HR: 15:25h
AN: A53E-08    [Abstracts]
TI: Oxidative Processing of Organic Aerosol: Observations of Surface and Bulk Reactions
AU: * Smith, G D
EM: gsmith@chem.uga.edu
AF: University of Georgia, Department of Chemistry, Athens, GA 30602-2556
AU: Hearn, J D
EM: jhearn@chem.uga.edu
AF: University of Georgia, Department of Chemistry, Athens, GA 30602-2556
AB: Aerosol particles in the atmosphere may contain significant quantities of organic species and these are continuously processed through oxidative reactions with traces gas species. In particular, reactions with O$_{3}$ and OH are believed to increase the degree of oxidation of such particles, though the rates and mechanisms are not well characterized. A more detailed understanding of such issues is required to predict how these reactions affect particles' abilities to participate in further reactions, take up water, act as cloud-condensation nuclei and grow. Using our Aerosol CIMS technique we have studied the oxidative transformation of organic aerosol by species such as O3 and OH in the laboratory. By measuring the rates of change of the organic constituent we can differentiate between reactions occurring at the surface of the particle and those occurring deeper in the particle. These findings suggest that the organic molecules orient and pack differently depending on their chemical functionality. Implications for the kinetics and mechanisms of reactions of tropospheric particles with different types of morphologies will be discussed.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0320 Cloud physics and chemistry
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting