanced under substrate temperature exceeding about 900 K. The conditions under which the growth of the thin film is governed by the diffusive deposition of metal organic vapor and Ga monomers are determined, and the effect of homogeneously nucleated particles on the growth of thin film has been clarified. The simulation results are in good agreement with the data of van de Ven et al [J. Cryst. Growth 76 (1986) 352].", "doi": "10.1143/jjap.31.1", "issn": "0021-4922", "publisher": "Japan Society of Applied Physics", "publication": "Japanese Journal of Applied Physics", "publication_date": "1992-01-01", "series_number": "1R", "volume": "31", "issue": "1R", "pages": "1-11" }, { "id": "authors:ez5zf-nx608", "collection": "authors", "collection_id": "ez5zf-nx608", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-111659703", "type": "article", "title": "Atmospheric photooxidation of isoprene part I: The hydroxyl radical and ground state atomic oxygen reactions", "author": [ { "family_name": "Paulson", "given_name": "Suzanne E.", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-Suzanne-E" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The OH reaction with isoprene is studied. Methyl nitrite photolysis experiments were carried out in an outdoor smog chamber in an attempt to identify as completely as possible OH-isoprene product distribution. Emphasis was placed on identification and quantification of oxygenated products. A Tenax-based cryo-trap thermal desorber used to trap, concentrate, and dry chamber samples for identification on a GC/MS is described. Analysis of the products revealed that O(\u00b3P) can form in reaction systems designed to study OH reactions that include high concentrations of NO, and consequently NO\u2082, hence, this reaction is also examined. The yields of methacrolein and methyl vinyl ketone are determined as 25 \u00b1 3 and 35.5 \u00b1 4%, respectively, with an additional 4 \u00b1 2% as 3-methyl furan, totaling 65 \u00b1 4%. These results, combined with those of previous studies allow 80% of isoprene's products to be explicitly identified, and the general structure of the remaining products to be ascertained. The O(\u00b3P) reaction produces 84 \u00b1 8% epoxides, and 8 \u00b1 3% species which result in production of HO\u2082, and subsequently, OH. A heretofore unidentified product of the O(\u00b3P) reaction, 2-methyl 2-butenal, is identified. The rate constant of the NO\u2082-isoprene reaction is measured.", "doi": "10.1002/kin.550240109", "issn": "0538-8066", "publisher": "Wiley", "publication": "International Journal of Chemical Kinetics", "publication_date": "1992-01", "series_number": "1", "volume": "24", "issue": "1", "pages": "79-101" }, { "id": "authors:qawpd-w2n12", "collection": "authors", "collection_id": "qawpd-w2n12", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-111822807", "type": "article", "title": "Atmospheric photooxidation of isoprene part II: The ozone-isoprene reaction", "author": [ { "family_name": "Paulson", "given_name": "Suzanne E.", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-Suzanne-E" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A series of experiments have been performed to study the ozone-isoprene reaction in a smog chamber by adding externally produced O_3 to the hydrocarbon in the dark. A chemical tracer, methyl cyclohexane, was added to probe the OH formation in the system. O(^3P) formation was also examined using the known distribution of products that are unique to the O(^3P)-isoprene reaction (part I). The results provide clear evidence that both OH and O(^3P) are produced by the O_3-isoprene reaction directly in large quantities; about 0.68 \u00b1 0.15 and 0.45 \u00b1 0.20 per O_3-isoprene reaction, respectively. These additional radicals severely complicate the analysis of the O_3 reaction, hence, computer kinetic modeling was necessary to ascertain the products of the O\u2083 reaction itself, corrected for OH and O(\u00b3P) reactions. The product distribution, which differs dramatically from that published previously, is: 67 \u00b1 9% methacrolein, 26 \u00b1 6% methyl vinyl ketone, and 7 \u00b1 3% propene, accounting for 100 \u00b1 10% of the reacted isoprene. Applicability of these results to the gas-phase O\u2083 reaction with other unsaturated hydrocarbons is briefly discussed.", "doi": "10.1002/kin.550240110", "issn": "0538-8066", "publisher": "Wiley", "publication": "International Journal of Chemical Kinetics", "publication_date": "1992-01", "series_number": "1", "volume": "24", "issue": "1", "pages": "103-125" }, { "id": "authors:e85q6-9bv23", "collection": "authors", "collection_id": "e85q6-9bv23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160303-162819560", "type": "article", "title": "Aerosol formation and growth in atmospheric organic/NO_x systems\u2014I. Outdoor smog chamber studies of C_7- and C_8-hydrocarbons", "author": [ { "family_name": "Wang", "given_name": "Shih Chen", "clpid": "Wang-Shih-Chen" }, { "family_name": "Paulson", "given_name": "Suzanne E.", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-S-E" }, { "family_name": "Grosjean", "given_name": "Daniel", "clpid": "Grosjean-D" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Outdoor smog chamber experiments have been performed to determine the aerosol-forming potential of selected C_7- and C_8-hydrocarbons in sunlight-irradiated hydrocarbon-NO_x mixtures. Measured aerosol size distributions were used to determine the rates of gas-to-particle conversion and to study the effects of the addition of SO_2 and/or NH_3 on aerosol formation and growth. The average aerosol yields by mass for the hydrocarbons studied were (the range of measured values for methylcyclohexane and 1-octene are in parentheses):\n\n\u2022 methylcyclohexane 9.2% (0.12\u201318.8);\n\u2022 1-octene 4.2% (0.17\u20136.9);\n\u2022 toluene 18.6%;\n\u2022 n-octane <0.001%.\n\nThe average yields are accompanied by large standard deviations (see Table 3) and depended strongly on the conditions, particularly the hydrocarbon to NO_x initial concentration ratio. Addition of SO_2 to the organic/NO_x systems led to an early nucleation burst and subsequent rapid growth of the newly formed aerosol. In the presence of NH_3, the gas-to-particle conversion rate of the organic/NO_x system was enhanced perhaps due to the formation of NH_4NO_3 or the reaction of NH_3 with carboxylic acids. Sustained particle formation was observed when both SO_2 and NH_3 were present, presumably as a result of (NH_4)_2SO_4 formation. We have estimated the complexity of the 1-octene aerosol and identified 5-propyl furanone as a component of the aerosol.", "doi": "10.1016/0960-1686(92)90326-G", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1992", "series_number": "3", "volume": "26A", "issue": "3", "pages": "403-420" }, { "id": "authors:p9f37-fv175", "collection": "authors", "collection_id": "p9f37-fv175", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230301-203933318", "type": "book_section", "title": "Aerosols", "author": [ { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Pfafflin", "given_name": "J. R.", "clpid": "Pfafflin-J-R" }, { "family_name": "Ziegler", "given_name": "E. N.", "clpid": "Ziegler-E-N" } ], "abstract": "An aerosol is a system of tiny particles suspended in a\ngas. Aerosols or particulate matter refer to any substance,\nexcept pure water, that exists as a liquid or solid in the\natmosphere under normal conditions and is of microscopic\nor submicroscopic size but larger than molecular\ndimensions.", "publisher": "Caltech Library", "publication_date": "1992" }, { "id": "authors:z0mtb-jty36", "collection": "authors", "collection_id": "z0mtb-jty36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160303-162355453", "type": "article", "title": "Aerosol formation and growth in atmospheric organic/NO\u03c7 systems\u2014II. Aerosol dynamics", "author": [ { "family_name": "Wang", "given_name": "Shih Chen", "clpid": "Wang-Shih-Chen" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aerosol dynamics that were observed in the outdoor smog chamber experiments described in Wang et al. (1992, Atmospheric Environment, 26A, 403-420) are simulated by numerical solution of the aerosol general dynamic equation. The vapor source generation rate was estimated directly from the experimental measurements assuming a single surrogate condensing species for each hydrocarbon studied. Sensitivity analysis of the simulated aerosol dynamics to various input parameters revealed that the physical properties of the condensing vapor are important in determining the interplay between nucleation and condensation while the vapor source generation rate is the only factor that determines the eventual total amount of vapor converted to aerosol. The simulations suggest that over 99% of the mass of condensible vapor is converted to aerosol by condensation even when a significant burst of nucleation occurs.", "doi": "10.1016/0960-1686(92)90327-H", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1992", "series_number": "3", "volume": "26A", "issue": "3", "pages": "421-434" }, { "id": "authors:d1dcq-7wx48", "collection": "authors", "collection_id": "d1dcq-7wx48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230302-162724808", "type": "book_section", "title": "Transient kinetics of nucleation", "book_title": "Nucleation and Atmospheric Aerosols", "author": [ { "family_name": "Shi", "given_name": "Frank G.", "clpid": "Shi-Frank-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Fukuta", "given_name": "N.", "clpid": "Fukuta-N" }, { "family_name": "Wagner", "given_name": "P. E.", "clpid": "Wagner-P-E" } ], "abstract": "A newly developed approach for solving the kinetic equation governing the cluster size distribution in the nucleation barrier region and beyond is outlined. New results obtained for the transient kinetics of nucleation and their experimental and theoretical implications are briefly reviewed.", "isbn": "0 937194 26 3", "publisher": "Deepak Publishing", "place_of_publication": "Hampton, VA", "publication_date": "1992", "pages": "1-10" }, { "id": "authors:x43yd-zwz20", "collection": "authors", "collection_id": "x43yd-zwz20", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200417-142716493", "type": "article", "title": "Reply to ''Comment on 'Transient kinetics of nucleation' ''", "author": [ { "family_name": "Shi", "given_name": "G.", "clpid": "Shi-Frank-Guojun" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Okuyama", "given_name": "K.", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" } ], "abstract": "The results obtained in our previous paper [Phys. Rev. A 41, 2101 (1990)] are extended to obtain N(g_d,t), the total accumulated number concentration of nucleated clusters at the detectable size, g_d. It is shown that N(g_d,t) obtained by Shneidman [preceding Comment, Phys. Rev. A 44, 8441 (1991)] is incorrect since the time lag associated with N(g_d,t) suffers a singularity at ln(-1)", "doi": "10.1103/physreva.44.8443", "issn": "1050-2947", "publisher": "American Physical Society", "publication": "Physical Review A", "publication_date": "1991-12-15", "series_number": "12", "volume": "44", "issue": "12", "pages": "8443-8445" }, { "id": "authors:8qf38-ge631", "collection": "authors", "collection_id": "8qf38-ge631", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-96242900.2", "type": "article", "title": "Second-generation inorganic aerosol model", "author": [ { "family_name": "Wexler", "given_name": "Anthony S.", "orcid": "0000-0003-1565-814X", "clpid": "Wexler-Anthony-S" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Accurate prediction of the size distribution of the inorganic components of atmospheric aerosols must account for both therthermodynamic properties of the aerosol particles and transport between the gas and aerosol phases. For volatile inorganic species the transport rate is governed by the particle surface partial pressures which, in turn, is determined by the phase state and composition of the aerosol. We develop a model of the temporal composition of atmospheric aerosol particles based on their transport and thermodynamic properties. Included in the model is an improved theory of the temperature and composition dependence of deliquescence. Components of the model are tested against measurements of activity coefficients in single- and multicomponent aqueous solutions and general agreement is found. Aerosol water predictions are significantly higher under conditions of low relative humidity due to the improved theory of deliquescence.", "doi": "10.1016/0960-1686(91)90203-j", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1991-12", "series_number": "12", "volume": "25", "issue": "12", "pages": "2731-2748" }, { "id": "authors:h7y2e-6bp33", "collection": "authors", "collection_id": "h7y2e-6bp33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230304-773476300.1", "type": "article", "title": "The effects of dimethylsulfide upon marine aerosol concentrations", "author": [ { "family_name": "Kreidenweis", "given_name": "S. M.", "orcid": "0000-0002-2561-2914", "clpid": "Kreidenweis-Sonia-M" }, { "family_name": "Penner", "given_name": "J. E.", "orcid": "0000-0001-5577-452X", "clpid": "Penner-Joyce-E" }, { "family_name": "Yin", "given_name": "F.", "clpid": "Yin-Fangdong" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A simplified dimethylsulfide (DMS) oxidation mechanism is used in a box model to predict the vapor source rates of the major sulfur-containing products, methanesulfonic acid and sulfuric acid, in the marine boundary layer. These vapor source rates drive an integral aerosol model that predicts gas-to-particle conversion of the acid species in the presence of water vapor. The effects of latitudinal variations in background hydroxyl radical concentrations, temperatures, and relative humidities upon the predicted aerosol number concentrations are presented, and the sensitivity of the predictions to uncertainties in aerosol model input parameters is discussed. The predictions support a dependence of marine aerosol concentrations on latitude, as noted in some observations. Realistic choices of aerosol model parameters yield number concentrations that are consistent with observed concentrations in remote marine areas.", "doi": "10.1016/0960-1686(91)90166-5", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1991-11", "series_number": "11", "volume": "25", "issue": "11", "pages": "2501-2511" }, { "id": "authors:28j1m-bcc94", "collection": "authors", "collection_id": "28j1m-bcc94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230302-604096900.2", "type": "article", "title": "Transient kinetics of nucleation and crystallization: Part I. Nucleation", "author": [ { "family_name": "Shi", "given_name": "G.", "clpid": "Shi-Frank-G" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Analytical results obtained for the transient kinetics of nucleation enable one to interpret N(g_d,t), the accumulated number concentration of clusters at the instrumentally detectable size, g_d. The new results enable one to extract kinetic and thermodynamic parameters of nucleation from experimentally measured cluster concentrations and to test nucleation theories experimentally. An approach to estimate the mean time to form the first nucleated cluster in a given sample is also presented.", "doi": "10.1557/jmr.1991.2091", "issn": "0884-2914", "publisher": "Materials Research Society", "publication": "Journal of Materials Research", "publication_date": "1991-10", "series_number": "10", "volume": "6", "issue": "10", "pages": "2091-2096" }, { "id": "authors:a1xd2-xhe19", "collection": "authors", "collection_id": "a1xd2-xhe19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230302-785990800.1", "type": "article", "title": "Transient kinetics of nucleation and crystallization: Part II. Crystallization", "author": [ { "family_name": "Shi", "given_name": "G.", "clpid": "Shi-Frank-Guojun" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Analytical expressions for the time-dependent crystallized volume fraction are derived from new results for the transient rate of nucleation reported in Part I. Conventional formulations that have been used in interpreting crystallization experimental data and for assessing the stability of amorphous phases are shown to be large time limits of the newly derived expressions. An approach for assessing the stability of an amorphous phase is proposed.", "doi": "10.1557/jmr.1991.2097", "issn": "0884-2914", "publisher": "Materials Research Society", "publication": "Journal of Materials Research", "publication_date": "1991-10", "series_number": "10", "volume": "6", "issue": "10", "pages": "2097-2102" }, { "id": "authors:c5kbe-enz77", "collection": "authors", "collection_id": "c5kbe-enz77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230304-774985600.6", "type": "article", "title": "On mass transport limitation to the rate of reaction of gases in liquid droplets", "author": [ { "family_name": "Shi", "given_name": "Binqiang", "clpid": "Shi-Binqiang" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Expressions are derived to readily compare contributions to overall mass transport limitation by gas-phase diffusion, interfacial transport and aqueous-phase diffusion to the overall rate of reaction in liquid droplets. The three criteria previously derived by Schwartz (1986, in Chemistry of Multiphase Atmospheric Systems, pp. 415\u2013471, Springer) for the absence of mass transport limitation are shown to be special cases of the more general criterion obtained here. Sensitivity of the characteristic time to achieve steady state to the accommodation coefficient is examined. Inequalities are established that give lower and upper bounds of mass transport limitation in cases of non-first-order chemical kinetics.", "doi": "10.1016/0960-1686(91)90111-j", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1991-10", "series_number": "10", "volume": "25", "issue": "10", "pages": "2371-2383" }, { "id": "authors:gy4v6-gf567", "collection": "authors", "collection_id": "gy4v6-gf567", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230302-263412500.1", "type": "article", "title": "Should bulk cloudwater or fogwater samples obey Henry's law?", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In this work we prove that mixing of droplets with different pH that are individually in Henry's law equilibrium with the surrounding atmosphere always results in a bulk mixture that is supersaturated with weak acids like S(IV) and HCOOH and bases like NH\u2083 with respect to the original atmosphere. The degree of supersaturation of the bulk liquid water sample for a particular species depends on its dissociation constant, on the initial pH of the bulk droplet mixture, and on the distribution of the pH and of the liquid water over the droplet spectrum. High supersaturations result only when the pH of the bulk droplet mixture exceeds the pKa of the species, in which pH range large pH differences among droplets of different sizes lead to large deviations from Henry's law for the bulk mixture. The deviation is shown to depend on the ratio of the arithmetic mean to the harmonic mean of the hydrogen ion concentrations of the droplets with the liquid water content used as weighting factor in the calculation of the means. The theory developed can explain observed discrepancies from Henry's law in atmospheric samples and also other observed phenomena like the reported increase of pH values of bulk aqueous samples during storage.", "doi": "10.1029/91jd01031", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1991-06-20", "series_number": "D6", "volume": "96", "issue": "D6", "pages": "10791-10798" }, { "id": "authors:gber7-g9w04", "collection": "authors", "collection_id": "gber7-g9w04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WYSjcp91b", "type": "article", "title": "Binary nucleation in acid\u2013water systems. II. Sulfuric acid\u2013water and a comparison with methanesulfonic acid\u2013water", "author": [ { "family_name": "Wyslouzil", "given_name": "B. E.", "orcid": "0000-0001-9763-5990", "clpid": "Wyslouzil-Barbara-E" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Okuyama", "given_name": "K.", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" } ], "abstract": "This work presents a systematic investigation of binary nucleation rates for sulfuric acid and water and the effect of temperature on these rates at isothermal, subsaturated conditions. The results from nucleation rate measurements for the sulfuric acid (H2SO4)\u2013water system are discussed and compared to those previously presented for methanesulfonic acid (MSA)\u2013water [B. E. Wyslouzil, J. H. Seinfeld, R. C. Flagan, and K. Okuyama, J. Chem. Phys. (submitted)]. Experiments were conducted at relative humidities (Rh) ranging from 0.006", "doi": "10.1063/1.460262", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1991-05-15", "series_number": "10", "volume": "94", "issue": "10", "pages": "6842-6850" }, { "id": "authors:n96f4-f7n15", "collection": "authors", "collection_id": "n96f4-f7n15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WYSjcp91a", "type": "article", "title": "Binary nucleation in acid\u2013water systems. I. Methanesulfonic acid\u2013water", "author": [ { "family_name": "Wyslouzil", "given_name": "B. E.", "orcid": "0000-0001-9763-5990", "clpid": "Wyslouzil-Barbara-E" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Okuyama", "given_name": "K.", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" } ], "abstract": "Experimental measurements of binary nucleation between methanesulfonic acid and water vapor were carried out for relative acidities (Ra), 0.05", "doi": "10.1063/1.460261", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1991-05-15", "series_number": "10", "volume": "94", "issue": "10", "pages": "6827-6841" }, { "id": "authors:7j03s-92327", "collection": "authors", "collection_id": "7j03s-92327", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-111504231", "type": "article", "title": "Electrical Mobility Measurements of Fine-Particle Formation during Chamber Studies of Atmospheric Photochemical Reactions", "author": [ { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Wang", "given_name": "Shih Chen", "clpid": "Wang-Shih-Chen" }, { "family_name": "Yin", "given_name": "Fangdong", "clpid": "Yin-Fangdong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Reischl", "given_name": "George P.", "clpid": "Reischl-G-P" }, { "family_name": "Winklmayr", "given_name": "Wolfgang", "clpid": "Winklmayr-W" }, { "family_name": "Karch", "given_name": "Rudolf", "clpid": "Karch-R" } ], "abstract": "New approaches have been applied to electrical mobility measurement of ultrafine aerosol particles in smog chamber studies of secondary aerosol formation. With several mobility classifiers operating in parallel, rapid new particle formation was followed in the photochemical oxidation of dimethyl disulfide. When foreign particles were present before reaction was initiated, multiple bursts of nucleation and oscillations in the concentrations of 3.4-nm particles were observed. Later experiments used the scanning electrical mobility spectrometer to make high-resolution particle size distribution measurements. With this measurement method, the rapid growth of nuclei from their initial appearance at 10-nm size was followed in hydrocarbon/NO_x and hydrocarbon/NO_x/SO_2 reactions. Again, multiple bursts of nucleation were observed in some experiments, and insights were gained into particle growth mechanisms.", "doi": "10.1021/es00017a009", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1991-05", "series_number": "5", "volume": "25", "issue": "5", "pages": "883-890" }, { "id": "authors:tc88t-zd044", "collection": "authors", "collection_id": "tc88t-zd044", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230304-774985600.2", "type": "article", "title": "Inversion of aerosol data from the epiphaniometer", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Baltensperger", "given_name": "Urs", "orcid": "0000-0003-0079-8713", "clpid": "Baltensperger-Urs" }, { "family_name": "Wolfenbarger", "given_name": "J. Kenneth", "clpid": "Wolfenbarger-J-Kenneth" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The epiphaniometer is a new instrument for continuous monitoring of the Fuchs surface of aerosol particles using the attachment of neutral radioactive \u00b2\u00b9\u00b9Pb atoms to the particles. Since the \u00b2\u00b9\u00b9Pb atoms have a half-life of 36.1 min, the ability of the epiphaniometer to detect short-term fluctuations in the Fuchs surface of the aerosol is limited. To overcome this drawback a general algorithm developed for the inversion of size distribution data from conventional aerosol instruments is adapted for the inversion of data from the epiphaniometer. This algorithm allows resolution of dramatic changes in the aerosol Fuchs surface occurring over a time scale of minutes. The method is applied to data collected during outdoor smog chamber experiments, with changes in aerosol concentration of several orders of magnitude occurring within a time period of 5 min. The inverted epiphaniometer data are in agreement with the corresponding data from a Scanning Electrical Mobility Spectrometer (SEMS) and an Optical Particle Counter.", "doi": "10.1016/0021-8502(91)90002-y", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "1991-04", "series_number": "4", "volume": "22", "issue": "4", "pages": "417-428" }, { "id": "authors:s5rjs-gcx95", "collection": "authors", "collection_id": "s5rjs-gcx95", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230302-260631600.1", "type": "article", "title": "Regularized Solutions to the Aerosol Data Inversion Problem", "author": [ { "family_name": "Wolfenbarger", "given_name": "J. Kenneth", "clpid": "Wolfenbarger-J-Kenneth" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Regularized solutions to the aerosol data inversion problem are presented. An approximate form of generalized cross validation is developed that is applicable to this linearly constrained inverse problem. The results obtained with this algorithm for choosing the smoothing parameter are compared with those obtained by the method of discrepancy and by minimizing an unbiased estimate of the inverted errors. Examples are presented that demonstrate the importance of using generalized cross validation to choose the smoothing parameter when the magnitude of the errors in the data is difficult to estimate.", "doi": "10.1137/0912019", "issn": "0196-5204", "publisher": "SIAM", "publication": "SIAM Journal on Scientific and Statistical Computing", "publication_date": "1991-03", "series_number": "2", "volume": "12", "issue": "2", "pages": "342-361" }, { "id": "authors:3eaq1-0sq19", "collection": "authors", "collection_id": "3eaq1-0sq19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-96242900.4", "type": "article", "title": "Estimating the Variance in Solutions to the Aerosol Data Inversion Problem", "author": [ { "family_name": "Wolfenbarger", "given_name": "J. Kenneth", "clpid": "Wolfenbarger-J-Kenneth" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Regularization has been successfully used for solving a wide variety of ill-posed problems such as the inversion of aerosol size distribution data. The solutions are well characterized and converge nicely to the true distribution as the number of data increases. If there are few data, then there can be many reasonable distributions that are consistent with the measurements. Here, in addition to knowing an optimal solution, one should also have an estimate of the variance of the solution or a characterization of the size of the solution set. We set up the necessary machinery to allow one to estimate the variance of linear functionals of the size distribution, e.g., the concentration of particles in a given size interval. This estimate depends on the form of the weighted average, the variance in one's a priori estimate of the size distribution, the data, and the uncertainty in the data. There are many applications. We demonstrate, for example, how to determine which of two instruments will better allow one to estimate the concentration of particles in a given size interval. Also, we determine the number of measurements necessary to ensure the variance of the estimated concentration is less than a specified value.", "doi": "10.1080/02786829108959497", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1991-03", "series_number": "3", "volume": "14", "issue": "3", "pages": "348-357" }, { "id": "authors:wrgd1-5d287", "collection": "authors", "collection_id": "wrgd1-5d287", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHAao91", "type": "article", "title": "Resonance structures in elastic and Raman scattering from microspheres", "author": [ { "family_name": "Chan", "given_name": "Chak K.", "orcid": "0000-0001-9687-8771", "clpid": "Chan-Chak-Keung" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "To study the interactions between Mie scattering and Raman emissions of spherical particles, we measured the Raman spectra together with the elastically scattered light of the excitation source of an evaporating aqueous sodium nitrate droplet. Resonance structures were observed in the temporal profiles of the elastically scattered light and Raman nitrate and water emissions. The resonance structures in these three profiles occurred in a concerted mode but sometimes occurred independently of each other. A model of inelastic scattering by microspheres by Kerker et al. [\"Raman and Fluorescent Scattering by Molecules Embedded in Spheres with Radii up to Several Multiples of the Wavelength,\" Appl. Opt. 18, 1172-1179 (1979); \"Lorenz-Mie Scattering by Spheres: Some Newly Recognized Phenomena,\" Aerosol Sci. Technol. 1, 275-291 (1982); \"Inelastic Light Scattering,\" in Aerosol Microphysics I: Particle Interaction, W. H. Marlow, Ed. (Springer-Verlag, New York, 1980); \"Model for Raman and Fluorescent Scattering by Molecules Embedded in Small Particles,\" Phys. Rev. A 13, 396-404 (1976)] and the behavior of low order Mie resonances were used to explain the data. This type of data can be used for the determination of chemical compositions of spherical particles.", "doi": "10.1364/ao.30.000459", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1991-02-01", "series_number": "4", "volume": "30", "issue": "4", "pages": "459-467" }, { "id": "authors:0b3r9-zj285", "collection": "authors", "collection_id": "0b3r9-zj285", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230303-12296000.2", "type": "article", "title": "Image potential between a charged particle and an uncharged particle in aerosol coagulation\u2014enhancement in all size regimes and interplay with van der Waals forces", "author": [ { "family_name": "Huang", "given_name": "David D.", "clpid": "Huang-David-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" } ], "abstract": "Coagulation between a charged particle and an uncharged particle arises in ionic aerosol clustering and in ion-induced nucleation. In this paper, we obtain an analytical expression for the image potential for situations of charged-uncharged particle coagulation. The interparticle coagulation rate enhancement in the presence of the newly derived image potential over the entire range of Knudson number is calculated. A simultaneous potential composed of the image potential and a van der Waals potential is subsequently considered. Conditions in which each of the component potentials predominates are determined.", "doi": "10.1016/0021-9797(91)90314-x", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1991-01", "series_number": "1", "volume": "141", "issue": "1", "pages": "191-198" }, { "id": "authors:kmpkn-9tb47", "collection": "authors", "collection_id": "kmpkn-9tb47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-111100989", "type": "article", "title": "Aerosol formation in the photooxidation of isoprene and \u03b2-pinene", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Paulson", "given_name": "Suzanne E.", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-Suzanne-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "Isoprene and \u03b2-pinene, at concentration levels ranging from a few ppb to a few ppm, were reacted photochemically with NO\u2093 in the Caltech outdoor smog chamber facility. Aerosol formation from the isoprene photooxidation is found to be negligible even under extreme ambient conditions due to the relatively high vapor pressure of its products. Aerosol carbon yield from the \u03b2-pinene photooxidation is as high as 8% and depends strongly on the initial HC/NO\u2093 ratio. The average vapor pressure of the \u03b2-pinene aerosol is estimated to be 37 \u00b1 24 ppt at 31 \u00b0C. Monoterpene photooxidation can be a significant source of secondary aerosol in rural environments and in urban areas with extended natural vegetation.", "doi": "10.1016/0960-1686(91)90141-S", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1991", "series_number": "5/6", "volume": "25", "issue": "5/6", "pages": "997-1008" }, { "id": "authors:a1wn9-nn134", "collection": "authors", "collection_id": "a1wn9-nn134", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230304-774985600.5", "type": "book_section", "title": "Environmental Chemical Engineering", "book_title": "Perspectives in Chemical Engineering: Research and Education", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Colton", "given_name": "Clark K.", "clpid": "Colton-Clark-K" } ], "abstract": "As environmental regulations have expanded and the technology being controlled has become more advanced, the associated chemical engineering problems have grown more complex. Chemical engineers have had prominent roles in the development of stack gas scrubbing technologies, in understanding the mechanisms of particle and NO_x, formation in coal combustion, and in developing mathematical models of air pollution. Research that can be classified as environmental engineering occurs in academic departments of civil engineering, mechanical engineering, and chemical engineering, and environmental engineering. In terms of numbers of faculty members, the majority is carried out in departments of civil and environmental engineering. There are certain problems and opportunities for chemical engineers in environmental research. This chapter discusses some important problems in environmental chemical engineering to convey their flavor and challenges. There exist significant environmental research opportunities for chemical engineers, for example, in incineration of hazardous wastes, environmental behavior of toxic substances, synthesis and design of nonpolluting plants, regional and global air pollution, and water chemistry. Most environmental problems are highly complex and often ill defined. At a minimum, they usually require a synthesis of virtually all elements of the chemical engineer's arsenal-thermodynamics, chemical kinetics, and transport phenomena; at the most, an interdisciplinary team.", "doi": "10.1016/s0065-2377(08)60157-x", "isbn": "9780120085163", "publisher": "Academic Press", "place_of_publication": "San Diego, CA", "publication_date": "1991", "pages": "267-292" }, { "id": "authors:jjqq2-20r92", "collection": "authors", "collection_id": "jjqq2-20r92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160303-161407528", "type": "article", "title": "Aerosol formation during photooxidation of organosulfur species", "author": [ { "family_name": "Kreidenweis", "given_name": "Sonia M.", "clpid": "Kreidenweis-S-M" }, { "family_name": "Yin", "given_name": "Fangdong", "clpid": "Yin-Fangdong" }, { "family_name": "Wang", "given_name": "Shih Chen", "clpid": "Wang-Shih-Chen" }, { "family_name": "Grosjean", "given_name": "Daniel", "clpid": "Grosjean-D" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Measurements of aerosol formation during the photooxidation of dimethylsulfide (DMS) and dimethyldisulfide (DMDS) in an outdoor smog chamber are compared with predictions from a model of aerosol nucleation and growth in the chemically reacting system. The aerosol is assumed to consist of methanesulfonic acid (MSA), sulfuric acid, and water. Source rates of the two acid species are obtained from a detailed chemical mechanism for the organosulfur precursor oxidation and are used to drive the aerosol model. Good agreement between experiment and predictions was observed for DMDS and DMS oxidation in the presence of NOx, but maximum total number concentrations achieved during DMDS oxidation in the absence of NOx were somewhat underpredicted. The effect upon model predictions of variations in model input parameters is evaluated.", "doi": "10.1016/0960-1686(91)90165-4", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1991", "series_number": "11", "volume": "25A", "issue": "11", "pages": "2491-2500" }, { "id": "authors:02c0w-7qt04", "collection": "authors", "collection_id": "02c0w-7qt04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120509-112420256", "type": "article", "title": "Kinetics of binary nucleation: Multiple pathways and the approach to stationarity", "author": [ { "family_name": "Shi", "given_name": "G.", "clpid": "Shi-Frank-Guojun" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Explicit analytical expressions are obtained for the rate of nucleation over different paths in a binary system. It is shown that anisotropy in reaction rates and anisotropy in the free energy surface can cause nucleation to occur bypassing the saddle point. Homomolecular nucleation is demonstrated to be the natural limit of binary nucleation as the concentration of one component goes to zero. Explicit expressions are also obtained for the time lag of binary nucleation by using the singular perturbation approach. It is shown that the time lag associated with different paths of nucleation is essential in determining the relative importance of different nucleation pathways.", "doi": "10.1063/1.459193", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1990-12-15", "series_number": "12", "volume": "93", "issue": "12", "pages": "9033-9041" }, { "id": "authors:pjah6-ghh83", "collection": "authors", "collection_id": "pjah6-ghh83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120503-090648960", "type": "article", "title": "Homogeneous nucleation in spatially inhomogeneous systems", "author": [ { "family_name": "Shi", "given_name": "G.", "clpid": "Shi-Frank-Guojun" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Okuyama", "given_name": "K.", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" } ], "abstract": "Homogeneous nucleation of a vapor in the presence of the loss of clusters by diffusion and thermophoretic drift is investigated. Analytical results are obtained for the cluster size distribution and the rate of nucleation by solving the modified kinetic equation for nucleation. The implications of cluster loss by diffusion and phoretic drift on the onset of the homogeneous nucleation of silicon vapor in the horizontal epitaxial chemical vapor deposition reactor is discussed. The range of conditions under which the loss of subcritical clusters by diffusion and drift becomes important for the interpretation of diffusion cloud chamber experimental data of the onset conditions of the homogeneous nucleation of vapors is also delineated.", "doi": "10.1063/1.346160", "issn": "0021-8979", "publisher": "American Institute of Physics", "publication": "Journal of Applied Physics", "publication_date": "1990-11-01", "series_number": "9", "volume": "68", "issue": "9", "pages": "4550-4555" }, { "id": "authors:7v1q3-0zj06", "collection": "authors", "collection_id": "7v1q3-0zj06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-96242900.6", "type": "article", "title": "BGK equation solution of coagulation for large Knudsen number aerosols with a singular attractive contact potential", "author": [ { "family_name": "Huang", "given_name": "David D.", "clpid": "Huang-David-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Marlow", "given_name": "William H.", "orcid": "0000-0003-0272-6473", "clpid": "Marlow-William-H" } ], "abstract": "Aerosol coagulation rate expressions in the presence of singular attractive contact potentials such as the van der Waals potential and the electrical image potential are obtained by integrating the characteristics of the BGK equation. The rate expression consists of two parts: (A) the free-molecule regime (Kn \u2192 \u221d) enhancement, and (B) the first-order correction for a finite but large Knudsen number. For situations involving either the van der Waals or image potential, we present closed form best-fit equations for data calculated from the theory. The experimental data of ionic charging of Pui et al. (9) and data on ultrafine particle coagulation rate of Okuyama et al. (10, 11) are compared with the predictions from the present theory and the empirical Fuchs matching method. We have considered the situations of a combined van der Waals, coulombic, and image potential. The conditions where either coulombic, image, or van der Waals forces predominate are determined.", "doi": "10.1016/0021-9797(90)90341-k", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1990-11", "series_number": "1", "volume": "140", "issue": "1", "pages": "258-276" }, { "id": "authors:001qf-kjr84", "collection": "authors", "collection_id": "001qf-kjr84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-839494500.1", "type": "article", "title": "Photooxidation of dimethyl sulfide and dimethyl disulfide. II: Mechanism evaluation", "author": [ { "family_name": "Yin", "given_name": "Fangdong", "clpid": "Yin-Fangdong" }, { "family_name": "Grosjean", "given_name": "Daniel", "orcid": "0000-0001-6941-2490", "clpid": "Grosjean-Daniel" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The mechanisms for atmospheric photooxidation of CH\u2083SCH\u2083 and CH\u2083SSCH\u2083 developed in Part I are evaluated by a series of outdoor smog chamber experiments. Measured product yields, including SO\u2082, H\u2082SO\u2084, CH\u2083SO\u2083H and HCHO, are reported. The predictions of the mechanisms developed in Part I are found to be in substantial agreement with the measured concentrations from the smog chamber. By comparison of mechanism predictions and observations, critical uncertainties in the mechanism are identified.", "doi": "10.1007/bf00053781", "issn": "0167-7764", "publisher": "Springer", "publication": "Journal of Atmospheric Chemistry", "publication_date": "1990-11", "series_number": "4", "volume": "11", "issue": "4", "pages": "365-399" }, { "id": "authors:xf427-ca427", "collection": "authors", "collection_id": "xf427-ca427", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-475492500.4", "type": "article", "title": "Photooxidation of dimethyl sulfide and dimethyl disulfide. I: Mechanism development", "author": [ { "family_name": "Yin", "given_name": "Fangdong", "clpid": "Yin-Fangdong" }, { "family_name": "Grosjean", "given_name": "Daniel", "orcid": "0000-0001-6941-2490", "clpid": "Grosjean-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Detailed theoretical (Part I, this article) and experimental (Part II) investigations are presented for the mechanism of the atmospheric photooxidation of dimethyl sulfide (CH\u2083SCH\u2083) and dimethyl disulfide (CH\u2083SSCH\u2083). In this paper, comprehensive mechanisms for the atmospheric chemistry of CH\u2083SCH\u2083 and CH\u2083SSCH\u2083 are developed based on fundamental considerations of all available kinetic and mechanistic information.", "doi": "10.1007/bf00053780", "issn": "0167-7764", "publisher": "Springer", "publication": "Journal of Atmospheric Chemistry", "publication_date": "1990-11", "series_number": "4", "volume": "11", "issue": "4", "pages": "309-364" }, { "id": "authors:9e4kk-9k121", "collection": "authors", "collection_id": "9e4kk-9k121", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-96748800.8", "type": "article", "title": "The smog-fog-smog cycle and acid deposition", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" } ], "abstract": "A model including descriptions of aerosol and droplet microphysics, gas and aqueous-phase chemistry, and deposition is used to study the transformation of aerosol to fog droplets and back to aerosol in an urban environment. Fogs in polluted environments have the potential to increase aerosol sulfate concentrations but at the same time to cause reductions in the aerosol concentration of nitrate, chloride, ammonium and sodium and well as in the total aerosol mass concentration. The sulfate produced during fog episodes favors the aerosol particles that have access to most of the fog liquid water which are usually the large particles. Aerosol scavenging efficiencies of around 80 percent are calculated for urban fogs. Sampling and subsequent mixing of fog droplets of different sizes may result in measured concentrations that are not fully representative of the fogwater chemical composition and can introduce errors in the reported values of the ionic species deposition velocities. Differences in the major ionic species deposition velocities can be explained by their distribution over the droplet size spectrum and can be correlated with the species average diameter. Two different expressions are derived for use in fog models for the calculation of the liquid water deposition velocity during fog growth and dissipation stages.", "doi": "10.1029/jd095id11p18489", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1990-10-20", "series_number": "D11", "volume": "95", "issue": "D11", "pages": "18489-18500" }, { "id": "authors:b7p7b-rcd42", "collection": "authors", "collection_id": "b7p7b-rcd42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-96748800.10", "type": "article", "title": "Fokker-Planck equation solution of aerosol Brownian coagulation with an interparticle potential", "author": [ { "family_name": "Huang", "given_name": "David D.", "clpid": "Huang-David-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "For the Brownian coagulation of aerosol particles in the transition regime of Knudsen number in the presence of an interparticle potential, the Fokker-Planck equation is solved by using Grad's 13-moment method. Mass and energy accommodation coefficients are interfaced with the Fokker\u2014Planck moment equations through the use of half-range fluxes. Analytical solutions of the potential-free situation are obtained for arbitrary values of the accomodation coefficients. Numerical solutions of the number and energy flux profiles for a repulsive or an attractive interparticle potential of power-law form are obtained by a two-dimensional shooting scheme. This numerical algorithm is further applied to calculate the coagulation coefficient between two transition regime particles under either a van der Waals potential or a Coulombic potential. The results are in good agreement with those predicted by the flux-matching method of Fuchs. The present fundamental approach, therefore, provides theoretical support of the coagulation coefficient expression obtained by the empirical flux-matching method in the presence of an interparticle potential.", "doi": "10.1016/0021-9797(90)90458-z", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1990-10", "series_number": "1", "volume": "139", "issue": "1", "pages": "213-237" }, { "id": "authors:7f8w9-mgg64", "collection": "authors", "collection_id": "7f8w9-mgg64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-954386000.1", "type": "article", "title": "On the interaction between equilibration processes and wet or dry deposition", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric equilibration processes between two phases with different deposition velocities have the potential to affect significantly the amount of total material deposited on the ground. The magnitude of the effects of the equilibration processes depends primarily on the ratio of the deposition velocities of the two phases, on the production/emission rate of the gas phase species, and on the initial distribution of species between the two phases. The deposition of a condensible species equilibrating between gas and aerosol phases can increase by as much as 20 times over that when equilibration processes are not present under appropriate conditions (very large aerosol particles, most of the material initially in the gas phase and high gas-phase production rate) or to decrease by as much as 15 times (very small aerosol particles, most of the material initially in the gas phase and high gas-phase production rate). In fog episodes, the deposition of a gaseous species with a Henry's Law constant between 10\u00b3 and 10\u2076 M atm\u207b\u00b9 (e.g. SO\u00b2 for pH between 4.5 and 7, H\u2082O\u2082, HCHO etc) can be enhanced by as much as a factor of 3 because of its transfer to the aqueous phase. For the NH\u2083-HNO\u2083-NH4NO\u2083 system the total deposition can be reduced by as much as a factor of 3 for typical conditions in a polluted atmosphere and small initial concentration of aerosol NH\u2084NO\u2083 with NH\u2083 initially dominating HNO\u2083 in the gas phase. If an operator splitting scheme is used in a mathematical both equilibration and removal processes should be included in the same operator or very small operator time steps (typically less than 1 min) will be necessary.", "doi": "10.1016/0960-1686(90)90325-h", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1990-09", "series_number": "9", "volume": "24A", "issue": "9", "pages": "2313-2327" }, { "id": "authors:pcx5c-j2p07", "collection": "authors", "collection_id": "pcx5c-j2p07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-473571200.1", "type": "article", "title": "The environment and chemical reaction engineering", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Chemical reaction engineering is central to virtually all aspects of environmental protection. We focus here on three problems in atmospheric chemistry - stratospheric ozone depletion, global climate change, and control of zone levels by the use of alternate fuels in motor vehicles that involve significant elements of chemical reaction engineering.", "doi": "10.1016/0009-2509(90)80076-q", "issn": "0009-2509", "publisher": "Elsevier", "publication": "Chemical Engineering Science", "publication_date": "1990-08", "series_number": "8", "volume": "45", "issue": "8", "pages": "2045-2055" }, { "id": "authors:5zvam-9ef65", "collection": "authors", "collection_id": "5zvam-9ef65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-956673300.2", "type": "article", "title": "Chemical composition differences in fog and cloud droplets of different sizes", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" } ], "abstract": "The distribution of acidity and solute concentration among the various droplet sizes in a fog or cloud and the effect of the evaporation-condensation cycle on the composition and size distribution of atmospheric aerosol is studied. Significant total solute concentration differences can occur in aqueous droplets inside a fog or cloud. For the fog simulated here, during the period of dense fog, the solute concentration in droplets larger than 10 \u03bcm diameter increased with size, in such a way that droplets of diameter 20 \u03bcm attain a solute concentration that is a factor of 3.6 larger than that in the 10 \u03bcm droplets. Droplets on which most of the liquid water condenses have access to most of the reacting medium for in situ S(IV) oxidation and are therefore preferentially enriched in sulfate. The gas and aqueous-phase chemical processes result in an increase of the total solute mass concentration nonuniform over the droplet spectrum for a mature fog. These chemical processes tend to decrease the total solute mass concentration differences among the various droplet sizes. Low cooling rates of the system also tend to decrease these concentration differences while high cooling rates have exactly the opposite effect. The mass/size distribution of the condensation nuclie influences quantitatively, but not qualitatively, the above concentration differences.", "doi": "10.1016/0960-1686(90)90529-v", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1990-07", "series_number": "7", "volume": "24", "issue": "7", "pages": "1957-1969" }, { "id": "authors:g8338-vhv60", "collection": "authors", "collection_id": "g8338-vhv60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-475492500.2", "type": "article", "title": "The distribution of ammonium salts among a size and composition dispersed aerosol", "author": [ { "family_name": "Wexler", "given_name": "Anthony S.", "orcid": "0000-0003-1565-814X", "clpid": "Wexler-Anthony-S" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The chemical and physical processes that govern the distribution of ammonium salt condensate over a size- and composition-dispersed aerosol particle population are considered. From an analysis of the concentration profiles of ammonia, nitric acid, and hydrochloric acid vapors surrounding an aerosol particle, the single particle fluxes of these species are derived. By evaluating the time scales for equilibration of the vapor-phase species with a population of aerosol particles, it is found that ammonium salts in the gas and aerosol phases are not always in equilibrium, especially under less polluted and cooler conditions. The principles that govern the distribution of ammonium salts on aerosol particles of different size and composition are identified, and it is found that thermodynamic equilibrium often does not uniquely determine the distribution of ammonium salt condensate. Thus it is concluded that both transport and thermodynamic properties of the aerosol population govern the distribution of ammonium salt condensate.", "doi": "10.1016/0960-1686(90)90088-5", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1990-05", "series_number": "5", "volume": "24", "issue": "5", "pages": "1231-1246" }, { "id": "authors:ceb59-2sh93", "collection": "authors", "collection_id": "ceb59-2sh93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-645296400.2", "type": "article", "title": "Homogeneous nucleation in the presence of an aerosol", "author": [ { "family_name": "Shi", "given_name": "Guojun", "clpid": "Shi-Guojun" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The explicit dependence of the homogeneous nucleation rate on the surface area concentration of preexisting free molecule particles is obtained by solving the Zeldovich-Frenkel-Becker-D\u00f6ring equation modified to account for cluster scavenging. The present analytical solution is found to be in full agreement with numerical results.", "doi": "10.1016/0021-9797(90)90306-9", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1990-03", "series_number": "1", "volume": "135", "issue": "1", "pages": "252-258" }, { "id": "authors:rgatm-2f057", "collection": "authors", "collection_id": "rgatm-2f057", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-645296400.3", "type": "article", "title": "Particle generation in a chemical vapor deposition process with seed particles", "author": [ { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Ushio", "given_name": "Ryuichi", "clpid": "Ushio-Ryuichi" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The formation of aerosol particles by gas-phase chemical reaction in the presence of seed particles has been studied experimentally and theoretically. Titanium tetraisopropoxide (TTIP) vapor containing ultrafine TiO\u2082 seed particles was introduced into a laminar flow aerosol reactor, and the properties of produced TiO\u2082 aerosol were measured. By comparing the particle numbers and size distributions of the resulting aerosol with those of the seed particles and those of homogeneously nucleated particles in the absence of seed particles, the effects of initial concentrations of TTIP vapor, reaction temperatures, and properties of seed particles on the suppression of homogeneous nucleation were experimentally clarified. In the theoretical analysis, the population balance equation expressing simultaneous generation of TiO\u2082 monomer, Brownian coagulation and diffusive deposition of TiO\u2082 monomer and aerosols was solved. The observed suppression of homogeneous nucleation by the seed particles is explained qualitatively by the theoretical analysis.", "doi": "10.1002/aic.690360310", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1990-03", "series_number": "3", "volume": "36", "issue": "3", "pages": "409-419" }, { "id": "authors:5dp2r-4p615", "collection": "authors", "collection_id": "5dp2r-4p615", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-331971400.2", "type": "article", "title": "Simulation of multicomponent aerosol condensation by the moving sectional method", "author": [ { "family_name": "Kim", "given_name": "Yong P.", "clpid": "Kim-Yong-P" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The moving sectional method is extended to simulate multicomponent aerosol dynamics resulting from condensation/evaporation processes. This method uses a Lagrangian approach in which section boundaries and component masses in a section vary according to the characteristics of condensation/evaporation rates while conserving number concentration in a section throughout the simulation. Simulation of model problems for which new analytical solutions have been obtained shows excellent agreement with the analytical solutions. Limitations and applicability of the sectional method are discussed.", "doi": "10.1016/0021-9797(90)90299-4", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1990-03", "series_number": "1", "volume": "135", "issue": "1", "pages": "185-199" }, { "id": "authors:vfveg-xnp94", "collection": "authors", "collection_id": "vfveg-xnp94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SHIpra90", "type": "article", "title": "Transient kinetics of nucleation", "author": [ { "family_name": "Shi", "given_name": "G.", "clpid": "Shi-Frank-Guojun" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Okuyama", "given_name": "K.", "clpid": "Okuyama-Kikuo" } ], "abstract": "Analytical solutions for the time-dependent cluster concentrations and nucleation rate in homogeneous nucleation are obtained by the singular perturbation approach. The effect of cluster scavenging by free molecule particles on the kinetics of nucleation is also investigated through analogous analytical solutions in this case. Apparent conflicting suggestions in the literature concerning the time lag of nucleation are resolved.", "doi": "10.1103/PhysRevA.41.2101", "issn": "1050-2947", "publisher": "American Physical Society", "publication": "Physical Review A", "publication_date": "1990-02-15", "series_number": "4", "volume": "41", "issue": "4", "pages": "2101-2108" }, { "id": "authors:9nxh5-mm278", "collection": "authors", "collection_id": "9nxh5-mm278", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-475492500.3", "type": "article", "title": "Inversion of aerosol size distribution data", "author": [ { "family_name": "Wolfenbarger", "given_name": "J. Kenneth", "clpid": "Wolfenbarger-J-Kenneth" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A comprehensive analysis of the problem of determining aerosol size distributions on the basis of data from convnetional measuring instruments is presented. An inversion algorithm based on regularization is developed that enables one to find size distributions that are both smooth and faithful to a set of data generated by a combination of instruments. The algorithm includes consideration of the dependent nature of errors in the data. Several numerical examples are presented that compare the present technique with previously available methods.", "doi": "10.1016/0021-8502(90)90007-k", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "1990-02", "series_number": "2", "volume": "21", "issue": "2", "pages": "227-247" }, { "id": "authors:q2vqk-7pz34", "collection": "authors", "collection_id": "q2vqk-7pz34", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120509-153058949", "type": "article", "title": "Effect of cluster scavenging on homogeneous nucleation", "author": [ { "family_name": "Shi", "given_name": "G.", "clpid": "Shi-Frank-Guojun" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A closed\u2010form expression for the effect of cluster scavenging on the rate of homogeneous nucleation of a vapor in the presence of continuum regime particles is obtained by solving the kinetic equation of nucleation by the method of singular perturbation. The reduction in nucleation rate of a condensing species at a given supersaturation is shown to be dependent largely on the number concentration, the size of the sink particles, and the molecular number concentration of the background gas. The reduction in the rate of nucleation due to the cluster scavenging by transition regime particles is also discussed.", "doi": "10.1063/1.458422", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1990-01-01", "series_number": "1", "volume": "92", "issue": "1", "pages": "687-693" }, { "id": "authors:8zx5v-1mc15", "collection": "authors", "collection_id": "8zx5v-1mc15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-956673300.3", "type": "article", "title": "Characterization of photochemical aerosols from biogenic hydrocarbons", "author": [ { "family_name": "Paulson", "given_name": "S. E.", "orcid": "0000-0003-0855-7615", "clpid": "Paulson-Suzanne-E" }, { "family_name": "Pandis", "given_name": "S. N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Baltensperger", "given_name": "U.", "orcid": "0000-0003-0079-8713", "clpid": "Baltensperger-Urs" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Palen", "given_name": "E. J.", "clpid": "Palen-Edward-J" }, { "family_name": "Allen", "given_name": "D. T.", "clpid": "Allen-David-T" }, { "family_name": "Schaffner", "given_name": "C.", "clpid": "Schaffner-Christian" }, { "family_name": "Giger", "given_name": "W.", "clpid": "Giger-W" }, { "family_name": "Portmann", "given_name": "A.", "clpid": "Portmann-A" } ], "abstract": "An extensive set of outdoor smog chamber experiments were carried out to study aerosol formation by two representative biogenic hydrocarbons; isoprene and \u03b2-pinene. The hydrocarbons, at concentrations ranging from a few ppb to a few ppm, were photooxidized in the presence of NO\u2093. Isoprene was found to produce negligible aerosol at ambient conditions, whereas \u03b2-pinene aerosol carbon yields were as high as 8%, depending strongly on the hydrocarbon to NO\u2093 ratio. Aerosol samples subjected to infrared absorption spectroscopy revealed that the dominant aerosol products for both isoprene and \u03b2-pinene are organic nitrates, organic acids, as well as other carbonyls and hydroxy compounds. GCMS of the neutral fraction of the \u03b2-pinene aerosol revealed nopinone and several other compounds with molecular weights ranging from 138\u2013200 amu, indicating mainly mono- and dioxygenated products. The average vapor pressure of the \u03b2-pinene aerosol was estimated to be 37 \u00b1 24 ppt at 31\u00b0C. Scanning electron micrographs showed that the particles consist of both liquid droplets and agglomerates of small (40\u201360 nm) solid particles.", "doi": "10.1016/0021-8502(90)90230-u", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "1990-01", "series_number": "S1", "volume": "21", "issue": "S1", "pages": "S245-S248" }, { "id": "authors:27pah-w5z82", "collection": "authors", "collection_id": "27pah-w5z82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-645296400.5", "type": "article", "title": "Facilitated Aerosol Sizing Using the Differential Mobility Analyzer", "author": [ { "family_name": "Adachi", "given_name": "Motoaki", "clpid": "Adachi-Motoaki" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Moon", "given_name": "Seong Won", "clpid": "Moon-Seong-Won" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The electrostatic size analysis of polydisperse aerosols using a differential mobility analyzer (DMA) has been studied from the following two standpoints: (1) the faster measurement of electrical mobility distribution, arid (2) the correction of particle loss by Brownian diffusion in the data inversion, fn electrical mobility measurements, the number of mobility channels in a scan of the full mobility range is decreased and the full electrical mobility distribution is estimated by interpolation with a spline fitting. The correction of the Brownian diffusive losses of particles in the DMA including a neutralizer are combined with the data inversion method in order to evaluate the size distribution of aerosols unaffected by the particle loss. The reliability of the corrected data inversion method is confirmed by the experiment, and the particle size distribution of an aerosol is determined within several minutes by means of a faster scanning technique.", "doi": "10.1080/02786829008959342", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1990-01", "series_number": "2", "volume": "12", "issue": "2", "pages": "225-239" }, { "id": "authors:19syc-j3n14", "collection": "authors", "collection_id": "19syc-j3n14", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-205525944", "type": "article", "title": "Evaluation of fine particle formation by CVD in laminar-flow aerosol reactor", "author": [ { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Ushio", "given_name": "Ryuichi", "clpid": "Ushio-Ryuichi" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "The nucleation and growth of aerosol particles by gas-phase chemical reaction in a laminar-flow aerosol reactor (LFAR) has been studied experimentally and theoretically. Titanium tetraisopropoxide (TTIP) vapor and gas mixture was introduced into a heated pipe in a laminar flow, and the particle number and size distribution of TiO\u2082 aerosol produced by homogeneous nucleation were measured under various conditions. The effects of initial concentration of TTIP vapor, temperature profiles of the reactor, and carrier gas on the properties of homogeneously nucleated aerosols were clarified experimentally. In the theoretical analysis, the simplified reaction and coagulation model was used to evaluate the particle formation by gas-phase chemical reaction, and the aerosol general dynamic equation expressing the simultaneous phenomena of generation of TiO\u2082 monomer by thermal decompositionof TTIP vapor, Brownian coagulation and Brownian diffusion of TiO\u2082 monomer, cluster and particle in the LFAR was solved. The observed experimental results were explained well by the theoretical analysis, and it was found that the deposition of TTIP vapor, monomer, cluster and particles produced onto the reactor wall is enhanced by low temperature, low concentration of feed TTIP vapor and carrier gas with large mean free path.", "doi": "10.1252/kakoronbunshu.16.526", "issn": "0386-216X", "publisher": "Society of Chemical Engineers, Japan", "publication": "Kagaku Kogaku Ronbunshu", "publication_date": "1990", "series_number": "3", "volume": "16", "issue": "3", "pages": "526-534" }, { "id": "authors:d8w6v-jhc64", "collection": "authors", "collection_id": "d8w6v-jhc64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-392627300.1", "type": "article", "title": "The dynamic behavior of charged aerosols: II. Numerical solution by the sectional method", "author": [ { "family_name": "Oron", "given_name": "Alexander", "orcid": "0000-0002-0383-388X", "clpid": "Oron-Alexander" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A general sectional method for computation of the size-charge distribution of coagulating charged particles is developed. The physical phenomena taken into account are coagulation, electrostatic dispersion, particle production, and removal. The sectional equations are based on a general moment conservation that includes as particular cases the principles of volume and charge conservation.", "doi": "10.1016/0021-9797(89)90282-8", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1989-11", "series_number": "1", "volume": "133", "issue": "1", "pages": "66-79" }, { "id": "authors:9wgm9-2cp86", "collection": "authors", "collection_id": "9wgm9-2cp86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-394589600.5", "type": "article", "title": "The dynamic behavior of charged aerosols: I. Particle charging in the low particle concentration limit", "author": [ { "family_name": "Oron", "given_name": "Alexander", "orcid": "0000-0002-0383-388X", "clpid": "Oron-Alexander" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" } ], "abstract": "This paper is the first of a three-part series examining the dynamic behavior of charged aerosols and the interaction between particle charging by ions and particle-particle coagulation. Part I focuses on the case in which particle concentrations are sufficiently low that particle-particle coagulation and particle-particle electrostatic dispersion may be neglected. The general equations governing the ion and particle concentrations are solved analytically in the cases of particles in a cloud of unipolarly charged ions and bipolarly charged ions. Certain previously available solutions are shown to be special cases of the general solutions obtained here.", "doi": "10.1016/0021-9797(89)90281-6", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1989-11", "series_number": "1", "volume": "133", "issue": "1", "pages": "57-65" }, { "id": "authors:3dw0d-dw321", "collection": "authors", "collection_id": "3dw0d-dw321", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-394589600.3", "type": "article", "title": "The dynamic behavior of charged aerosols: III. Simultaneous charging and coagulation", "author": [ { "family_name": "Oron", "given_name": "Alexander", "orcid": "0000-0002-0383-388X", "clpid": "Oron-Alexander" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A general sectional method for computation of the size-charge distribution during simultaneous charging and coagulation of ions and particles is developed. The time evolution of the ion (unipolar or bipolar) concentration and of the aerosol size-charge distribution is simulated under particle-particle coagulation, electrostatic dispersion, ion recombination, and ion and particle production and loss. Numerical examples illustrating the sectional method are presented.", "doi": "10.1016/0021-9797(89)90283-x", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1989-11", "series_number": "1", "volume": "133", "issue": "1", "pages": "80-90" }, { "id": "authors:va0vx-89374", "collection": "authors", "collection_id": "va0vx-89374", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141030-103823292", "type": "article", "title": "Mathematical modeling of acid deposition due to radiation fog", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-S-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A Lagrangian model has been developed to study acidic deposition due to radiation fog. The model couples submodels describing the development and dissipation of radiation fog, the gas-phase chemistry and transfer, and the aqueous-phase chemistry. The model is applied to a radiation fog episode in Bakersfield in the San Joaquin Valley of California over the period January 4\u20135, 1985. Model predictions for temperature profile, fog development, liquid water content, gas-phase concentrations of SO_2, HNO_3, and NH_3, pH, aqueous-phase concentrations of SO_4^(2\u2212), NH_4^+, and NO_3^\u2212, and finally deposition rates of the above ions are compared with the observed values. The deposition rates of the major ions are predicted to increase significantly during the fog episode, the most notable being the increase of sulfate deposition. Pathways for sulfate production that are of secondary importance in a cloud environment may become significant in a fog. Expressing the mean droplet settling velocity as a function of liquid water content is found to be quite influential in the model's predictions.", "doi": "10.1029/JD094iD10p12911", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "1989-09-20", "series_number": "D10", "volume": "94", "issue": "D10", "pages": "12911-12923" }, { "id": "authors:q201b-8ma26", "collection": "authors", "collection_id": "q201b-8ma26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230419-898284000.14", "type": "article", "title": "Water content of atmospheric aerosols", "author": [ { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Grosjean", "given_name": "Daniel", "orcid": "0000-0001-6941-2490", "clpid": "Grosjean-Daniel" } ], "abstract": "The water content of atmospheric aerosol particles is calculated, both above and below the classic deliquescent point. The existence of water in the paniculate phase is predicted to be strongly dependent on the aerosol composition. Liquid water may constitute a significant mass fraction of the aerosol concentration at r.h. <60%.", "doi": "10.1016/0004-6981(89)90419-8", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1989-07", "series_number": "7", "volume": "23", "issue": "7", "pages": "1601-1606" }, { "id": "authors:cts2d-k2j68", "collection": "authors", "collection_id": "cts2d-k2j68", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-43936800.1", "type": "article", "title": "A note on mass, momentum, and energy accommodation coefficients", "author": [ { "family_name": "Huang", "given_name": "David D.", "clpid": "Huang-David-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Ambiguity frequently arises in defining sticking probability\n(condensation coefficients) and accommodation coefficients of mass, momentum, and energy. In this note, we draw a clear distinction among these various parameters that are used to describe the results of collisional processes between molecules and surfaces.", "doi": "10.1016/0021-9797(89)90100-8", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1989-06", "series_number": "1", "volume": "130", "issue": "1", "pages": "275-280" }, { "id": "authors:yfn3k-vwc05", "collection": "authors", "collection_id": "yfn3k-vwc05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-45537200.2", "type": "article", "title": "Enhancement of brownian and turbulent diffusive deposition of charged aerosol particles in the presence of an electric field", "author": [ { "family_name": "Shimada", "given_name": "Manabu", "clpid": "Shimada-Manabu" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Okuyama", "given_name": "Yoshinari", "clpid": "Okuyama-Yoshinari" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The effect of an electric field upon diffusive deposition of aerosol particles is investigated. In the experiments, charged and uncharged monodisperse particles of 0.02\u20130.2 \u03bcm are confined in a metal stirred tank inside which an electric field exists. It is found from measurements of the particle concentration decay inside the tank that the deposition rates of charged particles are enhanced as the electric field strength increases. To evaluate the electrostatic enhancement theoretically, the diffusion and transport of particles in an electric field are described, accounting for Brownian and turbulent diffusion and coulombic force acting on the particles. Deposition rates predicted by numerically solving the convective diffusion equation agree with those measured.", "doi": "10.1016/0021-9797(89)90394-9", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1989-03", "series_number": "1", "volume": "128", "issue": "1", "pages": "157-168" }, { "id": "authors:w53nz-s4t45", "collection": "authors", "collection_id": "w53nz-s4t45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-105713382", "type": "article", "title": "Aerosol Dynamics in Atmospheric Aromatic Photooxidation", "author": [ { "family_name": "Stern", "given_name": "Jennifer E.", "clpid": "Stern-Jennifer-E" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aerosol formation and growth in aromatic hydrocarbon/NO\u2093 systems was studied in a series of outdoor smog chamber experiments. Analysis of the aerosol size distributions in those experiments that exhibited steady condensational growth provides estimates for the gas-phase partial pressures of the condensing species. Saturation ratios during these growth periods are estimated by comparing these partial pressures with vapor pressures obtained from an analysis of nucleation (Stern et al., 1987), and are found to be in the range of 5 to 20. Modeling of the size\u2013distribution dynamics during the experiments is carried out using the sectional model ESMAP (Warren and Seinfeld, 1985). The full size-distribution model predicts more nucleation than an integral model (Stern et al., 1987), because the polydisperse aerosol representation leads to a lower condensation rate than that predicted for a monodisperse aerosol.", "doi": "10.1080/02786828908959292", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1989-03", "series_number": "3", "volume": "10", "issue": "3", "pages": "515-534" }, { "id": "authors:c0qey-ckz79", "collection": "authors", "collection_id": "c0qey-ckz79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141223-074540549", "type": "article", "title": "Urban Air Pollution: State of the Science", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Urban air pollution is comprised of a highly complex mixture of gaseous and particulate components. Much progress has been made in our understanding of the detailed chemistry and physics of air pollution, but important areas of uncertainty still remain.", "doi": "10.1126/science.243.4892.745", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1989-02-10", "series_number": "4892", "volume": "243", "issue": "4892", "pages": "745-752" }, { "id": "authors:tw4rm-4e550", "collection": "authors", "collection_id": "tw4rm-4e550", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-110351772", "type": "article", "title": "Aerosol growth due to heterogeneous reaction: I. A continuous stirred tank reactor system for the study of aqueous aerosol chemistry", "author": [ { "family_name": "Jones Adkins", "given_name": "Carol L.", "clpid": "Jones-Adkins-Carol-L" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A continuous stirred tank reactor system for measuring particle growth as a result of heterogeneous aqueous-phase SO\u2082 reaction is described. Special attention was focused on the aerosol measurement instruments and care was taken to minimize size biasing as a result of humidity changes within the instruments. The differential mobility analyzer (DMA) inversion method developed by Hoppel was tested for its ability to predict distribution peak diameter. Less than 1% error in the diameter determination was found for experimentally plausible levels of either random particle number count error or instrument flowrate error. The DMA was determined to be capable of resolving a 0.001- to 0.002-\u03bcm-diameter change which is crucial in the particle growth experiments.", "doi": "10.1016/0021-9797(89)90050-7", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1989-02", "series_number": "2", "volume": "127", "issue": "2", "pages": "453-464" }, { "id": "authors:ynt52-hnq67", "collection": "authors", "collection_id": "ynt52-hnq67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-416379000.1", "type": "article", "title": "Aerosol growth due to heterogeneous reaction: II. The manganese-catalyzed aqueous phase oxidation of S(IV) to S(VI)", "author": [ { "family_name": "Jones Adkins", "given_name": "Carol L.", "clpid": "Jones-Adkins-Carol-L" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The continuous stirred tank reactor system described in Part I was used to measure the growth of aerosol salt particles containing manganese in an SO\u2082-containing atmosphere. A model of the aerosol behavior within the reactor was used to predict the reactor effluent size distribution given the input feed distribution and various reaction rate expressions. Comparing the reactor aerosol size distributions predicted by the various rate expressions to those experimentally measured provides a method to assess the compatibility of heterogeneous reaction rate theories and measurements made under realistic atmospheric conditions.", "doi": "10.1016/0021-9797(89)90051-9", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1989-02", "series_number": "2", "volume": "127", "issue": "2", "pages": "465-486" }, { "id": "authors:cw2pw-mg961", "collection": "authors", "collection_id": "cw2pw-mg961", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-418446100.3", "type": "article", "title": "Sensitivity analysis of a chemical mechanism for aqueous-phase atmospheric chemistry", "author": [ { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The sensitivity analysis of a comprehensive chemical mechanism for aqueous-phase atmospheric chemistry is performed. The main aqueous-phase reaction pathways for the system are the oxidation of S(IV) by H\u2082O\u2082, OH, O\u2082 (catalyzed by Fe\u00b3\u207a and Mn\u00b2\u207a), O\u2083 and HSO\u2085\u207b. The HO\u2082 (aq) and OH(aq) radicals contribute indirectly to this process by producing and consuming H\u2082O\u2082 (aq), respectively. The dominant pathway for HNO\u2083(aq) acidity is scavenging of nitric acid from the gas phase. HCOOH is produced because of the reaction of HCHO(aq) with OH(aq). The gas-phase concentrations of SO\u2082, H\u2082O\u2082, HO\u2082, OH, O\u2083, HCHO, NH\u2083, HNO\u2083, and HCl are of primary importance. An increase in the liquid water content of the cloud results in a decrease of the sulfate concentration but an increase of the total sulfate amount in the aqueous phase. A condensed mechanism is derived from the analysis.", "doi": "10.1029/jd094id01p01105", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "1989-01-20", "series_number": "D1", "volume": "94", "issue": "D1", "pages": "1105-1126" }, { "id": "authors:y4tq4-q7w48", "collection": "authors", "collection_id": "y4tq4-q7w48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230307-870297300.1", "type": "article", "title": "Parameterization of the formation potential of secondary organic aerosols", "author": [ { "family_name": "Grosjean", "given_name": "Daniel", "orcid": "0000-0001-6941-2490", "clpid": "Grosjean-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Urban particulate matter (PM\u2081\u2080) concentrations often include a large contribution from secondary aerosols, i.e. sulfate, nitrate and organic aerosols, which are formed in situ by chemical reactions of their gas phase precursors, SO\u2093, NO\u2093 and reactive organic gases (ROG), respectively. For secondary organic aerosols, the results of smog chamber experiments are used to estimate the fraction of ROG that is converted into aerosols, called the fractional aerosol coefficient. An 'emission parameter' for secondary organic aerosol can thus be calculated for each ROG. This emission parameter is simply taken as the product of the ROG emission factor and the fractional aerosol coefficient. The secondary organic aerosol emission parameters thus estimated can then be modeled as if secondary organic aerosols formed photochemically in urban air were primary emissions.", "doi": "10.1016/0004-6981(89)90058-9", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1989-01", "series_number": "8", "volume": "23", "issue": "8", "pages": "1733-1747" }, { "id": "authors:tkg4p-hf555", "collection": "authors", "collection_id": "tkg4p-hf555", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318359000.7", "type": "article", "title": "Binary nucleation of methanesulfonic acid and water", "author": [ { "family_name": "Kreidenweis", "given_name": "Sonia M.", "orcid": "0000-0002-2561-2914", "clpid": "Kreidenweis-Sonia-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" } ], "abstract": "A continuous-flow, mixing-type device for the study of binary nucleation phenomena has been developed and applied to the methanesulfonic acid-water system. Experimental measurements confirm the formation of particles from the binary gas at partial pressures of water vapor and acid vapor below saturation levels. Although trends in the data agree with the predictions of binary nucleation theory, the observed number concentrations are not well predicted using macroscopic values of the solution properties.", "doi": "10.1016/0021-8502(89)90105-5", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "1989-01", "series_number": "5", "volume": "20", "issue": "5", "pages": "585-607" }, { "id": "authors:h9x47-k2664", "collection": "authors", "collection_id": "h9x47-k2664", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:KARjas89", "type": "article", "title": "Smog chamber studies of aerosol formation in atmospheric mixtures", "author": [ { "family_name": "Karch", "given_name": "Rudolf", "clpid": "Karch-R" }, { "family_name": "Reischl", "given_name": "George P.", "clpid": "Reischl-G-P" }, { "family_name": "Winklmayr", "given_name": "Wolfgang", "clpid": "Winklmayr-W" }, { "family_name": "Paulson", "given_name": "Suzanne", "clpid": "Paulson-S" }, { "family_name": "Wang", "given_name": "Shih Chen", "clpid": "Wang-Shih-Chen" }, { "family_name": "Yin", "given_name": "Fangdong", "clpid": "Yin-Fangdong" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "During a joint experiment of the Department of Chemical Engineering (California\nInstitute of Technology) and the Institute of Experimental Physics (University\nof Vienna), measurements have been performed to study the dynamics of particle\ninception in photochemical smog. The goal of this study was to obtain an understanding\nof the fundamental mechanisms in the formation of organic aerosols\nduring atmospheric photochemical reactions. This paper presents results with new\napproaches to mobility analysis for aerosol-measurements that have been performed\nto trace the dynamics of ultrafine aerosol particles in smog chamber experiments.", "doi": "10.1016/0021-8502(89)90745-3", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "1989", "series_number": "8", "volume": "20", "issue": "8", "pages": "995-998" }, { "id": "authors:dv5na-vyv23", "collection": "authors", "collection_id": "dv5na-vyv23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230305-418446100.4", "type": "article", "title": "Nonlocal description of turbulent dispersion", "author": [ { "family_name": "Georgopoulos", "given_name": "P. G.", "orcid": "0000-0003-2119-0301", "clpid": "Georgopoulos-Panos-G" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Although it is common engineering practice to model turbulent mass transport by assuming the turbulent mass flux as proportional to the local mean concentration gradient, it is well known that the applicability of this assumption is very limited, especially when the length scales and time scales of the transport process are not much smaller than the scales of variations in either the velocity or the concentration fields. In the present work the formalism of stochastic Green's functions is used to derive general, nonlocal, integrodifferential equations for turbulent transport that incorporate the multiscale aspects of the phenomena of absolute and relative dispersion. It is shown that the turbulent mass fluxes are in general equal to convolutions over space and time of the mean concentration gradients with space- and time-dependent kernel functions. By introducing different closure approximations for the kernel functions one can obtain in a systematic, deductive, manner a variety of common models for turbulent transport, corresponding to either local or nonlocal descriptions of dispersion.", "doi": "10.1016/0009-2509(89)85137-1", "issn": "0009-2509", "publisher": "Elsevier", "publication": "Chemical Engineering Science", "publication_date": "1989", "series_number": "9", "volume": "44", "issue": "9", "pages": "1995-2016" }, { "id": "authors:jn0r4-mqr55", "collection": "authors", "collection_id": "jn0r4-mqr55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318379000.9", "type": "article", "title": "Identification of distributed parameter systems with pointwise constraints on the parameters", "author": [ { "family_name": "Yu", "given_name": "Wenhuan", "clpid": "Yu-Wenhuan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The problem of estimating k(x, y) in the parabolic equation \n\u2202u/\u2202t = \u2202/\u2202x(k(x,y)(\u2202u/\u2202x)) + \u2202/\u2202y(k(x,y)(\u2202u/\u2202y)) + f (x,y,t) on the basis of noisy measurements of k at discrete locations is considered subject to direct measurements of k at other discrete locations. Necessary conditions for optimality are derived based on a regularization formulation, and the computational implementation is carried out via a finite element representation of k.", "doi": "10.1016/0022-247x(88)90100-x", "issn": "0022-247X", "publisher": "Elsevier", "publication": "Journal of Mathematical Analysis and Applictions", "publication_date": "1988-12", "series_number": "2", "volume": "136", "issue": "2", "pages": "497-520" }, { "id": "authors:va7p7-qxy19", "collection": "authors", "collection_id": "va7p7-qxy19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:OKUjcp88b", "type": "article", "title": "Studies in binary nucleation: The dibutylphthalate/dioctylphthalate system", "author": [ { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Kreidenweis", "given_name": "Sonia", "orcid": "0000-0002-2561-2914", "clpid": "Kreidenweis-Sonia-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A continuous-flow mixing apparatus has been developed for the study of binary nucleation. This apparatus has been used to investigate the nucleation of mixed dibutylphthalate/dioctylphthalate vapors, and the interaction of the two vapors in particle formation has been demonstrated. A model that considers competition between nucleation and condensation processes during particle formation is applied in the analysis of the experimental results, allowing comparison of the magnitudes of the theoretical and actual nucleation rates in both the single-component and mixed vapor systems.", "doi": "10.1063/1.455413", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1988-11-15", "series_number": "10", "volume": "89", "issue": "10", "pages": "6442-6453" }, { "id": "authors:4cm3m-nz891", "collection": "authors", "collection_id": "4cm3m-nz891", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318386000.10", "type": "article", "title": "On the relation between binary diffusivity and mean free path", "author": [ { "family_name": "Huang", "given_name": "David D.", "clpid": "Huang-David-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In problems of diffusion of a vapor species A through a background gas B (e.g., air) the relation between the binary mixture diffusivity, D_(AB), the mean free path, \u03bb_(AB), and the mean thermal speed, c\u0305_A, is of interest.", "doi": "10.1016/0021-9797(88)90042-2", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1988-10", "series_number": "2", "volume": "125", "issue": "2", "pages": "733-735" }, { "id": "authors:hye7v-68r09", "collection": "authors", "collection_id": "hye7v-68r09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318414000.15", "type": "article", "title": "A model calculation of particle deposition onto a rough wall by Brownian and turbulent diffusion", "author": [ { "family_name": "Shimada", "given_name": "Manabu", "clpid": "Shimada-Manabu" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A model, in which the particle number concentration above a rough wall is predicted based on the turbulence distribution near the wall, has been developed in order to theoretically evaluate the influence of the wall roughness upon Brownian and turbulent diffusive deposition of particles. Measurements of particle deposition rates onto rough walls have also been carried out using model surfaces of regularly shaped roughness affixed to the inner wall of a stirred tank. The dependence upon particle size, turbulent intensity, and roughness size of the enhancement of deposition due to a rough surface has been studied. From the model calculation of deposition rates accounting for the shape and configuration of the roughness elements, the model proposed is found to give good agreement with the measurements for surfaces with regularly shaped roughness as well as for irregular sandpaper surfaces.", "doi": "10.1016/0021-9797(88)90069-0", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1988-09", "series_number": "1", "volume": "125", "issue": "1", "pages": "198-211" }, { "id": "authors:1aeq4-8wg39", "collection": "authors", "collection_id": "1aeq4-8wg39", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318435000.18", "type": "article", "title": "Development and evaluation of an Eulerian photochemical gas-aerosol model", "author": [ { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A three-dimensional Eulerian model that simulates the concentrations of gaseous pollutants and the size-composition distribution of multicomponent atmospheric aerosols has been developed and used to study the evolution of the aerosol-size distribution and composition in the South Coast Air Basin of California. The predictions of the model are compared with ambient measurements of sulfate, nitrate, sodium, chloride and ammonium aerosol.", "doi": "10.1016/0004-6981(88)90088-1", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1988-09", "series_number": "9", "volume": "22", "issue": "9", "pages": "1985-2001" }, { "id": "authors:sfm3y-f9t80", "collection": "authors", "collection_id": "sfm3y-f9t80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318401000.13", "type": "article", "title": "Identification of parabolic distributed parameter systems by regularization with differential operators", "author": [ { "family_name": "Yu", "given_name": "Wenhuan", "clpid": "Yu-Wenhuan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The theory of identification of variable coefficients in parabolic distributed parameter systems by regularization is extended to the case in which the stabilizing functional is the norm of a differential operator. Stability and convergence of the method are proved. A detailed computational evaluation of the approach is presented via the estimation of a spatially varying conductivity in the two-dimensional heat equation.", "doi": "10.1016/0022-247x(88)90068-6", "issn": "0022-247X", "publisher": "Elsevier", "publication": "Journal of Mathematical Analysis and Applictions", "publication_date": "1988-06", "series_number": "2", "volume": "132", "issue": "2", "pages": "365-387" }, { "id": "authors:4a3v9-mdk48", "collection": "authors", "collection_id": "4a3v9-mdk48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200428-083634078", "type": "article", "title": "Ozone Air Quality Models: A Critical Review", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The field of ozone air quality modeling, or as it is commonly referred to, photochemical air quality modeling, has undergone rapid change in recent years. Improvements in model components, as well as in methods of interpreting model performance, have contributed to this change. Attendant with this rapid change has been a growing need for those developing and using air quality models and policy makers to have a common understanding of the use and role of models in the decision making process. This Critical Review highlights recent advances and continuing problem areas in photochemical air quality modeling. Emphasis is placed on the components and input data for such models, model performance evaluation, and the implications for their use in regulatory decisions.", "doi": "10.1080/08940630.1988.10466404", "issn": "0894-0630", "publisher": "Informa UK Limited", "publication": "JAPCA", "publication_date": "1988-05", "series_number": "5", "volume": "38", "issue": "5", "pages": "616-645" }, { "id": "authors:y6swx-1c295", "collection": "authors", "collection_id": "y6swx-1c295", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768637000.6", "type": "article", "title": "Optimal estimators for time-averaged measurement systems", "author": [ { "family_name": "Omatu", "given_name": "Sigeru", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The optimal linear prediction estimator and filter are derived for dynamic systems with time-averaged measurements using the Wiener-Hopf theory. The estimates are compared with other optimal estimators for various measurement systems.", "doi": "10.1080/00207728808967626", "issn": "0020-7721", "publisher": "Informa UK Limited", "publication": "International Journal of Systems Science", "publication_date": "1988-04", "series_number": "4", "volume": "19", "issue": "4", "pages": "573-581" }, { "id": "authors:twwp0-vzg64", "collection": "authors", "collection_id": "twwp0-vzg64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318453000.21", "type": "article", "title": "Nucleation of sulfuric acid-water and methanesulfonic acid-water solution particles: Implications for the atmospheric chemistry of organosulfur species", "author": [ { "family_name": "Kreidenweis", "given_name": "Sonya M.", "clpid": "Kreidenweis-Sonya-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Binary nucleation theory is applied to the formation of aqueous sulfuric acid and aqueous methanesulfonic acid particles and the relative rates of aerosol formation in humid atmospheres are compared. An integral model is presented which describes nucleation of solution particles, aerosol growth, and condensable vapor source and depletion rates. To extend this model, the water activities of the ternary solution, sulfuric acid-methanesulfonic acid-water, are estimated, and growth of the nucleated aerosol by incorporation of both types of acid is considered. Predictions of both forms of the model are compared with the experimental results of Hatakeyama et al. [Atmospheric Environment 19, 135\u2013141 (1985)] for the photooxidation of dimethylsulfide in humid air.", "doi": "10.1016/0004-6981(88)90034-0", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1988-02", "series_number": "2", "volume": "22", "issue": "2", "pages": "283-296" }, { "id": "authors:rfs73-f6077", "collection": "authors", "collection_id": "rfs73-f6077", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318465000.23", "type": "article", "title": "Trajectory models and the deformation of air parcels", "author": [ { "family_name": "Ghim", "given_name": "Young Sung", "clpid": "Ghim-Young-Sung" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A long-standing problem in the use of Lagrangian air quality trajectory models is assessing the validity of the concept of an air parcel that maintains its integrity over a certain travel time. This issue is addressed by simulating the advection and diffusion of an inert air parcel in a flow generated by a planetary boundary layer model. Measures of the difference between the actual concentration distribution of the parcel and those resulting from two forms of trajectory models are introduced.", "doi": "10.1016/0004-6981(88)90296-x", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1988-01", "series_number": "1", "volume": "22", "issue": "1", "pages": "25-29" }, { "id": "authors:xt4md-khc18", "collection": "authors", "collection_id": "xt4md-khc18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318471000.24", "type": "article", "title": "Estimation of relative dispersion parameters from atmospheric turbulence spectra", "author": [ { "family_name": "Georgopoulos", "given_name": "P. G.", "orcid": "0000-0003-2119-0301", "clpid": "Georgopoulos-Panos-G" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A practical method for estimating relative dispersion parameters from observed atmospheric turbulence spectra is presented and discussed. This method is based on the association of the relative dispersion and meandering processes with appropriately defined time scales, allowing the computation of dispersion parameters from the filtered Lagrangian turbulent velocity spectra. The parameters for the appropriate high-pass filter functions, required for the calculation of properties relevant to in-plume phenomena, are not assumed a priori but are determined through an iterative integral technique. Comparison with field data confirms the validity of the method and shows it appropriate for application in conjunction with various spectral functions.", "doi": "10.1016/0004-6981(88)90297-1", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1988-01", "series_number": "1", "volume": "22", "issue": "1", "pages": "31-41" }, { "id": "authors:hgdar-qq737", "collection": "authors", "collection_id": "hgdar-qq737", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200930-113055318", "type": "book_section", "title": "Optimal sensor and actuator locations in distributed parameter systems", "book_title": "System Modelling and Optimization", "author": [ { "family_name": "Omatu", "given_name": "Sigeru", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Iri", "given_name": "Masao", "clpid": "Iri-Masao" }, { "family_name": "Yajima", "given_name": "Keiji", "clpid": "Yajima-Keiji" } ], "abstract": "The optimal sensor and actuator location problem in distributed parameter systems is considered. The sensor and actuator locations are chosen to minimize the performance criterion on the LQG problem with noises dependening on the actuator and sensor locations. The existence theorem for the optimal sensor and actuator locations is proved based on a property of evolution operators. Necessary and sufficient conditions are derived by using properties of operator-valued Riccati equations and evolution operators. It is shown that a duality holds between the sensor and actuator locations.", "doi": "10.1007/bfb0042795", "isbn": "3540192387", "publisher": "Springer-Verlag", "place_of_publication": "Berlin/Heidelberg", "publication_date": "1988", "pages": "269-276" }, { "id": "authors:ct9b4-4jj24", "collection": "authors", "collection_id": "ct9b4-4jj24", "cite_using_url": "https://resolver.caltech.edu/CaltechBOOK:1988.001", "type": "book", "title": "Fundamentals of air pollution engineering", "author": [ { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Analysis and abatement of air pollution involve a variety of technical disciplines. Formation of the most prevalent pollutants occurs during the combustion process, a tightly coupled system involving fluid flow, mass and energy transport, and chemical kinetics. Its complexity is exemplified by the fact that, in many respects, the simplest hydrocarbon combustion, the methane-oxygen flame, has been quantitatively modeled only within the last several years. Nonetheless, the development of combustion modifications aimed at minimizing the formation of the unwanted by-products of burning fuels requires an understanding of the combustion process. Fuel may be available in solid, liquid, or gaseous form; it may be mixed with the air ahead of time or only within the combustion chamber; the chamber itself may vary from the piston and cylinder arrangement in an automobile engine to a 10-story-high boiler in the largest power plant; the unwanted byproducts may remain as gases, or they may, upon cooling, form small particles. \n\nThe only effective way to control air pollution is to prevent the release of pollutants at the source. Where pollutants are generated in combustion, modifications to the combustion process itself, for example in the manner in which the fuel and air are mixed, can be quite effective in reducing their formation. Most situations, whether a combustion or an industrial process, however, require some degree of treatment of the exhaust gases before they are released to the atmosphere. Such treatment can involve intimately contacting the effluent gases with liquids or solids capable of selectively removing gaseous pollutants or, in the case of particulate pollutants, directing the effluent flow through a device in which the particles are captured on surfaces. \n\nThe study of the generation and control of air pollutants can be termed air pollution engineering and is the subject of this book. Our goal here is to present a rigorous and fundamental analysis of the production of air pollutants and their control. The book is intended for use at the senior or first-year graduate level in chemical, civil, environmental, and mechanical engineering curricula. We assume that the student has had basic first courses in thermodynamics, fluid mechanics, and heat transfer. The material treated in the book can serve as the subject of either a full-year or a one-term course, depending on the choice of topics covered. \n\nIn the first chapter we introduce the concept of air pollution engineering and summarize those species classified as air pollutants. Chapter 1 also contains four appendices that present certain basic material that will be called upon later in the book. This material includes chemical kinetics, the basic equations of heat and mass transfer, and some elementary ideas from probability and turbulence. \n\nChapter 2 is a basic treatment of combustion, including its chemistry and the role of mixing processes and flame structure. Building on the foundation laid in Chapter 2, we present in Chapter 3 a comprehensive analysis of the formation of gaseous pollutants in combustion. Continuing in this vein, Chapter 4 contains a thorough treatment of the internal combustion engine, including its principles of operation and the mechanisms of formation of pollutants therein. Control methods based on combustion modification are discussed in both Chapters 3 and 4. \n\nParticulate matter (aerosols) constitutes the second major category of air pollutants when classified on the basis of physical state. Chapter 5 is devoted to an introduction to aerosols and principles of aerosol behavior, including the mechanics of particles in flowing fluids, the migration of particles in external force fields, Brownian motion of small particles, size distributions, coagulation, and formation of new particles from the vapor by homogeneous nucleation. Chapter 6 then treats the formation of particles in combustion processes. \n\nChapters 7 and 8 present the basic theories of the removal of particulate and gaseous pollutants, respectively, from effluent streams. We cover all the major air pollution control operations, such as gravitational and centrifugal deposition, electrostatic precipitation, filtration, wet scrubbing, gas absorption and adsorption, and chemical reaction methods. Our goal in these two chapters, above all, is to carefully derive the basic equations governing the design of the control methods. Limited attention is given to actual equipment specification, although with the material in Chapters 7 and 8 serving as a basis, one will be able to proceed to design handbooks for such specifications. \n\nChapters 2 through 8 treat air pollution engineering from a process-by-process point of view. Chapter 9 views the air pollution control problem for an entire region or airshed. To comply with national ambient air quality standards that prescribe, on the basis of health effects, the maximum atmospheric concentration level to be attained in a region, it is necessary for the relevant governmental authority to specify the degree to which the emissions from each of the sources in the region must be controlled. Thus it is generally necessary to choose among many alternatives that may lead to the same total quantity of emission over the region. Chapter 9 establishes a framework by which an optimal air pollution control plan for an airshed may be determined. In short, we seek the least-cost combination of abatement measures that meets the necessary constraint that the total emissions not exceed those required to meet an ambient air quality standard. \n\nOnce pollutants are released into the atmosphere, they are acted on by a variety of chemical and physical phenomena. The atmospheric chemistry and physics of air pollution is indeed a rich arena, encompassing the disciplines of chemistry, meteorology, fluid mechanics, and aerosol science. As noted above, the subject matter of the present book ends at the stack (or the tailpipe); those readers desiring a treatment of the atmospheric behavior of air pollutants are referred to J. H. Seinfeld, Atmospheric Chemistry and Physics of Air Pollution (Wiley-Interscience, New York, 1986). \n\nWe wish to gratefully acknowledge David Huang, Carol Jones, Sonya Kreidenweis, Ranajit Sahu, and Ken Wolfenbarger for their assistance with calculations in the book.\nFinally, to Christina Conti, our secretary and copy editor, who, more than anyone else, kept safe the beauty and precision of language as an effective means of communication, we owe an enormous debt of gratitude. She nurtured this book as her own; through those times when the task seemed unending, she was always there to make the road a little smoother. \n\nR. C. Flagan\nJ. H. Seinfeld", "isbn": "0-13-332537-7", "publisher": "Prentice-Hall, Inc.", "place_of_publication": "Englewood Cliffs, New Jersey", "publication_date": "1988" }, { "id": "authors:9p17e-atc36", "collection": "authors", "collection_id": "9p17e-atc36", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-104608694", "type": "article", "title": "Aerosol formation and growth in atmospheric aromatic hydrocarbon photooxidation", "author": [ { "family_name": "Stern", "given_name": "Jennifer E.", "clpid": "Stern-Jennifer-E" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Grosjean", "given_name": "Daniel", "orcid": "0000-0001-6941-2490", "clpid": "Grosjean-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An experimental study of aerosol formation in aromatic hydrocarbon/NO_x systems has been conducted in an outdoor smog chamber. Aerosol size distributions were measured as a function of time in toluene, m-xylene, ethylbenzene, or 1,3,5-trimethylbenzene photooxidations to determine the rates of new particle formation and the effects of initial particles on aerosol formation and growth. Aerosol yields from the aromatic gas-phase photooxidations were found to be approximately 2-5% by mass of the starting aromatic species. Simulations of the aerosol behavior in these experiments have been carried out using an integral model that includes a vapor source, homogeneous nucleation, condensational growth, and particle loss by deposition. Predictions from the model are in relatively good agreement with the experimental observations. Results indicate that the nucleation mechanism in these systems is still not completely understood.", "doi": "10.1021/es00165a011", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1987-12", "series_number": "12", "volume": "21", "issue": "12", "pages": "1224-1231" }, { "id": "authors:vqaaw-q1r90", "collection": "authors", "collection_id": "vqaaw-q1r90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170718-165813154", "type": "book_section", "title": "Estimation of petroleum reservoir properties", "author": [ { "family_name": "Lee", "given_name": "Tai-yong", "clpid": "Lee-Tai-Yong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We present an algorithm for estimating the absolute and relative permeabilities in petroleum reservoir models based on regularization and spline approximation. A computational example is included.", "doi": "10.1109/CDC.1987.272638", "publisher": "IEEE", "publication_date": "1987-12" }, { "id": "authors:shykt-j6k37", "collection": "authors", "collection_id": "shykt-j6k37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318504000.29", "type": "article", "title": "Continued development of a general equilibrium model for inorganic multicomponent atmospheric aerosols", "author": [ { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A model is presented that predicts the total quantities of ammonium, chloride, nitrate and water contained in atmospheric aerosols, their physical state and their distribution among aerosol particles of different sizes. The model is based on the thermodynamic equilibrium calculation of the ammonium/chloride/nitrate/sodium/sulfate/water system. The existence of water in the aerosol phase at low relative humidities is shown to be explained. Observed aerosol concentrations at Long Beach, California during 30\u201331 August 1982 are successfully predicted.", "doi": "10.1016/0004-6981(87)90380-5", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1987-11", "series_number": "11", "volume": "21", "issue": "11", "pages": "2453-2466" }, { "id": "authors:b2nx3-rf715", "collection": "authors", "collection_id": "b2nx3-rf715", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LEEip87.898", "type": "article", "title": "Estimation of absolute and relative permeabilities in petroleum reservoirs", "author": [ { "family_name": "Lee", "given_name": "Tai-yong", "clpid": "Lee-Tai-Yong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The estimation of absolute and relative permeabilities for petroleum reservoirs on the basis of noisy data at wells is considered. The spatially varying absolute permeability is estimated by regularisation combined with a bi-cubic spline approximation. Relative permeability is represented by a given function of saturation with unknown coefficients. Numerical results provide an indication of the estimability of the two permeabilities in conventional petroleum production operations.", "doi": "10.1088/0266-5611/3/4/015", "issn": "0266-5611", "publisher": "IOP", "publication": "Inverse Problems", "publication_date": "1987-11", "series_number": "4", "volume": "3", "issue": "4", "pages": "711-728" }, { "id": "authors:d3h1b-epa87", "collection": "authors", "collection_id": "d3h1b-epa87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571280000.9", "type": "article", "title": "Three-dimensional behavior of mixing limited chemistry in the atmosphere", "author": [ { "family_name": "Georgopoulos", "given_name": "P. G.", "orcid": "0000-0003-2119-0301", "clpid": "Georgopoulos-Panos-G" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This paper addresses an important and complex problem, that is the effect of incomplete fine-scale mixing (\"micromixing\"), in the near-source evolution of fast, second order atmospheric reactions. The significance and the complexity of this problem are indeed nicely presented by Karamchandani and Peters (1987) in their Introduction and in the first part of their section entitled Problem description. However their subsequent analysis contains some serious errors and inconsistencies that we will discuss briefly in the following.", "doi": "10.1016/0004-6981(87)90358-1", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1987-10", "series_number": "10", "volume": "21", "issue": "10", "pages": "2262-2264" }, { "id": "authors:k2s5c-0ef40", "collection": "authors", "collection_id": "k2s5c-0ef40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571215000.2", "type": "article", "title": "Homogeneous and heterogeneous nucleation in a laminar flow aerosol generator", "author": [ { "family_name": "Nguyen", "given_name": "Hung V.", "clpid": "Nguyen-Hung-V" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Mimura", "given_name": "Tadaaki", "clpid": "Mimura-Tadaaki" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The formation of aerosol particles by homogeneous and heterogeneous nucleation has been studied experimentally using a laminar flow aerosol generator. Dry gas (N\u2082 or air) saturated with dibutylphthalate (DBP), either particle-free or containing an ultrafine monodisperse aerosol, was cooled well below the saturation temperature causing the highly supersaturated vapor to nucleate. The resulting particle number concentrations were observed under various conditions of the gas stream and properties of the introduced foreign condensation nuclei. The dependence of the nucleation rate on the vapor concentration, cooling rate, and seed aerosol concentration was studied. Comparisons of the measured number concentrations with predictions based on the model of A. J. Pesthy, R. C. Flagan, and J. H. Seinfeld (J. Colloid Interface Sci. 91, 525 (1981)) showed good qualitative agreement when the classical homogeneous nucleation rates were enhanced by a factor of 10\u2075\u201310\u2077. The laminar flow aerosol generator is found to be an effective system for the study of the influence of foreign particles on the rate of homogeneous nucleation of a vapor.", "doi": "10.1016/0021-9797(87)90295-5", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1987-10", "series_number": "2", "volume": "119", "issue": "2", "pages": "491-504" }, { "id": "authors:sbb4e-eqv04", "collection": "authors", "collection_id": "sbb4e-eqv04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-103745250", "type": "article", "title": "Studies of concentrated electrolyte solutions using the electrodynamic balance. 2. Water activities for mixed-electrolyte solutions", "author": [ { "family_name": "Cohen", "given_name": "Mark D.", "orcid": "0000-0003-3183-2558", "clpid": "Cohen-Mark-D" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An electrodynamic balance has been used to measure the water activity as a function of solute concentration at 20 \u00b0C for three aqueous electrolyte mixtures: NaCI-KCI, NaCl-KBr, and NaCl-(NH\u2084)\u2082SO\u2084. The measurements were performed by levitating single, charged particles of these electrolyte mixtures within the balance and measuring the mass of the particles as a function of the surrounding relative humidity. The deliquescence behavior of the mixed-electrolyte particles was also observed. For the alkali halide mixtures, the low-concentration data were consistent with earlier investigations. Data were obtained at higher concentrations than previously reported. The amount of water in the NaC1-(NH\u2084)\u2082SO\u2084 particles after drying was unknown. This, together with the lack of previously reported water activity data for this mixture, complicated the analysis of these experiments. Three models of mixed-electrolyte solutions-the Zdanovskii-Stokes-Robinson, Reilly-Wood-Robinson, and Pitzer methods-agreed well with the experimental data for the NaCl-KCl and NaCl-KBr systems over the range of concentrations that the models could be applied. The mixing rules' predictions were consistent with the experimental observations for the NaCl-(NH\u2084)\u2082SO\u2084 system assuming a small amount of water was retained in the particles after drying.", "doi": "10.1021/j100301a030", "issn": "0022-3654", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry", "publication_date": "1987-08", "series_number": "17", "volume": "91", "issue": "17", "pages": "4575-4582" }, { "id": "authors:ws04a-ry783", "collection": "authors", "collection_id": "ws04a-ry783", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-104039418", "type": "article", "title": "Studies of concentrated electrolyte solutions using the electrodynamic balance. 3. Solute nucleation", "author": [ { "family_name": "Cohen", "given_name": "Mark D.", "orcid": "0000-0003-3183-2558", "clpid": "Cohen-Mark-D" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The nucleation of crystals from aqueous solution has been investigated for several common inorganic salts alone and in mixtures. Single, charged solution droplets approximately 20 \u00b5m in diameter were suspended in an electrodynamic balance and continuously weighed. The solute concentration in the droplet was changed by adjusting the relative humidity of the air surrounding the particle. Nucleation theory was used to estimate the surface excess free energy and critical nucleus size from the measured supersaturation at which nucleation occurred.", "doi": "10.1021/j100301a031", "issn": "0022-3654", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry", "publication_date": "1987-08", "series_number": "17", "volume": "91", "issue": "17", "pages": "4583-4590" }, { "id": "authors:7wb1z-wrv21", "collection": "authors", "collection_id": "7wb1z-wrv21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150805-103257066", "type": "article", "title": "Studies of concentrated electrolyte solutions using the electrodynamic balance. 1. Water activities for single-electrolyte solutions", "author": [ { "family_name": "Cohen", "given_name": "Mark D.", "orcid": "0000-0003-3183-2558", "clpid": "Cohen-Mark-D" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An electrodynamic balance apparatus has been used to suspend single, 20-\u00b5m-diameter, charged droplets of aqueous salt solutions in a humid environment. From measurements of the humidity surrounding the droplet and the relative mass of the particle in its wet and dry states, the dependence of water activity on solute concentration was determined for aqueous solutions of the following salts at 20^oC: NaCl, NaBr, KCl, KBr, NH_4Cl, Na_2SO_4, (NH_4)_2SO4, CaC1_2, MnC1_2, and FeC1_3. This technique allowed the thermodynamics of highly supersaturated solutions to be studied, and for most of the salts, the measurements were made to higher concentrations than have previously been reported at comparable temperatures. The dependence of the solute activity coefficient on concentration was calculated for each of the salts, and the features of this dependence are discussed in relationship to ionic hydration and association. Several semiempirical electrolyte solution models were tested against the data, and it was found that salt-specific model parameters estimated from low-concentration data could not be reliably used to predict the solution behavior at high concentrations. However, with estimated parameters based on the full range of the data, the models were able to represent the experimental data to within the uncertainty in the measurements.", "doi": "10.1021/j100301a029", "issn": "0022-3654", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry", "publication_date": "1987-08", "series_number": "17", "volume": "91", "issue": "17", "pages": "4563-4574" }, { "id": "authors:xqasz-23808", "collection": "authors", "collection_id": "xqasz-23808", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SAGjcp87", "type": "article", "title": "Fourier transform infrared spectroscopy of a single aerosol particle", "author": [ { "family_name": "Sageev Grader", "given_name": "Gideon", "orcid": "0000-0003-4371-4575", "clpid": "Grader-Gideon" }, { "family_name": "Arnold", "given_name": "Stephen", "clpid": "Arnold-Stephen" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A method is developed for obtaining the molecular composition of a single suspended microparticle by Fourier transform infrared spectroscopy. The particle is held in an electrodynamic balance and irradiated simultaneously by the infrared output from a Michelson interferometer and the visible light from a dye laser. The laser is tuned to an edge of an optical resonance of the particle while the IR beam is chopped. Through evaporation and condensation the chopped IR beam causes a size modulation of the droplet, which in turn induces a fluctuation in the laser light scattered from the particle. The scattered light is detected at 90\u00b0 with a photomultiplier, and the amplitude of the light fluctuation is measured with a lock-in amplifier. The lock-in signal is then inverted by a discrete fast Fourier transform routine (FFT), to yield the particle absorption spectrum. Spectra of (NH\u2084)\u2082SO\u2084 droplets at different solute concentrations are presented. The data shown include the first infrared spectrum of a highly supersaturated solution.", "doi": "10.1063/1.452473", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1987-06-01", "series_number": "11", "volume": "86", "issue": "11", "pages": "5897-5903" }, { "id": "authors:2r9zs-zz239", "collection": "authors", "collection_id": "2r9zs-zz239", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318508000.30", "type": "article", "title": "Optimal estimators for distributed-parameter systems with time-averaged pointwise measurements", "author": [ { "family_name": "Omatu", "given_name": "Sigeru", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The optimal linear estimators for distributed-parameter systems are derived in the case of pointwise observations that are time-averaged during the sampling interval. The filter structure derived is compared with that for the discrete-time observation case, and the finite-dimensional approximation of the results is presented.", "doi": "10.1080/00207178708933859", "issn": "0020-7179", "publisher": "Taylor & Francis", "publication": "International Journal of Control", "publication_date": "1987-06", "series_number": "6", "volume": "45", "issue": "6", "pages": "1963-1974" }, { "id": "authors:q1hwc-n6h79", "collection": "authors", "collection_id": "q1hwc-n6h79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318439000.19", "type": "article", "title": "Estimation of Nitrogen Dioxide Concentrations in the Vicinity of a Roadway by Optimal Filtering Theory", "author": [ { "family_name": "Omatu", "given_name": "S.", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Distributed parameter filtering theory and maximum likelihood parameter estimation are applied to the joint estimation of atmospheric diffusion parameters and of nitrogen dioxide concentration levels in the vicinity of a heavily travelled roadway in Tokushima, Japan. An algorithm is presented that can be used in conjunction with urban air pollution models to estimate the spatial and temporal distribution of airborne concentrations based on data obtained at a network of monitoring stations.", "doi": "10.1016/s1474-6670(17)59297-6", "issn": "1474-6670", "publisher": "Pergamon", "publication": "IFAC Proceedings Volumes", "publication_date": "1987-06", "series_number": "1", "volume": "20", "issue": "1", "pages": "185-192" }, { "id": "authors:vympz-8q569", "collection": "authors", "collection_id": "vympz-8q569", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150630-170240427", "type": "article", "title": "Homogeneous nucleation in supersaturated vapor containing foreign seed aerosol", "author": [ { "family_name": "Warren", "given_name": "Dale R.", "clpid": "Warren-Dale-R" }, { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "The formation of aerosol particles by homogeneous nucleation in a supersaturated vapor containing seed aerosol has been studied experimentally and theoretically. In the laboratory, a room-temperature gas optionally containing zinc chloride particles is continuously mixed with a high-temperature gas saturated with dibutyl phthalate (DBP) vapor in a previously discussed device for the study of aerosol nucleation known as a particle size magnifier (PSM). A highly supersaturated vapor is rapidly formed in the mixing zone of the PSM, and gas-to-particle conversion ensues. The vapor may be converted to the aerosol phase by condensation onto the preexisting particles or by homogeneous nucleation to form new particles which then serve as condensation sites themselves. The split between these alternate pathways for gas-to-particle conversion may be deduced from measurements of the resulting aerosol concentrations for different initial supersaturations, seed aerosol concentrations, and seed aerosol sizes. The measured final aerosol concentrations are compared with those predicted by a dynamic model that combines expressions for classical nucleation theory and for steady-state particle growth, and agreement is found to within experimental uncertainties. Suppression of homogeneous nucleation by seed aerosol is not predicted to be strong unless seed aerosol number concentrations are larger than the number concentrations which would result from homogeneous nucleation alone.", "doi": "10.1016/0021-9797(87)90152-4", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1987-04", "series_number": "2", "volume": "116", "issue": "2", "pages": "563-581" }, { "id": "authors:36drq-wb137", "collection": "authors", "collection_id": "36drq-wb137", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318499000.28", "type": "article", "title": "Mathematical modeling of the dynamics of multicomponent atmospheric aerosols", "author": [ { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Seigneur", "given_name": "Christian", "orcid": "0000-0002-3079-4839", "clpid": "Seigneur-Christian" } ], "abstract": "A model is developed to simulate the dynamics of multicomponent atmospheric aerosols, including new particle formation by homogeneous heteromolecular nucleation, gas-to-particle conversion, coagulation and dry deposition. Both equilibrium and non-equilibrium aspects involving sulfate, nitrate and ammonium compounds are considered. The model is used to predict the dynamics of the composition of the aerosol observed on an air trajectory in the Los Angeles basin on 31 August 1982.", "doi": "10.1016/0004-6981(87)90090-4", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1987-04", "series_number": "4", "volume": "21", "issue": "4", "pages": "943-955" }, { "id": "authors:18jhj-11r74", "collection": "authors", "collection_id": "18jhj-11r74", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SAGrsi87", "type": "article", "title": "Fourier transform infrared spectrometer for a single aerosol particle", "author": [ { "family_name": "Sageev Grader", "given_name": "Gideon", "orcid": "0000-0003-4371-4575", "clpid": "Grader-Gideon" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Arnold", "given_name": "Stephen", "clpid": "Arnold-S" } ], "abstract": "A spectrometer is reported here for obtaining the infrared spectrum of a single aqueous aerosol particle by a Fourier transform technique. The particle is held in an electrodynamic balance and irradiated simultaneously by the infrared output from a Michelson interferometer and the visible light from a dye laser. The size of the particle is modulated by chopping the IR beam, and the resulting visible scattered light fluctuation is detected at 90\u00b0 with a photomultiplier tube. The amplitude of the scattered light fluctuation is measured with a lock-in amplifier at each interferometer mirror position. The electronic circuitry for stepping the interferometer mirror is presented and discussed. Inverting the lock-in signal by a discrete fast Fourier transform routine (FFT) yields the particle absorption spectrum. The resulting spectrum for an (NH4)2SO4 droplet is presented.", "doi": "10.1063/1.1139220", "issn": "0034-6748", "publisher": "American Institute of Physics", "publication": "Review of Scientific Instruments", "publication_date": "1987-04", "series_number": "4", "volume": "58", "issue": "4", "pages": "584-587" }, { "id": "authors:qqbeg-fa233", "collection": "authors", "collection_id": "qqbeg-fa233", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318480000.25", "type": "article", "title": "Estimation of two-phase petroleum reservoir properties by regularization", "author": [ { "family_name": "Lee", "given_name": "Tai-yong", "clpid": "Lee-Tai-Yong" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An algorithm is developed, based on the theory of regularization and on spline approximation, to estimate the absolute permeability in two-phase petroleum reservoirs from noisy well pressure data. The regularization feature of the algorithm converts the ill-posed estimation problem to a well-posed one. The algorithm, which employs the partial conjugate gradient method of Nazareth as its core minimization technique, automatically chooses the regularization parameter based on the non-regularized estimation. It is shown that regularized estimation is more stable and insensitive to the choice of initial guess as compared to non-regularized conventional estimation.", "doi": "10.1016/0021-9991(87)90174-4", "issn": "0021-9991", "publisher": "Elsevier", "publication": "Journal of Computational Physics", "publication_date": "1987-04", "series_number": "2", "volume": "69", "issue": "2", "pages": "397-419" }, { "id": "authors:qrr5s-52n81", "collection": "authors", "collection_id": "qrr5s-52n81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-318493000.27", "type": "article", "title": "Asymptotic solution of the aerosol general dynamic equation for small coagulation", "author": [ { "family_name": "Pilinis", "given_name": "Christodoulos", "clpid": "Pilinis-Christodoulos" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The aerosol general dynamic equation is solved in the limit of small coagulation. The solution includes particle growth by gas-phase diffusion, surface and volume reaction, particle production, and loss by deposition to surfaces.", "doi": "10.1016/0021-9797(87)90064-6", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1987-02", "series_number": "2", "volume": "115", "issue": "2", "pages": "472-479" }, { "id": "authors:w4236-ac367", "collection": "authors", "collection_id": "w4236-ac367", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571248000.6", "type": "article", "title": "Evaporation and Growth of Multicomponent Aerosols Laboratory Applications", "author": [ { "family_name": "Kreidenweis", "given_name": "Sonya M.", "clpid": "Kreidenweis-Sonya-M" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Design equations for two types of devices used in aerosol growth and evaporation studies, the well-mixed vessel and the diffusion dryer, are developed and their use demonstrated for aqueous salt solution particles. The results of several common simplifying approximations are evaluated. An approximate method for determining residence times required for drying particles that exhibit a hysteresis effect, accurate to within several percent for the cases considered, is suggested.", "doi": "10.1080/02786828708959115", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1987-01", "series_number": "1", "volume": "6", "issue": "1", "pages": "1-14" }, { "id": "authors:sz8w7-frd84", "collection": "authors", "collection_id": "sz8w7-frd84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150630-165846934", "type": "article", "title": "Homogeneous Nucleation by Continuous Mixing of High Temperature Vapor with Room Temperature Gas", "author": [ { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Warren", "given_name": "Dale R.", "clpid": "Warren-Dale-R" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The formation of aerosol particles by homogeneous nucleation in a supersaturated vapor has been studied experimentally and theoretically. In the laboratory, a particle-free gas at room temperature is continuously mixed with a high-temperature gas containing dibutylphthalate vapor in a new device for the study of aerosol nucleation called a particle size magnifier. A highly supersaturated vapor is rapidly formed in the mixing zone of the particle size magnifier, and the resulting number concentrations of aerosol particles are measured under various temperatures, mixing ratios, and mixing methods. Measured number concentrations are compared with those predicted by the classical and Lothe-Pound nucleation theories. The measured concentrations lie between the predictions of the two theories, and the trends with temperature and saturation ratio are consistent with either nucleation theory, provided vapor depletion is considered.", "doi": "10.1080/02786828708959116", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1987-01", "series_number": "1", "volume": "6", "issue": "1", "pages": "15-27" }, { "id": "authors:bvv9j-41344", "collection": "authors", "collection_id": "bvv9j-41344", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571259000.7", "type": "book_section", "title": "Mathematical Modeling of Packed Bed Reactors: Numerical Solutions and Control Model Development", "book_title": "Advances in Chemical Engineering", "author": [ { "family_name": "Khanna", "given_name": "Rohit", "clpid": "Khanna-Rohit" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Anderson", "given_name": "John L.", "clpid": "Anderson-John-L" }, { "family_name": "Bischoff", "given_name": "Kenneth B.", "clpid": "Bischoff-Kenneth-B" }, { "family_name": "Denn", "given_name": "Morton M.", "clpid": "Denn-Morton-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This chapter presents an analysis of the development of dynamic models for packed bed reactors, with particular emphasis on models that can be used in control system design. The method of approach formulates a comprehensives, relatively detailed packed bed reactor model. The chapter also considers the techniques available for numerical solution of the model; and utilizes one such numerical solution to examine simplifications of the model based on its underlying physics. It then describes how the model may be reduced mathematically to one useful for control system design. Mathematical models of packed bed reactors are needed for the description of steady-state and dynamic behavior for process design, optimization, and control. Although insufficient detail can lead to a model incapable of accurately representing the reactor's response to changes in operating variables, excessive detail can lead to a model that is computationally impractical or contains parameters the values of which cannot accurately be determined from operating data. Thus, although the development is intended to be generally applicable to packed bed reactor modeling, all numerical results are obtained for the methanation system. As a result, some approximations that are found to apply in the methanation system may not in other reaction systems, and, where possible. The chapter discusses approaches to numerical solution of the model with a detailed exposition of one approach, orthogonal collocation. Common physical assumptions made in packed bed reactor modeling are evaluated.", "doi": "10.1016/s0065-2377(08)60017-4", "isbn": "978-0-12-008513-2", "publisher": "Elsevier", "place_of_publication": "New York, NY", "publication_date": "1987", "pages": "113-191" }, { "id": "authors:4qpgf-fba38", "collection": "authors", "collection_id": "4qpgf-fba38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571299000.11", "type": "article", "title": "Analysis of atmospheric photooxidation mechanisms for organosulfur compounds", "author": [ { "family_name": "Yin", "given_name": "Fangdong", "clpid": "Yin-Fangdong" }, { "family_name": "Grosjean", "given_name": "Daniel", "orcid": "0000-0001-6941-2490", "clpid": "Grosjean-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Reaction mechanisms are formulated for the atmospheric photooxidation of the organosulfur compounds, dimethyl sulfide, CH\u2083SCH\u2083, methanethiol, CH\u2083SH, and diethyl sulfide, C\u2082H\u2085SC\u2082H\u2085. Predictions of the mechanisms are compared with available data on laboratory photooxidations of these three species to identify critical uncertainties in chemical pathways and reaction rate constants. The sensitivity of product yields to these uncertainties is investigated.", "doi": "10.1029/jd091id13p14417", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research D", "publication_date": "1986-12-20", "series_number": "D13", "volume": "91", "issue": "D13", "pages": "14417-14438" }, { "id": "authors:86sqp-j5s34", "collection": "authors", "collection_id": "86sqp-j5s34", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150630-165604475", "type": "article", "title": "Production of ultrafine metal oxide aerosol particles by thermal decomposition of metal alkoxide vapors", "author": [ { "family_name": "Okuyama", "given_name": "Kikuo", "orcid": "0000-0002-1477-1442", "clpid": "Okuyama-Kikuo" }, { "family_name": "Kousaka", "given_name": "Yasuo", "clpid": "Kousaka-Yasuo" }, { "family_name": "Tohge", "given_name": "Noboru", "clpid": "Tohge-Noboru" }, { "family_name": "Yamamoto", "given_name": "Satoru", "orcid": "0000-0002-0238-3039", "clpid": "Yamamoto-Satoru" }, { "family_name": "Wu", "given_name": "Jin Jwang", "clpid": "Wu-Jin-Jwang" }, { "family_name": "Flagan", "given_name": "R. C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Ultrafine spherical titanium, silicon, and aluminium oxide particles were prepared by the thermal decomposition of their alkoxide vapors, produced by evaporation and subsequent heating. High-concentration ultrafine particles having geometric mean diameters ranging between 0.01 and 0.06 \u03bcm and a geometric standard deviation of about 1.4 were obtained by varying the temperatures of the evaporator containing the liquid alkoxides and the reactor furnace, and the flow rate of carrier gas. For furnace temperatures lower than 400\u00b0C for TiO\u2082 and 1000\u00b0C for SiO\u2082 and Al\u2082O\u2083, the particles obtained were found to be amorphous. The observed changes in the particle size distributions due to changes in operating conditions were compared with those predicted theoretically by solving the discrete-continuous aerosol general dynamic equation accounting for coagulation and generation of monomer by thermal decomposition. The effect of monomer number concentration on the size distribution of generated particles was found to be qualitatively explained.", "doi": "10.1002/aic.690321211", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1986-12", "series_number": "12", "volume": "32", "issue": "12", "pages": "2010-2019" }, { "id": "authors:fq1ym-qgx12", "collection": "authors", "collection_id": "fq1ym-qgx12", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377701000.10", "type": "article", "title": "Robust multivariable control system design for a fixed-bed reactor", "author": [ { "family_name": "Mandler", "given_name": "Jorge A.", "clpid": "Mandler-Jorge-A" }, { "family_name": "Morari", "given_name": "Manfred", "orcid": "0000-0002-7696-5058", "clpid": "Morari-Manfred" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The design of multivariable controllers in the face of model uncertainty is addressed. Recently developed structured\nsingular value (\u00b5) based analysis techniques allow a nonconservative assessment of robust stability and robust\nperformance of multivariable systems. On the basis of these techniques a methodology for the design of robust\nmultivariable controllers is outlined and is applied to the design of control systems for a fixed-bed methanation\nreactor. In one configuration the inlet temperature and the flow rate are optimally combined as manipulated\nvariables for the regulation of the outlet temperature in the face of inlet concentration disturbances. In a second\nconfiguration the optimal regulation of the product concentration is investigated when only temperature measurements are available. First, H\u2082 optimal controllers are designed for the nominal cases. Next, knowledge about\nthe model uncertainty is incorporated explicitly\nthe basis of H\u2082 or H_\u221e performance criteria.", "doi": "10.1021/i100024a028", "issn": "0196-4313", "publisher": "American Chemical Society", "publication": "Industrial & Engineering Chemistry Fundamentals", "publication_date": "1986-11", "series_number": "4", "volume": "25", "issue": "4", "pages": "645-655" }, { "id": "authors:5zsvn-v2v38", "collection": "authors", "collection_id": "5zsvn-v2v38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160629-142631276", "type": "article", "title": "On Some Aspects of Nighttime Atmospheric Chemistry", "author": [ { "family_name": "Russell", "given_name": "Armistead G.", "orcid": "0000-0003-2027-8870", "clpid": "Russell-Armistead-G" }, { "family_name": "Cass", "given_name": "Glen R.", "clpid": "Cass-G-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Nighttime atmospheric chemistry is simulated in two\ndifferent situations: an offshore oceanic environment, the\nSanta Barbara Channel region of the south central coast\nof California, and a dry environment, the Mojave Desert\nof California. In the marine case, conversion of NO\u2093 to\nperoxyacetyl nitrate (PAN) and HNO\u2083 is rapid; HNO\u2083 is\nformed by homogeneous hydrolysis of N\u2082O\u2085 and by nitrate\nradical reactions with organic gases, and the rate of HNO\u2083\nproduction is limited by the abundance of O\u2083. Even in the\ndesert case, predictions indicate that homogeneous hydrolysis of N\u2082O\u2085 dominates HNO\u2083 formation at night. The\nimplications of recent studies concerning the unimolecular\ndecomposition of NO\u2083 are discussed.", "doi": "10.1021/es00153a013", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1986-11", "series_number": "11", "volume": "20", "issue": "11", "pages": "1167-1172" }, { "id": "authors:97vzd-das68", "collection": "authors", "collection_id": "97vzd-das68", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571332000.14", "type": "article", "title": "Identification of spatially varying parameters in distributed parameter systems by discrete regularization", "author": [ { "family_name": "Kravaris", "given_name": "Costas", "clpid": "Kravaris-Costas" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Identification of spatially varying parameters in distributed parameter systems from noisy data is an ill-posed problem. The regularization identification approach, developed by C. Kravaris and J. H. Seinfeld [SIAM J. Control Optim. 23 (1985), 217\u2013241] provides stable approximate solutions to that problem. In this work, a discretized minimization of the smoothing functional is proposed by using finite-dimensional convergent approximations in Sobolev spaces. A convergence theorem for the discretized minimization of the smoothing functional is established. The performance of this discrete regularization approach is evaluated by numerical experiments on the identification of spatially varying diffusivity in the two-dimensional diffusion equation.", "doi": "10.1016/0022-247x(86)90148-4", "issn": "0022-247X", "publisher": "Elsevier", "publication": "Journal of Mathematical Analysis and Applictions", "publication_date": "1986-10", "series_number": "1-2", "volume": "119", "issue": "1-2", "pages": "128-152" }, { "id": "authors:yt23a-26537", "collection": "authors", "collection_id": "yt23a-26537", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571311000.12", "type": "article", "title": "Condensation rate of water on aqueous droplets in the transition regime", "author": [ { "family_name": "Sageev", "given_name": "Gideon", "orcid": "0000-0003-4371-4575", "clpid": "Grader-Gideon" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Arnold", "given_name": "Stephen", "clpid": "Arnold-Stephen-R" } ], "abstract": "The rate of condensation of water on single aqueous solution drops in the transition regime is measured with an electrodynamic balance. Observed characteristic relaxation times are compared with those predicted theoretically to determine the thermal accommodation coefficient, which is found to be unity (consistent with the accepted value in the literature). Due to the large heat of vaporization of water and the experimental conditions used, the relaxation time is relatively insensitive to the water mass accommodation coefficient, although the data would support a value close to unity.", "doi": "10.1016/0021-9797(86)90177-3", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1986-10", "series_number": "2", "volume": "113", "issue": "2", "pages": "421-429" }, { "id": "authors:y7q01-5mf43", "collection": "authors", "collection_id": "y7q01-5mf43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571335000.15", "type": "article", "title": "Instantaneous concentration fluctuations in point-source plumes", "author": [ { "family_name": "Georgopoulos", "given_name": "P. G.", "orcid": "0000-0003-2119-0301", "clpid": "Georgopoulos-Panos-G" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A model for the variance \u03c3\ua700\u00b2 of instantaneous plume concentrations, at a level corresponding to that of the Gaussian formulas for the mean field, is developed and tested against available data. Starting from the Eulerian species transport equation, theoretical and empirical information is used to estimate parameters and simplify the form of the transport equation for \u03c3\ua700\u00b2 in a meandering frame of reference. Then, introduction of a localized production of fluctuations (LPF) scheme allows construction of analytical expressions for \u03c3\ua700\u00b2 that provide a direct means for calculating the concentration variance inside the instantaneous boundaries of plumes resulting from continuous point emissions in turbulent flows with uniform mean velocity.", "doi": "10.1002/aic.690321008", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1986-10", "series_number": "10", "volume": "32", "issue": "10", "pages": "1642-1654" }, { "id": "authors:fe480-d5d51", "collection": "authors", "collection_id": "fe480-d5d51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377728000.13", "type": "article", "title": "Mathematical modeling of Turbulent Reacting Plumes\u2014II. Application to the NO-NO\u2082-O\u2083 system", "author": [ { "family_name": "Georgopoulos", "given_name": "Panos G.", "orcid": "0000-0003-2119-0301", "clpid": "Georgopoulos-Panos-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Calculations performed with the Turbulent Reacting Plume Model (TRPM) developed in Part I are compared with the experimental data of Builtjes (1981, Netherlands Organization for Applied Scientific Research, Div. of Technology for Soc., Ref. No. 81-013563) for the reaction between NO in a point source plume and ambient O\u2083, taking place in a wind tunnel simulating a neutral atmospheric boundary layer. The comparison shows the TRPM capable of quantitatively predicting the retardation imposed on the evolution of nonlinear plume chemistry by incomplete mixing.", "doi": "10.1016/0004-6981(86)90129-0", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1986-09", "series_number": "9", "volume": "20", "issue": "9", "pages": "1809-1818" }, { "id": "authors:f5qf4-9za83", "collection": "authors", "collection_id": "f5qf4-9za83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571404000.17", "type": "article", "title": "History Matching by Spline Approximation and Regularization in Single-Phase Areal Reservoirs", "author": [ { "family_name": "Lee", "given_name": "Tai-yong", "clpid": "Lee-Tai-Yong" }, { "family_name": "Kravaris", "given_name": "Costas", "clpid": "Kravaris-Costas" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An automatic history-matching algorithm is developed from bicubic spline approximations of permeability and porosity distributions and from the theory of regularization to estimate permeability or porosity in a single-phase, two-dimensional (2D) areal reservoir from well pressure data. The regularization feature of the algorithm, the theoretical details of which are described by Kravaris and Seinfeld, is used to convert the ill-posed history-matching problem into a well-posed problem. The algorithm uses Nazareth's conjugate gradient method as its core minimization method. A number of numerical experiments are carried out to evaluate the performance of the algorithm. Comparisons with conventional (nonregularized) automatic history-matching algorithms indicate the superiority of the new algorithm with respect to the parameter estimates obtained. A quasioptimal regularization parameter is determined without requiring a priori information on the statistical properties of the observations.", "doi": "10.2118/13931-pa", "issn": "0885-9248", "publisher": "Society of Petroleum Engineers", "publication": "SPE Reservoir Engineering", "publication_date": "1986-09", "series_number": "5", "volume": "1", "issue": "5", "pages": "521-534" }, { "id": "authors:eddha-ap994", "collection": "authors", "collection_id": "eddha-ap994", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377736000.14", "type": "article", "title": "Mathematical modeling of turbulent reacting plumes\u2014I. General theory and model formulation", "author": [ { "family_name": "Georgopoulos", "given_name": "Panos G.", "orcid": "0000-0003-2119-0301", "clpid": "Georgopoulos-Panos-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new, comprehensive model for a chemically reacting plume is presented that accounts for the effects of incomplete turbulent macro- and micromixing on chemical reactions between plume and atmospheric constituents. The model is modular in nature, allowing for the use of different levels of approximation of the phenomena involved. The core of the model consists of the evolution equations for reaction progress variables appropriate for evolving spatially varying systems. These equations estimate the interaction of mixing and chemical reaction and require input parameters characterizing internal plume behavior, such as relative dispersion and fine scale plume segregation. The model addresses deficiencies in previous reactive plume models. Part II is devoted to atmospheric application of the model.", "doi": "10.1016/0004-6981(86)90128-9", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1986-09", "series_number": "9", "volume": "20", "issue": "9", "pages": "1791-1807" }, { "id": "authors:w5a91-kym87", "collection": "authors", "collection_id": "w5a91-kym87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571478000.25", "type": "article", "title": "A comparative study of equilibrium approaches to the chemical characterization of secondary aerosols", "author": [ { "family_name": "Saxena", "given_name": "Pradeep", "clpid": "Saxena-Pradeep" }, { "family_name": "Hudischewskyj", "given_name": "A. Belle", "clpid": "Hudischewskyj-A-Belle" }, { "family_name": "Seigneur", "given_name": "Christian", "orcid": "0000-0002-3079-4839", "clpid": "Seigneur-Christian" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This paper presents an equilibrium model for prediction of the mass and chemical composition of atmospheric aerosols containing sulfate, nitrate, ammonium, and water. The \nModel for an Aerosol Reacting System (MARS) is particularly intended for incorporation into larger air quality, visibility, or aerosol dynamics models. Computational efficiency, in addition to satisfactory performance, is an important consideration in such applications. The predictions of MARS agree with those of two comprehensive models currently available. However, the computational efficiency of MARS is shown to be substantially greater than that of the other two models.", "doi": "10.1016/0004-6981(86)90019-3", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1986-07", "series_number": "7", "volume": "20", "issue": "7", "pages": "1471-1483" }, { "id": "authors:9jygd-k9891", "collection": "authors", "collection_id": "9jygd-k9891", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377697000.9", "type": "article", "title": "Control system design for a fixed-bed methanation reactor", "author": [ { "family_name": "Mandler", "given_name": "Jorge A.", "clpid": "Mandler-Jorge-A" }, { "family_name": "Morari", "given_name": "Manfred", "orcid": "0000-0002-7696-5058", "clpid": "Morari-Manfred" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A systematic approach is applied to the design of robust controllers for a fixed-bed, non-adiabatic, laboratory methanation reactor, a unit inherently difficult to control. The fundamental limitations to the achievable closed-loop performance are established by both physical arguments and dynamic resilience considerations. The Internal Model Control (IMC) structure provides a suitable framework for this analysis. IMC controllers are designed and their performance in the face of model uncertainty is tested both by simulation and by means of the Structured Singular Value (\u03bc) analysis technique. The paper provides a basic insight into the characterization and solution of control problems that are particular to fixed-bed reactor systems and constitutes the first account of the application of several recent advances in control theory to a complex chemical process.", "doi": "10.1016/0009-2509(86)85239-3", "issn": "0009-2509", "publisher": "Elsevier", "publication": "Chemical Engineering Science", "publication_date": "1986-06", "series_number": "6", "volume": "41", "issue": "6", "pages": "1577-1597" }, { "id": "authors:wcgnh-7f709", "collection": "authors", "collection_id": "wcgnh-7f709", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571418000.18", "type": "article", "title": "Identifiability of Spatially-Varying Conductivity from Point Observation as an Inverse Sturm\u2013Liouville Problem", "author": [ { "family_name": "Kravaris", "given_name": "Costas", "clpid": "Kravaris-Costas" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This paper discusses identifiability of the spatially varying parameter \u03b1(x) in the heat equation u\u209c - (\u03b1u\u2093)\u2093= f from measurement of u at a single point. The identifiability problem is formulated as an inverse Sturm\u2013Liouville problem for (\u03b1y\u2032)\u2032 + \u03bby = 0 . It is proved that the eigenvalues and the normalizing constants determine the above Sturm\u2013Liouville operator uniquely. Identifiability and nonidentifiability results are obtained for three heat conduction problems.", "doi": "10.1137/0324030", "issn": "0363-0129", "publisher": "SIAM", "publication": "SIAM Journal on Control and Optimization", "publication_date": "1986-05", "series_number": "3", "volume": "24", "issue": "3", "pages": "522-542" }, { "id": "authors:7y58y-jdb03", "collection": "authors", "collection_id": "7y58y-jdb03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SAGrsi86", "type": "article", "title": "Particle sizing in the electrodynamic balance", "author": [ { "family_name": "Sageev", "given_name": "Gideon", "orcid": "0000-0003-4371-4575", "clpid": "Grader-Gideon" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" } ], "abstract": "We report a new technique for sizing particles in the electrodynamic balance. In this technique, the trajectory of a falling particle is followed with a photomultiplier tube. Particle velocities are measured by placing a mask between the particle and the detector. The masked region in the particle trajectory is roughly 0.6 mm wide. Output from the PMT is sampled every millisecond by an A/D converter and stored in a computer. Flight times of several hundred milliseconds are measured and the size is then computed from the particle's terminal velocity. With a modification of the mask, the technique is used to verify the uniformity of the electric field through which the particle is falling. In the present work we use the technique to determine size of polystryrene latex microspheres having nominal diameters of 10 and 20 \u00b5. The technique can be used on any size particle, independent of its charge-to-mass ratio, and provides the size information in a short time.", "doi": "10.1063/1.1138837", "issn": "0034-6748", "publisher": "American Institute of Physics", "publication": "Review of Scientific Instruments", "publication_date": "1986-05", "series_number": "5", "volume": "57", "issue": "5", "pages": "933-936" }, { "id": "authors:ne9hq-9t224", "collection": "authors", "collection_id": "ne9hq-9t224", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150630-165408412", "type": "article", "title": "Effect of spatial inhomogeneities on the rate of homogeneous nucleation in systems with aerosol particles", "author": [ { "family_name": "Stern", "given_name": "Jennifer E.", "clpid": "Stern-Jennifer-E" }, { "family_name": "Wu", "given_name": "Jin-Jwang", "clpid": "Wu-Jin-Jwang" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The presence of growing particles in a system leads to spatial inhomogeneities in the vapor concentration. The effect of these spatial variations on the rate of formation of new particles by homogeneous nucleation is examined theoretically using a cell model. Results indicate that the presence of these inhomogeneities in systems both with and without initial aerosol has generally little effect on the final number concentration of particles following a nucleation \"event.\"", "doi": "10.1016/0021-9797(86)90406-6", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1986-04", "series_number": "2", "volume": "110", "issue": "2", "pages": "533-543" }, { "id": "authors:6n9n9-7n855", "collection": "authors", "collection_id": "6n9n9-7n855", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571429000.20", "type": "article", "title": "Effect of spatial inhomogeneities on the rate of homogeneous nucleation in systems with aerosol particles", "author": [ { "family_name": "Stern", "given_name": "Jennifer E.", "clpid": "Stern-Jennifer-E" }, { "family_name": "Wu", "given_name": "Jin-Jwang", "clpid": "Wu-Jin-Jwang" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The presence of growing particles in a system leads to spatial inhomogencities in the vapor concentration. The effect of these spatial variations on the rate of formation of new particles by homogeneous nucleation is examined theoretically using a cell model. Results indicate that the presence of these inhomogeneities in systems both with and without initial aerosol has generally little effect on the final number concentration of particles following a nucleation \"event.\"", "doi": "10.1016/0021-9797(86)90406-6", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1986-04", "series_number": "2", "volume": "110", "issue": "2", "pages": "533-543" }, { "id": "authors:bt2wf-tj607", "collection": "authors", "collection_id": "bt2wf-tj607", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571453000.22", "type": "article", "title": "Comparative analysis of chemical reaction mechanisms for photochemical smog\u2014II. Sensitivity of EKMA to chemical mechanism and input parameters", "author": [ { "family_name": "Shafer", "given_name": "Toby B.", "clpid": "Shafer-Toby-B" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The six chemical reaction mechanisms for photochemical smog described in Pan I (Leone and Seinfeld, 1985, Atmospheric Environment 19,437\u2013464) were used to study the effect of input parameters on volatile organic compound (VOC) control requirements needed to meet the National Ambient Air Quality Standard for ozone. The parameters studied were initial VOC composition, dilution rate, post 8-a.m. emissions, base case (present day) O\u2083 levels, entrainment from aloft of VOC and ozone and initial VOC/NO\u2093 ratio. The Empirical Kinetic Modeling Approach (EKMA) was used to generate ozone isopleths for each chemical mechanism. The VOC control needed to reduce the maximum ozone concentration from some present day value to 0.12 ppm, assuming no NO\u2093 control and a specified initial VOC/NO\u2093 ratio, was calculated using the six chemical reaction mechanisms. The initial VOC/NO\u2093 ratio was found to have the largest effect of all the parameters studied on VOC control requirements. Choice of chemical mechanism, ozone and VOC entrainment from aloft, base-case ozone and the composition of the initial VOC mixture also had a large effect on predicted control requirements. To reduce the degree of uncertainty in control predictions using EKMA it is necessary to establish as accurately as possible the composition of urban air in early morning. Also, because of the substantial effect the choice of chemical mechanism has on the predicted control requirements using EKMA, it is important that future work continues to be directed toward evaluating candidate chemical mechanisms with respect to their ability to simulate atmospheric smog chemistry.", "doi": "10.1016/0004-6981(86)90089-2", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1986-03", "series_number": "3", "volume": "20", "issue": "3", "pages": "487-499" }, { "id": "authors:d3m6j-rfq85", "collection": "authors", "collection_id": "d3m6j-rfq85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230418-571461000.23", "type": "article", "title": "Simulation of Aerosol Dynamics: A Comparative Review of Mathematical Models", "author": [ { "family_name": "Seigneur", "given_name": "Christian", "orcid": "0000-0002-3079-4839", "clpid": "Seigneur-Christian" }, { "family_name": "Hudischewskyj", "given_name": "A. Belle", "clpid": "Hudischewskyj-A-Belle" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Whitby", "given_name": "Kenneth T.", "clpid": "Whitny-Kemmeth-T" }, { "family_name": "Whitby", "given_name": "Evan R.", "clpid": "Whitby-Evan-R" }, { "family_name": "Brock", "given_name": "James R.", "clpid": "Brock-James-R" }, { "family_name": "Barnes", "given_name": "Harold M.", "clpid": "Barnes-Harold-M" } ], "abstract": "A comparative review of mathematical models of aerosol dynamics is presented. Three approaches are considered that are based on continuous, discrete (sectional), and parametrized (lognormal) representations of the aerosol size distribution. Simulations of coagulation and diffusion-limited condensation are performed with these modeling approaches for three case studies typical of clear, hazy, and urban atmospheric aerosol concentrations. The relative accuracies and computational costs of models based on these approaches are compared. The models based on a continuous size distribution provide an accurate solution for both coagulation and condensation. Sectional approaches simulate coagulation very well but require a fine size resolution to minimize numerical diffusion in the simulation of condensation. The parametrized model based on log-normal modal size distributions is computationally efficient but tends to overestimate the rate of coagulation and the peak aerosol concentration resulting from condensational growth. The results of this study provide useful information for the selection of an aerosol model, depending on the accuracy requirements and computational constraints associated with a specific application.", "doi": "10.1080/02786828608959088", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1986-02", "series_number": "2", "volume": "5", "issue": "2", "pages": "205-222" }, { "id": "authors:hw1s3-w5w71", "collection": "authors", "collection_id": "hw1s3-w5w71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377759000.17", "type": "article", "title": "Prediction of aerosol concentrations resulting from a burst of nucleation", "author": [ { "family_name": "Warren", "given_name": "Dale R.", "clpid": "Warren-Dale-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The number of particles formed by a burst of homogeneous nucleation in a closed system is predicted approximately and found to depend, in the absence of initial aerosol, only on the dimensionless source rate of vapor, a dimensionless surface tension, and an appropriately defined Knudsen number. The effect of a seed aerosol on the ultimate number of particles formed is also studied. For the purposes of exploring the nature of systems in which a competition for vapor exists between nucleation and condensation, a closed system with a steady source of vapor is considered. It is shown that a narrow window exists within which seed particles can be used to control the ultimate number of particles formed in such a system.", "doi": "10.1016/0021-9797(85)90356-x", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1985-05", "series_number": "1", "volume": "105", "issue": "1", "pages": "136-142" }, { "id": "authors:w48h3-2se92", "collection": "authors", "collection_id": "w48h3-2se92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150616-170135922", "type": "article", "title": "An outdoor smog chamber and modeling study of toluene-NO\u2093 photooxidation", "author": [ { "family_name": "Leone", "given_name": "Joseph A.", "clpid": "Leone-Joseph-A" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Grosjean", "given_name": "Daniel", "orcid": "0000-0001-6941-2490", "clpid": "Grosjean-Daniel" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An experimental investigation of the gas-phase photooxidation of toluene\u2013NO\u2093\u2013air mixtures at part-per-million concentrations has been carried out in a 65-m\u00b3, outdoor smog chamber to assess our understanding of the atmospheric chemistry of toluene. In addition, six CO-NO\u2093\u2013air irradiations were conducted to characterize the chamber with regard to any wall radical sources. Measured parameters in the toluene\u2013NO\u2093 experiments included O\u2083, NO, NO\u2082, HNO\u2083, peroxyacetyl nitrate (PAN), CO, toluene, benzaldehyde, o-cresol, m-nitrotoluene, peroxybenzoyl nitrate (PBZN), temperature, relative humidity, aerosol size distributions, and particulate organic carbon. Predictions of the reaction mechanism of Leone and Seinfeld [7] are found to be in good agreement with the data under a variety of initial conditions. Additional simulations are used to investigate various mechanistic pathways in areas where our understanding of toluene chemistry is still incomplete.", "doi": "10.1002/kin.550170206", "issn": "0538-8066", "publisher": "Wiley", "publication": "International Journal of Chemical Kinetics", "publication_date": "1985-05", "series_number": "2", "volume": "17", "issue": "2", "pages": "177-216" }, { "id": "authors:05vcn-90p32", "collection": "authors", "collection_id": "05vcn-90p32", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377764000.18", "type": "article", "title": "Identification of Parameters in Distributed Parameter Systems by Regularization", "author": [ { "family_name": "Kravaris", "given_name": "Costas", "clpid": "Kravaris-Costas" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Identification of spatially varying parameters in distributed parameter systems from noisy data is an ill-posed problem. The concept of regularization, widely used in solving linear Fredholm integral equations, is developed for the identification of parameters in distributed parameter systems. A general regularization identification theory is first presented and then applied to the identification of parabolic systems. The performance of the regularization identification method is evaluated by numerical experiments on the identification of a spatially varying diffusivity in the diffusion equation.", "doi": "10.1137/0323017", "issn": "0363-0129", "publisher": "SIAM", "publication": "SIAM Journal on Control and Optimization", "publication_date": "1985-03", "series_number": "2", "volume": "23", "issue": "2", "pages": "217-241" }, { "id": "authors:k9xen-x8953", "collection": "authors", "collection_id": "k9xen-x8953", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377803000.24", "type": "article", "title": "Comparative analysis of chemical reaction mechanisms for photochemical smog", "author": [ { "family_name": "Leone", "given_name": "Joseph A.", "clpid": "Leone-Joseph-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Six chemical reaction mechanisms for photochemical smog are analyzed to determine why, under identical conditions, they predict different maximum ozone concentrations. Answers to previously inaccessible questions such as the relative contributions of individual organic species to photochemical ozone formation are obtained. Based on the results of the analysis we have identified specific aspects of each mechanism that are responsible for the discrepancies with other mechanisms and with an explicit mechanism based on the latest understanding of atmospheric chemistry. For each mechanism critical areas are identified that when altered bring the predictions of the various mechanisms into much closer agreement. Thus, we identify why the predictions of the mechanisms are different, and have recommended research efforts that are needed to eliminate many of the discrepancies.", "doi": "10.1016/0004-6981(85)90166-0", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1985-03", "series_number": "3", "volume": "19", "issue": "3", "pages": "437-464" }, { "id": "authors:h8kf3-h6k75", "collection": "authors", "collection_id": "h8kf3-h6k75", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377771000.19", "type": "article", "title": "Simulation of Aerosol Size Distribution Evolution in Systems with Simultaneous Nucleation, Condensation, and Coagulation", "author": [ { "family_name": "Warren", "given_name": "Dale R.", "clpid": "Warren-Dale-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A sectional model is presented that will simulate formation, growth, and coagulation processes for an aerosol formed by gas-to-particle conversion. Test cases have simulated a system with a source of condensable vapor, showing a burst of nucleation that is quenched by condensation onto the freshly generated and rapidly growing fine aerosol. The influence of preexisting aerosol on the size distribution evolution and on the rate of nucleation and criteria for inhibition of nucleation by initial aerosol are presented.", "doi": "10.1080/02786828508959037", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1985-01", "series_number": "1", "volume": "4", "issue": "1", "pages": "31-43" }, { "id": "authors:32ymh-70088", "collection": "authors", "collection_id": "32ymh-70088", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SAGao84", "type": "article", "title": "Laser heating of an aqueous aerosol particle", "author": [ { "family_name": "Sageev", "given_name": "Gideon", "clpid": "Sageev-Gideon" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Approximate analytical and full numerical solutions are obtained for the transient response of both a pure water and solution droplets to both short- and long-time laser heating. The differences in the temperature and size histories between pure water and solution droplets are elucidated. The validity of of the approximate analytical solution, extended from that of Armstrong [\"Aerosol Heating and Vaporization by Pulsed Light Beams,\" Appl. Opt. 23, 148 (1984)] in pure water droplets, is evaluated by comparison to solution of the full governing equations.", "doi": "10.1364/ao.23.004368", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1984-12-01", "series_number": "23", "volume": "23", "issue": "23", "pages": "4368-4374" }, { "id": "authors:hvxk0-dnp32", "collection": "authors", "collection_id": "hvxk0-dnp32", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377880000.30", "type": "article", "title": "Identifiability of Estimates of Two-Phase Reservoir Properties in History Matching", "author": [ { "family_name": "Watson", "given_name": "A. T.", "clpid": "Watson-A-T" }, { "family_name": "Gavalas", "given_name": "G. R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Since the number of parameters to be estimated in a reservoir history match is potentially quite large, it is important to determine which parameters can be estimated with reasonable accuracy from the available data. This aspect can be called determining the identifiability of the parameters. The identifiability of porosity and absolute and relative permeabilities on the basis of flow and pressure data in a two-phase (oil/water) reservoir is considered. The question posed is: How accurately can one expect to estimate spatially variable porosity and absolute permeability and relative permeabilities given typical production and pressure data? To gain insight into this question, analytical solutions for pressure and saturation in a one-dimensional (ID) waterflood are used. The following conclusions are obtained.\n\n1. Only the average value of the porosity can be determined on the basis of water/oil flow measurements. \n\n2. The permeability distribution can be determined from pressure drop data with an accuracy depending on the mobility ratio. \n\n3. Exponents in a power function representation of the relative permeabilities can be determined from WOR data alone but not nearly so accurately as when pressure drop and flow data are used simultaneously.", "doi": "10.2118/12579-pa", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1984-12", "series_number": "6", "volume": "24", "issue": "6", "pages": "697-706" }, { "id": "authors:hy9t0-1xc16", "collection": "authors", "collection_id": "hy9t0-1xc16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140923-081142954", "type": "article", "title": "Analysis of the Characteristics of Complex Chemical Reaction Mechanisms: Application to Photochemical Smog Chemistry", "author": [ { "family_name": "Leone", "given_name": "Joseph A.", "clpid": "Leone-Joseph-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "To elucidate the features of complex chemical reaction\nmechanisms, we develop an analysis based on the use of\nso-called \"counter species\", fictitious products added to\nthe reactions in the mechanism that allow one to determine\nthe relative contributions of individual reactions to the\noverall behavior of the mechanism. The method is developed\nby considering a mechanism for the atmospheric photooxidation of the three simplest aldehydes and is then\napplied, in a full-scale simulation, to analyze the behavior\nof a complex chemical reaction mechanism for photochemical smog. The method is shown capable of providing answers to previously inaccessible questions such as the relative contributions of individual hydrocarbons to photochemical\nozone formation. Application of the counter species concept to analyze complex environmental reaction mechanisms is straightforward and can be readily implemented in the standard routines in widespread use for solving seta of chemical reaction rate equations.", "doi": "10.1021/es00122a014", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1984-04", "series_number": "4", "volume": "18", "issue": "4", "pages": "280-287" }, { "id": "authors:e4aq0-qej21", "collection": "authors", "collection_id": "e4aq0-qej21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140702-150501626", "type": "article", "title": "Updated chemical mechanism for atmospheric photooxidation of toluene", "author": [ { "family_name": "Leone", "given_name": "Joseph A.", "clpid": "Leone-Joseph-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new reaction mechanism describing the atmospheric photochemical oxidation of toluene is formulated and tested against environmental chamber data from the University of California, Riverside, Statewide Air Pollution Research Center (SAPRC). On simulations of toluene\u2014NO\u2093 and toluene\u2014benzaldehyde\u2014NO\u2093 irradiations, the average predicted O\u2083 and PAN maxima are within 3% of the experimental values. Simulations performed with the new mechanism are used to investigate various mechanistic paths, and to gain insight into areas where our understanding is not complete. Specific areas that are investigated include benzaldehyde photolysis, organic nitrate formation, alternate ring fragmentation pathways, and conjugated \u03b3-dicarbonyl condensation to the aerosol phase.", "doi": "10.1002/kin.550160207", "issn": "0538-8066", "publisher": "Wiley", "publication": "International Journal of Chemical Kinetics", "publication_date": "1984-02", "series_number": "2", "volume": "16", "issue": "2", "pages": "159-193" }, { "id": "authors:zvt14-b3806", "collection": "authors", "collection_id": "zvt14-b3806", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377882000.31", "type": "article", "title": "Nucleation and Growth of Aerosol From a Continuously Reinforced Vapor", "author": [ { "family_name": "Warren", "given_name": "Dale R.", "clpid": "Warren-Dale-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In this paper the dynamic coupling of the vapor and aerosol phases in spatially uniform systems undergoing new particle formation and driven by a constant source of vapor is considered. In such a system, freshly nucleated particles are sites of rapid condensation, causing vapor depletion and the cessation of homogeneous nucleation. Modifications of classical nucleation theory to account for cluster scavenging by the aerosol are evaluated. Extensive numerical experiments show that cluster scavenging by aerosols generally has negligible effect on the resulting aerosol distribution and that, except for the very earliest stages of nucleation, condensation dominates over nucleation as the route of gas-to-particle formation even in initially particle-free systems. The total number and size of the resulting particles are shown to depend strongly on the source rate, vapor pressure, and surface tension.", "doi": "10.1080/02786828408959003", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1984-02", "series_number": "2", "volume": "3", "issue": "2", "pages": "135-153" }, { "id": "authors:yvbtm-xcq61", "collection": "authors", "collection_id": "yvbtm-xcq61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-547185000.7", "type": "article", "title": "Atmospheric equilibrium model of sulfate and nitrate aerosols\u2014II. Particle size analysis", "author": [ { "family_name": "Bassett", "given_name": "Mark E.", "clpid": "Bassett-Mark-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Part I of this work presented a thermodynamic equilibrium model for the quantity, composition, and physical state of atmospheric sulfate/nitrate/ammonium aerosols. In this work we extend that model to include particle size. That is, given total nitrate and ammonium levels, relative humidity and temperature, and the distribution of sulfate by particle size, we calculate the equilibrium quantity, composition, and physical state of the aerosol as a function of particle size. The model provides an explanation for the differences in observed ambient sulfate and nitrate size distributions.", "doi": "10.1016/0004-6981(84)90147-1", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1984-01", "series_number": "6", "volume": "18", "issue": "6", "pages": "1163-1170" }, { "id": "authors:zk3md-cv981", "collection": "authors", "collection_id": "zk3md-cv981", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:OMAlss84.170", "type": "article", "title": "Brief survey of approaches to deriving the optimal linear distributed parameter filter", "author": [ { "family_name": "Omatu", "given_name": "Sigeru", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This survey paper reviews the approaches to deriving the optimal filter for linear distributed parameter systems. We discuss the five main approaches: the orthogonal projection or Wiener-Hopf theory, the least squares method, the innovation theory, the maximum likelihood method, and the Bayesian theory. We also consider the optimal sensor location problem for distributed parameter systems, one closely related to the optimal filtering problem.", "issn": "0167-420X", "publisher": "Elsevier", "publication": "Large Scale Systems in Information and Decision Technologies", "publication_date": "1984", "series_number": "3", "volume": "6", "issue": "3", "pages": "203-220" }, { "id": "authors:1j4c7-dwn80", "collection": "authors", "collection_id": "1j4c7-dwn80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140702-132626554", "type": "book_section", "title": "Thermodynamic Equilibrium Properties of Aqueous Solutions of Nitrate, Sulfate and Ammonium", "book_title": "Chemistry of particles, fogs, and rain", "author": [ { "family_name": "Stelson", "given_name": "Arthur W.", "clpid": "Stelson-A-W" }, { "family_name": "Bassett", "given_name": "Mark E.", "clpid": "Bassett-M-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Durham", "given_name": "Jack L.", "clpid": "Durham-J-L" } ], "abstract": "Knowledge of the thermodynamic equilibrium properties of aqueous solutions is\nrequired in virtually any calculation associated with particle and droplet acidification.\nFor example, prediction of the equilibrium vapor pressures of dissolved solutes\nand water is necessary when predicting the rate of uptake of pollutant gases into\ncloud- and raindrops and aerosol particles. In addition, evidence indicates that\natmospheric aerosols and small droplets are frequently in chemical equilibrium\nwith the local surrounding air. In such a situation, given the ambient gaseous\nconcentrations of pollutant species, and the temperature and relative humidity, it\nis desired to determine the physical state (liquid or solid) and the chemical composition\nof the particle or drop in equilibrium with the air.", "isbn": "9780250405671", "publisher": "Butterworth Publishers", "place_of_publication": "Boston. MA", "publication_date": "1984", "pages": "1-52" }, { "id": "authors:ta91x-9b509", "collection": "authors", "collection_id": "ta91x-9b509", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170727-163809593", "type": "book_section", "title": "Identification of parameters in distributed parameter systems by regularization", "author": [ { "family_name": "Kravaris", "given_name": "Costas", "clpid": "Kravaris-Costas" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Identification of spatially varying parameters in distributed parameter systems from noisy data is an ill-posed problem. The concept of regularization, widely used in solving linear Fredholm integral equations, is developed for the identification of parameters in distributed parameter systems. A general regularization identification theory is first presented and then applied to a parabolic identification problem. Methods for the numerical implementation of the regularization identification approach are also presented.", "doi": "10.1109/CDC.1983.269793", "publisher": "IEEE", "publication_date": "1983-12" }, { "id": "authors:nre73-07v13", "collection": "authors", "collection_id": "nre73-07v13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140917-162227008", "type": "article", "title": "Atmospheric equilibrium model of sulfate and nitrate aerosols", "author": [ { "family_name": "Bassett", "given_name": "Mark", "clpid": "Bassett-Mark-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Given local rates of production of gas-phase sulfate and nitrate, ammonia concentration, relative humidity and temperature, a model is presented that enables calculation of the quantity of sulfate/nitrate/ammonium/water aerosol, its precise chemical composition and physical state. The model is based on a complete thermodynamic chemical and phase equilibrium calculation for the sulfate/nitrate/ammonium system. Detailed simulations of sulfate/nitrate/ammonium aerosol evolution are presented, and recent ambient data from Tanner are interpreted. Some new results on temperature variation of activity coefficients are presented in the Appendix.", "doi": "10.1016/0004-6981(83)90221-4", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1983-11", "series_number": "11", "volume": "17", "issue": "11", "pages": "2237-2252" }, { "id": "authors:2jzv0-nzp77", "collection": "authors", "collection_id": "2jzv0-nzp77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-547230000.13", "type": "article", "title": "The oxidation of NO\u2082 to nitrate-day and night", "author": [ { "family_name": "Jones", "given_name": "Carol L.", "clpid": "Jones-Adkins-Carol-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In a recent article Richards (1983) has suggested a chemical\nreaction mechanism, given in Table 1, for night-time NO\u2082 oxidation. Richards makes several qualitative statements concerning the ability of this mechanism to represent measured night-time NO\u2093 concentrations but does not present simulated results based on this mechanism. In order to assess the validity of Richards' suggested mechanism, we have integrated the rate equations corresponding to the reactions in Table 1 under the following conditions: (1) There is a constant source of NO, S_(NO) (ppm min\u207b\u00b9) during the night, (2) At t = 0 (1800 PDT) the initial concentrations are those reported by Platt et al. (1980) from the Los Angeles area. These initial conditions are summarized in Table 2. Since the NO concentration at 1800 PDT was not reported by Platt et al. (1980), to obtain an initial condition we have assumed that the concentration of NO at this time can be obtained from the NO\u2082 and O\u2083 concentrations through the photostationary state relation with an approximate NO\u2082 photolysis rate of 0.1 min\u207b\u00b9. The NO emission flux, S_(NO) must be specified to carry out the calculation, and we have considered values typical for Los Angeles. The object of our calculation is, as we noted above, to ascertain if the reaction set in Table 1 is capable of explaining observed night-time NO\u2093 chemistry.", "doi": "10.1016/0004-6981(83)90239-1", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1983-11", "series_number": "11", "volume": "17", "issue": "11", "pages": "2370-2373" }, { "id": "authors:c4ap6-wgd86", "collection": "authors", "collection_id": "c4ap6-wgd86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140922-133728609", "type": "article", "title": "An experimental study of the oxidation of sulfur dioxide in aqueous manganese sulfate aerosols", "author": [ { "family_name": "Crump", "given_name": "James G.", "clpid": "Crump-James-G" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A continuous stirred tank reactor is used to study growth of manganese sulfate (MnSO\u2084) aerosols due to catalytic oxidation of SO\u2082 in humid air. Humidities ranged from 91\u201397% and SO\u2082 concentrations from 0 to 92 ppm. The results of the growth studies are consistent with the rate expression for production of sulfuric acid:\nd[H\u2082SO\u2084]/dt = (8.3 \u00b1 2.5) x 10\u207b\u2075/[H\u207a]Ms\u207b\u00b9. This expression is estimated to hold for [Mn\u00b2\u207a] \u2a7e 0.O1 M and [SO\u2082] \u2a7e 10 ppm.", "doi": "10.1016/0004-6981(83)90402-X", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1983-07", "series_number": "7", "volume": "17", "issue": "7", "pages": "1277-1289" }, { "id": "authors:ynjkv-kec43", "collection": "authors", "collection_id": "ynjkv-kec43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-547200000.9", "type": "article", "title": "Optimization of sensor and actuator locations in a distributed parameter system", "author": [ { "family_name": "Omatu", "given_name": "Sigeru", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The distributed parameter Linear Quadratic Gaussian (LQG) optimal sensor and actuator location problem is considered. The sensor and actuator locations are chosen to minimize the performance criterion on the LQG problem. Necessary and sufficient conditions for the optimal locations are derived based on evolution operator theory. It is shown that the optimal sensor and actuator locations can be determined separately and that a duality holds between them. Numerical examples involving a one-dimensional heat conduction system are presented.", "doi": "10.1016/0016-0032(83)90060-1", "issn": "0016-0032", "publisher": "Elsevier", "publication": "Journal of the Franklin Institute", "publication_date": "1983-05", "series_number": "5-6", "volume": "315", "issue": "5-6", "pages": "407-421" }, { "id": "authors:8p6rx-3v641", "collection": "authors", "collection_id": "8p6rx-3v641", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140917-104636097", "type": "article", "title": "Development of a second-generation mathematical model for urban air pollution\u2014II. Evaluation of model performance", "author": [ { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-Gregory-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The performance of a new comprehensive model for urban-scale photochemical air pollution is evaluated. The model accurately reproduced the important features of ozone (O\u2083) and nitrogen dioxide (NO\u2082) distributions over the South Coast Air Basin of California for a two-day period 26\u201327 June 1974. Various statistical measures of model performance are reported together with predicted and observed concentration time histories at selected monitoring sites. A new technique for estimating error bounds on emission inventories is also described. The method incorporates the influence of uncertainties in both mass emission rates and chemical reactivity.", "doi": "10.1016/0004-6981(83)90124-5", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1983-03", "series_number": "3", "volume": "17", "issue": "3", "pages": "501-522" }, { "id": "authors:zc4yc-rkp10", "collection": "authors", "collection_id": "zc4yc-rkp10", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140701-140708107", "type": "article", "title": "Environmental data display", "author": [ { "family_name": "Hussey", "given_name": "Kevin J.", "clpid": "Hussey-Kevin-J" }, { "family_name": "Blackwell", "given_name": "Richard J.", "clpid": "Blackwell-Richard-J" }, { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-Gregory-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Large amounts of information can be portrayed in very compact form\nand used for many applications, thanks to a combination\nof color-coded graphics and image processing techniques.", "doi": "10.1021/es00108a721", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1983-02", "series_number": "2", "volume": "17", "issue": "2", "pages": "A78-A85" }, { "id": "authors:5fpvf-s4g87", "collection": "authors", "collection_id": "5fpvf-s4g87", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150630-105245886", "type": "article", "title": "Theory of Aerosol Formation and Growth in Laminar Flow", "author": [ { "family_name": "Pesthy", "given_name": "Andrew J.", "clpid": "Pesthy-Andrew" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A detailed theoretical analysis of aerosol nucleation and growth in laminar flow, including the important aspects of mass and energy transfer and aerosol size distribution dynamics, is presented. Simulations of aerosol formation and growth in a laminar flow cooled pipe, in the presence and absence of seed particles, are carried out using the classical and Lothe-Pound theories of homogeneous nucleation. The competition between new particle formation and vapor growth onto seed particles in such systems is explored in detail, The theory developed has application to the design and analysis of aerosol generators and continuous flow condensation nuclei counters.", "doi": "10.1016/0021-9797(83)90367-3", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1983-02", "series_number": "2", "volume": "91", "issue": "2", "pages": "525-545" }, { "id": "authors:m8ryd-gwz40", "collection": "authors", "collection_id": "m8ryd-gwz40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140922-140302253", "type": "article", "title": "Particle Wall Loss Rates in Vessels", "author": [ { "family_name": "Crump", "given_name": "James G.", "clpid": "Crump-James-G" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Aerosol particle wall loss rates were determined experimentally in a spherical continuous stirred tank reactor.\nTbe particle size and mixing rate dependences are shown\nto agree with \n\u03b2=12k_eD/R\u03c0v\u0283^nv/2\u221ak_2D_0 te^t/e^t-1dt+v/4R3\nthe theoretical result of Crump and Seinfeld, in which the\nparticle loss coefficient \u03b2 is related to particle diffusivity D, particle settling velocity r, the coefficient of the eddy diffusivity k_e, and vessel radius R. For the vessel used in these experiments, k_e was found to be proportional to the 3/2 power of the volumetric now rate, in accordance with theoretical expectations. Results of a similar nature may be expected to hold in vessels of arbitrary shape.", "doi": "10.1080/02786828308958636", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1983", "series_number": "3", "volume": "2", "issue": "3", "pages": "303-309" }, { "id": "authors:a60vs-87864", "collection": "authors", "collection_id": "a60vs-87864", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140922-151812161", "type": "article", "title": "The oxidation of NO_2 to nitrate day and night", "author": [ { "family_name": "Jones", "given_name": "Carol L.", "clpid": "Jones-C-L" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In a recent article Richards (1983) has suggested a chemical\nreaction mechanism, given in Table 1, for night-time NO_2\noxidation. Richards makes several qualitative statements\nconcerning the ability of this mechanism to represent\nmeasured night-time NO_x, concentrations but does not\npresent simulated results based on this mechanism. In order\nto assess the validity of Richards' suggested mechanism, we\nhave integrated the rate equations corresponding to the\nreactions in Table 1 under the following conditions: (1) There is a constant source of NO, S_(NO) (ppm min^(-1)) during the night, (2) At t = 0 (1800 PDT) the initial concentrations are those reported by Platt et al. (1980) from the Los Angeles area.", "doi": "10.1016/0004-6981(83)90239-1", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1983", "series_number": "11", "volume": "17", "issue": "11", "pages": "2370-2373" }, { "id": "authors:rq7dk-h8v15", "collection": "authors", "collection_id": "rq7dk-h8v15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-547331000.18", "type": "article", "title": "On existence of steady-state solutions to the coagulation equations", "author": [ { "family_name": "Crump", "given_name": "James G.", "clpid": "Crump-James-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The general steady-state coagulation equations with sources and sinks are examined. These equations are shown to admit physically unacceptable solutions in some cases, and it is hypothesized that in such a case a gelation or precipitation phenomenon occurs. General conditions on the coagulation and loss coefficients are given that insure the existence of physically realistic solutions. The physically realistic solutions have tails that decay faster than any power of particle size.", "doi": "10.1016/0021-9797(82)90312-5", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1982-12", "series_number": "2", "volume": "90", "issue": "2", "pages": "469-476" }, { "id": "authors:wqt50-77e67", "collection": "authors", "collection_id": "wqt50-77e67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140922-112703276", "type": "article", "title": "Thermodynamic prediction of the water activity, NH\u2084NO\u2083 dissociation constant, density and refractive index for the NH\u2084NO\u2083-(NH\u2084)\u2082SO\u2084-H\u2082O system at 25\u00b0C", "author": [ { "family_name": "Stelson", "given_name": "A. W.", "clpid": "Stelson-Arthur-W" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The thermodynamic properties, water activity, density and refractive index of NH\u2084NO\u2083-(NH\u2084)\u2082SO\u2084-H\u2082O aerosols are estimated from binary solution data and existing mixing rules. Particle growth is shown to be predictable from the particle composition, the NH\u2084NO\u2083-(NH\u2084)\u2082SO\u2084-H\u2082O phase diagram and the water activity calculation technique of C.L. Kusik and H.P. Meissner (1978, A.I.Ch. E. Symp. 173, 14\u201320). Good agreement between the theoretical predictions and the experimental measurements of I.N. Tang et al. (1981, Atmospheric Environment15, 2463\u20132471), J. Thudium (1978,Pageoph. 116, 130\u2013148) and H.H. Emons and W. Hahn (1970, Wiss Z.12, 129\u2013132) is shown. Also, the effect of (NH\u2084)\u2082SO\u2084 on the relative humidity dependence of the NH\u2084NO\u2083 dissociation constant is evaluated.", "doi": "10.1016/0004-6981(82)90142-1", "issn": "0960-1686", "publisher": "Elsevier", "publication": "Atmospheric Environment Part A-General Topics", "publication_date": "1982-10", "series_number": "10", "volume": "16", "issue": "10", "pages": "2507-2514" }, { "id": "authors:xdkkk-ycg35", "collection": "authors", "collection_id": "xdkkk-ycg35", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140625-160504290", "type": "article", "title": "Sensitivity Analysis of Distributed Parameter Systems", "author": [ { "family_name": "Koda", "given_name": "Masato", "clpid": "Koda-Masato" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A method is developed for the calculation of sensitivity\ncoefficients of general distributed parameter systems to the variation of\nspatially and temporally varying parameters appearing in the system equations\nand initial and boundary conditions.", "doi": "10.1109/TAC.1982.1103029", "issn": "0018-9286", "publisher": "IEEE", "publication": "IEEE Transactions on Automatic Control", "publication_date": "1982-08", "series_number": "4", "volume": "27", "issue": "4", "pages": "951-955" }, { "id": "authors:fzthq-e5y46", "collection": "authors", "collection_id": "fzthq-e5y46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377635000.2", "type": "article", "title": "Analysis of multivariable control strategies on a heat conduction system", "author": [ { "family_name": "Khanna", "given_name": "Rohit", "clpid": "Khanna-Rohit" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A detailed analysis of a number of multivariable process control strategies, including non-interacting control, optimal control, inverse Nyquist array and characteristic locus techniques, is carried out theoretically on a one-dimensional, two-input heat conduction system. Additionally, a new non-interacting control strategy, termed inner-loop decoupling, is developed. The potential improvements in control system performance through the use of extra measurements and through the appropriate selection of measurement locations is assessed. Results show the advantages and disadvantages of the techniques, point to the flexibility of the characteristic locus method and indicate the effectiveness of the new method of inner-loop decoupling.", "doi": "10.1080/00207178208932871", "issn": "0020-7179", "publisher": "Taylor & Francis", "publication": "International Journal of Control", "publication_date": "1982-07", "series_number": "1", "volume": "36", "issue": "1", "pages": "1-24" }, { "id": "authors:d7m3x-x9w88", "collection": "authors", "collection_id": "d7m3x-x9w88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140701-132507408", "type": "article", "title": "Statistical distributions of air pollutant concentrations", "author": [ { "family_name": "Georgopoulos", "given_name": "Panos G.", "orcid": "0000-0003-2119-0301", "clpid": "Georgopoulos-Panos-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Air pollutant concentrations are\ninherently random variables because\nof their dependence on the fluctuations\nof a variety of meteorological and\nemission variables. When sets of air\nquality data are available, various\nstatistical characteristics can be determined\nand assigned to the pollutant\nconcentrations.", "doi": "10.1021/es00101a727", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1982-07", "series_number": "7", "volume": "16", "issue": "7", "pages": "401A-416A" }, { "id": "authors:83ajw-2sy51", "collection": "authors", "collection_id": "83ajw-2sy51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140922-132618300", "type": "article", "title": "Further Results on Inversion of Aerosol Size Distribution Data: Higher-Order Sobolev Spaces and Constraints", "author": [ { "family_name": "Crump", "given_name": "James G.", "clpid": "Crump-James-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The aerosol size distribution inversion algorithm of Crump and Seinfeld, based on the concept of regularization with generalized cross-validation, is extended to Sobolev spaces of order m. The use of the cross-validation function for choice of an appropriate value of m in a particular application is discussed. An inversion algorithm that constrains the size distribution to be nonnegative is introduced and shown to be of value for sharply peaked distributions.", "doi": "10.1080/02786828208958601", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1982-06-30", "series_number": "4", "volume": "1", "issue": "4", "pages": "363-369" }, { "id": "authors:maksp-5d211", "collection": "authors", "collection_id": "maksp-5d211", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140626-131825546", "type": "article", "title": "Sensitivity analysis of a mathematical model for photochemical air pollution", "author": [ { "family_name": "Tilden", "given_name": "James W.", "clpid": "Tilden-James-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The effect of simultaneous \u00b1 50 per cent uncertainties in the emission and meteorological parameters on the predictions of a mathematical model for photochemical air pollution is studied. Predicted concentrations are found to be most sensitive to uncertainties in mixing height, photolysis intensity, initial conditions and emission intensity. A general method for air quality model sensitivity analysis is discussed and employed.", "doi": "10.1016/0004-6981(82)90056-7", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1982-06", "series_number": "6", "volume": "16", "issue": "6", "pages": "1357-1364" }, { "id": "authors:z2tmg-qek45", "collection": "authors", "collection_id": "z2tmg-qek45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-547364000.23", "type": "article", "title": "Relative humidity and temperature dependence of the ammonium nitrate dissociation constant", "author": [ { "family_name": "Stelson", "given_name": "A. W.", "clpid": "Stelson-Arthur-W" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Expressions for predicting the temperature and relative humidity dependence of the NH\u2084NO\u2083 dissociation constant are derived from fundamental thermodynamic principles. The general trends predicted by the theory agree with the atmospheric data of Appel et al. (1979, 1980), Pitts (1978, 1979) and Tuazon et al. (1980)", "doi": "10.1016/0004-6981(82)90184-6", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1982-05", "series_number": "5", "volume": "16", "issue": "5", "pages": "983-992" }, { "id": "authors:dgchq-wmp25", "collection": "authors", "collection_id": "dgchq-wmp25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-547371000.24", "type": "article", "title": "Relative humidity and pH dependence of the vapor pressure of ammonium nitrate-nitric acid solutions at 25\u00b0 C", "author": [ { "family_name": "Stelson", "given_name": "Arthur W.", "clpid": "Stelson-Arthur-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Quantitative expressions for the ammonia-nitric acid equilibrium product and the partial pressures of ammonia and nitric acid over non-ideal nitric acid-ammonium nitrate solutions are developed. The relative humidity and pH dependence of the equilibrium product and the partial pressures are obtained from free energy thermodynamic data. The thermodynamic predictions show the ammonia-nitric acid equilibrium product is inversely related to relative humidity. The importance of correcting for non-ideality is demonstrated. The assumption of ideality for ammonium nitrate in solution incurs an error of an order of magnitude in the ammonia-nitric acid equilibrium product prediction at the point of deliquescence and of 20% in the relative humidity of deliquescence. The trends indicated by the analysis are consistent with the filter study results of Forrest, Tanner, Spandau. D'Ottavio and Newman ( 1980, Atmospheric Environment 14, 137\u2013144) and Appel, Wall, Tokiwa and Haik (1980, Atmospheric Environment 14, 549\u2013554).", "doi": "10.1016/0004-6981(82)90185-8", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1982-05", "series_number": "5", "volume": "16", "issue": "5", "pages": "993-1000" }, { "id": "authors:bfxb7-stm96", "collection": "authors", "collection_id": "bfxb7-stm96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-547385000.26", "type": "article", "title": "Reversible absorption of a pollutant from an area source in a stagnant fog layer", "author": [ { "family_name": "Shukla", "given_name": "J. B.", "clpid": "Shukla-J-B" }, { "family_name": "Nallaswamy", "given_name": "R.", "clpid": "Nallaswamy-R" }, { "family_name": "Verma", "given_name": "S.", "clpid": "Verma-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The vertical concentration distribution of a gaseous pollutant emitted at ground level into a stagnant fog layer is calculated. Reversible absorption of the species in the droplets is assumed.", "doi": "10.1016/0004-6981(82)90190-1", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1982-05", "series_number": "5", "volume": "16", "issue": "5", "pages": "1035-1037" }, { "id": "authors:hhfvj-9v934", "collection": "authors", "collection_id": "hhfvj-9v934", "cite_using_url": "https://resolver.caltech.edu/CaltechEQL:EQL-R-18", "type": "monograph", "title": "Mathematical modeling of photochemical air pollution", "author": [ { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-G-J" }, { "family_name": "Goodin", "given_name": "William R.", "clpid": "Goodin-W-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A particularly serious problem facing densely populated areas is the environmental degradation caused by the presence of photochemical air pollution. The problem is both pervasive and difficult to control. An important element of any rational approach directed at attempting to improve the situation is a reliable means for evaluating the air quality impact of alternative control measures. This report presents such a capability in the form of a mathematical description of the production and transport of photochemical oxidants within an urban airshed.", "doi": "10.7907/Z9BR8Q4D", "publisher": "California Institute of Technology", "publication_date": "1982-04-27" }, { "id": "authors:12y9d-pxw41", "collection": "authors", "collection_id": "12y9d-pxw41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140701-144054543", "type": "article", "title": "Estimation of Atmospheric Species Concentrations from Remote Sensing Data", "author": [ { "family_name": "Omatu", "given_name": "Sigeru", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A basic problem in the interpretation of atmospheric remote sensing data is to estimate species concentration distributions. Typical remote sensing data involve a field of view that moves across the region and represent integrated species burdens from the ground to the altitude of the instrument. The estimation problem arising from this special measurement configuration is solved based on the partial differential equation for atmospheric diffusion and Wiener-Hopf theory. The estimation of the concentration distribution downwind of a hypothetical continous ground-level source of pollutants is studied numerically.", "doi": "10.1109/TGRS.1982.350388", "issn": "0196-2892", "publisher": "IEEE", "publication": "IEEE Transactions on Geoscience and Remote Sensing", "publication_date": "1982-04", "series_number": "2", "volume": "20", "issue": "2", "pages": "142-153" }, { "id": "authors:kh2gc-f7b62", "collection": "authors", "collection_id": "kh2gc-f7b62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140917-085931131", "type": "article", "title": "Development of a second-generation mathematical model for urban air pollution\u2014I. Model formulation", "author": [ { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-Gregory-J" }, { "family_name": "Goodin", "given_name": "William R.", "clpid": "Goodin-William-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A new comprehensive modeling system for urban air pollution, including three-dimensional, grid-based as well as Lagrangian trajectory, vertically integrated and single cell formulations, is described. Recent developments in photochemistry, turbulent diffusion, surface removal processes, objective analysis procedures and numerical solution techniques are incorporated and described.", "doi": "10.1016/0004-6981(82)90386-9", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1982-04", "series_number": "4", "volume": "16", "issue": "4", "pages": "679-696" }, { "id": "authors:8smw3-9s597", "collection": "authors", "collection_id": "8smw3-9s597", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-547380000.25", "type": "article", "title": "On the densities of aqueous sulfate solutions", "author": [ { "family_name": "Stelson", "given_name": "A. W.", "clpid": "Stelson-Arthur-W" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "We have noted a disagreement among density data from\ndifferent sources for NH\u2084HSO\u2084, solutions. The most recent\nsource of data on NH\u2084HSO\u2084, solution densities is Tang (1980).", "doi": "10.1016/0004-6981(82)90453-x", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1982-02", "series_number": "2", "volume": "16", "issue": "2", "pages": "355-357" }, { "id": "authors:9qmcg-6m359", "collection": "authors", "collection_id": "9qmcg-6m359", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170731-155607098", "type": "article", "title": "Reconstruction of atmospheric pollutant concentrations from remote sensing data--An application of distributed parameter observer theory", "author": [ { "family_name": "Koda", "given_name": "Masato", "clpid": "Koda-Masato" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The reconstruction of a concentration distribution from spatially averaged and noise-corrupted data is a central problem in processing atmospheric remote sensing data. Distributed parameter observer theory is used to develop reconstructibility conditions for distributed parameter systems having measurements typical of those in remote sensing. The relation of the reconstructibility condition to the stability of the distributed parameter observer is demonstrated. The theory is applied to a variety of remote sensing situations, and it is found that those in which concentrations are measured as a function of altitude satisfy the conditions of distributed state reconstructibility.", "doi": "10.1109/TAC.1982.1102885", "issn": "0018-9286", "publisher": "IEEE", "publication": "IEEE Transactions on Automatic Control", "publication_date": "1982-02", "series_number": "1", "volume": "27", "issue": "1", "pages": "74-80" }, { "id": "authors:c4c9z-yer62", "collection": "authors", "collection_id": "c4c9z-yer62", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-547349000.21", "type": "article", "title": "Existence and comparison theorems for partial differential equations of Riccati type", "author": [ { "family_name": "Omatu", "given_name": "S.", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In this paper, we discuss the partial differential equation of Riccati type that describes the optimal filtering error covariance function for a linear distributed-parameter system with pointwise observations. Since this equation contains the Dirac delta function, it is impossible to apply directly the usual methods of functional analysis to prove existence and uniqueness of a bounded solution. By using properties of the fundamental solution and the classical technique of successive approximation, we prove the existence and uniqueness theorem. We then prove the comparison theorem for partial differential equations of Riccati type. Finally, we consider some applications of these theorems to the distributed-parameter optimal sensor location problem.", "doi": "10.1007/bf00933833", "issn": "0022-3239", "publisher": "Springer", "publication": "Journal of Optimization Theory and Applications", "publication_date": "1982-02", "series_number": "2", "volume": "36", "issue": "2", "pages": "263-276" }, { "id": "authors:ekcqp-raq40", "collection": "authors", "collection_id": "ekcqp-raq40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230417-377668000.6", "type": "article", "title": "A New Algorithm for Inversion of Aerosol Size Distribution Data", "author": [ { "family_name": "Crump", "given_name": "James G.", "clpid": "Crump-James-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The determination of an aerosol size distribution from conventional data is an ill-posed problem. The general characteristics of the aerosol size distribution inversion problem are discussed, and several existing methods are assessed. A new algorithm, in the spirit of Twomey's constrained linear inversion algorithm, employing the concept of generalized cross validation is developed. Extensive numerical tests on simulated data from a Marple impactor show superior performance of the method. Different versions of the algorithm are available based on different choices of the function spaces in which the assumed distributions lie. The new algorithm offers promise as the most accurate now available for inversion of aerosol data.", "doi": "10.1080/02786828208958576", "issn": "0278-6826", "publisher": "American Association for Aerosol Research", "publication": "Aerosol Science and Technology", "publication_date": "1982-01", "series_number": "1", "volume": "1", "issue": "1", "pages": "15-34" }, { "id": "authors:mhj3j-6fs39", "collection": "authors", "collection_id": "mhj3j-6fs39", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140626-133334379", "type": "article", "title": "Numerical solution of the atmospheric diffusion equation for chemically reacting flows", "author": [ { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-Gregory-J" }, { "family_name": "Goodin", "given_name": "William R.", "clpid": "Goodin-William-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A comprehensive study of numerical techniques for solving the atmospheric diffusion equation is reported. Operator splitting methods are examined in which the three-dimensional problem is converted into a sequence of one-dimensional problems. A Galerkin, linear finite element scheme with a nonlinear filter is found to be computationally superior to the other methods tested for the advection-diffusion components. The chemical reaction dynamics component, treated within the splitting scheme, is generally highly stiff. A second-order predictor, iterated corrector technique, in combination with an asymptotic treatment of the stiff components, is found to be computationally superior for the chemical kinetics. The validity of the pseudo steady state approximation for certain reactive species is also investigated.", "doi": "10.1016/0021-9991(82)90101-2", "issn": "0021-9991", "publisher": "Elsevier", "publication": "Journal of Computational Physics", "publication_date": "1982-01", "series_number": "1", "volume": "45", "issue": "1", "pages": "1-42" }, { "id": "authors:ja6m7-rjz61", "collection": "authors", "collection_id": "ja6m7-rjz61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140916-105634044", "type": "article", "title": "Optimal emission control strategies for photochemical smog", "author": [ { "family_name": "Costanza", "given_name": "Vicente", "orcid": "0000-0002-2409-0632", "clpid": "Costanza-Vicente" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A study of certain aspects of the selection of reactive\nhydrocarbon and nitrogen oxide emission reductions for\nphotochemical oxidant abatement is carried out. Optimal\nemission control paths are defined as those minimizing a\ntotal cost function consisting of control cost and ozone\ndosage contributions. Los Angeles County ozone air quality and control cost data are used to formulate an optimal emission reduction path. The analysis is presented primarily to provide insight into the factors involved in\ndesigning oxidant control strategies.", "doi": "10.1021/es00096a008", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1982", "series_number": "2", "volume": "16", "issue": "2", "pages": "98-102" }, { "id": "authors:38stb-bx353", "collection": "authors", "collection_id": "38stb-bx353", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768813000.30", "type": "book_section", "title": "Effect of the mechanism of gas-to-particle conversion on the evolution of aerosol size distributions", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Bassett", "given_name": "Mark", "clpid": "Bassett-Mark-E" } ], "contributor": [ { "family_name": "Schryer", "given_name": "David R.", "clpid": "Schryer-David-R" } ], "abstract": "The evolution of the size distribution of an aerosol undergoing growth by gas-to-particle conversion is investigated theoretically when growth occurs by any of three mechanisms, vapor phase diffusion, reaction of adsorbed vapor species on the particle surface, and reaction of dissolved vapor species in the particle volume.", "doi": "10.1029/gm026p0006", "publisher": "American Geophysical Union", "publication_date": "1982" }, { "id": "authors:kyqh6-ft648", "collection": "authors", "collection_id": "kyqh6-ft648", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140917-081623660", "type": "article", "title": "Global sensitivity analysis\u2014a computational implementation of the Fourier Amplitude Sensitivity Test (FAST)", "author": [ { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-G-J" }, { "family_name": "Tilden", "given_name": "James W.", "clpid": "Tilden-J-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This paper describes a computational implementation of the Fourier Amplitude Sensitivity Test (FAST) and illustrates its use with a sample problem. The FAST procedure is ideally suited to the task of determining the global sensitivity of nonlinear mathematical models subjected to variations of arbitrary size in either the system parameters or initial conditions. A FORTRAN computer program, capable of performing sensitivity analyses of either algebraic or differential equation systems is described.", "doi": "10.1016/0098-1354(82)80003-3", "issn": "0098-1354", "publisher": "Elsevier", "publication": "Computers & Chemical Engineering", "publication_date": "1982", "series_number": "1", "volume": "6", "issue": "1", "pages": "15-25" }, { "id": "authors:px9er-66b89", "collection": "authors", "collection_id": "px9er-66b89", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140917-110121675", "type": "article", "title": "Filtering and Smoothing for Linear Discrete-Time Distributed Parameter Systems Based on Wiener-Hopf Theory with Application to Estimation of Air Pollution", "author": [ { "family_name": "Omatu", "given_name": "Sigeru", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Optimal filtering and smoothing algorithms for linear discrete-time distributed parameter systems are derived by a unified approach based on the Wiener-Hopf theory. The Wiener-Hopf equation for the estimation problems is derived using the least-squares estimation error criterion. Using the basic equation, three types of the optimal smoothing estimators are derived, namely, fixed-point, fixed-interval, and fixed-lag smoothers. Finally, the results obtained are applied to estimation of atmospheric sulfur dioxide concentrations in the Tokushima prefecture of Japan.", "doi": "10.1109/TSMC.1981.4308618", "issn": "0018-9472", "publisher": "IEEE", "publication": "IEEE Transactions on Systems Man and Cybernetics", "publication_date": "1981-12", "series_number": "12", "volume": "11", "issue": "12", "pages": "785-801" }, { "id": "authors:cje26-mr039", "collection": "authors", "collection_id": "cje26-mr039", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170802-143430922", "type": "book_section", "title": "Application of multivariable measurement and control strategies to a problem in heat conduction", "author": [ { "family_name": "Khanna", "given_name": "Rohit", "clpid": "Khanna-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A detailed analysis of the boundary control of a one-dimensional heat conduction system is performed using recent results in multivariable feedback theory. Non-interacting control, optimal control, inverse Nyquist array and characteristic locus techniques were applied to the system. An analysis is made of the potential improvements in performance through the use of extra measurements and through the change in measurement location. Results show the advantages and disadvantages of the techniques and point to the flexibility of the characteristic locus method with and without the squaring down of extra measurements.", "doi": "10.1109/CDC.1981.269570", "publisher": "IEEE", "publication_date": "1981-12" }, { "id": "authors:rx8yn-zrp96", "collection": "authors", "collection_id": "rx8yn-zrp96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768601000.2", "type": "article", "title": "Prediction of the density of ammonium bisulfate solutions", "author": [ { "family_name": "Stelson", "given_name": "A. W.", "clpid": "Stelson-Arthur-W" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The concentration dependence of the density of ammonium bisulfate solutions has recently been studied. It was found that the NH\u2084HSO\u2084 solution densities calculated from the data for the molarities of NH\u2084HSO\u2084, [NH\u2084HSO\u2084], and water, [H\u2082O], in Table I of Irish and Chen differed substantially from available data. The objective of this communication is twofold: (a) to determine the source of this discrepancy, and (b) to ascertain whether the extent of bisulfate dissociation in NH\u2084HSO\u2084 solutions is accurately represented by the data in Irish and Chen. The validity of the NH\u2084HSO\u2084 molarity and extent of bisulfate dissociation data in that table will be determined by comparing predicted and measured NH\u2084HSO\u2084 solution densities.", "doi": "10.1021/j150624a042", "issn": "0022-3654", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry", "publication_date": "1981-11-26", "series_number": "24", "volume": "85", "issue": "24", "pages": "3730-3733" }, { "id": "authors:rkxaw-6q633", "collection": "authors", "collection_id": "rkxaw-6q633", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140917-091018499", "type": "article", "title": "Convective Downmixing of Plumes in a Coastal Environment", "author": [ { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-Gregory-J" }, { "family_name": "Shair", "given_name": "Frederick H.", "clpid": "Shair-Frederick-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This paper describes the results of an atmospheric tracer study in which sulfur hexafluoride (SF\u2086) was used to investigate the transport and dispersion of effluent from a power plant located in a coastal environment. The field study demonstrated that material emitted into an elevated stable layer at night can be transported out over the ocean, fumigated to the surface, and then he returned at ground level by the sea breeze on the next day. At night when cool stable air from the land encounters the warmer ocean convective mixing erodes the stable layer forming an internal boundary layer. When the growing boundary layer encounters an elevated plume the pollutant material, entrained at the top of the mixed layer, can be rapidly transported in \u223c20 min to the surface. Various expressions for the characteristic downmixing time (\u03bb = Z_i/w_*) are developed utilizing the gradient Richardson number, the Monin-Obukhov length and turbulence intensifies. Calculations using these expressions and the field data are compared with similar studies of convective mixing over the land.", "doi": "10.1175/1520-0450(1981)020<1312:CDOPIA>2.0.CO;2", "issn": "0021-8952", "publisher": "American Meteorology Society", "publication": "Journal of Applied Meteorology", "publication_date": "1981-11", "series_number": "11", "volume": "20", "issue": "11", "pages": "1312-1324" }, { "id": "authors:f8rp4-qfx41", "collection": "authors", "collection_id": "f8rp4-qfx41", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768733000.12", "type": "article", "title": "Comparison of Sensitivity Coefficient Calculation Methods in Automatic History Matching", "author": [ { "family_name": "Dogru", "given_name": "Ali H.", "clpid": "Dogru-Ali-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The efficiency of automatic history matching algorithms depends on two factors: the computation time needed per iteration and the number of iterations needed for convergence. In most history matching algorithms, the most time-consuming aspect is the calculation of the sensitivity coefficients \u2013 the derivatives of the reservoir variables (pressure and saturation) with respect to the reservoir properties (permeabilities and porosity). This paper presents an analysis of two methods \u2013 the direct and the variational \u2013 for calculating sensitivity coefficients, with particular emphasis on the computational requirements of the methods.\n\nIf the simulator consists of a set of N ordinary differential equations for the grid-block variables (e.g., pressures) and there are M parameters for which the sensitivity coefficients are desired, the ratio of the computational efforts of the direct to the variational method is\n R = [N(M + 1)]/[N(N + 1) + M\u2022]\n\nThus, for M", "doi": "10.2118/8251-pa", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1981-10", "series_number": "5", "volume": "21", "issue": "5", "pages": "551-557" }, { "id": "authors:ewef2-xf108", "collection": "authors", "collection_id": "ewef2-xf108", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120717-155342781", "type": "article", "title": "A differentiable trajectory approximation to turbulent\n diffusion", "author": [ { "family_name": "Costanza", "given_name": "Vicente", "orcid": "0000-0002-2409-0632", "clpid": "Costanza-V" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The problem of turbulent diffusion is posed as determining the time evolution of the probability density of the\nconcentration given those for the fluid velocity components, sources, and the initial concentration. At each\ntime, all variables are elements of the Hilbert space L^2_R(R^3), and a finite-dimensional approximation based on expansions in orthonormal basis functions is developed. An expression for the joint probability density of all\nthe Fourier coefficients is derived, the evaluation of which is shown to be particularly straightforward.\nDiffusion of material from a single source in an unbounded mildly turbulent fluid is considered as an\napplication.", "doi": "10.1063/1.863253", "issn": "1070-6631", "publisher": "American Institute of Physics", "publication": "Physics of Fluids", "publication_date": "1981-10", "series_number": "10", "volume": "24", "issue": "10", "pages": "1769-1773" }, { "id": "authors:2vaqa-bd758", "collection": "authors", "collection_id": "2vaqa-bd758", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768766000.18", "type": "article", "title": "Mathematical model for multicomponent aerosol formation and growth in plumes", "author": [ { "family_name": "Bassett", "given_name": "Mark", "clpid": "Bassett-Mark-E" }, { "family_name": "Gelbard", "given_name": "Fred", "clpid": "Gelbard-Fred" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Description of the evolution of the size and chemical composition of aerosols in plumes is fundamental to the ability to predict visibility impairment. Previously it has only been possible to predict changes in aerosol size distributions in plumes. In this work the first model for predicting both size and chemical composition evolution of plume aerosols is presented. Coagulation, homogeneous particle formation, heterogeneous condensation and particulate phase chemical equilibria and kinetics are explicitly included. The model is based on a sectional representation of the size-composition spectrum and computation is easy to implement. This model holds promise to be a standard component of all plume visibility calculations that require plume aerosol size and composition information.", "doi": "10.1016/0004-6981(81)90268-7", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1981-10", "series_number": "10-11", "volume": "15", "issue": "10-11", "pages": "2395-2406" }, { "id": "authors:esm8p-2nr38", "collection": "authors", "collection_id": "esm8p-2nr38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768742000.14", "type": "article", "title": "Turbulent deposition and gravitational sedimentation of an aerosol in a vessel of arbitrary shape", "author": [ { "family_name": "Crump", "given_name": "James G.", "clpid": "Crump-James-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A general formula for the rate of aerosol deposition due to turbulent diffusion, Brownian diffusion, and gravitational sedimentation in a turbulently mixed, enclosed vessel of arbitrary shape is derived. It is shown to reduce to the formula of Corner and Pendlebury Proc. Phys. Soc. B64, 645 (1951) for a cubical vessel. The result is essentially independent of the form of the eddy diffusivity near the wall and demonstrates that for vessels with non-vertical walls, sedimentation and diffusion are intimately coupled in determining the total deposition rate. The effect of inertia is estimated and used to assess the range of particle sizes for which the analysis is applicable.", "doi": "10.1016/0021-8502(81)90036-7", "issn": "0021-8502", "publisher": "Elsevier", "publication": "Journal of Aerosol Science", "publication_date": "1981-09", "series_number": "5", "volume": "12", "issue": "5", "pages": "405-415" }, { "id": "authors:8h52e-h8s03", "collection": "authors", "collection_id": "8h52e-h8s03", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150623-111211281", "type": "article", "title": "The effect of a growing aerosol on the rate of homogeneous nucleation of a vapor", "author": [ { "family_name": "Pesthy", "given_name": "Andrew J.", "clpid": "Pesthy-Andrew-J" }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Growing particles in a supersaturated vapor act as sources of latent heat and sinks for vapor, altering the vapor concentration and gas temperature near the particles, and, consequently, decreasing the homogeneous nucleation rate in the vicinity of the particles. Solutions for the vapor concentration and temperature profiles around a growing particle are obtained, and the solutions are used to predict the average nucleation rate per unit volume of fluid as a function of time. The average nucleation rate is shown to be proportional to the initially undisturbed rate and proportional to a term dependent largely on the total volume fraction of growing aerosol present. Under a wide range of conditions, the nucleation rate for dibutyl phthalate is calculated to quench gradually at the time when the fraction of available vapor condensed into aerosol approaches 5 to 9%.", "doi": "10.1016/0021-9797(81)90388-X", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1981-08", "series_number": "2", "volume": "82", "issue": "2", "pages": "465-479" }, { "id": "authors:k576z-xnx81", "collection": "authors", "collection_id": "k576z-xnx81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160526-122032404", "type": "article", "title": "Chemical mass accounting of urban aerosol", "author": [ { "family_name": "Stelson", "given_name": "Arthur W.", "clpid": "Stelson-A-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A chemical mass accounting technique emphasizing the\nimportance of chemical speciation is developed for analyzing\natmospheric-aerosol data. The technique demonstrates that\ntotal aerosol mass can generally be characterized from measurements of SO_4, Cl, Br, NO_3, NH_4, Na, K, Ca, Fe, Mg, Al, Si, Pb, carbonaceous material, and aerosol water, the predominant species being SO_4, NO_3, NH_4, Si, carbonaceous material, and aerosol water. Since water is the major species distributed between the gas and aerosol phases, the interrelation between water and electrolytic mass is explored. It is shown that aerosol water is significantly correlated with electrolyte mass. Calculated aerosol ionic strengths lie in the region where the relative humidity/ionic strength relation is most sensitive, thereby suggesting the importance of relative-humidity monitoring during aerosol sampling.", "doi": "10.1021/es00088a005", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1981-06", "series_number": "6", "volume": "15", "issue": "6", "pages": "671-679" }, { "id": "authors:4ska2-f7k70", "collection": "authors", "collection_id": "4ska2-f7k70", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768633000.4", "type": "article", "title": "A unified approach to discrete-time distributed parameter estimation by the least-squares method", "author": [ { "family_name": "Omatu", "given_name": "Sigeru", "clpid": "Omatu-Sigeru" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Optimal prediction, filtering, and smoothing for a discrete-time distributed parameter system are approached in a unified manner using the least-squares method. Based on an unibiased, minimum variance estimation error criterion, the optimal filter is derived. Then the optimal prediction and smoothing estimators are derived, including fixed-point, fixed-interval, and fixed-lag smoothers.", "doi": "10.1080/00207728108963776", "issn": "0020-7721", "publisher": "Informa UK Limited", "publication": "International Journal of Systems Science", "publication_date": "1981-06", "series_number": "6", "volume": "12", "issue": "6", "pages": "665-686" }, { "id": "authors:dezsh-j2a52", "collection": "authors", "collection_id": "dezsh-j2a52", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:COSjcp81", "type": "article", "title": "Stochastic sensitivity analysis in chemical kinetics", "author": [ { "family_name": "Costanza", "given_name": "Vicente", "orcid": "0000-0002-2409-0632", "clpid": "Costanza-Vicente" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The stochastic sensitivity analysis problem in chemical kinetics is defined as determining the probability density function (pdf) of the concentrations given probability density functions for the parameters and initial conditions. The joint concentration parameter pdf is found to satisfy the equation ([partial-derivative]p/[partial-derivative]t)+div(Fp) = 0, where the system dynamics are given by ? = F(x). The properties of the solution of this equation are studied, and the approach is applied to analyze the sensitivity of the kinetics of the photolysis of a mixture of carbon monoxide, nitrogen dioxide, nitric oxide, and water in air to uncertainties in the initial concentrations of the nitrogen oxides and in the values of two photolysis rate constants. Comparisons to other sensitivity analysis approaches are discussed.", "doi": "10.1063/1.441615", "issn": "0021-9606", "publisher": "American Institute of Physics", "publication": "Journal of Chemical Physics", "publication_date": "1981-04-01", "series_number": "7", "volume": "74", "issue": "7", "pages": "3852-3858" }, { "id": "authors:gc7ke-1r338", "collection": "authors", "collection_id": "gc7ke-1r338", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768772000.20", "type": "article", "title": "Solution of the steady state, three-dimensional atmospheric diffusion equation for Sulfur dioxide and Sulfate dispersion from point sources", "author": [ { "family_name": "Alam", "given_name": "M. Khairul", "clpid": "Alam-M-Khairul" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Analytical solutions of the steady state, three-dimensional atmospheric diffusion equation for sulfur dioxide and sulfate dispersion from point sources are presented. First-order transformation of SO\u2082 to sulfate and wet and dry deposition of both SO\u2082 and sulfate are included. The solutions permit prediction of the three-dimensional concentration distributions of SO\u2082 and sulfate downwind of a continuous, elevated point source of SO\u2082, with or without an elevated inversion layer present.", "doi": "10.1016/0004-6981(81)90314-0", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1981-01", "series_number": "7", "volume": "15", "issue": "7", "pages": "1221-1225" }, { "id": "authors:n0vw8-3xp67", "collection": "authors", "collection_id": "n0vw8-3xp67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140627-142424318", "type": "book_section", "title": "Sensivity Analysis of Chemically Reacting Systems", "book_title": "Modelling of chemical reaction systems", "author": [ { "family_name": "Tilden", "given_name": "J. W.", "clpid": "Tilden-J-W" }, { "family_name": "Costanza", "given_name": "V.", "orcid": "0000-0002-2409-0632", "clpid": "Costanza-V" }, { "family_name": "McRae", "given_name": "G. J.", "clpid": "McRae-G-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Ebert", "given_name": "Klaus H.", "clpid": "Ebert-K-H" }, { "family_name": "Deuflhard", "given_name": "P.", "clpid": "Deuflhard-P" }, { "family_name": "J\u00e4ger", "given_name": "Willi", "clpid": "J\u00e4ger-W" } ], "abstract": "The complexity of systems of chemical reactions makes it difficult to determine\nthe effect uncertainties in rate constants and other parameters have on\nthe behavior of .the species concentrations. Mathematically, the sensitivity\nanalysis of a system of chemical reactions consists in the problem of determining\nthe effect of uncertainties in parameters and initial conditions on\nthe solution of a set of ordinary differential equations. Sensitivity analysis\nprocedures may be classed as deterministic or stochastic in nature. Currently\navailable sensitivity analysis techniques are reviewed, and the entire\nproblem is presented in a unified framework.", "doi": "10.1007/978-3-642-68220-9", "isbn": "978-3-642-68220-9", "publisher": "Springer-Verlag", "place_of_publication": "Berlin", "publication_date": "1981", "pages": "69-91" }, { "id": "authors:ryb9h-bt284", "collection": "authors", "collection_id": "ryb9h-bt284", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768778000.22", "type": "article", "title": "History Matching in Two-Phase Petroleum Reservoirs", "author": [ { "family_name": "Watson", "given_name": "A. T.", "clpid": "Watson-Albert-T" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Gavalas", "given_name": "G. R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Woo", "given_name": "P. T.", "clpid": "Woo-P-T" } ], "abstract": "An automatic history-matching algorithm based on an optimal control approach has been formulated for joint estimation of spatially varying permeability and porosity and coefficients of relative permeability functions in two-phase reservoirs. The algorithm uses pressure and production rate data simultaneously. The performance of the algorithm for the water-flooding of one- and two-dimensional hypothetical reservoirs is examined, and properties associated with the parameter estimation problem are discussed.", "doi": "10.2118/8250-pa", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1980-12", "series_number": "6", "volume": "20", "issue": "6", "pages": "521-532" }, { "id": "authors:k8gbx-qpd79", "collection": "authors", "collection_id": "k8gbx-qpd79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768795000.24", "type": "article", "title": "Aerosol behavior in the continuous stirred tank reactor", "author": [ { "family_name": "Crump", "given_name": "James G.", "clpid": "Crump-James-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The basic features of aerosol behavior in the CSTR are examined. Solutions are obtained for the steady state aerosol size distribution during simultaneous coagulation, particle growth by vapor condensation and new particle formation by nucleation. Explicit distributions are shown for the case of a monodisperse feed aerosol.", "doi": "10.1002/aic.690260412", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1980-07", "series_number": "4", "volume": "26", "issue": "4", "pages": "610-616" }, { "id": "authors:wsam9-k4606", "collection": "authors", "collection_id": "wsam9-k4606", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120928-114602569", "type": "monograph", "title": "Relation of emissions to air quality for photochemical smog", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Effective evaluation of air pollution control strategies requires\nthe use of validated and reliable mathemtical models that can relate\npollutant emissions to atmospheric air quality. The primary objective\nof this research program has been to develop a fundamental capability\nto assess the effectiveness of air pollution control measures in\nreducing photochemical air pollution. An important aspect of the\ndevelopment has been to simplify the preparation of input data and\noperational use of the resulting model. The system has been designed\nto be used by air pollution agencies with relatively little experience\nin atmospheric physics and chemistry. The assumptions commonly\nemployed in model formulations have been evaluated to ensure a valid\nrepresentation of the physical and chemical processes in the atmosphere.\nIn the most recent phase of this research the comprehensive photochemical\nairshed model has been evaluated against data available in\nthe South Coast Air Basin of Southern California. This task was\nundertaken in collaboration with the California Air Resources Board,\nAir Quality Modeling Section. A statistical analysis package has been\nused to evaluate the correspondence of predicted and observed concentrations\nfor the days on which the model was evaluated. An assessment\nof the EPA ozone isopleth modeling technique has been initiated.", "doi": "10.7907/wsam9-k4606", "publisher": "California Institute of Technology", "publication_date": "1980-04" }, { "id": "authors:yrcqz-gqx07", "collection": "authors", "collection_id": "yrcqz-gqx07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768803000.26", "type": "article", "title": "Solution of the discrete coagulation equation", "author": [ { "family_name": "Tambour", "given_name": "Yoram", "clpid": "Tambour-Yoram" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An approximate analytical solution of the discrete coagulation equation is obtained for an arbitrary initial distribution and a general form of the coagulation coefficient, \n\n\u03b2\u1d62\u2c7c = c\u2080 + \u03a3_(q=1)^Q c_q \u0192_(iq)g_(jq)\n\nthat encompasses most of the forms used in practice. The classic Smoluchowski solution for monodisperse initial distribution and constant \u03b2ij is thus extended. The approximate nature of the solution arises from the solution for the total number concentration N_\u221e(t), in which certain moments of the distribution must be assumed constant. In implementing the solution these moments can be updated as a function of time, so that the present solution can be viewed as an alternative to direct numerical solution of the coagulation equation.", "doi": "10.1016/0021-9797(80)90189-7", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1980-03", "series_number": "1", "volume": "74", "issue": "1", "pages": "260-272" }, { "id": "authors:cyety-pmg18", "collection": "authors", "collection_id": "cyety-pmg18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120719-094919741", "type": "article", "title": "An Objective Analysis Technique for Constructing Three-Dimensional Urban-Scale Wind Fields", "author": [ { "family_name": "Goodin", "given_name": "William R.", "clpid": "Goodin-W-R" }, { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-G-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An objective analysis procedure for generating mass-consistent, urban-scale three-dimensional wind fields is presented together with a comparison against existing techniques. The algorithm employs terrain following coordinates and variable vertical grid spacing. Initial estimates of the velocity field are developed by interpolating surface and upper level wind measurements. A local terrain adjustment technique, involving solution of the Poisson equation, is used to establish the horizontal components of the surface field. Vertical velocities are developed from successive solutions of the continuity equation followed by an iterative procedure which reduces anomalous divergence in the complete field. Major advantages of the procedure are that it is computationally efficient and allows boundary values to adjust in response to changes in the interior flow. The method has been successfully tested using field measurements and problems with known analytic solutions.", "doi": "10.1175/1520-0450(1980)019<0098:AOATFC>2.0.CO;2", "issn": "0894-8763", "publisher": "American Meteorological Society", "publication": "Journal of Applied Meteorology", "publication_date": "1980-01", "series_number": "1", "volume": "19", "issue": "1", "pages": "98-108" }, { "id": "authors:8ngsj-app50", "collection": "authors", "collection_id": "8ngsj-app50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:PETaest80.375", "type": "book_section", "title": "Heterogenous condensation and chemical reaction in droplets- application to the heterogenous atmospheric oxidation of SO\u2082", "book_title": "Advances in Environmental Science and Technology", "author": [ { "family_name": "Peterson", "given_name": "Thomas W.", "clpid": "Peterson-Thomas-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Pitts", "given_name": "James", "clpid": "Pitts-James" }, { "family_name": "Metcalf", "given_name": "Robert", "clpid": "Metcalf-Robert" } ], "abstract": "In this chapter we develop a general framework for describing simultaneous chemical reaction and growth of multicomponent liquid droplets. The general framework is then used to study sulfate formation in atmospheric droplets. \n\nThe formation of secondary particulate species, such as sulfates and nitrates, has been of considerable interest in atmospheric chemistry. Sulfate formation resulting from emissions of SO\u2082 has been of particular concern. Two paths have been identified for the oxidation of SO\u2082 to sulfate:\n(1) Homogeneous, gas-phase oxidation (1, 2).\n(2) Heterogeneous oxidation in droplets and on aerosol particles (3).\nBoth aspects have received considerable study, however there are still important areas of uncertainty in our understanding of both processes. This chapter focuses on the latter process.\nThe chapter is divided essentially into two parts. In the first part we develop a general theory for calculating the simultaneous growth and composition changes accompanying heterogeneous condensation of gaseous species on a droplet and heterogeneous chemical reaction in the droplet. In the second part we study in some detail heterogeneous oxidation of SO\u2082 in the aqueous phase by catalytic and noncatalytic mechanisms in order to assess the importance of the various mechanisms.", "isbn": "9780471064800", "publisher": "John Wiley and Sons", "place_of_publication": "Hoboken, NJ", "publication_date": "1980", "pages": "125-180" }, { "id": "authors:ckpq6-xje44", "collection": "authors", "collection_id": "ckpq6-xje44", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768807000.28", "type": "book_section", "title": "Dynamics of Aerosols", "book_title": "Dynamics and Modelling of Reactive Systems", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "contributor": [ { "family_name": "Stewart", "given_name": "Warren E.", "clpid": "Stewart-Warren-E" }, { "family_name": "Ray", "given_name": "W. Harmon", "clpid": "Ray-W-Harmon" }, { "family_name": "Conley", "given_name": "Charles C.", "clpid": "Conley-Charles-C" } ], "abstract": "This chapter presents dynamics of aerosols. Aerosols, or atmospheric particles, can vary in size from collections of a few molecules to cloud droplets. The evolution of these particles occurs as a result of particle-particle collisions and individual particle growth because of accretion of vapor molecules. The process of individual particle growth can involve chemical reactions occurring in the particles. The chapter also presents the basic conservation equations for the aerosol number concentration as a function of particle size. It discusses the kinetic coefficients that appear in the basic equations and describes dimensionless groups that characterize the aerosol. It also illustrates the results of certain interesting cases of aerosol evolution during pure growth. The dynamic behavior of an aerosol is described by a population balance equation, which can be termed as the general dynamic equation. The evolving size spectra, in the three cases of diffusion-, surface reaction-, and volume reaction-controlled growth, exhibits certain distinct features characteristic of the growth mechanism.", "doi": "10.1016/b978-0-12-669550-2.50014-2", "isbn": "978-0-12-669550-2", "publisher": "Elsevier", "place_of_publication": "New York, NY", "publication_date": "1980", "pages": "225-258" }, { "id": "authors:0kykz-dcp91", "collection": "authors", "collection_id": "0kykz-dcp91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140625-152050423", "type": "article", "title": "Sensitivity and Uncertainty of Reaction Mechanisms for Photochemical Air Pollution", "author": [ { "family_name": "Falls", "given_name": "Andrew H.", "clpid": "Falls-Andrew-H" }, { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-Gregory-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A sensitivity/uncertainty analysis is performed on a mechanism describing the chemistry of the polluted troposphere. General features of the photochemical reaction system are outlined together with an assessment of the uncertainties associated with the formulations of mechanistic details and rate data. The combined effects of sensitivity and uncertainty are determined using the Fourier amplitude sensitivity test (FAST) method. The results of this analysis identify the key parameters influencing the chemistry of NO\u2082, O\u2083, and PAN. Based on these findings, a series of recommendations are made for future experimental kinetic studies.", "doi": "10.1002/kin.550111102", "issn": "0538-8066", "publisher": "Wiley", "publication": "International Journal of Chemical Kinetics", "publication_date": "1979-11", "series_number": "11", "volume": "11", "issue": "11", "pages": "1137-1162" }, { "id": "authors:xm2xn-x2r72", "collection": "authors", "collection_id": "xm2xn-x2r72", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768881000.38", "type": "article", "title": "Calculation of sulfate and nitrate levels in a growing, reacting aerosol", "author": [ { "family_name": "Peterson", "given_name": "Thomas W.", "clpid": "Peterson-Thomas-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The temporal variation of particle size and chemical composition of a marine aerosol exposed to SO\u2082, NH\u2083, NO, NO\u2082, H\u2082SO\u2084 and H\u2082O vapor is studied to determine the effect of these parameters on the sulfate and nitrate levels in the particle. Results show that, for gas phase SO\u2082 oxidation to sulfate, and liquid phase nitrate formation, those parameters that enhance sulfate formation tend to inhibit nitrate formation, and vice versa. Further, for the situation considered, the ratio predicted for sulfate and nitrate ions to ammonium ions is very nearly that found if all these ions were present in the form of NH\u2084NO\u2083 and (NH\u2084)\u2082SO\u2084. This compares favorably with data on sulfate, nitrate and ammonium levels in the Los Angeles area. The model used is capable of representing a general growing, reacting aerosol; other cases studied by this approach are briefly outlined. Limitations of its use are discussed.", "doi": "10.1002/aic.690250511", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1979-09", "series_number": "5", "volume": "25", "issue": "5", "pages": "831-838" }, { "id": "authors:0n2dj-qzs43", "collection": "authors", "collection_id": "0n2dj-qzs43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768919000.50", "type": "article", "title": "An air quality model performance assessment package", "author": [ { "family_name": "Bencala", "given_name": "Kenneth E.", "clpid": "Bencala-Kenneth-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Methods for evaluating the performance of air quality models through comparison of observed and predicted concentrations are summarized and categorized. The comparisons are based on techniques for analyzing residuals, trends, and common air quality indices. The techniques have been incorporated into a computational package for the automatic assessment of model performance.", "doi": "10.1016/0004-6981(79)90043-x", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1979-08", "series_number": "8", "volume": "13", "issue": "8", "pages": "1181-1185" }, { "id": "authors:15k96-rmv37", "collection": "authors", "collection_id": "15k96-rmv37", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120726-074013431", "type": "article", "title": "A Comparison of Interpolation Methods for Sparse Data:\n Application to Wind and Concentration Fields", "author": [ { "family_name": "Goodin", "given_name": "William R.", "clpid": "Goodin-William-R" }, { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-Gregory-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "In order to produce gridded fields of pollutant concentration data and surface wind data for use in an air quality model, a number of techniques for interpolating sparse data values are compared. The techniques are compared using three data sets. One is an idealized concentration distribution to which the exact solution is known, the second is a potential flow field, while the third consists of surface ozone concentrations measured in the Los Angeles Basin on a particular day. The results of the study indicate that fitting a second-degree polynomial to each subregion (triangle) in the plane with each data point weighted according to its distance from the subregion provides a good compromise between accuracy and computational cost.", "doi": "10.1175/1520-0450(1979)018<0761:ACOIMF>2.0.CO;2", "issn": "0021-8952", "publisher": "American Meteorological Society", "publication": "Journal of Applied Meteorology", "publication_date": "1979-06", "series_number": "6", "volume": "18", "issue": "6", "pages": "761-771" }, { "id": "authors:n95sb-p5d65", "collection": "authors", "collection_id": "n95sb-p5d65", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768923000.51", "type": "article", "title": "Distributed parameter filtering: boundary noise and discrete observations", "author": [ { "family_name": "Bencala", "given_name": "Kenneth E.", "clpid": "Bencala-Kenneth-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The linear distributed parameter filtering problem is considered for systems of engineering interest. Formal derivations arc employed to develop filters for systems with stochastic boundary conditions and for observation processes which are continuous, discrete, or average in time and discrete in space.", "doi": "10.1080/00207727908941598", "issn": "0020-7721", "publisher": "Informa UK Limited", "publication": "International Journal of Systems Science", "publication_date": "1979-05", "series_number": "5", "volume": "10", "issue": "5", "pages": "493-512" }, { "id": "authors:bs1ct-cjw80", "collection": "authors", "collection_id": "bs1ct-cjw80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140625-132824054", "type": "article", "title": "Automatic Sensitivity Analysis of Kinetic Mechanisms", "author": [ { "family_name": "Koda", "given_name": "Masato", "clpid": "Koda-Masato" }, { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-Gregory-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An algorithm for the automatic sensitivity analysis of kinetic mechanisms based on the Fourier amplitude sensitivity test (FAST) method of Shuler and co-workers is reported. The algorithm computes a measure of the relative sensitivity of each concentration to each parameter of interest, such as rate constants, Arrhenius parameters, stoichiometric coefficients, and initial concentrations. Arbitrary variations in the magnitude of the parameters are allowable. The algorithm is illustrated for the simple example of computing the sensitivity of the concentration of species A to variation of the two Arrhenius parameters for the hypothetical reaction A + A \u2192.", "doi": "10.1002/kin.550110408", "issn": "0538-8066", "publisher": "Wiley", "publication": "International Journal of Chemical Kinetics", "publication_date": "1979-04", "series_number": "4", "volume": "11", "issue": "4", "pages": "427-444" }, { "id": "authors:wzndv-xec15", "collection": "authors", "collection_id": "wzndv-xec15", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768895000.43", "type": "article", "title": "The general dynamic equation for aerosols. Theory and application to aerosol formation and growth", "author": [ { "family_name": "Gelbard", "given_name": "Fred", "clpid": "Gelbard-Fred" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Conservation equations for aerosol size distribution dynamics are derived and compared. A new discrete-continuous conservation equation is derived that overcomes the limitations of the purely discrete or continuous equations in simulating aerosol dynamics over a broad particle size spectrum. Several issues related to aerosol formation and growth not previously amenable to exact analysis are studied in detail using the discrete-continuous equation: (1) the establishment of a steady state concentration profile of molecular clusters in the presence of a preexisting aerosol; (2) the relative importance of nucleation, condensation, and scavenging in gas-to-particle conversion; and (3) the importance of cluster-cluster agglomeration relative to other processes. The formation and growth of a sulfuric acid/water aerosol in a smog chamber is simulated using the discrete-continuous equation, and the results are compared with recent experimental data. The above issues related to aerosol formation and growth are investigated for the simulated experiment.", "doi": "10.1016/0021-9797(79)90289-3", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1979-02", "series_number": "2", "volume": "68", "issue": "2", "pages": "363-382" }, { "id": "authors:mta5j-wxy58", "collection": "authors", "collection_id": "mta5j-wxy58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768891000.42", "type": "article", "title": "Sensitivity analysis of partial differential equations with application to reaction and diffusion processes", "author": [ { "family_name": "Koda", "given_name": "Masato", "clpid": "Koda-Masato" }, { "family_name": "Dogru", "given_name": "Ali H.", "clpid": "Dogru-Ali-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Methods for the computation of sensitivity coefficients for constant, spatially varying, and temporally varying parameters in parabolic partial differential equations characteristic of reaction and diffusion processes are developed. Computational requirements associated with the methods are estimated, and the methods are applied to the sensitivity analysis of atmospheric diffusion.", "doi": "10.1016/0021-9991(79)90103-7", "issn": "0021-9991", "publisher": "Elsevier", "publication": "Journal of Computational Physics", "publication_date": "1979-02", "series_number": "2", "volume": "30", "issue": "2", "pages": "259-282" }, { "id": "authors:26p8c-g4n77", "collection": "authors", "collection_id": "26p8c-g4n77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120928-111332964", "type": "monograph", "title": "Relation of Emissions to Air Quality for Photochemical Smog", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Effective evaluation of air pollution control strategies requires\nthe use of validated and reliable mathematical models that can relate\npollutant emissions to atmospheric air quality. The primary objective\nof this research program has been to develop a fundamental modeling\ncapability to assess the effectiveness of air pollution control\nmeasures in reducing smog. An important aspect of the development\nhas been to simplify the preparation of input data and operational\nuse of the resulting model. The system has been designed to be used\nby air pollution agencies with relatively little experience in\natmospheric physics and chemistry. The assumptions commonly employed\nin model formulations have been evaluated to ensure a valid representation\nof the physical and chemical processes in the atmosphere.\n\nAs part of this project a new set of objective analysis procedures\nhas been developed to generate meteorological fields from sparse and\ndiscrete surface level observations (Publications 6a and 6b). New\nparameterizations of turbulent diffusivity and surface interactions\nhave led to a better understanding of the mixing and removal of chemically\nreacting pollutants. Numerical techniques have been developed to solve\nthe large system of coupled nonlinear partial differential equations\nwhich describe the pollutant transport and chemical reactions.", "doi": "10.7907/26p8c-g4n77", "publisher": "California Institute of Technology", "publication_date": "1979-02" }, { "id": "authors:wbrsn-d4890", "collection": "authors", "collection_id": "wbrsn-d4890", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768885000.40", "type": "article", "title": "A note on the equilibrium relationship between ammonia and nitric acid and particulate ammonium nitrate", "author": [ { "family_name": "Stelson", "given_name": "A. W.", "clpid": "Stelson-A-W" }, { "family_name": "Friedlander", "given_name": "S. K.", "clpid": "Friedlander-S-K" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Theoretical predictions of the atmospheric equilibrium involving gaseous ammonia and nitric acid and solid ammonium nitrate are compared with atmospheric measurements of ammonia and nitric acid concentrations reported by Spicer (1974) at West Covina, California. Qualitative agreement between the equilibrium constant and the product of the measured NH\u2083 and HNO\u2083 concentrations is found.", "doi": "10.1016/0004-6981(79)90293-2", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1979-01", "series_number": "3", "volume": "13", "issue": "3", "pages": "369-371" }, { "id": "authors:y4t43-c9652", "collection": "authors", "collection_id": "y4t43-c9652", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768902000.45", "type": "article", "title": "Exact solution of the general dynamic equation for aerosol growth by condensation", "author": [ { "family_name": "Gelbard", "given_name": "Fred", "clpid": "Gelbard-Fred" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Exact solution of the general dynamic equation for aerosol growth by condensation is obtained in dimensionless form for particle growth occurring by gas phase diffusion-, surface reaction-, and volume reaction-controlled processes. Analytic expressions for the size distribution of an aerosol undergoing growth by gas-to-particle conversion and influenced by homogeneous source and removal processes are presented over the complete range of particle Knudsen number, Kn. Numerical results are presented to show the effect of the different growth mechanisms on size distribution dynamics.", "doi": "10.1016/0021-9797(79)90269-8", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1979-01", "series_number": "1", "volume": "68", "issue": "1", "pages": "173-183" }, { "id": "authors:3ha13-zp508", "collection": "authors", "collection_id": "3ha13-zp508", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140918-130351446", "type": "book_section", "title": "Use of models to establish source-receptor relationships and estimate relative source contributions of NO_x to air quality problems", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "McRae", "given_name": "Gregory J.", "clpid": "McRae-G-J" } ], "contributor": [ { "family_name": "Romanovsky", "given_name": "Jerry", "clpid": "Romanovsky-J" } ], "abstract": "A basic objective of the Technical Symposium on the Implications of a Low NO_x Vehicle Emission Standard is to examine the need for and technical feasibility of a low NO_x emission standard for future light-duty motor vehicles.\nA major component of this assessment is to estimate the changes in air quality that would result from the imposition of a low NO_x vehicle emission standard. Such an assessment requires a method for relating emission to air\nquality changes, i.e. a so-called air quality model. In this summary, we focus on those air quality models that may be used to estimate the impact of changes in the NO_x emission levels from motor vehicles.", "publisher": "U.S. Environmental Protection Agency", "publication_date": "1979" }, { "id": "authors:h1dpg-a6753", "collection": "authors", "collection_id": "h1dpg-a6753", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532640000.17", "type": "article", "title": "Continued development of a kinetic mechanism for photochemical smog", "author": [ { "family_name": "Falls", "given_name": "Andrew H.", "clpid": "Falls-Andrew-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A kinetic mechanism for photochemical smog is developed to incorporate recent new information on rate constants and mechanisms. The predictions of the mechanism are compared with smog chamber data on propylene, n-butane, and propylene/n-butane systems. Areas of uncertainty are delineated, and the influence of these uncertainties on the predictions of the mechanism is discussed.", "doi": "10.1021/es60148a005", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1978-12", "series_number": "13", "volume": "12", "issue": "13", "pages": "1398-1406" }, { "id": "authors:pecp2-vd778", "collection": "authors", "collection_id": "pecp2-vd778", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532632000.15", "type": "article", "title": "Optimal location of measurements in tubular reactors", "author": [ { "family_name": "Kumar", "given_name": "S.", "clpid": "Kumar-Sudarshan" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The optimal location of temperature measurements along the length of a non-adiabatic tubular reactor in which a first-order exothermic reaction is occurring is considered. The optimal locations are defined to be those at which the most accurate estimates of the concentration and temperature profiles in the reactor can be obtained. The problem is approached by first discretizing the reactor model equations at a certain number of collection points. The optimal sensor location problem is then posed as that of selecting a desired number of points out of the prespecified locations given by the collocation points. It is found, for the particular set of paramters considered, that the quality of state estimates obtainable can be strongly dependent on the locations of the sensors, even more so than on the number of sensors. A general theory for optimal locations of sensors in nonlinear distributed parameter systems is presented.", "doi": "10.1016/0009-2509(78)85201-4", "issn": "0009-2509", "publisher": "Elsevier", "publication": "Chemical Engineering Science", "publication_date": "1978-11", "series_number": "11", "volume": "33", "issue": "11", "pages": "1507-1516" }, { "id": "authors:17dbq-xg437", "collection": "authors", "collection_id": "17dbq-xg437", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532636000.16", "type": "article", "title": "Estimation of urban air pollution", "author": [ { "family_name": "Koda", "given_name": "Masato", "clpid": "Koda-Masato" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The problem of real-time estimation of air pollutant concentrations in an urban atmosphere based on concentration measurements made intermittently at a set of monitoring stations is considered. A square-root distributed parameter filter for a general class of dynamic urban air pollution models is developed. The filter is tested by application to a hypothetical urban area, and the effect of the number of monitoring stations on the estimated concentrations is studied.", "doi": "10.1016/0005-1098(78)90047-x", "issn": "0005-1098", "publisher": "Elsevier", "publication": "Automatica", "publication_date": "1978-11", "series_number": "6", "volume": "14", "issue": "6", "pages": "583-595" }, { "id": "authors:gh918-jag46", "collection": "authors", "collection_id": "gh918-jag46", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-768929000.53", "type": "article", "title": "Numerical solution of the dynamic equation for particulate systems", "author": [ { "family_name": "Gelbard", "given_name": "Fred", "clpid": "Gelbard-Fred" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The method of collocation using two finite element techniques is applied to the solution of the general population balance equation for particulate systems. Numerical solutions by both techniques are obtained in six cases for which analytical or asymptotic solutions are available. Errors associated with solving the equation on a finite particle size domain are analyzed. The results indicate that, for simulating particulate system dynamics, both techniques are highly accurate and efficient.", "doi": "10.1016/0021-9991(78)90058-x", "issn": "0021-9991", "publisher": "Elsevier", "publication": "Journal of Computational Physics", "publication_date": "1978-09", "series_number": "3", "volume": "28", "issue": "3", "pages": "357-375" }, { "id": "authors:qyncx-dvj43", "collection": "authors", "collection_id": "qyncx-dvj43", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532618000.11", "type": "article", "title": "A model of second-order chemical reactions in turbulent fluid \u2014 part II. Application to atmospheric plumes", "author": [ { "family_name": "Shu", "given_name": "Winston R.", "clpid": "Shu-Winston-R" }, { "family_name": "Lamb", "given_name": "Robert G.", "clpid": "Lamb-Robert-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The model developed in Part I to describe second order chemical reactions in turbulence is adapted for predicting the rates of chemical reactions occurring in plumes from atmospheric sources. The numerical planetary boundary layer model of Deardorff is employed to obtain the turbulence statistics required to implement the closure model in this role under unstable atmospheric conditions. A test of the model is performed by simulating the rate of nitric oxide oxidation in the near-source portion of a plume from the Potomac Electric Company's power plant at Morgantown, Maryland. The results, which agree well with observations, indicate that turbulent concentration fluctuations greatly inhibit the rate of nitric oxide conversion in the plume for a period of about 2z\u1d62/w*, where z\u1d62 is the height of the inversion layer below which convection is confined and w* is the convective velocity scale. When fluctuation effects were eliminated from the model in one particular case, the 50%-conversion time dropped from 20 minutes to about three minutes.", "doi": "10.1016/0004-6981(78)90318-9", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1978-08", "series_number": "8", "volume": "12", "issue": "8", "pages": "1695-1704" }, { "id": "authors:mnptc-2xz58", "collection": "authors", "collection_id": "mnptc-2xz58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532282000.1", "type": "article", "title": "Optimal location of measurements for distributed parameter estimation", "author": [ { "family_name": "Kumar", "given_name": "Sudarshan", "clpid": "Kumar-Sudarshan" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The problem of optimal measurement locations for state estimation in linear distributed parameter systems is considered. It has previously been shown that the optimal sensor location problem for distributed systems can be posed as an optimal control problem for a system described by the infinite-dimensional matrix Riccati equation for the filter covariance. A more efficient approach based on an upper bound of the filter covariance is developed in the present study. The relationship between the present approach and that of minimizing a measure of the filter covariance is studied. A detailed example is considered, and the results of the two approaches are compared.", "doi": "10.1109/tac.1978.1101803", "issn": "0018-9286", "publisher": "IEEE", "publication": "IEEE Transactions on Automatic Control", "publication_date": "1978-08", "series_number": "4", "volume": "23", "issue": "4", "pages": "690-698" }, { "id": "authors:mvjs6-5cs07", "collection": "authors", "collection_id": "mvjs6-5cs07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532588000.3", "type": "article", "title": "Error Analysis in History Matching: The Optimum Level of Parameterization", "author": [ { "family_name": "Shah", "given_name": "P. C.", "clpid": "Shah-P-C" }, { "family_name": "Gavalas", "given_name": "G. R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The accuracy of the porosity and permeability estimates obtained in reservoir history matching is investigated using covariance analysis. The estimate covariance matrix is obtained for the following cases: (1) estimation of all individual grid properties, (2) parametrization using sensitivity vectors, (3) parametrization by zonation, and (4) Bayesian estimation. The trace of the covariance matrix used as a measure of the over-all accuracy is studied as a function of the number of unknown parameters, and a procedure for selecting the parameters, and a procedure for selecting the optimum parametrization is developed. Numerical calculations with a one-dimensional reservoir are used to illustrate the theory.", "doi": "10.2118/6508-pa", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1978-06", "series_number": "3", "volume": "18", "issue": "3", "pages": "219-228" }, { "id": "authors:m2cf5-6j066", "collection": "authors", "collection_id": "m2cf5-6j066", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532609000.9", "type": "article", "title": "Solution of atmospheric diffusion problems by pseudo-spectral and orthogonal collocation methods", "author": [ { "family_name": "Wengle", "given_name": "Hans", "clpid": "Wengle-Hans" }, { "family_name": "van den Bosch", "given_name": "Bruno", "clpid": "van-den-Bosch-Bruno" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Atmospheric diffusion problems are generally approached by numerical solution of the atmospheric diffusion equation to predict the spatial and temporal distribution of atmospheric contaminants. Two numerical techniques not previously used for atmospheric diffusion problems, the pseudo-spectral method and orthogonal collocation on finite elements, are adapted for use in such problems. The diffusion of an inert contaminant from an elevated, crosswind line source is considered in detail as a test problem for the two methods.", "doi": "10.1016/0004-6981(78)90347-5", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1978-05", "series_number": "5", "volume": "12", "issue": "5", "pages": "1021-1032" }, { "id": "authors:2xwnn-z3473", "collection": "authors", "collection_id": "2xwnn-z3473", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532601000.6", "type": "article", "title": "Coagulation and growth of a multicomponent aerosol", "author": [ { "family_name": "Gelbard", "given_name": "F. M.", "clpid": "Gelbard-Fred-M" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Analytical solutions to the coagulation equation in the absence and presence of particle growth for a multicomponent aerosol are presented. From the general solutions corresponding to a class of initial composition distributions, four cases are considered in an attempt to elucidate the effects of coagulation and growth on the evolving composition distribution.", "doi": "10.1016/s0021-9797(78)80008-3", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1978-03-01", "series_number": "3", "volume": "63", "issue": "3", "pages": "472-479" }, { "id": "authors:vkv61-pj520", "collection": "authors", "collection_id": "vkv61-pj520", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532593000.4", "type": "article", "title": "Dynamics of source-reinforced, coagulating, and condensing aerosols", "author": [ { "family_name": "Peterson", "given_name": "Thomas W.", "clpid": "Peterson-Thomas-W" }, { "family_name": "Gelbard", "given_name": "Fred", "clpid": "Gelbard-Fred" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The dynamic behavior of aerosol size distributions is studied. By selection of simplified, but physically realistic, mechanisms for coagulation, condensation, nucleation, and removal, certain analytic solutions to the aerosol population balance equation are obtained. In those cases in which analytic solutions cannot be obtained, a numerical technique based on orthogonal collocation on finite elements is employed to obtain the solution. Also studied is the time evolution of the total number and total volume of aerosol within the system as a function of the relative importance of the mechanisms mentioned.", "doi": "10.1016/s0021-9797(78)80004-6", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1978-03", "series_number": "3", "volume": "63", "issue": "3", "pages": "426-445" }, { "id": "authors:bc6w6-gjh93", "collection": "authors", "collection_id": "bc6w6-gjh93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180404-114154037", "type": "book_section", "title": "Environmental Reaction Engineering", "book_title": "Chemical Reaction Engineering Reviews\u2014Houston", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Chemical reaction engineering problems associated with environmental systems are numerous. Design of gas cleaning absorption processes, waste water treatment facilities, low-emission combustion processes, and catalytic mufflers are typical problems. A review of the state of environmental reaction engineering cannot be accomplished in a chapter of modest length. Rather than attempt a comprehensive review of environmental reaction engineering, therefore, we have chosen to focus here somewhat more narrowly. Specifically, we will discuss several challenging problems in what might be termed atmospheric reaction engineering.", "doi": "10.1021/bk-1978-0072.ch005", "isbn": "9780841204324", "publisher": "American Chemical Society", "place_of_publication": "Washington, DC", "publication_date": "1978-01-19", "pages": "162-192" }, { "id": "authors:k5az0-6ma11", "collection": "authors", "collection_id": "k5az0-6ma11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532606000.8", "type": "article", "title": "Pseudospectral solution of atmospheric diffusion problems", "author": [ { "family_name": "Wengle", "given_name": "Hans", "clpid": "Wengle-Hans" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The pseudospectral method is applied to the solution of advection/diffusion problems arising from the dispersion of contaminants in the atmosphere. Two techniques are developed for the pseudospectral treatment of nonperiodic boundary conditions that typically exist in such problems. Calculations using the two forms of the pseudospectral method are presented for the dispersion of a contaminant emitted from an elevated, crosswind line source in the atmosphere. The results indicate that pseudospectral methods offer a promising alternative to finite-difference methods for such problems.", "doi": "10.1016/0021-9991(78)90101-8", "issn": "0021-9991", "publisher": "Elsevier", "publication": "Journal of Computational Physics", "publication_date": "1978-01", "series_number": "1", "volume": "26", "issue": "1", "pages": "87-106" }, { "id": "authors:7bs47-bvs97", "collection": "authors", "collection_id": "7bs47-bvs97", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532654000.22", "type": "article", "title": "Mathematical model for transport, interconversion, and removal of gaseous and particulate air pollutants\u2014application to the urban plume", "author": [ { "family_name": "Peterson", "given_name": "Thomas W.", "clpid": "Peterson-Thomas-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A steady state, three-dimensional solution of the atmospheric diffusion equation including settling, deposition, and first-order removal is presented. The solution is applied to the prediction of airborne concentrations of gaseous and particulate pollutants in the case in which gases are converted to secondary particulate matter. The conversion of sulfur dioxide, nitrogen oxides, and hydrocarbons to particulate sulfate, nitrate, and organics in the Los Angeles atmosphere and urban plume is analysed.", "doi": "10.1016/0004-6981(77)90093-2", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1977-12", "series_number": "12", "volume": "11", "issue": "12", "pages": "1171-1184" }, { "id": "authors:1f0wm-qy279", "collection": "authors", "collection_id": "1f0wm-qy279", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-707449000.2", "type": "article", "title": "History Matching in Two-Phase Petroleum Reservoirs: Incompressible Flow", "author": [ { "family_name": "van den Bosch", "given_name": "Bruno", "clpid": "van-den-Bosch-Bruno" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The estimation of porosity, absolute permeability, and relative permeability-saturation relations in a two-phase petroleum reservoir is considered The data available for estimation are assumed to be the oil flow rates and the pressures at the wells. A situation in which the reservoir may be represented by incompressible flow of oil and water also is considered. A hypothetical, circular reservoir with a centrally located producing well is studied in detail. In principle, the porosity can be estimated on the basis of saturation behavior, absolute permeability on The basis of pressure behavior, and permeability on The basis of pressure behavior, and coefficients in the relative permeability-saturation relations on the basis of both saturation and pressure behavior. The ability to achieve good pressure behavior. The ability to achieve good estimates was found to depend on the nature of the flow in a given situation.", "doi": "10.2118/6579-pa", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1977-12", "series_number": "6", "volume": "17", "issue": "6", "pages": "398-406" }, { "id": "authors:gzsbm-kwd59", "collection": "authors", "collection_id": "gzsbm-kwd59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532646000.19", "type": "article", "title": "Nitrate formation in atmospheric aerosols", "author": [ { "family_name": "Orel", "given_name": "Ann E.", "clpid": "Orel-Ann-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Equilibrium nitrate levels in aqueous solution in the presence of sodium chloride, nitric oxide, nitrogen dioxide, sulfur dioxide, carbon dioxide, ammonia, and sulfuric acid are calculated. Nitrate levels in solution are of the order of those observed in the atmosphere when the gaseous concentrations are at typical urban levels. Sulfate levels in such solutions are predicted to be relatively low in the absence of oxidation catalysts. When sulfate formation is assumed to occur by gas-phase oxidation of sulfur dioxide to sulfuric acid followed by absorption of the sulfuric acid in aerosols, predicted nitrate and sulfate size distributions are in qualitative agreement with those observed in the atmosphere.", "doi": "10.1021/es60133a009", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1977-10-01", "series_number": "10", "volume": "11", "issue": "10", "pages": "1000-1007" }, { "id": "authors:ckyqm-7ad42", "collection": "authors", "collection_id": "ckyqm-7ad42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230414-532651000.21", "type": "article", "title": "Brownian coagulation in the transition regime", "author": [ { "family_name": "Sitarski", "given_name": "Marek", "clpid": "Sitarski-Marek" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The rate of Brownian coagulation of aerosols is studied theoretically. The particle distribution function is assumed to be governed by the Fokker-Planck equation, which is solved analytically by the 13-moment method of Grad. An expression for the coagulation parameter \u03b2(a\u1d62, a\u2c7c) is obtained from the solution over all ranges of particle radii a\u1d62 and a\u2c7c. The coagulation rates predicted by the solution agree closely with those predicted by the empirical expression of Fuchs as well as with those recently obtained experimentally by Chatterjee, Kerker, and Cooke.", "doi": "10.1016/0021-9797(77)90389-7", "issn": "0021-9797", "publisher": "Elsevier", "publication": "Journal of Colloid and Interface Science", "publication_date": "1977-09", "series_number": "2", "volume": "61", "issue": "2", "pages": "261-271" }, { "id": "authors:e4816-dvp22", "collection": "authors", "collection_id": "e4816-dvp22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139427000.9", "type": "article", "title": "Reservoir History Matching by Bayesian Estimation", "author": [ { "family_name": "Gavalas", "given_name": "G. R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Shah", "given_name": "P. C.", "clpid": "Shah-P-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The estimation of reservoir properties is inherently an underdetermined problem (one having a nonunique solution) because of the large number of unknown parameters relative to the available data. parameters relative to the available data. The common zonation approach to reducing the number of parameters introduces considerable modeling error by insisting that reservoir properties are uniform within each zone and by assigning the boundaries of these zones more or less arbitrarily. In this paper, Bayesian estimation theory is applied to history matching as an alternative to zonation. By using a priori statistical information on the unknown parameters, the problem becomes statistically better determined. Bayesian estimation and zonation are applied to the problem of porosity and permeability estimation in a one-dimensional, permeability estimation in a one-dimensional, one-phase reservoir.", "doi": "10.2118/5740-pa", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1976-12", "series_number": "6", "volume": "16", "issue": "6", "pages": "337-350" }, { "id": "authors:vmx89-35m51", "collection": "authors", "collection_id": "vmx89-35m51", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200428-084748306", "type": "article", "title": "Chemical kinetics of homogeneous atmospheric oxidation of sulfur dioxide", "author": [ { "family_name": "Sander", "given_name": "Stanley P.", "orcid": "0000-0003-1424-3620", "clpid": "Sander-S-P" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A systematic evaluation of known homogeneous SO\u2082 reactions\nwhich might be important in air pollution chemistry\nis carried out. A mechanism is developed to represent the\nchemistry of NO_x/hydrocarbon/SO\u2082 systems, and the mechanism\nis used to analyze available experimental data appropriate\nfor quantitative analysis of SO\u2082 oxidation kinetics.\nDetailed comparisons of observed and predicted concentration\nbehavior are presented. In all cases, observed SO\u2082 oxidation\nrates cannot be explained solely on the basis of those SO\u2082 reactions\nfor which rate constants have been measured. The role\nof ozone-olefin reactions in SO\u2082 oxidation is elucidated.", "doi": "10.1021/es60122a007", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1976-11-01", "series_number": "12", "volume": "10", "issue": "12", "pages": "1114-1123" }, { "id": "authors:88k1a-r5979", "collection": "authors", "collection_id": "88k1a-r5979", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139328000.3", "type": "article", "title": "Dynamics of aerosol coagulation and condensation", "author": [ { "family_name": "Ramabhadran", "given_name": "T. E.", "clpid": "Ramabhadran-T-E" }, { "family_name": "Peterson", "given_name": "T. W.", "clpid": "Peterson-T-W" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The dynamic behavior of aerosol size distributions under the influence of coagulation and growth by heterogeneous condensation of gaseous species is studied. Analytical solutions are obtained to the integro-differential equation governing the aerosol size distribution density function. Two modes of coagulation (constant and linear coagulation constants) and two modes of condensation (growth independent of particle volume and linearly dependent on particle volume) are considered. The interaction of the two growth mechanisms on aerosol size distributions is elucidated.", "doi": "10.1002/aic.690220505", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1976-09", "series_number": "5", "volume": "22", "issue": "5", "pages": "840-851" }, { "id": "authors:x08jk-e2f76", "collection": "authors", "collection_id": "x08jk-e2f76", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120808-134849794", "type": "article", "title": "Wakes in stratified flow past a hot or cold two-dimensional body", "author": [ { "family_name": "Robertson", "given_name": "G. E.", "clpid": "Robertson-Grant-E" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Leal", "given_name": "L. G.", "orcid": "0000-0002-6358-7828", "clpid": "Leal-L-G" } ], "abstract": "This paper considers the general problem of laminar, steady, horizontal, Oseen flow at large distances upstream and downstream of a two-dimensional body which is represented as a line source of horizontal or vertical momentum, or as a line heat source or heat dipole. The fluid is assumed to be incompressible, diffusive, viscous and stably stratified. The analysis is focused on the general properties of the horizontal velocity component, as well as on explicit calculation of the horizontal velocity profiles and disturbance stream-function fields for varying degrees of stratification. For stable stratifications, the flow fields for all four types of singularities exhibit the common feature of multiple recirculating rotors of finite thicknesses, which leads to an alternating jet structure both upstream and downstream for the horizontal velocity component and to leewaves downstream in the overall flow. The self-similar formulae for the velocity, temperature and pressure at very large distances upstream and downstream are also derived and compared with the Oseen solutions.", "doi": "10.1017/S0022112076000190", "issn": "0022-1120", "publisher": "Cambridge University Press", "publication": "Journal of Fluid Mechanics", "publication_date": "1976-05", "series_number": "2", "volume": "75", "issue": "2", "pages": "233-256" }, { "id": "authors:2yyhk-1hp17", "collection": "authors", "collection_id": "2yyhk-1hp17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200428-094555609", "type": "article", "title": "On frequency distributions of air pollutant concentrations", "author": [ { "family_name": "Bencala", "given_name": "Kenneth E.", "clpid": "Bencala-Kenneth-E" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Observed frequency distributions of air pollutant concentration levels are critically analyzed with respect to their statistical description. It is demonstrated that several common distributions can be used to fit observed data, one of which is the popular log-normal distribution. The observation that concentration distributions for all averaging times are approximately log-normal can be explained if the short averaging time data are themselves assumed to be log-normally distributed. The near log-normality of pollutant concentration frequency distributions can be explained on the basis of the near log-normality of wind speed distributions, although this explanation does not establish that wind speed distributions are solely responsible for observed concentration distributions. It is concluded that pollutant concentration frequency distributions are the result of complex phenomena and cannot be predicted exactly, but that the approximate log-normal character of the distributions is useful from a practical point of view and can be understood qualitatively on the basis of the relation between wind speed and concentration.", "doi": "10.1016/0004-6981(76)90200-6", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1976-01", "series_number": "11", "volume": "10", "issue": "11", "pages": "941-950" }, { "id": "authors:csewp-de381", "collection": "authors", "collection_id": "csewp-de381", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140625-124007805", "type": "book_section", "title": "Validity and Accuracy of Atmospheric Air Quality Models", "author": [ { "family_name": "Goodin", "given_name": "W. R.", "clpid": "Goodin-W-R" }, { "family_name": "McRae", "given_name": "G. J.", "clpid": "McRae-G-J" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Effective evaluation of air pollution\ncontrol strategies requires the use of validated\nand reliable mathematical models that can relate\npollutant emissions to atmospheric air quality.\nThe derivation and use of such models, at least\nfor inert and linearly decaying pollutants such\nas CO and SO_2, has received a great deal of\nattention. Much less work has been devoted to\nassessing how the model predictions are related\nto actual atmospheric concentrations. The\nobjectives of this paper are to formulate the\nconcepts of validity and accuracy and to suggest\nand describe some experiments that can be performed\nto assess these features.", "publisher": "American Meteorological Society", "publication_date": "1976" }, { "id": "authors:40x8k-gsg29", "collection": "authors", "collection_id": "40x8k-gsg29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139552000.15", "type": "article", "title": "Atmospheric aerosol growth by heterogeneous condensation", "author": [ { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Ramabhadran", "given_name": "T. E.", "clpid": "Ramabhadran-T-E" } ], "abstract": "Heterogeneous condensation of gases has been shown to be an important process in determining the size distribution of urban aerosols. The rate of condensation depends on the gas phase concentration of the condensing species. The effect of turbulent gas phase concentration fluctuations on the rate of growth of an aerosol by heterogeneous condensation is considered. First, a simulation of heterogeneous condensation growth of an aerosol in a spatially homogeneous system in which local gas phase concentration fluctuations exist is performed. It is found that the fluctuations lead to a size distribution that is broader than that obtained in the absence of fluctuations. Then, an extension of the Prandtl mixing length theory is developed for the term accounting for the turbulent contribution to condensation growth in the equation governing the mean aerosol size distribution function.", "doi": "10.1016/0004-6981(75)90184-5", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1975-12", "series_number": "12", "volume": "9", "issue": "12", "pages": "1091-1097" }, { "id": "authors:544cz-nq298", "collection": "authors", "collection_id": "544cz-nq298", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:LAMjas75", "type": "article", "title": "Numerico-empirical analyses of atmospheric diffusion theories", "author": [ { "family_name": "Lamb", "given_name": "Robert G.", "clpid": "Lamb-Robert-G" }, { "family_name": "Chen", "given_name": "Wen H.", "clpid": "Chen-Wen-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Numerico-empirical expressions for the particle displacement probability density function from which the mean concentration of material in turbulent fluid may be obtained are derived from the numerical planetary boundary layer model of Deardorff. These expressions are then used to compute profiles of the mean, cross-wind-integrated concentration of an inert pollutant issuing from a continuous point source below a stable layer. Profiles are derived for each of two conditions of atmospheric stability: zi/L=0 and \u20134.5, where zi is the inversion base height and L the Monin-Obukhov length. The resulting concentration profiles [referred to as the numerico-empirical (NE) profiles] are then used in two separate experiments designed to assess the adequacy of conventional atmospheric diffusion formulations. \n\nFirst, the validity of the atmospheric diffusion equation is assessed by determining for each of the two stabilities cited above the profile of vertical eddy diffusivity that produces the closest fit of the mean concentration predicted by the atmospheric diffusion equation with the NE profiles. \n\nSecond, comparisons are made between the NE profiles and the corresponding concentration distributions predicted by the Gaussian plume formula with Pasquill-Gifford dispersion parameters, and the Gaussian puff equation with McElroy-Pooler travel-time-dependent dispersion parameters.", "doi": "10.1175/1520-0469(1975)032<1794:NEAOAD>2.0.CO;2", "issn": "0022-4928", "publisher": "American Meteorological Society", "publication": "Journal of the Atmospheric Sciences", "publication_date": "1975-09", "series_number": "9", "volume": "32", "issue": "9", "pages": "1794-1807" }, { "id": "authors:6854a-kyw71", "collection": "authors", "collection_id": "6854a-kyw71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139559000.17", "type": "article", "title": "Filtering in distributed parameter systems with moving boundaries", "author": [ { "family_name": "Ray", "given_name": "W. H.", "clpid": "Ray-W-H" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A general filter is presented for nonlinear distributed parameter systems having an arbitrary number of moving boundaries. The filter is capable of including both volume and boundary process noise as well as measurement errors. A large number of potential applications of the results, ranging from the estimation of the extent of crude oil spills to metallurgical solidification problems, are discussed.", "doi": "10.1016/0005-1098(75)90026-6", "issn": "0005-1098", "publisher": "Elsevier", "publication": "Automatica", "publication_date": "1975-09", "series_number": "5", "volume": "11", "issue": "5", "pages": "509-515" }, { "id": "authors:68z1z-f4181", "collection": "authors", "collection_id": "68z1z-f4181", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139563000.19", "type": "article", "title": "Self-preserving theory of particulate systems", "author": [ { "family_name": "Ramabhadran", "given_name": "T. E.", "clpid": "Ramabhadran-T-E" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The similarity solution of the population balance equation for pure kinetic coagulation (coalescence) has proved to be a useful means of representing the evolution of size distributions of homogeneous particulate systems. The resulting solution is termed self-preserving since neither particle size nor time appears explicitly in the solution. In the present work similarity solutions are developed for a wide class of particulate processes that are governed by a general population balance equation for the inhomogeneous size distribution density function. The general theory has application to the analysis of size spectra of atmosphere aerosols undergoing simultaneous coagulation, turbulent diffusion, and growth by gas-to-particle condensation, to the analysis of size spectra during grinding processes, and to several other physical systems of interest.", "doi": "10.1016/0009-2509(75)87003-5", "issn": "0009-2509", "publisher": "Elsevier", "publication": "Chemical Engineering Science", "publication_date": "1975-09", "series_number": "9", "volume": "30", "issue": "9", "pages": "1019-1025" }, { "id": "authors:vcnx9-6z308", "collection": "authors", "collection_id": "vcnx9-6z308", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139537000.13", "type": "article", "title": "Practical Applications of Optimal-Control Theory to History-Matching Multiphase Simulator Models", "author": [ { "family_name": "Wasserman", "given_name": "M. L.", "clpid": "Wasserman-M-L" }, { "family_name": "Emanuel", "given_name": "A. S.", "clpid": "Emanuel-A-S" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This paper applies material presented by Chen et al. and by Chavent et al to practical reservoir problems. The pressure history-matching algorithm used is initially based on a discretized single-phase reservoir model. Multiphase effects are approximately treated in the single-phase model by multiplying the transmissibility and storage terms by saturation-dependent terms that are obtained from a multiphase simulator run. Thus, all the history matching is performed by a \"pseduo\" single-phase model. The multiplicative factors for transmissibility and storage are updated when necessary. The matching technique can change any model permeability thickness or porosity thickness value. Three field examples are given.", "doi": "10.2118/5020-pa", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1975-08", "series_number": "4", "volume": "15", "issue": "4", "pages": "347-355" }, { "id": "authors:9nywc-6by14", "collection": "authors", "collection_id": "9nywc-6by14", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139633000.22", "type": "article", "title": "Optimal location of process measurements", "author": [ { "family_name": "Chen", "given_name": "Wen H.", "clpid": "Chen-Wen-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The problem of optimally locating a given number of Bensors for observing a general linear distributed parameter system is considered. Measurements at the sensors are assumed to be available continuously in time, and the design criterion is minimization of a scalar measure of the covariance of the estimate error in the optimal linear filter. Necessary conditions for optimality are derived based on the formulation of a distributed parameter matrix minimum principle. A computational algorithm is developed for determining the optimum set of measurement locations. The algorithm is applied to the problem of optimally locating temperature sensors in a solid undergoing transient heat conduction.", "doi": "10.1080/00207177508922052", "issn": "0020-7179", "publisher": "Taylor & Francis", "publication": "International Journal of Control", "publication_date": "1975-06", "series_number": "6", "volume": "21", "issue": "6", "pages": "1003-1014" }, { "id": "authors:7r4zs-8rm56", "collection": "authors", "collection_id": "7r4zs-8rm56", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200428-095311193", "type": "article", "title": "On the validity of grid and trajectory models of urban air pollution", "author": [ { "family_name": "Liu", "given_name": "Mei-Kao", "clpid": "Liu-Mei-Kao" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Of the two types of dynamic urban air pollution models commonly used, grid models emply a coordinate system fixed with respect to the ground, whereas trajectory models have a coordinate system centered on a fictitious vertical air column which moves horizontally with the advective wind. Both models are based on the atmospheric diffusion equation as the essential description of turbulent advection and diffusion. The primary errors committed in the grid model are those attributed to finite-difference approximations, whereas the errors in the trajectory model are mainly a result of the assumptions inherent in the model formulation, such as neglect of horizontal turbulent diffusion across the parcel boundaries and neglect of wind shear. Quantitative conditions based on comparison of exact solutions of the atmospheric diffusion equation with those of the grid and trajectory models are derived to indicate when these two classes of models may be accurately employed for various regimes of stability, wind shear and source configuration.", "doi": "10.1016/0004-6981(75)90001-3", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1975-06", "series_number": "6-7", "volume": "9", "issue": "6-7", "pages": "555-574" }, { "id": "authors:xgjn5-nt848", "collection": "authors", "collection_id": "xgjn5-nt848", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139436000.11", "type": "article", "title": "Interim evaluation of strategies for meeting ambient air quality standard for photochemical oxidant", "author": [ { "family_name": "Reynolds", "given_name": "Steven D.", "clpid": "Reynolds-Steven-D" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Two strategies proposed for meeting ambient air quality standards for photochemical oxidant in the South Coast Air Basin of California are evaluated: (1) the 1977 EPA Transportation Control Plan and (2) the current federal light-duty vehicle exhaust emission standards. Currently available means of relating emissions to air quality for photochemical smog are employed in the evaluation. The methods used include modified rollback based on ambient data and laboratory data, the statistical model of Trijonis, and the physicochemical model of Reynolds et al. The Appendix contains a detailed emission inventory projection for Los Angeles in 1977.", "doi": "10.1021/es60103a001", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1975-05-01", "series_number": "5", "volume": "9", "issue": "5", "pages": "433-447" }, { "id": "authors:26h5t-8r102", "collection": "authors", "collection_id": "26h5t-8r102", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139630000.21", "type": "article", "title": "Formulation and initial application of a dynamic model for urban aerosols", "author": [ { "family_name": "Chu", "given_name": "Kuang J.", "clpid": "Chu-Kuang-J" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A dynamic model for prediction of the spatial and temporal behavior of the size and chemical composition distributions of an urban air pollution aerosol is developed. Particular attention is given to the description of aerosol formation and growth in photochemical smog, in which the aerosol of interest lies primarily in the size range, 0.1\u20131 \u03bcm dia. The dynamic model developed is used to simulate aerosol number and mass concentrations and size distributions along several typical air trajectories on 20 September 1972 in the Los Angeles basin. Predictions of the model are compared with total aerosol mass concentrations computed from light-scattering measurements. The sensitivity of the predictions to assumptions concerning the nature of gas to particle conversion processes is explored.", "doi": "10.1016/0004-6981(75)90124-9", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1975-04", "series_number": "4", "volume": "9", "issue": "4", "pages": "375-402" }, { "id": "authors:m715g-med05", "collection": "authors", "collection_id": "m715g-med05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139697000.26", "type": "article", "title": "The application of an approximate non-linear filter to systems governed by coupled ordinary and partial differential equations", "author": [ { "family_name": "Ajinkya", "given_name": "M. B.", "clpid": "Ajinkya-M-B" }, { "family_name": "Ray", "given_name": "W. H.", "clpid": "Ray-W-H" }, { "family_name": "Yu", "given_name": "T. K.", "clpid": "Yu-Thomas-King-Lin" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "An approximate non-linear filter is applied to systems described by coupled ordinary and partial differential equations with both volume and boundary disturbances and measurement errors. Measurements are assumed to be carried out at u discrete number of spatial positions in the distributed portion of the system. The filter is applicable to cases in which the data are available continuously in time and at discrete sampling instants. Both versions of the filter are applied to an ingot heating problem of some interest in steel-making. The numerical results show that the filter is rapidly convergent and quite robust.", "doi": "10.1080/00207727508941819", "issn": "0020-7721", "publisher": "Informa UK Limited", "publication": "International Journal of Systems Science", "publication_date": "1975-04", "series_number": "4", "volume": "6", "issue": "4", "pages": "313-332" }, { "id": "authors:k55cb-zxk50", "collection": "authors", "collection_id": "k55cb-zxk50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139689000.24", "type": "article", "title": "Estimation