HR: 1340h
AN: A33B-1183    [Abstracts]
TI: Volatility of Primary and Secondary Organic Aerosols in the Field Contradicts Current Model Representations
AU: * Huffman, J
EM: alex.huffman@colorado.edu
AF: University of Colorado at Boulder, Department of Chemistry and Biochemistry, and Cooperative Institute for Research in the Environmental Sciences (CIRES) UCB 216, Room 318, Boulder, CO 80309-0216, United States
AU: Aiken, A C
EM: allison.aiken@colorado.edu
AF: University of Colorado at Boulder, Department of Chemistry and Biochemistry, and Cooperative Institute for Research in the Environmental Sciences (CIRES) UCB 216, Room 318, Boulder, CO 80309-0216, United States
AU: Docherty, K S
EM: kenneth.docherty@colorado.edu
AF: University of Colorado at Boulder, Department of Chemistry and Biochemistry, and Cooperative Institute for Research in the Environmental Sciences (CIRES) UCB 216, Room 318, Boulder, CO 80309-0216, United States
AU: Ulbrich, I M
EM: ingrid.ulbrich@colorado.edu
AF: University of Colorado at Boulder, Department of Chemistry and Biochemistry, and Cooperative Institute for Research in the Environmental Sciences (CIRES) UCB 216, Room 318, Boulder, CO 80309-0216, United States
AU: DeCarlo, P F
EM: peter.decarlo@colorado.edu
AF: University of Colorado at Boulder, Department of Chemistry and Biochemistry, and Cooperative Institute for Research in the Environmental Sciences (CIRES) UCB 216, Room 318, Boulder, CO 80309-0216, United States
AU: Jayne, J T
EM: jayne@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Rd., Billerica, MA 01821-3976, United States
AU: Onasch, T B
EM: onasch@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Rd., Billerica, MA 01821-3976, United States
AU: Trimborn, A
EM: trimborn@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Rd., Billerica, MA 01821-3976, United States
AU: Worsnop, D R
EM: worsnop@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Rd., Billerica, MA 01821-3976, United States
AU: Ziemann, P J
EM: pziemann@ucrac1.ucr.edu
AF: University of California, Riverside, Air Pollution Research Center, Riverside, CA 92521, United States
AU: Jimenez, J L
EM: jose.jimenez@colorado.edu
AF: University of Colorado at Boulder, Department of Chemistry and Biochemistry, and Cooperative Institute for Research in the Environmental Sciences (CIRES) UCB 216, Room 318, Boulder, CO 80309-0216, United States
AB: A novel combination of a temperature-stepping thermodenuder (TD) in front of an Aerosol Mass Spectrometer (AMS) has allowed rapid quantification of chemically-resolved volatility in the field for the first time. The TD consists of a tube heated to a uniform temperature, followed by a carbon charcoal denuder to adsorb volatilized gases, leaving a core of less volatile material for detection by the AMS. The TD temperature can be changed quickly (1 to 10 min) to allow rapid measurements of volatility spectra. The volatility of organic aerosols (OA) influences the concentration and lifetime of OA, secondary OA (SOA) formation, and OA measurements. The TD- AMS system was used to characterize urban OA, primary OA (POA) from biomass burning, and chamber- generated SOA. Almost all atmospheric models represent POA as non-volatile and SOA as semi-volatile. Our results indicate nearly the opposite: urban POA is semi-volatile, while urban SOA is much less volatile. Biomass burning POA exhibited a wide range of volatilities, but was often similar in volatility to urban OA. Chamber- generated SOA was significantly more volatile than urban OOA, challenging the extrapolation of laboratory volatility measurements to the atmosphere. Our results indicate that the representation of OA volatility in most current models is highly inaccurate and should be revised.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting