HR: 0800h
AN: A41A-0002    [Abstracts]
TI: Chamber studies of aerosol growth by glyoxal polymerization
AU: * Kroll, J H
EM: kroll@caltech.edu
AF: California Institute of Technology, Department of Chemical Engineering Mail Code 210-41, Pasadena, CA 91125 United States
AU: Ng, N L
EM: ng@caltech.edu
AF: California Institute of Technology, Department of Chemical Engineering Mail Code 210-41, Pasadena, CA 91125 United States
AU: Varutbangkul, V
EM: tomtor@caltech.edu
AF: California Institute of Technology, Department of Chemical Engineering Mail Code 210-41, Pasadena, CA 91125 United States
AU: Surratt, J D
EM: surratt@caltech.edu
AF: California Institute of Technology, Department of Chemical Engineering Mail Code 210-41, Pasadena, CA 91125 United States
AU: Gao, S
EM: sgao@caltech.edu
AF: California Institute of Technology, Department of Chemical Engineering Mail Code 210-41, Pasadena, CA 91125 United States
AU: Flagan, R C
EM: flagan@caltech.edu
AF: California Institute of Technology, Department of Chemical Engineering Mail Code 210-41, Pasadena, CA 91125 United States
AU: Seinfeld, J H
EM: seinfeld@caltech.edu
AF: California Institute of Technology, Department of Chemical Engineering Mail Code 210-41, Pasadena, CA 91125 United States
AB: Recent experiments indicate that heterogeneous reactions may contribute to the growth of secondary organic aerosol (SOA). Such reactions increase the partitioning of gas-phase organics into the particle phase, so that even relatively volatile organics may contribute to the organic fraction of atmospheric aerosols. With the aim of obtaining a framework for the inclusion of such reactions into tropospheric models, we measure particle growth by reactive uptake of simple organics, using the same approach taken previously in our laboratory for the measurement of SOA yields from the oxidation of VOC's. Seed aerosol (ammonium sulfate or ammonium sulfate/sulfuric acid) is added to 28 m$^{3}$ Teflon chambers, and after equilibration a single reactive organic is added. For these studies we focus on glyoxal (CHOCHO), a volatile but reactive compound formed in a number of atmospheric oxidation processes and believed to contribute to aerosol growth via heterogeneous reactions. Particle size is monitored using differential mobility analyzers; significant growth is always observed following glyoxal addition. Mass spectrometric measurements of sampled aerosol show an abundance of polymeric products, indicating heterogeneous reactions as the cause of aerosol growth. The influences of seed particle acidity and glyoxal concentration on particle growth and composition are examined, and compared to results from our earlier studies of SOA formation from $\alpha$-pinene ozonolysis.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting