[ { "id": "authors:tgqy1-vf194", "collection": "authors", "collection_id": "tgqy1-vf194", "cite_using_url": "https://authors.library.caltech.edu/records/tgqy1-vf194", "type": "article", "title": "The John H. Seinfeld Festschrift", "author": [ { "family_name": "Chan", "given_name": "Chak K.", "orcid": "0000-0001-9687-8771" }, { "family_name": "Cocker", "given_name": "David R." }, { "family_name": "Flagan", "given_name": "Richard C.", "orcid": "0000-0001-5690-770X", "clpid": "Flagan-R-C" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795" }, { "family_name": "Paulson", "given_name": "Suzanne E.", "orcid": "0000-0003-0855-7615" }, { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375" }, { "family_name": "Sander", "given_name": "Stanley P.", "orcid": "0000-0003-1424-3620", "clpid": "Sander-S-P" }, { "family_name": "Wennberg", "given_name": "Paul O.", "orcid": "0000-0002-6126-3854", "clpid": "Wennberg-P-O" } ], "abstract": "

In August 2024, guest editors and editors at ACS ES&T Air opened an honorary special issue call for papers to acknowledge the transformative impact of John H. Seinfeld on atmospheric science. The call coincided with the Seinfeld100 symposium held at Caltech in September 2025 to recognize him as he graduated his 100th Ph.D. student. The special issue call was for the latest broad research contributions covering the many fields John H. Seinfeld nucleated and expanded, including air quality engineering, organic aerosol formation and dynamics, aerosol microphysics and climate change, and atmospheric chemistry and physics. We are delighted to present this completed special issue collection in honor of John Seinfeld. Papers in this special issue come from all over the world, and their authors include many former Ph.D. recipients, postdoctoral scholars, and colleagues who wish to recognize and celebrate his impact on atmospheric and aerosol science and air quality engineering by presenting their latest impactful research.

", "doi": "10.1021/acsestair.6c00091", "issn": "2837-1402", "publisher": "American Chemical Society", "publication": "ACS ES&T Air", "publication_date": "2026-04-10", "series_number": "4", "volume": "3", "issue": "4", "pages": "908-909" }, { "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:x0qdq-9tb57", "collection": "authors", "collection_id": "x0qdq-9tb57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210811-170707088", "type": "article", "title": "Room-level ventilation in schools and universities", "author": [ { "family_name": "McNeill", "given_name": "V. Faye", "orcid": "0000-0003-0379-6916", "clpid": "McNeill-V-Faye" }, { "family_name": "Corsi", "given_name": "Richard", "orcid": "0000-0002-1291-3566", "clpid": "Corsi-Richard" }, { "family_name": "Huffman", "given_name": "J. Alex", "orcid": "0000-0002-5363-9516", "clpid": "Huffman-J-Alex" }, { "family_name": "King", "given_name": "Cathleen", "orcid": "0000-0003-3147-4834", "clpid": "King-Cathleen" }, { "family_name": "Klein", "given_name": "Robert", "clpid": "Klein-Robert" }, { "family_name": "Lamore", "given_name": "Michael", "clpid": "Lamore-Michael" }, { "family_name": "Maeng", "given_name": "Do Young", "orcid": "0000-0001-8371-5404", "clpid": "Maeng-Do-Young" }, { "family_name": "Miller", "given_name": "Shelly L.", "orcid": "0000-0002-1967-7551", "clpid": "Miller-Shelly-L" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Olsiewski", "given_name": "Paula", "orcid": "0000-0001-7014-6126", "clpid": "Olsiewski-Paula" }, { "family_name": "Godri Pollitt", "given_name": "Krystal J.", "orcid": "0000-0001-7332-2228", "clpid": "Godri-Pollitt-Krystal-J" }, { "family_name": "Segalman", "given_name": "Rachel", "orcid": "0000-0002-4292-5103", "clpid": "Segalman-Rachel-A" }, { "family_name": "Sessions", "given_name": "Alex", "orcid": "0000-0001-6120-2763", "clpid": "Sessions-A-L" }, { "family_name": "Squires", "given_name": "Todd", "orcid": "0000-0001-6609-9275", "clpid": "Squires-Todd" }, { "family_name": "Westgate", "given_name": "Sabrina", "orcid": "0000-0001-7272-2465", "clpid": "Westgate-Sabrina" } ], "abstract": "Ventilation is of primary concern for maintaining healthy indoor air quality and reducing the spread of airborne infectious disease, including COVID-19. In addition to building-level guidelines, increased attention is being placed on room-level ventilation. However, for many universities and schools, ventilation data on a room-by-room basis are not available for classrooms and other key spaces. We present an overview of approaches for measuring ventilation along with their advantages and disadvantages. We also present data from recent case studies for a variety of institutions across the United States, with various building ages, types, locations, and climates, highlighting their commonalities and differences, and examples of the use of this data to support decision making.", "doi": "10.1016/j.aeaoa.2022.100152", "pmcid": "PMC8789458", "issn": "2590-1621", "publisher": "Elsevier", "publication": "Atmospheric Environment: X", "publication_date": "2022-01", "volume": "13", "pages": "Art. No. 100152" }, { "id": "authors:p51md-jrb80", "collection": "authors", "collection_id": "p51md-jrb80", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211201-231209943", "type": "article", "title": "Evaluation of a New Aerosol Chemical Speciation Monitor (ACSM) System at an Urban Site in Atlanta, GA: The Use of Capture Vaporizer and PM_(2.5) Inlet", "author": [ { "family_name": "Joo", "given_name": "Taekyu", "orcid": "0000-0002-8252-4232", "clpid": "Joo-Taekyu" }, { "family_name": "Chen", "given_name": "Yunle", "orcid": "0000-0001-9904-2638", "clpid": "Chen-Yunle" }, { "family_name": "Xu", "given_name": "Weiqi", "clpid": "Xu-Weiqi" }, { "family_name": "Croteau", "given_name": "Philip", "clpid": "Croteau-Philip" }, { "family_name": "Canagaratna", "given_name": "Manjula R.", "clpid": "Canagaratna-Manjula-R" }, { "family_name": "Gao", "given_name": "Dong", "clpid": "Gao-Dong" }, { "family_name": "Guo", "given_name": "Hongyu", "clpid": "Guo-Hongyu" }, { "family_name": "Saavedra", "given_name": "Gabriela", "clpid": "Saavedra-Gabriela" }, { "family_name": "Kim", "given_name": "Seong Shik", "orcid": "0000-0003-2604-6392", "clpid": "Kim-Seong-Shik" }, { "family_name": "Sun", "given_name": "Yele", "orcid": "0000-0003-2354-0221", "clpid": "Sun-Yele" }, { "family_name": "Weber", "given_name": "Rodney", "orcid": "0000-0003-0765-8035", "clpid": "Weber-Rodney-J" }, { "family_name": "Jayne", "given_name": "John", "clpid": "Jayne-John-T" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" } ], "abstract": "Aerosol mass spectrometers (AMSs) and aerosol chemical speciation monitors (ACSMs) have been deployed at numerous locations to quantify nonrefractory aerosol composition. Recent instrumentation advancement includes the development of a new capture vaporizer (CV) to improve collection efficiency and a PM_(2.5) aerodynamic lens to measure aerosol up to 2.5 \u03bcm in diameter. To validate these new instrument capabilities and investigate differences in composition of atmospheric PM\u2081 and PM_(2.5), a PM\u2081-SV-AMS, and a PM_(2.5)-CV-ACSM were deployed in urban Atlanta, GA in winter 2018 with other instruments. Nonrefractory species measured by the two instruments agree well and are dominated by organic aerosol (OA). About 85% of the nonrefractory species in PM_(2.5) are in the PM\u2081. Positive matrix factorization (PMF) analysis was performed and the same number and OA subtypes were resolved for both instruments. While the relative contribution of each factor to OA was different, more-oxidized oxygenated organic aerosol (MO-OOA) is determined to be the major type of OA in both instruments. The biomass burning organic aerosol (BBOA) resolved from CV-ACSM significantly contributes to signals at m/z 26, 42, 68, and 96. Cross-comparison with other instruments demonstrates that \u223c80% of PM\u2081 and \u223c90% of PM_(2.5) is nonrefractory species. The mass concentrations of PM\u2081 and PM_(2.5) are comparable in general. During time periods when PM_(2.5)/PM\u2081 is enhanced, the PM_(1\u20132.5) composition is dominated by OA and corresponds to higher less-oxidized-OOA (LO-OOA)/OA and organic nitrate/total nitrate ratios. Results from this study demonstrate the capability of PM_(2.5)-CV-ACSM and provide new insights into PM_(2.5) composition and sources in the southeastern US.", "doi": "10.1021/acsearthspacechem.1c00173", "issn": "2472-3452", "publisher": "American Chemical Society", "publication": "ACS Earth and Space Chemistry", "publication_date": "2021-10-21", "series_number": "10", "volume": "5", "issue": "10", "pages": "2565-2576" }, { "id": "authors:pryq9-dcz05", "collection": "authors", "collection_id": "pryq9-dcz05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200806-153948183", "type": "article", "title": "Chemical characterization of secondary organic aerosol at a rural site in the southeastern US: insights from simultaneous high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and FIGAERO chemical ionization mass spectrometer (CIMS) measurements", "author": [ { "family_name": "Chen", "given_name": "Yunle", "orcid": "0000-0001-9904-2638", "clpid": "Chen-Yunle" }, { "family_name": "Takeuchi", "given_name": "Masayuki", "clpid": "Takeuchi-Masayuki" }, { "family_name": "Nah", "given_name": "Theodora", "orcid": "0000-0002-8755-6153", "clpid": "Nah-Theodora" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Canagaratna", "given_name": "Manjula R.", "clpid": "Canagaratna-M-R" }, { "family_name": "Stark", "given_name": "Harald", "orcid": "0000-0002-0731-1202", "clpid": "Stark-H" }, { "family_name": "Baumann", "given_name": "Karsten", "orcid": "0000-0003-4045-5539", "clpid": "Baumann-K" }, { "family_name": "Canonaco", "given_name": "Francesco", "clpid": "Canonaco-F" }, { "family_name": "Pr\u00e9v\u00f4t", "given_name": "Andr\u00e9 S. H.", "orcid": "0000-0002-9243-8194", "clpid": "Pr\u00e9v\u00f4t-A-S-H" }, { "family_name": "Huey", "given_name": "L. Gregory", "orcid": "0000-0002-0518-7690", "clpid": "Huey-L-G" }, { "family_name": "Weber", "given_name": "Rodney J.", "orcid": "0000-0003-0765-8035", "clpid": "Weber-R-J" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" } ], "abstract": "The formation and evolution of secondary organic aerosol (SOA) were investigated at Yorkville, GA, in late summer (mid-August to mid-October 2016). The organic aerosol (OA) composition was measured using two online mass spectrometry instruments, the high-resolution time-of-flight aerosol mass spectrometer (AMS) and the Filter Inlet for Gases and AEROsols coupled to a high-resolution time-of-flight iodide-adduct chemical ionization mass spectrometer (FIGAERO-CIMS). Through analysis of speciated organics data from FIGAERO-CIMS and factorization analysis of data obtained from both instruments, we observed notable SOA formation from isoprene and monoterpenes during both day and night. Specifically, in addition to isoprene epoxydiol (IEPOX) uptake, we identified isoprene SOA formation from non-IEPOX pathways and isoprene organic nitrate formation via photooxidation in the presence of NO_x and nitrate radical oxidation. Monoterpenes were found to be the most important SOA precursors at night. We observed significant contributions from highly oxidized acid-like compounds to the aged OA factor from FIGAERO-CIMS. Taken together, our results showed that FIGAERO-CIMS measurements are highly complementary to the extensively used AMS factorization analysis, and together they provide more comprehensive insights into OA sources and composition.", "doi": "10.5194/acp-20-8421-2020", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2020-07-17", "series_number": "14", "volume": "20", "issue": "14", "pages": "8421-8440" }, { "id": "authors:nj8q2-mp577", "collection": "authors", "collection_id": "nj8q2-mp577", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190906-093254969", "type": "article", "title": "Mixing order of sulfate aerosols and isoprene epoxydiols affect secondary organic aerosol formation in chamber experiments", "author": [ { "family_name": "Nah", "given_name": "Theodora", "orcid": "0000-0002-8755-6153", "clpid": "Nah-Theodora" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Osborne-Benthaus", "given_name": "Kymberlee A.", "clpid": "Osborne-Benthaus-K-A" }, { "family_name": "White", "given_name": "S. Meghan", "orcid": "0000-0002-1215-116X", "clpid": "White-S-M" }, { "family_name": "France", "given_name": "Stefan", "clpid": "France-S" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" } ], "abstract": "The reactive uptake of isoprene epoxydiols (IEPOX) is a significant source of isoprene-derived secondary organic aerosols (SOA). Multiple field studies have reported that summertime isoprene-derived SOA in the Southeastern U.S. correlated strongly with sulfate mass concentration. However, previous laboratory studies have focused largely on the effect of aerosol acidity on the reactive uptake of IEPOX. In this study, we investigated the role of inorganic sulfate aerosols in SOA formation arising from the reactive uptake of trans-\u03b2-IEPOX (the predominant IEPOX isomer) at 50\u201356% RH in laboratory chamber experiments. Our measurements showed that the SOA mass concentration increased with the sulfate mass for both highly acidic and less acidic seed aerosols. This was due to the roles that sulfate played in SOA formation as a particle-phase reactant and as a contributor to aerosol surface area and volume. Higher concentrations of SOA were formed when highly acidic seed aerosols were used, consistent with previous laboratory studies. SOA mass concentration and composition were also observed to be dependent on the injection order of IEPOX and sulfate seed aerosols (i.e., injection of IEPOX first vs. Injection of seed aerosols first) in the chamber experiments. Higher SOA mass concentrations were measured in experiments where sulfate seed aerosols were introduced into the chamber first, followed by IEPOX. Volatility measurements showed that the SOA formed in the \"seed aerosols first\" experiments likely contained larger quantities of low volatility organic matter compared to SOA formed in the \"IEPOX first\" experiments. These results showed that the mass concentration and composition of IEPOX-derived SOA formed in chamber experiments can be sensitive to mixing conditions in the chamber brought about by slight differences in experimental methodology (in this case injection procedure). The sensitivity of SOA formation to the amount of seed aerosols and injection procedure used in chamber experiments indicated that caution should be exercised when extrapolating laboratory data to ambient conditions.", "doi": "10.1016/j.atmosenv.2019.116953", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2019-11-15", "volume": "217", "pages": "Art. No. 116953" }, { "id": "authors:ankvr-5v818", "collection": "authors", "collection_id": "ankvr-5v818", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190402-135702303", "type": "article", "title": "Response of the Aerodyne Aerosol Mass Spectrometer to Inorganic Sulfates and Organosulfur Compounds: Applications in Field and Laboratory Measurements", "author": [ { "family_name": "Chen", "given_name": "Yunle", "orcid": "0000-0001-9904-2638", "clpid": "Chen-Yunle" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Humphry", "given_name": "Tim", "clpid": "Humphry-T" }, { "family_name": "Hettiyadura", "given_name": "Anusha P. S.", "clpid": "Hettiyadura-A-P-S" }, { "family_name": "Ovadnevaite", "given_name": "Jurgita", "clpid": "Ovadnevaite-J" }, { "family_name": "Huang", "given_name": "Shan", "orcid": "0000-0001-5575-4510", "clpid": "Huang-Shan" }, { "family_name": "Poulain", "given_name": "Laurent", "clpid": "Poulain-L" }, { "family_name": "Schroder", "given_name": "Jason C.", "clpid": "Schroder-J-C" }, { "family_name": "Campuzano-Jost", "given_name": "Pedro", "orcid": "0000-0003-3930-010X", "clpid": "Campuzano-Jost-P" }, { "family_name": "Jimenez", "given_name": "Jose L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Herrmann", "given_name": "Hartmut", "orcid": "0000-0001-7044-2101", "clpid": "Herrmann-H" }, { "family_name": "O'Dowd", "given_name": "Colin D.", "clpid": "O'Dowd-C-D" }, { "family_name": "Stone", "given_name": "Elizabeth A.", "clpid": "Stone-E-A" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" } ], "abstract": "Organosulfur compounds are important components of secondary organic aerosols (SOA). While the Aerodyne high-resolution time-of-flight aerosol mass spectrometer (AMS) has been extensively used in aerosol studies, the response of the AMS to organosulfur compounds is not well-understood. Here, we investigated the fragmentation patterns of organosulfurs and inorganic sulfates in the AMS, developed a method to deconvolve total sulfate into components of inorganic and organic origins, and applied this method in both laboratory and field measurements. Apportionment results from laboratory isoprene photooxidation experiment showed that with inorganic sulfate seed, sulfate functionality of organic origins can contribute \u223c7% of SOA mass at peak growth. Results from measurements in the Southeastern U.S. showed that 4% of measured sulfate is from organosulfur compounds. Methanesulfonic acid was estimated for measurements in the coastal and remote marine boundary layer. We explored the application of this method to unit mass-resolution data, where it performed less well due to interferences. Our apportionment results demonstrate that organosulfur compounds could be a non-negligible source of sulfate fragments in AMS laboratory and field data sets. A reevaluation of previous AMS measurements over the full range of atmospheric conditions using this method could provide a global estimate/constraint on the contribution of organosulfur compounds.", "doi": "10.1021/acs.est.9b00884", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2019-05-07", "series_number": "9", "volume": "53", "issue": "9", "pages": "5176-5186" }, { "id": "authors:t051b-mfn20", "collection": "authors", "collection_id": "t051b-mfn20", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181126-105903700", "type": "article", "title": "Regional Similarities and NO\u2093-Related Increases in Biogenic Secondary Organic Aerosol in Summertime Southeastern United States", "author": [ { "family_name": "Liu", "given_name": "Jun", "orcid": "0000-0002-2504-3651", "clpid": "Liu-Jun" }, { "family_name": "Russell", "given_name": "Lynn M.", "orcid": "0000-0002-6108-2375", "clpid": "Russell-Lynn-M" }, { "family_name": "Ruggeri", "given_name": "Giulia", "clpid": "Ruggeri-Giulia" }, { "family_name": "Takahama", "given_name": "Satoshi", "orcid": "0000-0002-3335-8741", "clpid": "Takahama-Satoshi" }, { "family_name": "Claflin", "given_name": "Megan S.", "orcid": "0000-0003-0878-8712", "clpid": "Claflin-Megan-S" }, { "family_name": "Ziemann", "given_name": "Paul J.", "orcid": "0000-0001-7419-0044", "clpid": "Ziemann-Paul-J" }, { "family_name": "Pye", "given_name": "Havala O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-Havala-O-T" }, { "family_name": "Murphy", "given_name": "Benjamin N.", "orcid": "0000-0003-3542-5378", "clpid": "Murphy-Benjamin-N" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "McKinney", "given_name": "Karena A.", "orcid": "0000-0003-1129-1678", "clpid": "McKinney-Karena-A" }, { "family_name": "Budisulistiorini", "given_name": "Sri Hapsari", "orcid": "0000-0002-5715-9157", "clpid": "Budisulistiorini-Sri-Hapsari" }, { "family_name": "Bertram", "given_name": "Timothy H.", "orcid": "0000-0002-3026-7588", "clpid": "Bertram-Timothy-H" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Surratt", "given_name": "Jason D.", "orcid": "0000-0002-6833-1450", "clpid": "Surratt-Jason-D" } ], "abstract": "During the 2013 Southern Oxidant and Aerosol Study, Fourier transform infrared spectroscopy (FTIR) and aerosol mass spectrometer (AMS) measurements of submicron mass were collected at Look Rock (LRK), Tennessee, and Centreville (CTR), Alabama. Carbon monoxide and submicron sulfate and organic mass concentrations were 15\u201360% higher at CTR than at LRK, but their time series had moderate correlations (r ~ 0.5). However, NO\u2093 had no correlation (r = 0.08) between the two sites with nighttime\u2010to\u2010early\u2010morning peaks 3\u201310 times higher at CTR than at LRK. Organic mass (OM) sources identified by FTIR Positive Matrix Factorization (PMF) had three very similar factors at both sites: fossil fuel combustion\u2010related organic aerosols, mixed organic aerosols, and biogenic organic aerosols (BOA). The BOA spectrum from FTIR is similar (cosine similarity > 0.6) to that of lab\u2010generated particle mass from the photochemical oxidation of both isoprene and monoterpenes under high NO\u2093 conditions from chamber experiments. The BOA mass fraction was highest during the night at CTR but in the afternoon at LRK. AMS PMF resulted in two similar pairs of factors at both sites and a third nighttime NOx\u2010related factor (33% of OM) at CTR but a daytime nitrate\u2010related factor (28% of OM) at LRK. NO\u2093 was correlated with BOA and LO\u2010OOA for NO\u2093 concentrations higher than 1 ppb at both sites, producing 0.5 \u00b1 0.1 \u03bcg/m\u00b3 for CTR\u2010LO\u2010OOA and 1.0 \u00b1 0.3 \u03bcg/m\u00b3 for CTR\u2010BOA additional biogenic OM for each 1 ppb increase of NO\u2093.", "doi": "10.1029/2018jd028491", "issn": "2169-897X", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research. Atmospheres", "publication_date": "2018-09-27", "series_number": "18", "volume": "123", "issue": "18", "pages": "10620-10636" }, { "id": "authors:w0t19-tvz84", "collection": "authors", "collection_id": "w0t19-tvz84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180912-122527741", "type": "article", "title": "Experimental and model estimates of the contributions from biogenic monoterpenes and sesquiterpenes to secondary organic aerosol in the southeastern United States", "author": [ { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Pye", "given_name": "Havala O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-H-O-T" }, { "family_name": "He", "given_name": "Jia", "clpid": "He-Jia" }, { "family_name": "Chen", "given_name": "Yunle", "orcid": "0000-0001-9904-2638", "clpid": "Chen-Yunle" }, { "family_name": "Murphy", "given_name": "Benjamin N.", "clpid": "Murphy-B-N" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" } ], "abstract": "Atmospheric organic aerosol (OA) has important impacts on climate and human health but its sources remain poorly understood. Biogenic monoterpenes and sesquiterpenes are important precursors of secondary organic aerosol (SOA), but the amounts and pathways of SOA generation from these precursors are not well constrained by observations. We propose that the less-oxidized oxygenated organic aerosol (LO-OOA) factor resolved from positive matrix factorization (PMF) analysis on aerosol mass spectrometry (AMS) data can be used as a surrogate for fresh SOA from monoterpenes and sesquiterpenes in the southeastern US. This hypothesis is supported by multiple lines of evidence, including lab-in-the-field perturbation experiments, extensive ambient ground-level measurements, and state-of-the-art modeling. We performed lab-in-the-field experiments in which the ambient air is perturbed by the injection of selected monoterpenes and sesquiterpenes, and the subsequent SOA formation is investigated. PMF analysis on the perturbation experiments provides an objective link between LO-OOA and fresh SOA from monoterpenes and sesquiterpenes as well as insights into the sources of other OA factors. Further, we use an upgraded atmospheric model and show that modeled SOA concentrations from monoterpenes and sesquiterpenes could reproduce both the magnitude and diurnal variation of LO-OOA at multiple sites in the southeastern US, building confidence in our hypothesis. We estimate the annual average concentration of SOA from monoterpenes and sesquiterpenes in the southeastern US to be roughly 2\u00b5gm^(\u22123).", "doi": "10.5194/acp-18-12613-2018", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2018-08-31", "series_number": "17", "volume": "18", "issue": "17", "pages": "12613-12637" }, { "id": "authors:ya1wz-88r11", "collection": "authors", "collection_id": "ya1wz-88r11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180803-162243930", "type": "article", "title": "Parameterized Yields of Semivolatile Products from Isoprene Oxidation under Different NO_x Levels: Impacts of Chemical Aging and Wall-Loss of Reactive Gases", "author": [ { "family_name": "Xing", "given_name": "Li", "clpid": "Xing-Li" }, { "family_name": "Shrivastava", "given_name": "Manish", "orcid": "0000-0002-9053-2400", "clpid": "Shrivastava-M" }, { "family_name": "Fu", "given_name": "Tzung-May", "clpid": "Fu-Tzung-May" }, { "family_name": "Roldin", "given_name": "Pontus", "clpid": "Roldin-P" }, { "family_name": "Qian", "given_name": "Yun", "clpid": "Qian-Yun" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Shilling", "given_name": "John", "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": "Cappa", "given_name": "Christopher D.", "orcid": "0000-0002-3528-3368", "clpid": "Cappa-C-D" } ], "abstract": "We developed a parametrizable box model to empirically derive the yields of semivolatile products from VOC oxidation using chamber measurements, while explicitly accounting for the multigenerational chemical aging processes (such as the gas-phase fragmentation and functionalization and aerosol-phase oligomerization and photolysis) under different NO_x levels and the loss of particles and gases to chamber walls. Using the oxidation of isoprene as an example, we showed that the assumptions regarding the NO_x-sensitive, multigenerational aging processes of VOC oxidation products have large impacts on the parametrized product yields and SOA formation. We derived sets of semivolatile product yields from isoprene oxidation under different NO_x levels. However, we stress that these product yields must be used in conjunction with the corresponding multigenerational aging schemes in chemical transport models. As more mechanistic insights regarding SOA formation from VOC oxidation emerge, our box model can be expanded to include more explicit chemical aging processes and help ultimately bridge the gap between the process-based understanding of SOA formation from VOC oxidation and the bulk-yield parametrizations used in chemical transport models.", "doi": "10.1021/acs.est.8b00373", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2018-08-21", "series_number": "16", "volume": "52", "issue": "16", "pages": "9225-9234" }, { "id": "authors:rmq28-7n659", "collection": "authors", "collection_id": "rmq28-7n659", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180711-160223298", "type": "article", "title": "Source apportionment of organic carbon in Centreville, AL using organosulfates in organic tracer-based positive matrix factorization", "author": [ { "family_name": "Hettiyadura", "given_name": "Anusha P. S.", "orcid": "0000-0002-5757-9784", "clpid": "Hettiyadura-Anusha-P-S" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Jayarathne", "given_name": "Thilina", "clpid": "Jayarathne-Thilina" }, { "family_name": "Skog", "given_name": "Kate", "clpid": "Skog-Kate-M" }, { "family_name": "Guo", "given_name": "Hongyu", "clpid": "Guo-Hongyu" }, { "family_name": "Weber", "given_name": "Rodney J.", "orcid": "0000-0003-0765-8035", "clpid": "Weber-Rodney-J" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Keutsch", "given_name": "Frank N.", "orcid": "0000-0002-1442-6200", "clpid": "Keutsch-Frank-N" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Stone", "given_name": "Elizabeth A.", "clpid": "Stone-Elizabeth-A" } ], "abstract": "Organic tracer-based positive matrix factorization (PMF) was used to apportion fine particulate (PM_(2.5)) organic carbon (OC) to its sources in Centreville, AL, USA, a rural forested site influenced by anthropogenic emissions, during the Southern Oxidant and Aerosol Study (SOAS) in the summer of 2013. Model inputs included organosulfates, a group of organic compounds that are tracers of anthropogenically-influenced biogenic secondary organic aerosols (SOA), as well as, OC, elemental carbon, water-soluble organic carbon, and other organic tracers for primary and secondary sources measured during day and night. The organic tracer-based PMF resolved eight factors that were identified as biomass burning (11%, average contribution to PM_(2.5) OC), vehicle emissions (8%), isoprene SOC formed under low-NO_x conditions (13%), isoprene SOC formed under high-NO_x conditions (11%), SOC formed by photochemical reactions (9%), oxidatively aged biogenic SOC (6%), sulfuric acid-influenced SOC (21%, that also includes isoprene and monoterpene SOC), and monoterpene SOC formed under high-NO_x conditions (21%). These results indicate that OC in Centreville during summer is mainly secondary in origin (81%). Fossil fuel combustion is the major source of NO_x, ozone, and sulfuric acid that play a key role in SOA formation in the southeastern US. Fossil fuel was found to influence 61\u201376% of OC through vehicle emissions and SOA formation. Together with prescribed burns, which were the major type of biomass burning during this study, the OC influenced by anthropogenic activities reached 87%. The organic tracer-based PMF results were further compared with two complementary source apportionment techniques: PMF factors resolved for submicron organic aerosols measured using aerosol mass spectrometry (AMS) by Xu et al. (2015a) in Centreville during SOAS; biomass burning organic aerosols (BBOA, 11% of OC), isoprene-derived organic aerosols (isoprene-OA, 20% of OC), more-oxidized oxygenated organic aerosols (MO-OOA, 34% of OC), and less-oxidized oxygenated organic aerosols (LO-OOA, 35% of OC); and PM_(2.5) OC apportioned by chemical-mass balance model (CMB), considering the same chemical species as this study, save for organosulfates; biomass burning (5%), diesel engines (2%), gasoline smokers (3%), vegetative detritus (1%), isoprene SOC (23%) and monoterpene SOC (34%), and other (likely biogenic secondary) sources (33%). Overall, this study indicates the primary and secondary sources resolved by the organic tracer-based PMF are in good agreement with CMB and AMS-PMF results, while the organic tracer-based PMF provides additional insight to the SOC formation pathways through the inclusion of organosulfates and other organic tracers measured during day and night.", "doi": "10.1016/j.atmosenv.2018.05.007", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2018-08", "volume": "186", "pages": "74-88" }, { "id": "authors:4pyat-srh35", "collection": "authors", "collection_id": "4pyat-srh35", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180808-140939979", "type": "article", "title": "Ambient Measurements of Highly Oxidized Gas-Phase Molecules during the Southern Oxidant and Aerosol Study (SOAS) 2013", "author": [ { "family_name": "Massoli", "given_name": "Paola", "orcid": "0000-0002-6378-9366", "clpid": "Massoli-P" }, { "family_name": "Stark", "given_name": "Harald", "orcid": "0000-0002-0731-1202", "clpid": "Stark-H" }, { "family_name": "Canagaratna", "given_name": "Manjula R.", "clpid": "Canagaratna-M-R" }, { "family_name": "Krechmer", "given_name": "Jordan E.", "orcid": "0000-0003-3642-0659", "clpid": "Krechmer-J-E" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Mauldin", "given_name": "Roy L., III", "clpid": "Mauldin-R-L-III" }, { "family_name": "Yan", "given_name": "Chao", "clpid": "Yan-Chao" }, { "family_name": "Kimmel", "given_name": "Joel", "clpid": "Kimmel-J" }, { "family_name": "Misztal", "given_name": "Pawel K.", "orcid": "0000-0003-1060-1750", "clpid": "Misztal-P-K" }, { "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": "Worsnop", "given_name": "Douglas R.", "orcid": "0000-0002-8928-8017", "clpid": "Worsnop-D-R" } ], "abstract": "We present measurements of highly oxidized multifunctional molecules (HOMs) detected in the gas phase using a high-resolution time-of-flight chemical ionization mass spectrometer with nitrate reagent ion (NO_3\u2013 CIMS). The measurements took place during the 2013 Southern Oxidant and Aerosol Study (SOAS 2013) at a forest site in Alabama, where emissions were dominated by biogenic volatile organic compounds (BVOCs). Primary BVOC emissions were represented by isoprene mixed with various terpenes, making it a unique sampling location compared to previous NO_3\u2013 CIMS deployments in monoterpene-dominated environments. During SOAS 2013, the NO_3\u2013CIMS detected HOMs with oxygen-to-carbon (O:C) ratios between 0.5 and 1.4 originating from both isoprene (C_5) and monoterpenes (C_(10)) as well as hundreds of additional HOMs with carbon numbers between C_3 and C_(20). We used positive matrix factorization (PMF) to deconvolve the complex data set and extract information about classes of HOMs with similar temporal trends. This analysis revealed three isoprene-dominated and three monoterpene-dominated PMF factors. We observed significant amounts of isoprene- and monoterpene-derived organic nitrates (ONs) in most factors. The abundant presence of ONs was consistent with previous studies that have highlighted the importance of NO_x-driven chemistry at the site. One of the isoprene-dominated factors had a strong correlation with SO_2 plumes likely advected from nearby coal-fired power plants and was dominated by an isoprene-derived ON (C_5H_(10)N_2O_8). These results indicate that anthropogenic emissions played a significant role in the formation of low-volatility compounds from BVOC emissions in the region.", "doi": "10.1021/acsearthspacechem.8b00028", "issn": "2472-3452", "publisher": "American Chemical Society", "publication": "ACS Earth and Space Chemistry", "publication_date": "2018-07-19", "series_number": "7", "volume": "2", "issue": "7", "pages": "653-672" }, { "id": "authors:vfke2-qmz40", "collection": "authors", "collection_id": "vfke2-qmz40", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180620-093608936", "type": "article", "title": "Modeling biogenic secondary organic aerosol (BSOA) formation from monoterpene reactions with NO_3: A case study of the SOAS campaign using CMAQ", "author": [ { "family_name": "Qin", "given_name": "Momei", "orcid": "0000-0003-2583-6878", "clpid": "Qin-Momei" }, { "family_name": "Hu", "given_name": "Yongtao", "orcid": "0000-0002-5161-0592", "clpid": "Hu-Yongtao" }, { "family_name": "Wang", "given_name": "Xuesong", "clpid": "Wang-Xuesong" }, { "family_name": "Vasilakos", "given_name": "Petros", "clpid": "Vasilakos-Petros" }, { "family_name": "Boyd", "given_name": "Christopher M.", "clpid": "Boyd-Christopher-M" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Song", "given_name": "Yu", "clpid": "Song-Yu-ENV-ENG" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Russell", "given_name": "Armistead G.", "orcid": "0000-0003-2027-8870", "clpid": "Russell-Armistead-G" } ], "abstract": "Monoterpenes react with nitrate radicals (NO3), contributing substantially to nighttime organic aerosol (OA) production. In this study, the role of reactions of monoterpenes + NO_3 in forming biogenic secondary organic aerosol (BSOA) was examined using the Community Multiscale Air Quality (CMAQ) model, with extended emission profiles of biogenic volatile organic compounds (BVOCs), species-specific representations of BSOA production from individual monoterpenes and updated aerosol yields for monoterpene + NO_3. The model results were compared to detailed measurements from the Southern Oxidants and Aerosol Study (SOAS) at Centreville, Alabama. With the more detailed model, monoterpene-derived BSOA increased by \u223c1\u202f\u03bcg\u202fm^(\u22123)\u202fat night, accounting for one-third of observed less-oxidized oxygenated OA (LO-OOA), more closely agreeing with observations (lower error, stronger correlation). Implementation of a multigenerational oxidation approach resulted in the model capturing elevated OA episodes. With the aging model, aged semi-volatile organic compounds (ASVOCs) contributed over 60% of the monoterpene-derived BSOA, followed by SOA formation via nitrate radical chemistry, making up to 34% of that formed at night. Among individual monoterpenes, \u03b2-pinene and limonene contributed most to the monoterpene-derived BSOA from nighttime reactions.", "doi": "10.1016/j.atmosenv.2018.03.042", "issn": "1352-2310", "publisher": "Elsevier", "publication": "Atmospheric Environment", "publication_date": "2018-07", "volume": "184", "pages": "146-155" }, { "id": "authors:1xr3z-71d83", "collection": "authors", "collection_id": "1xr3z-71d83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180516-132632080", "type": "article", "title": "Organic aerosol in the summertime southeastern United States: components and their link to volatility distribution, oxidation state and hygroscopicity", "author": [ { "family_name": "Kostenidou", "given_name": "Evangelia", "orcid": "0000-0001-6574-6741", "clpid": "Kostenidou-Evangelia" }, { "family_name": "Karnezi", "given_name": "Eleni", "clpid": "Karnezi-Eleni" }, { "family_name": "Hite", "given_name": "James R., Jr.", "clpid": "Hite-James-R-Jr" }, { "family_name": "Bougiatioti", "given_name": "Aikaterini", "orcid": "0000-0001-6945-034X", "clpid": "Bougiatioti-Aikaterini" }, { "family_name": "Cerully", "given_name": "Kate", "clpid": "Cerully-Kate-M" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Nenes", "given_name": "Athanasios", "orcid": "0000-0003-3873-9970", "clpid": "Nenes-Athanasios" }, { "family_name": "Pandis", "given_name": "Spyros N.", "orcid": "0000-0001-8085-9795", "clpid": "Pandis-Spyros-N" } ], "abstract": "The volatility distribution of the organic aerosol (OA) and its sources during the Southern Oxidant and Aerosol Study (SOAS; Centreville, Alabama) was constrained using measurements from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a thermodenuder (TD). Positive matrix factorization (PMF) analysis was applied on both the ambient and thermodenuded high-resolution mass spectra, leading to four factors: more oxidized oxygenated OA (MO-OOA), less oxidized oxygenated OA (LO-OOA), an isoprene epoxydiol (IEPOX)-related factor (isoprene-OA) and biomass burning OA (BBOA). BBOA had the highest mass fraction remaining (MFR) at 100\u202f\u00b0C, followed by the isoprene-OA, and the LO-OOA. Surprisingly the MO-OOA evaporated the most in the TD. The estimated effective vaporization enthalpies assuming an evaporation coefficient equal to unity were 58\u202f\u00b1\u202f13\u202fkJ\u202fmol^(\u22121) for the LO-OOA, 89\u202f\u00b1\u202f10\u202fkJ\u202fmol^(\u22121) for the MO-OOA, 55\u202f\u00b1\u202f11\u202fkJ\u202fmol^(\u22121) for the BBOA, and 63\u202f\u00b1\u202f15\u202fkJ\u202fmol^(\u22121) for the isoprene-OA. The estimated volatility distribution of all factors covered a wide range including both semi-volatile and low-volatility components. BBOA had the lowest average volatility of all factors, even though it had the lowest O\u202f\u2009:\u2009\u202fC ratio among all factors. LO-OOA was the more volatile factor and its high MFR was due to its low enthalpy of vaporization according to the model. The isoprene-OA factor had intermediate volatility, quite higher than suggested by a few other studies. The analysis suggests that deducing the volatility of a factor only from its MFR could lead to erroneous conclusions. The oxygen content of the factors can be combined with their estimated volatility and hygroscopicity to provide a better view of their physical properties.", "doi": "10.5194/acp-18-5799-2018", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2018-04-26", "series_number": "8", "volume": "18", "issue": "8", "pages": "5799-5819" }, { "id": "authors:zxz3j-b1f50", "collection": "authors", "collection_id": "zxz3j-b1f50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180425-165416022", "type": "article", "title": "Modelling carbonaceous aerosol from residential solid fuel burning with different assumptions for emissions", "author": [ { "family_name": "Ots", "given_name": "Riinu", "clpid": "Ots-R" }, { "family_name": "Heal", "given_name": "Mathew R.", "clpid": "Heal-M-R" }, { "family_name": "Young", "given_name": "Dominique E.", "clpid": "Young-D-E" }, { "family_name": "Williams", "given_name": "Leah R.", "clpid": "Williams-L-R" }, { "family_name": "Allan", "given_name": "James D.", "clpid": "Allan-J-D" }, { "family_name": "Nemitz", "given_name": "Eiko", "clpid": "Nemitz-E" }, { "family_name": "Di Marco", "given_name": "Chiara", "clpid": "Di-Marco-C" }, { "family_name": "Detournay", "given_name": "Anais", "clpid": "Detournay-A" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Coe", "given_name": "Hugh", "clpid": "Coe-H" }, { "family_name": "Herndon", "given_name": "Scott C.", "clpid": "Herndon-S-C" }, { "family_name": "Mackenzie", "given_name": "Ian A.", "clpid": "Mackenzie-I-A" }, { "family_name": "Green", "given_name": "David C.", "clpid": "Green-D-C" }, { "family_name": "Kuenen", "given_name": "Jeroen J. P.", "clpid": "Kuenen-J-J-P" }, { "family_name": "Reis", "given_name": "Stefan", "clpid": "Reis-S" }, { "family_name": "Vieno", "given_name": "Massimo", "clpid": "Vieno-M" } ], "abstract": "Evidence is accumulating that emissions of primary particulate matter (PM) from residential wood and coal combustion in the UK may be underestimated and/or spatially misclassified. In this study, different assumptions for the spatial distribution and total emission of PM from solid fuel (wood and coal) burning in the UK were tested using an atmospheric chemical transport model. Modelled concentrations of the PM components were compared with measurements from aerosol mass spectrometers at four sites in central and Greater London (ClearfLo campaign, 2012), as well as with measurements from the UK black carbon network. \n\nThe two main alternative emission scenarios modelled were Base4x and combRedist. For Base4x, officially reported PM_(2.5) from the residential and other non-industrial combustion source sector were increased by a factor of four. For the combRedist experiment, half of the baseline emissions from this same source were redistributed by residential population density to simulate the effect of allocating some emissions to the smoke control areas (that are assumed in the national inventory to have no emissions from this source). The Base4x scenario yielded better daily and hourly correlations with measurements than the combRedist scenario for year-long comparisons of the solid fuel organic aerosol (SFOA) component at the two London sites. However, the latter scenario better captured mean measured concentrations across all four sites. A third experiment, Redist \u2013 all emissions redistributed linearly to population density, is also presented as an indicator of the maximum concentrations an assumption like this could yield. \n\nThe modelled elemental carbon (EC) concentrations derived from the combRedist experiments also compared well with seasonal average concentrations of black carbon observed across the network of UK sites. Together, the two model scenario simulations of SFOA and EC suggest both that residential solid fuel emissions may be higher than inventory estimates and that the spatial distribution of residential solid fuel burning emissions, particularly in smoke control areas, needs re-evaluation. The model results also suggest the assumed temporal profiles for residential emissions may require review to place greater emphasis on evening (including discretionary) solid fuel burning.", "doi": "10.5194/acp-18-4497-2018", "issn": "1680-7316", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2018-04-04", "series_number": "7", "volume": "18", "issue": "7", "pages": "4497-4518" }, { "id": "authors:wkvqn-dz761", "collection": "authors", "collection_id": "wkvqn-dz761", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180202-135249540", "type": "article", "title": "Coupling of organic and inorganic aerosol systems and the effect on gas-particle partitioning in the southeastern US", "author": [ { "family_name": "Pye", "given_name": "Havala O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-H-O-T" }, { "family_name": "Zuend", "given_name": "Andreas", "orcid": "0000-0003-3101-8521", "clpid": "Zuend-A" }, { "family_name": "Fry", "given_name": "Juliane L.", "clpid": "Fry-J-L" }, { "family_name": "Isaacman-VanWertz", "given_name": "Gabriel", "clpid": "Isaacman-VanWertz-G" }, { "family_name": "Capps", "given_name": "Shannon L.", "clpid": "Capps-S-L" }, { "family_name": "Appel", "given_name": "K. Wyat", "clpid": "Appel-K-W" }, { "family_name": "Foroutan", "given_name": "Hosein", "clpid": "Foroutan-H" }, { "family_name": "Xu", "given_name": "Lu", "orcid": "0000-0002-0021-9876", "clpid": "Xu-Lu" }, { "family_name": "Ng", "given_name": "Nga L.", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Goldstein", "given_name": "Allen H.", "orcid": "0000-0003-4014-4896", "clpid": "Goldstein-A-H" } ], "abstract": "Several models were used to describe the partitioning of ammonia, water, and organic compounds between the gas and particle phases for conditions in the southeastern US during summer 2013. Existing equilibrium models and frameworks were found to be sufficient, although additional improvements in terms of estimating pure-species vapor pressures are needed. Thermodynamic model predictions were consistent, to first order, with a molar ratio of ammonium to sulfate of approximately 1.6 to 1.8 (ratio of ammonium to 2\u202f\u2009\u00d7\u2009\u202fsulfate, R_(N\u22152S)\u202f\u2009\u2248\u2009\u202f0.8 to 0.9) with approximately 70\u202f% of total ammonia and ammonium (NH_x) in the particle. Southeastern Aerosol Research and Characterization Network (SEARCH) gas and aerosol and Southern Oxidant and Aerosol Study (SOAS) Monitor for AeRosols and Gases in Ambient air (MARGA) aerosol measurements were consistent with these conditions. CMAQv5.2 regional chemical transport model predictions did not reflect these conditions due to a factor of 3 overestimate of the nonvolatile cations. In addition, gas-phase ammonia was overestimated in the CMAQ model leading to an even lower fraction of total ammonia in the particle. Chemical Speciation Network (CSN) and aerosol mass spectrometer (AMS) measurements indicated less ammonium per sulfate than SEARCH and MARGA measurements and were inconsistent with thermodynamic model predictions. Organic compounds were predicted to be present to some extent in the same phase as inorganic constituents, modifying their activity and resulting in a decrease in [H^+]_(air) (H^+ in \u00b5g\u202fm^(\u22123) air), increase in ammonia partitioning to the gas phase, and increase in pH compared to complete organic vs. inorganic liquid\u2013liquid phase separation. In addition, accounting for nonideal mixing modified the pH such that a fully interactive inorganic\u2013organic system had a pH roughly 0.7 units higher than predicted using traditional methods (pH\u202f\u2009=\u2009\u202f1.5 vs. 0.7). Particle-phase interactions of organic and inorganic compounds were found to increase partitioning towards the particle phase (vs. gas phase) for highly oxygenated (O\u202f:\u202fC\u202f\u2009\u2265\u2009\u202f0.6) compounds including several isoprene-derived tracers as well as levoglucosan but decrease particle-phase partitioning for low O\u202f:\u202fC, monoterpene-derived species.", "doi": "10.5194/acp-18-357-2018", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2018-01-12", "series_number": "1", "volume": "18", "issue": "1", "pages": "357-370" }, { "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: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:sypde-epa17", "collection": "authors", "collection_id": "sypde-epa17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170407-094115503", "type": "article", "title": "Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms, and organic aerosol", "author": [ { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Brown", "given_name": "Steven S.", "clpid": "Brown-S-S" }, { "family_name": "Archibald", "given_name": "Alexander T.", "clpid": "Archibald-A-T" }, { "family_name": "Atlas", "given_name": "Elliot", "orcid": "0000-0003-3847-5346", "clpid": "Atlas-E-L" }, { "family_name": "Cohen", "given_name": "Ronald C.", "orcid": "0000-0001-6617-7691", "clpid": "Cohen-R-C" }, { "family_name": "Crowley", "given_name": "John N.", "clpid": "Crowley-J-N" }, { "family_name": "Day", "given_name": "Douglas A.", "orcid": "0000-0003-3213-4233", "clpid": "Day-D-A" }, { "family_name": "Donahue", "given_name": "Neil M.", "clpid": "Donahue-N-M" }, { "family_name": "Fry", "given_name": "Juliane L.", "clpid": "Fry-J-L" }, { "family_name": "Fuchs", "given_name": "Hendrik", "clpid": "Fuchs-H" }, { "family_name": "Griffin", "given_name": "Robert J.", "clpid": "Griffin-R-J" }, { "family_name": "Guzm\u00e1n", "given_name": "Marcelo I.", "orcid": "0000-0002-6730-7766", "clpid": "Guzm\u00e1n-M-I" }, { "family_name": "Herrmann", "given_name": "Hartmut", "orcid": "0000-0001-7044-2101", "clpid": "Herrmann-H" }, { "family_name": "Hodzic", "given_name": "Alma", "clpid": "Hodzic-A" }, { "family_name": "Iinuma", "given_name": "Yoshiteru", "clpid": "Iinuma-Yoshiteru" }, { "family_name": "Jimenez", "given_name": "Jos\u00e9 L.", "orcid": "0000-0001-6203-1847", "clpid": "Jimenez-J-L" }, { "family_name": "Kiendler-Scharr", "given_name": "Astrid", "clpid": "Kiendler-Scharr-A" }, { "family_name": "Lee", "given_name": "Ben H.", "clpid": "Lee-Ben-H" }, { "family_name": "Luecken", "given_name": "Deborah J.", "clpid": "Luecken-D-J" }, { "family_name": "Mao", "given_name": "Jingqiu", "clpid": "Mao-Jingqiu" }, { "family_name": "McLaren", "given_name": "Robert", "clpid": "McLaren-R" }, { "family_name": "Mutzel", "given_name": "Anke", "clpid": "Mutzel-A" }, { "family_name": "Osthoff", "given_name": "Hans D.", "clpid": "Osthoff-H-D" }, { "family_name": "Ouyang", "given_name": "Bin", "clpid": "Ouyang-Bin" }, { "family_name": "Picquet-Varrault", "given_name": "Benedicte", "clpid": "Picquet-Varrault-B" }, { "family_name": "Platt", "given_name": "Ulrich", "clpid": "Platt-U" }, { "family_name": "Pye", "given_name": "Havala O. T.", "orcid": "0000-0002-2014-2140", "clpid": "Pye-H-O-T" }, { "family_name": "Rudich", "given_name": "Yinon", "clpid": "Rudich-Y" }, { "family_name": "Schwantes", "given_name": "Rebecca H.", "orcid": "0000-0002-7095-3718", "clpid": "Schwantes-R-H" }, { "family_name": "Shiraiwa", "given_name": "Manabu", "orcid": "0000-0003-2532-5373", "clpid": "Shiraiwa-Manabu" }, { "family_name": "Stutz", "given_name": "Jochen", "clpid": "Stutz-J" }, { "family_name": "Thornton", "given_name": "Joel A.", "orcid": "0000-0002-5098-4867", "clpid": "Thornton-J-A" }, { "family_name": "Tilgner", "given_name": "Andreas", "clpid": "Tilgner-A" }, { "family_name": "Williams", "given_name": "Brent J.", "clpid": "Williams-B-J" }, { "family_name": "Zaveri", "given_name": "Rahul A.", "orcid": "0000-0001-9874-8807", "clpid": "Zaveri-R-A" } ], "abstract": "Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO_3) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO_3-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number of important uncertainties remain. These include an incomplete understanding of the rates, mechanisms, and organic aerosol yields for NO_3-BVOC reactions, lack of constraints on the role of heterogeneous oxidative processes associated with the NO_3 radical, the difficulty of characterizing the spatial distributions of BVOC and NO_3 within the poorly mixed nocturnal atmosphere, and the challenge of constructing appropriate boundary layer schemes and non-photochemical mechanisms for use in state-of-the-art chemical transport and chemistry\u2013climate models. \n\nThis review is the result of a workshop of the same title held at the Georgia Institute of Technology in June 2015. The first half of the review summarizes the current literature on NO_3-BVOC chemistry, with a particular focus on recent advances in instrumentation and models, and in organic nitrate and secondary organic aerosol (SOA) formation chemistry. Building on this current understanding, the second half of the review outlines impacts of NO_3-BVOC chemistry on air quality and climate, and suggests critical research needs to better constrain this interaction to improve the predictive capabilities of atmospheric models.", "doi": "10.5194/acp-17-2103-2017", "issn": "1680-7324", "publisher": "European Geosciences Union", "publication": "Atmospheric Chemistry and Physics", "publication_date": "2017-02-13", "series_number": "3", "volume": "17", "issue": "3", "pages": "2103-2162" }, { "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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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: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:rbwcs-zna49", "collection": "authors", "collection_id": "rbwcs-zna49", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170315-125424636", "type": "article", "title": "Hygroscopicity of Water-Soluble Organic Compounds in Atmospheric Aerosols: Amino Acids and Biomass Burning Derived Organic Species", "author": [ { "family_name": "Chan", "given_name": "Man Nin", "orcid": "0000-0002-2384-2695", "clpid": "Chan-Man-Nin" }, { "family_name": "Choi", "given_name": "Man Yee", "clpid": "Choi-Man-Yee" }, { "family_name": "Ng", "given_name": "Nga Lee", "orcid": "0000-0001-8460-4765", "clpid": "Ng-Nga-Lee" }, { "family_name": "Chan", "given_name": "Chak K.", "orcid": "0000-0001-9687-8771", "clpid": "Chan-Chak-Keung" } ], "abstract": "Amino acids and organic species derived from biomass burning can potentially affect the hygroscopicity and cloud condensation activities of aerosols. The hygroscopicity of seven amino acids (glycine, alanine, serine, glutamine, threonine, arginine, and asparagine) and three organic species most commonly detected in biomass burning aerosols (levoglucosan, mannosan, and galactosan) were measured using an electrodynamic balance. Crystallization was observed in the glycine, alanine, serine, glutamine, and threonine particles upon evaporation of water, while no phase transition was observed in the arginine and asparagine particles even at 5% relative humidity (RH). Water activity data from these aqueous amino acid particles, except arginine and asparagine, was used to revise the interaction parameters in UNIQUAC functional group activity coefficients to give predictions to within 15% of the measurements. Levoglucosan, mannosan, and galactosan particles did not crystallize nor did they deliquesce. They existed as highly concentrated liquid droplets at low RH, suggesting that biomass burning aerosols retain water at low RH. In addition, these particles follow a very similar pattern in hygroscopic growth. A generalized growth law (G_f = (1 \u2212 RH/100)^(-0.095)) is proposed for levoglucosan, mannosan, and galactosan particles.", "doi": "10.1021/es049584l", "issn": "0013-936X", "publisher": "American Chemical Society", "publication": "Environmental Science and Technology", "publication_date": "2005-03-15", "series_number": "6", "volume": "39", "issue": "6", "pages": "1555-1562" }, { "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" } ]