HR: 0800h
AN: A11A-0849    [Abstracts]
TI: Secondary Organic Aerosol Formation from the Photooxidation of Complex Hydrocarbon Mixtures: Composition, effect of SO2, and Relevance to Ambient Aerosol
AU: * Surratt, J D
EM: surratt@caltech.edu
AF: Caltech, 1200 E. California Blvd. M/C 210-41, Pasadena, CA 91125 United States
AU: Gao, S
EM: sgao@caltech.edu
AF: Caltech, 1200 E. California Blvd. M/C 210-41, Pasadena, CA 91125 United States
AU: Knipping, E
EM: eknippin@epri.com
AF: Electric Power Research Institute, 3420 Hillview Ave, Palo Alto, CA 94304 United States
AU: Edgerton, E
EM: ericedge@gte.net
AF: Atmospheric Research and Analysis, Inc., 410 Midenhall Way, Cary, NC 27513 United States
AU: Shahgoli, M
EM: monas@caltech.edu
AF: Caltech, 1200 E. California Blvd. M/C 210-41, Pasadena, CA 91125 United States
AU: Seinfeld, J H
EM: seinfeld@caltech.edu
AF: Caltech, 1200 E. California Blvd. M/C 210-41, Pasadena, CA 91125 United States
AU: Edney, E
EM: edney.edward@epamail.epa.gov
AF: National Exposure Laboratory, US EPA, 109 T.W. Alexander Drive, Durham, NC 27711 United States
AU: Kleindiesnt, T
EM: kleindienst.tad@epamail.epa.gov
AF: National Exposure Laboratory, US EPA, 109 T.W. Alexander Drive, Durham, NC 27711 United States
AU: Lewandowski, M
EM: lewandowski.michael@epamail.epa.gov
AF: National Exposure Laboratory, US EPA, 109 T.W. Alexander Drive, Durham, NC 27711 United States
AU: Offenberg, J
EM: offenberg.john@epamail.epa.gov
AF: National Exposure Laboratory, US EPA, 109 T.W. Alexander Drive, Durham, NC 27711 United States
AU: Jaoui, M
EM: jaoui.mohammed@epamail.epa.gov
AF: Alion Science and Technology, P.O. Box 12313, Research Triangle Pa, NC 27709 United States
AB: Secondary organic aerosol (SOA) formation from single hydrocarbon precursors is commonly studied in smog chamber experiments to obtain SOA yield and organic composition data. However, very few complex air mixture experiments have been conducted to simulate possible conditions in ambient atmospheres. A six-phase experiment involving various combinations of alpha-pinene, toluene, isoprene, and SO2 were irradiated in the EPA's dynamic smog chamber at the National Exposure Research Laboratory in Raleigh, NC. Glass fiber filters and impactor plates were collected for each phase of the experiment to identify and quantify the nature of the SOA composition. The following suite of analytical techniques analyzed the resultant polar organic compounds and the high molecular weight species: liquid chromatography-electrospray ionization (ESI)-mass spectrometry, gas chromatography-mass spectrometry, ESI-ion trap mass spectrometry, matrix assisted laser desorption (MALDI)-time of flight mass spectrometry, and high-resolution mass spectrometry. When SO2 is present in the chamber, increases in the gravimetric aerosol mass concentration and in the abundance of polar organic compounds are observed, likely suggesting an acid catalysis effect stemming from the conversion of SO2 to H2SO4 that condenses onto aerosol formed. The addition of isoprene to a alpha-pinene/toluene mixture is found to lower the amount of aerosol produced and is also found to lower the abundance of organic compounds identified by the various analytical techniques. Lastly, many of the polar organic compounds identified and quantified here are also seen in the Southeastern Aerosol Research and Characterization (SEARCH) network during the summer of 2004. In particular, a sulfur and nitrogen containing organic species (MW = 295 gmol) is found to be the most abundant polar organic species identified in this field study (~28 % on average of the total identified organic mass). This species is also detected in the chamber experiment only when alpha-pinene and SO2 are both present in the chamber, suggesting that this abundant species is likely formed from monoterpene photooxidation. High-resolution mass spectrometry suggests the molecular formula for this species is C10H16NO7S.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005