[ { "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: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: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: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" } ]