of the Location of the Boundary of a Petroleum Reservoir", "author": [ { "family_name": "Chen", "given_name": "Wen H.", "clpid": "Chen-Wen-H" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "This paper considers the problem of estimating the shape of a petroleum reservoir on the basis of pressure data from wells within the boundaries of pressure data from wells within the boundaries of the reservoir. It is assumed that the reservoir properties, such as permeability and porosity, are properties, such as permeability and porosity, are known but that the location of the boundary is unknown. Thus, this paper addresses a new class of history-matching problems in which the boundary position is the reservoir property to be estimated. position is the reservoir property to be estimated. The problem is formulated as an optimal-control problem (the location of the boundary being the problem (the location of the boundary being the control variable). Two iterative methods are derived for the determination of the boundary location that minimizes a functional, depending on the deviation between observed and predicted pressures at the wells. The steepest-descent pressures at the wells. The steepest-descent algorithm is illustrated in two sample problems: 1. the estimation of the radius of a bounded circular reservoir with a centrally located well, and 2. the estimation of the shape of a two-dimensional, single-phase reservoir with a constant-pressure outer boundary.", "doi": "10.2118/4814-pa", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1975-02", "series_number": "1", "volume": "15", "issue": "1", "pages": "19-38" }, { "id": "authors:jwgev-rw988", "collection": "authors", "collection_id": "jwgev-rw988", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120802-124203574", "type": "article", "title": "Natural convection in a shallow cavity with differentially heated end walls. Part 2. Numerical solutions", "author": [ { "family_name": "Cormack", "given_name": "D. E.", "clpid": "Cormack-Donald-E" }, { "family_name": "Leal", "given_name": "L. G.", "orcid": "0000-0002-6358-7828", "clpid": "Leal-L-G" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Numerical solutions of the full Navier-Stokes equations are obtained for the problem of natural convection in closed cavities of small aspect ratio with differentially\nheated end walls. These solutions cover the parameter range\nPr = 6.983, 10 \u2264 Gr \u2264 2 x 10\u2074 and 0.05 \u2264 A \u2264 1. A comparison with the asymptotic theory of part 1 shows excellent agreement between the analytical and numerical solutions provided that A \u227e 0.1 and Gr\u00b2A\u00b3Pr\u00b2 \u227e l0\u2075. In addition,\nthe numerical solutions demonstrate the transition between the shallow-cavity limit of part 1 and the boundary-layer limit; A fixed, Gr \u2192 \u221e.", "doi": "10.1017/S0022112074001364", "issn": "0022-1120", "publisher": "Cambridge University Press", "publication": "Journal of Fluid Mechanics", "publication_date": "1974-08-28", "series_number": "2", "volume": "65", "issue": "2", "pages": "231-246" }, { "id": "authors:rdk9a-6ph64", "collection": "authors", "collection_id": "rdk9a-6ph64", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150115-123226682", "type": "article", "title": "Filtering in nonlinear time delay systems", "author": [ { "family_name": "Yu", "given_name": "Thomas K.", "clpid": "Yu-Thomas-K" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Ray", "given_name": "W. Harmon", "clpid": "Ray-W-H" } ], "abstract": "Linear and nonlinear (extended Kalman-Bucy) filters are derived for systems governed by coupled partial and integro-differential equations. The framework used is sufficiently general that filters for 1) lumped parameter systems having multiple time varying or constant time delays, 2) coupled lumped and hyperbolic distributed parameter systems, and 3) lumped parameter systems with functional time delays, evolve as special cases. Although the filtering equations are the final result, the corresponding smoothing equations are developed as well. The performance of the filter is illustrated through application to a well stirred chemical reactor with external heat exchange.", "doi": "10.1109/TAC.1974.1100579", "issn": "0018-9286", "publisher": "IEEE", "publication": "IEEE Transactions on Automatic Control", "publication_date": "1974-08", "series_number": "4", "volume": "19", "issue": "4", "pages": "324-333" }, { "id": "authors:fjqjp-ek183", "collection": "authors", "collection_id": "fjqjp-ek183", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139707000.29", "type": "article", "title": "Further development of a generalized kinetic mechanism for photochemical smog. Addendum", "author": [ { "family_name": "Hecht", "given_name": "T. A.", "clpid": "Hecht-Thomas-A" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Dodge", "given_name": "M. C.", "clpid": "Dodge-M-C" } ], "abstract": "For those readers who might wish to reproduce the simulations reported in the article which appeared in Environmental Science and Technology, Vol. 8, No. 4, pages 327-39, we present here some additional data.", "doi": "10.1021/es60091a012", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1974-06-01", "series_number": "6", "volume": "8", "issue": "6", "pages": "588" }, { "id": "authors:qp0a6-pk419", "collection": "authors", "collection_id": "qp0a6-pk419", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200428-102318746", "type": "article", "title": "Mathematical modeling of photochemical air pollution\u2014III. Evaluation of the model", "author": [ { "family_name": "Reynolds", "given_name": "Steven D.", "clpid": "Reynolds-Steven-D" }, { "family_name": "Liu", "given_name": "Mei-Kao", "clpid": "Liu-Mei-Kao" }, { "family_name": "Hecht", "given_name": "Thomas A.", "clpid": "Hecht-Thomas-A" }, { "family_name": "Roth", "given_name": "Philip M.", "clpid": "Roth-Philip-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The results of model evaluation exercises carried out for the urban airshed model developed in Parts I and II are presented. Concentrations of CO, hydrocarbons, NO, NO\u2082 and O\u2083 in the Los Angeles airshed were simulated for 6 days in the fall of 1969. Prior to carrying out these simulations, rate constants and stoichiometric coefficients used in the kinetic mechanism that has been incorporated in the airshed model were determined by separately validating the kinetic mechanism with laboratory smog chamber data for several hydrocarbon-NO_x, systems, including auto exhaust. In addition, to take into account the effect of local sources on concentrations measured at certain Los Angeles County Air Pollution Control District monitoring stations, a simple microscale model was developed. This model was used to predict the local effect of a heavily-travelled roadway on concentrations measured at a near-by monitoring station. The overall results exhibit good enough agreement with the monitoring data to suggest that in the future air pollution models based on representation of actual physical and chemical processes can be important components of abatement strategy planning.", "doi": "10.1016/0004-6981(74)90143-7", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1974-06", "series_number": "6", "volume": "8", "issue": "6", "pages": "563-596" }, { "id": "authors:80hdj-29a81", "collection": "authors", "collection_id": "80hdj-29a81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139713000.30", "type": "article", "title": "Generalized kinetic mechanism for photochemical smog", "author": [ { "family_name": "Hecht", "given_name": "Thomas A.", "clpid": "Hecht-Thomas-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Dodge", "given_name": "Marcia C.", "clpid": "Dodge-Marcia-C" } ], "abstract": "A generalized kinetic mechanism for photochemical smog is formulated and tested. The most important feature of the mechanism is its general nature; that is, the mechanism is applicable to a large number of hydrocarbons and, ultimately, the entire atmospheric mix. By design, the mechanism takes advantage of the common features of hydrocarbon and free radical reactions to maintain at a minimum the number of species included while at the same time retaining a high degree of detail, especially as concerns the chemistry of the inorganic species. The mechanism is tested using n-butane-NO\u2093, propylene-NO\u2093, and n-butane-propylene-NO\u2093 smog chamber data at 13 different sets of initial reactant concentrations and a wide variety of hydrocarbon to NO\u2093 ratios. The predicted effect of initial reactant ratios on ozone formation is in agreement with the data that were analyzed.", "doi": "10.1021/es60089a004", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1974-04-01", "series_number": "4", "volume": "8", "issue": "4", "pages": "327-339" }, { "id": "authors:yxj9k-xp042", "collection": "authors", "collection_id": "yxj9k-xp042", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139705000.28", "type": "article", "title": "On meeting the provisions of the Clean Air Act", "author": [ { "family_name": "Kyan", "given_name": "Chwan P.", "clpid": "Kyan-Chwan-P" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A general structure is proposed for determining a set of long-term (multi-year) source control measures which achieve specified levels of air quality for an airshed at least cost. Such a structure is useful in evaluating alternative air pollution abatement strategies from the standpoint of air quality and total cost. The theory is applied to the problem of evaluating sets of control actions over the period 1973-1975 in Los Angeles. Costs of achieving various levels of air quality in Los Angeles over this period are determined.", "doi": "10.1002/aic.690200115", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1974-01", "series_number": "1", "volume": "20", "issue": "1", "pages": "118-127" }, { "id": "authors:e969q-ezt22", "collection": "authors", "collection_id": "e969q-ezt22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHEspej74", "type": "article", "title": "A New Algorithm for Automatic History Matching", "author": [ { "family_name": "Chen", "given_name": "Wen H.", "clpid": "Chen-Wen-H" }, { "family_name": "Gavalas", "given_name": "George R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Wasserman", "given_name": "M. L.", "clpid": "Wasserman-M-L" } ], "abstract": "History-matching problems, in which reservoir parameters arc to be estimated from well pressure data, are formulated as optimal control problems. The necessary conditions for optimality lead naturally to gradient optimization methods for determining the optimal parameter estimates. The key feature of the approach is that reservoir properties are considered as continuous functions\nof position rather than as uniform in a certain number of zones. The optimal control approach is illustrated on a hypothetical reservoir and on an actual Saudi Arabian reservoir, both characterized by single-phase flow. A significant saving in computing time over conventional constant-zone gradient optimization methods is demonstrated.", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1974", "series_number": "6", "volume": "14", "issue": "6", "pages": "593-608" }, { "id": "authors:ew197-gp872", "collection": "authors", "collection_id": "ew197-gp872", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139792000.41", "type": "article", "title": "Reservoirs With Spatially Varying Properties: Estimation of Volume From Late Transient Pressure Data", "author": [ { "family_name": "Gavalas", "given_name": "G. R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The transient pressure in a reservoir of arbitrary shape and spatially varying properties is expressed in terms of the eigenvalues and eigenfunctions of the region. Although these eigenvalues and eigenfunctions cannot be obtained analytically, except in homogeneous reservoirs of regular shape, the structure of the solution allows the estimation of the pore volume in the general case using data in the pseudosteady or the late-transient period. A least-squares analysis of late transient data is presented which yields, in addition to the pore presented which yields, in addition to the pore volume, the first eigenvalue, which can often be related to reservoir properties. Numerical examples are given using simulated data from a rectangular 4 x 1 reservoir with constant permeability and with spatially varying permeability.", "doi": "10.2118/4169-pa", "issn": "0197-7520", "publisher": "Society of Petroleum Engineers", "publication": "Society of Petroleum Engineers Journal", "publication_date": "1973-12-01", "series_number": "6", "volume": "13", "issue": "6", "pages": "335-342" }, { "id": "authors:gzjq9-6pv04", "collection": "authors", "collection_id": "gzjq9-6pv04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139740000.37", "type": "article", "title": "Mathematical modeling of photochemical air pollution\u2014I: Formulation of the model", "author": [ { "family_name": "Reynolds", "given_name": "Steven D.", "clpid": "Reynolds-Steven-D" }, { "family_name": "Roth", "given_name": "Philip M.", "clpid": "Roth-Philip-M" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The formulation of a model for predicting the dynamic behavior of chemically reacting air pollutants in an urban atmosphere is presented. The Los Angeles airshed was chosen as the region for initial application of the model. The model development and validation program is divided into three parts: \n1. I\u2014Formulation of the model; \n2. II\u2014A model and inventory of pollutant emissions; \n3. III\u2014Evaluation of the model. \n\nIn this paper (Part I) we derive the basic equations governing the model, discuss the treatment of meteorological variables (inversion height, wind field, and turbulent eddy diffusivity), present a kinetic mechanism for photochemical smog, and describe the technique employed for numerical integration of the governing partial differential equations for the mean concentrations of carbon monoxide, hydrocarbons, nitric oxide, nitrogen dioxide, and ozone.", "doi": "10.1016/0004-6981(73)90214-x", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1973-11", "series_number": "11", "volume": "7", "issue": "11", "pages": "1033-1061" }, { "id": "authors:d5jak-55f39", "collection": "authors", "collection_id": "d5jak-55f39", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139737000.36", "type": "article", "title": "Combined forced and free convection flow past a horizontal flat plate", "author": [ { "family_name": "Robertson", "given_name": "G. E.", "clpid": "Robertson-Grant-E" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Leal", "given_name": "L. G.", "orcid": "0000-0002-6358-7828", "clpid": "Leal-L-G" } ], "abstract": "The problem of simultaneous forced and free convection flow of a Newtonian fluid past a hot or cold horizontal flat plate is investigated by means of numerical solutions of the full equations of motion and thermal energy subject only to the Boussinesq approximation. These solutions span the parameter ranges 10 \u2264 Re \u2264 100, 0.1 \u2264 Pr \u2264 10, and \u20132.215 \u2264 Gr/Re^(5/2) \u2264 2.215 where Re, Pr, and Gr are based on the ambient free stream fluid properties and the overall plate length l. When Gr > 0, the boundary flow near the plate surface is accelerated relative to the corresponding forced convection flow, with a resulting increase in both the local skin friction and heat transfer coefficients. When Gr < 0, the boundary flow is decelerated, the local skin friction and heat transfer are decreased, and the flow actually separates for Gr/Re^(5/2) < \u20130.8 when Pr = 0.7. In the latter circumstance, an increasing degree of upstream influence is observed as Gr/Re^(5/2) is further decreased.", "doi": "10.1002/aic.690190517", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1973-09", "series_number": "5", "volume": "19", "issue": "5", "pages": "998-1008" }, { "id": "authors:gxxnp-4rv71", "collection": "authors", "collection_id": "gxxnp-4rv71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139730000.34", "type": "article", "title": "Observability and optimal measurement location in linear distributed parameter systems", "author": [ { "family_name": "Yu", "given_name": "Thomas K.", "clpid": "Yu-Thomas-King-Lin" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Observability and the optimal location of measurements are developed for a class of linear distributed parameter systems whose solutions can be represented by eigen-function expansions (the so-called modal form). A key question studied is the effect of measurement locations on the observability of this class of systems. Since observability is realty a prerequisite to state estimation, an algorithm is developed to determine a set of measurement locations which, in some sense, lead to the beat state estimates. This is accomplished by minimizing the trace of the steady-state covariance matrix of the state estimates.", "doi": "10.1080/00207177308932556", "issn": "0020-7179", "publisher": "Taylor & Francis", "publication": "International Journal of Control", "publication_date": "1973-07", "series_number": "4", "volume": "18", "issue": "4", "pages": "785-799" }, { "id": "authors:nzsm5-wwt83", "collection": "authors", "collection_id": "nzsm5-wwt83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200417-142717806", "type": "article", "title": "Measurement of ultraviolet radiation intensity in photochemical smog studies", "author": [ { "family_name": "Holmes", "given_name": "John R.", "clpid": "Holmes-John-R" }, { "family_name": "O'Brien", "given_name": "Robert J.", "clpid": "O'Brien-Robert-J" }, { "family_name": "Crabtree", "given_name": "James H.", "clpid": "Crabtree-James-H" }, { "family_name": "Hecht", "given_name": "Thomas A.", "clpid": "Hecht-Thomas-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The most widely used technique of measuring ultraviolet radiation intensity in photochemical smog studies is to irradiate NO\u2082 in a nitrogen atmosphere. In the past a fictitious first-order rate constant, k_d, has been used to characterize the nonlinear NO\u2082-time behavior in such a system. The inadequacy in the use of k_d stems from the need to extrapolate the NO\u2082-time curve to zero time. The actual photolysis rate constant for NO\u2082 dissociation, k\u2081, provides an unambiguous measure of uv intensity. If the NO\u2082 photolysis is performed in the usual fashion, we show that k\u2081 can be computed directly from the NO\u2082-time data by the equation, \n\nk\u2081 = 1/(2\u0394t){(1 + R\u2081 -R\u2082) ln [NO\u2082]\u2080/[NO\u2082] + R\u2082[[NO\u2082]\u2080/[NO\u2082] - 1] \n\nwhere the constants R_i are defined in the text. The validity of this equation has been established both experimentally and by computer simulation.", "doi": "10.1021/es60078a002", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1973-06", "series_number": "6", "volume": "7", "issue": "6", "pages": "519-523" }, { "id": "authors:91arc-rjg49", "collection": "authors", "collection_id": "91arc-rjg49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139750000.39", "type": "article", "title": "Real-time control of air pollution", "author": [ { "family_name": "Kyan", "given_name": "Chwan P.", "clpid": "Kyan-Chwan-P" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The problem of determining real-time (episode) air pollution control strategies for an urban airshed is posed as selecting those control measures from among all possible such that air quality is maintained at a certain level over a given time period and the total control imposed is minimum. The real-time control is based on meteorological predictions made over a several-hour to several-day period. A computational algorithm is developed for solving the class of control problems that result. The theory is applied to a hypothetical study of the effect of implementation of the optimal control on September 29, 1969, in the Los Angeles basin.", "doi": "10.1002/aic.690190325", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1973-05", "series_number": "3", "volume": "19", "issue": "3", "pages": "579-589" }, { "id": "authors:zrsyk-7kj55", "collection": "authors", "collection_id": "zrsyk-7kj55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200417-142717871", "type": "article", "title": "Mathematical modeling of urban air pollution. General theory", "author": [ { "family_name": "Lamb", "given_name": "Robert G.", "clpid": "Lamb-Robert-G" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The fundamental theory of urban air pollution modeling is developed. A number of points are considered including: The definition of the mean and random components of the wind velocity field, the necessary conditions for obtaining conventional Eulerian and Lagrangian models, the proper inclusion of nonlinear chemical reactions in a model, the nature of the spatial and temporal averages implicit in the computed concentrations, and the requirements for simulating photochemical smog formation in an urban area.", "doi": "10.1021/es60075a006", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1973-03", "series_number": "3", "volume": "7", "issue": "3", "pages": "253-261" }, { "id": "authors:a0g37-8rf16", "collection": "authors", "collection_id": "a0g37-8rf16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139722000.32", "type": "article", "title": "Suboptimal control of stochastic distributed parameter systems", "author": [ { "family_name": "Yu", "given_name": "T. K.", "clpid": "Yu-Thomas-King-Lin" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A problem with important process applications is the control of distributed parameter systems subject to boundary and volume disturbances and measurement errors. The optimal control of linear stochastic distributed systems has been studied by Tzafestas and Nightingale (1968), Kushner (1968), Thau (1969), Pel1 and Aris (1970), Bensoussian (1971), and Sholar and Wiberg (1972), while feedback control of onlinear stochastic distributed systems was investigated by Yu and Seinfeld (1972). The objective of this communication is to propose a suboptimal scheme for control of nonlinear noisy distributed parameter systems. Briefly, the scheme is based on the extension of the Lyapunov functional method and is designed to be easy to implement in practice.", "doi": "10.1002/aic.690190234", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1973-03", "series_number": "2", "volume": "19", "issue": "2", "pages": "389-392" }, { "id": "authors:dsg8w-94j45", "collection": "authors", "collection_id": "dsg8w-94j45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SEIate73", "type": "article", "title": "Optimal distribution of air pollution sources", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Chen", "given_name": "Wen H.", "clpid": "Chen-Wen-H" } ], "abstract": "The problem of determining the optimal distribution of air pollutant sources in an airshed is defined. Essentially one wishes to allocate a given total quantity of source emissions over an airshed, subject perhaps to prior zoning decisions. Two cases are considered, the first in which the distribution of sources is continuous, and the second in which the source is concentrated at a point. An airshed simulation model which relates emission strengths to atmospheric concentrations is assumed to be available for the airshed. Since the air pollution model may not have a readily available analytical solution, an iterative procedure is necessary in general to solve the optimization problem. Iterative algorithms based on the method of steepest descent are developed for the continuous distribution and point source cases. A simple example of optimally locating an infinite crosswind, ground-level line source is presented.", "doi": "10.1016/0004-6981(73)90198-4", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1973-01", "series_number": "1", "volume": "7", "issue": "1", "pages": "87-99" }, { "id": "authors:qmbpr-cxs84", "collection": "authors", "collection_id": "qmbpr-cxs84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200428-102926989", "type": "article", "title": "Optimal location of pollutant monitoring stations in an airshed", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "One possible criterion for locating a given number of pollutant monitoring stations is selected. That criterion is that the locations be chosen as those at which the concentration measurements are most sensitive to perturbations in source emission strengths. A theory and computational algorithm is developed whereby, assuming an airshed simulation model is available, the optimal locations of a given number of stations can be determined. The algorithm proposed actually encompasses the general problem of the optimal location of measurements both in space and time for a system governed by a set of parabolic or first-order hyperbolic partial differential equations. The theory is illustrated on the simple example of optimally locating one monitoring station downwind of a continuous, elevated crosswind line source.", "doi": "10.1016/0004-6981(72)90056-x", "issn": "0004-6981", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "1972-11", "series_number": "11", "volume": "6", "issue": "11", "pages": "847-858" }, { "id": "authors:fnq7g-kw123", "collection": "authors", "collection_id": "fnq7g-kw123", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151104-143219672", "type": "article", "title": "Estimation of Catalyst Deactivation Parameters from Operating Reactor Data", "author": [ { "family_name": "Gavalas", "given_name": "G. R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Hsu", "given_name": "G. C.", "clpid": "Hsu-G-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Techniques are presented for estimating the parameters of catalyst deactivation models from the operating data of industrial reactors. In the case of a first-order deactivation model, the partial differential equations describing the main reaction and deactivation are transformed to an ordinary differential equation for which estimation techniques are well established. The general power deactivation model can only be treated approximately and the case of a bifunctional catalyst must be treated by special methods. A numerical example is presented for the oxidation of butene to butadiene.", "doi": "10.1016/0300-9467(72)80056-X", "issn": "1385-8947", "publisher": "Elsevier", "publication": "Chemical Engineering Journal", "publication_date": "1972-10", "series_number": "1", "volume": "4", "issue": "1", "pages": "77-84" }, { "id": "authors:7hp1m-sxq18", "collection": "authors", "collection_id": "7hp1m-sxq18", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151008-112331825", "type": "article", "title": "On the Estimation of Kinetic Rate Constants", "author": [ { "family_name": "Churchill", "given_name": "Stuart W.", "clpid": "Churchill-S-W" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Gavalas", "given_name": "George R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Tanner", "given_name": "Robert D.", "clpid": "Tanner-R-D" } ], "abstract": "[No abstract]", "doi": "10.1021/i160043a031", "issn": "0196-4313", "publisher": "American Chemical Society", "publication": "Industrial & Engineering Chemistry Fundamentals", "publication_date": "1972-08", "series_number": "3", "volume": "11", "issue": "3", "pages": "429-429" }, { "id": "authors:qqs99-frn77", "collection": "authors", "collection_id": "qqs99-frn77", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139802000.43", "type": "book_section", "title": "Simulation of Urban Air Pollution", "book_title": "Photochemical Smog and Ozone Reactions", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Reynolds", "given_name": "Steven D.", "clpid": "Reynolds-Steven-D" }, { "family_name": "Roth", "given_name": "Philip M.", "clpid": "Roth-Philip-M" } ], "abstract": "Several types of models are commonly used to describe the dispersion of atmospheric contaminants. Among these are the box, plume, and puff models. None are suitable, however, for describing the coupled transport and reaction phenomena that characterize atmospheres in which chemical reaction processes are important. Simulation models that have been proposed for the prediction of concentrations of photochemically formed pollutants in an urban airshed are reviewed here. The development of a generalized kinetic mechanism for photochemical smog suitable for inclusion in an urban airshed model, the treatment of emissions from automobiles, aircraft, power plants, and distributed sources, and the treatment of temporal and spatial variations of primary meteorological parameters are also discussed.", "doi": "10.1021/ba-1972-0113.ch003", "isbn": "9780841201552", "publisher": "American Chemical Society", "place_of_publication": "Washington, DC", "publication_date": "1972-06-01", "pages": "58-100" }, { "id": "authors:9vb1m-n3204", "collection": "authors", "collection_id": "9vb1m-n3204", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151104-112517076", "type": "article", "title": "Estimation of catalyst activity profiles in fixed bed reactors", "author": [ { "family_name": "Gavalas", "given_name": "G. R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Hsu", "given_name": "G. C.", "clpid": "Hsu-G-C" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "The description of the steady state operation of a fixed bed catalytic reactor requires a certain amount of information about the catalyst activity distribution. For a monofunctional catalyst with no transport limitations the total catalyst activity is sufficient for describing the steady reactor operation. The total activity can be easily estimated from measurements at the reactor exit. In the presence of diffusional limitations, or in the case of bifunctional catalysts, the reactor description requires knowledge of the detailed activity profile. This can be approximately determined by parametrization and estimation of the parameters from a few measurements along the reactor. An application of the parametrization technique is made to a simplified model of naphtha reforming.", "doi": "10.1016/0009-2509(72)85069-3", "issn": "0009-2509", "publisher": "Pergamon", "publication": "Chemical Engineering Science", "publication_date": "1972-02", "series_number": "2", "volume": "27", "issue": "2", "pages": "329-338" }, { "id": "authors:1ck3j-4hn57", "collection": "authors", "collection_id": "1ck3j-4hn57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139796000.42", "type": "article", "title": "Development and validation of a generalized mechanism for photochemical smog", "author": [ { "family_name": "Hecht", "given_name": "Thomas A.", "clpid": "Hecht-Thomas-A" }, { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A detailed 81-step mechanism for the photooxidation kinetics of the propylene-NO\u2093-air system, based on consideration of the possible important reactions which might be occurring, is presented. From the detailed mechanism is deduced a general 15-step mechanism for photochemical smog formation. The flexibility of this mechanism lies in adjustable rate constants and stoichiometric coefficients, which are chosen according to the particular hydrocarbon and initial reactant ratios. The general mechanism is validated with smog chamber data on propylene, isobutylene, n-butane, and a mixture of propylene and n-butane. The general mechanism is also shown to simulate accurately the effect of CO on smog\nchamber photooxidation kinetics as well as the inhibitory\neffect of high initial concentrations of nitric oxide on the\nmaximum concentration of ozone attained.", "doi": "10.1021/es60060a003", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "1972-01-01", "series_number": "1", "volume": "6", "issue": "1", "pages": "47-57" }, { "id": "authors:v6cp7-w9093", "collection": "authors", "collection_id": "v6cp7-w9093", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170810-165157453", "type": "article", "title": "Observability of a class of hyperbolic distributed parameter systems", "author": [ { "family_name": "Yu", "given_name": "T. K.", "clpid": "Yu-Thomas-Kiing-Lin" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "Necessary and sufficient conditions are presented for the observability of a class of linear hyperbolic distributed parameter systems. Observations are assumed to be made along paths intersecting the characteristic curves of the system.", "doi": "10.1109/TAC.1971.1099793", "issn": "0018-9286", "publisher": "IEEE", "publication": "IEEE Transactions on Automatic Control", "publication_date": "1971-10", "series_number": "5", "volume": "16", "issue": "5", "pages": "495-496" }, { "id": "authors:g1c0y-nk970", "collection": "authors", "collection_id": "g1c0y-nk970", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-744259000.2", "type": "article", "title": "Determination of optimal air pollution control strategies", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Kyan", "given_name": "Chwan P.", "clpid": "Kyan-Chwan-P" } ], "abstract": "A general theoretical framework for the determination of long-term air pollution control strategies for an airshed is presented. The problem is stated as determining the set of control measures to be exercised on airshed source emissions such that the total cost of control is minimized subject to the constraint of maintaining a certain level of air quality. It is assumed that a dynamic airshed simulation, model exists that is capable of describing atmospheric diffusion and chemical reaction, thus relating total mass emissions to atmospheric concentrations. The problem is based on the typical daily air pollution syndrome with air quality being defined as some function of the daily pollutant concentrations. It is shown that the overall optimization problem can be decomposed into two problems, the first, one of linear programming, the second, one of a dynamic optimization. The theory is illustrated by means of detailed hypothetical example of selecting air pollution controls for 1 yr.", "doi": "10.1016/0038-0121(71)90028-0", "issn": "0038-0121", "publisher": "Elsevier", "publication": "Socio-Economic Planning Sciences", "publication_date": "1971-06", "series_number": "3", "volume": "5", "issue": "3", "pages": "173-190" }, { "id": "authors:jdx41-a5j26", "collection": "authors", "collection_id": "jdx41-a5j26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151008-112332705", "type": "article", "title": "Control of Plug-Flow Tubular Reactors by Variation of Flow Rate", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Gavalas", "given_name": "George R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Hwang", "given_name": "Myungkyu", "clpid": "Hwang-Myungkyu" } ], "abstract": "The control of isothermal and adiabatic plug-flow tubular reactors by variation of flow rate was studied. Proportional feedback, feedforward, and optimal control responses were compared for the regulation of reactor conversion in the presence of inlet disturbances. The optimal control, consisting of a singular solution in each case, produces a considerably improved response over both feedforward and proportional feedback control.", "doi": "10.1021/i160036a021", "issn": "0196-4313", "publisher": "American Chemical Society", "publication": "Industrial & Engineering Chemistry Fundamentals", "publication_date": "1970-11", "series_number": "4", "volume": "9", "issue": "4", "pages": "651-655" }, { "id": "authors:h57wg-y0s93", "collection": "authors", "collection_id": "h57wg-y0s93", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151105-083031329", "type": "article", "title": "Analysis of Kinetic Parameters from Batch and Integral Reaction Experiments", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Gavalas", "given_name": "George R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" } ], "abstract": "The estimation of chemical reaction rate constants from experimental batch or integral reactor data is examined. Consideration is given to the effect on the accuracy of the parameter estimates of the number of concentrations measured, extending the range of measurements to higher conversions, and experimental errors. The study is based on estimates of two rate constants obtained by quasilinearization in the pyrolytic dehydrogenation of benzene. It is found that if fewer than the number of independent components are to be measured, certain components produce better parameter estimates than others. The level of experimental errors is by far the most significant factor in obtaining reliable parameter estimates.", "doi": "10.1002/aic.690160423", "issn": "0001-1541", "publisher": "Wiley", "publication": "AIChE Journal", "publication_date": "1970-07", "series_number": "4", "volume": "16", "issue": "4", "pages": "644-647" }, { "id": "authors:q8wwz-4xw21", "collection": "authors", "collection_id": "q8wwz-4xw21", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-743795000.1", "type": "article", "title": "Review of Numerical Integration Techniques for Stiff Ordinary Differential Equations", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Lapidus", "given_name": "Leon", "clpid": "Lapidus-Leon" }, { "family_name": "Hwang", "given_name": "Myungkyu", "clpid": "Hwang-Myungkyu" } ], "abstract": "Ordinary differential equations with widely separated eigenvalues (stiff O.D.E.) occur often in practice and present severe numerical integration problems. The stability and accuracy problems associated with the numerical solution of such equations are outlined. Several methods, including a modified Runge-Kutta method due to Treanor, a class of implicit Runge-Kutta methods, extrapolation methods, and methods based on the inclusion of second derivatives and exponential fitting, are considered. Numerical results are given on three stiff systems for stiff and conventional methods and recommendations are made on what methods to use for particular systems.", "doi": "10.1021/i160034a013", "issn": "0196-4313", "publisher": "American Chemical Society", "publication": "Industrial & Engineering Chemistry Fundamentals", "publication_date": "1970-05-01", "series_number": "2", "volume": "9", "issue": "2", "pages": "266-275" }, { "id": "authors:ebeeq-zd774", "collection": "authors", "collection_id": "ebeeq-zd774", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-139812000.45", "type": "article", "title": "Optimization with Multiple Performance Criteria. Application to Minimization of Parameter Sensitivlties in a Refinery Model", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "McBride", "given_name": "Warren L.", "clpid": "McBride-Warren-L" } ], "abstract": "In complex optimization problems there often exist several noncomparable performance criteria which a designer must consider. This situation is formulated as a vector maximum problem, for which the available theory on proper efficient solutions is outlined. A practical scheme is proposed for problems in which the criteria can be ranked in order of importance. A simplified refinery model is formulated in which it is desired to maximize total yearly profit as well as minimize the sensitivity of the profit to variations in refinery conditions. Detailed nonlinear programming results are presented.", "doi": "10.1021/i260033a010", "issn": "0196-4305", "publisher": "American Chemical Society", "publication": "Industrial & Engineering Chemistry Process Design and Development", "publication_date": "1970-01-01", "series_number": "1", "volume": "9", "issue": "1", "pages": "53-57" }, { "id": "authors:5g94e-2hm20", "collection": "authors", "collection_id": "5g94e-2hm20", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151008-112333015", "type": "article", "title": "Control of Nonlinear Stochastic Systems", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Gavalas", "given_name": "George R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Hwang", "given_name": "Myung", "clpid": "Hwang-Myung" } ], "abstract": "The control of nonlinear lumped-parameter dynamical systems subject to random inputs and measurement errors is considered. A scheme is developed whereby a nonlinear filter is included in the control loop to improve system performance. The case of pure time delays occurring in the control loop is also treated. Computations are presented for the proportional control on temperature of a CSTR subject to random disturbances.", "doi": "10.1021/i160030a013", "issn": "0196-4313", "publisher": "American Chemical Society", "publication": "Industrial & Engineering Chemistry Fundamentals", "publication_date": "1969-05", "series_number": "2", "volume": "8", "issue": "2", "pages": "257-262" }, { "id": "authors:fsd9v-mqq86", "collection": "authors", "collection_id": "fsd9v-mqq86", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151104-112516816", "type": "article", "title": "Sequential estimation of states and kinetic parameters in tubular reactors with catalyst decay", "author": [ { "family_name": "Gavalas", "given_name": "G. R.", "orcid": "0000-0003-1468-6835", "clpid": "Gavalas-G-R" }, { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" } ], "abstract": "A method is presented for the on-line sequential estimation (filtering) of state variables and kinetic parameters in plug flow reactors with slow catalyst decay. The essential element of this method is the approximation, for purposes of estimation only, of the distributed parameter system by a lumped parameter system. This approximation is made possible by the slow catalyst decay The resulting sequential estimation algorithms, or filters, are computationally simple, especially the discrete filters, i e those based on a difference equation description. An application of two alternative discrete filters to a plug flow reactor with a first order irreversible reaction and catalyst decay has given good results The paper includes a brief general discussion of sequential estimation and its possible applications.", "doi": "10.1016/0009-2509(69)80056-4", "issn": "0009-2509", "publisher": "Pergamon", "publication": "Chemical Engineering Science", "publication_date": "1969-04", "series_number": "4", "volume": "24", "issue": "4", "pages": "625-636" }, { "id": "authors:jm0vv-0h671", "collection": "authors", "collection_id": "jm0vv-0h671", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-744279000.5", "type": "article", "title": "Aspects of Forward Dynamic Programming Algorithm", "author": [ { "family_name": "Seinfeld", "given_name": "John H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Lapidus", "given_name": "Leon", "clpid": "Lapidus-Leon" } ], "abstract": "The computational features of the forward dynamic programming algorithm as applied to a nonautonomous optimal control problem are discussed and a detailed numerical example is presented.", "doi": "10.1021/i260027a027", "issn": "0196-4305", "publisher": "American Chemical Society", "publication": "Industrial & Engineering Chemistry Process Design and Development", "publication_date": "1968-07-01", "series_number": "3", "volume": "7", "issue": "3", "pages": "475-478" }, { "id": "authors:rtnfg-3m995", "collection": "authors", "collection_id": "rtnfg-3m995", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230413-744269000.3", "type": "article", "title": "Discrete Dynamic Programming Algorithms", "author": [ { "family_name": "Seinfeld", "given_name": "J. H.", "orcid": "0000-0003-1344-4068", "clpid": "Seinfeld-J-H" }, { "family_name": "Lapidus", "given_name": "Leon", "clpid": "Lapidus-Leon" } ], "abstract": "Systems engineering problems which can be cast in the shortest-route format and a class of discrete optimal control problems are considered to provide better understanding of the elements of the optimal control problem by comparison to the shortest-route problem from operations research and to redefine the optimal problem for further application of available computational algorithms in systems engineering.", "doi": "10.1021/i260027a028", "issn": "0196-4305", "publisher": "American Chemical Society", "publication": "Industrial & Engineering Chemistry Process Design and Development", "publication_date": "1968-07-01", "series_number": "3", "volume": "7", "issue": "3", "pages": "479-480" } ]