Probing the photochemistry of organic and secondary organic aerosols via chemical ionization mass spectrometry and cavity ringdown spectroscopy

COLL 14

Joelle Underwood1, Xiang Pan, xpan@uci.edu1, Robert Bennigsdorf, rbennigs@uci.edu2, and Sergey Nizkorodov, nizkorod@uci.edu3. (1) Department of Chemistry, University of California, 1102 Natural Sciences II, Irvine, CA 92697, (2) Chemistry Department, University of California, Irvine, 516 Rowland Hall, Irvine, 96267, (3) Department of Chemistry, University of California at Irvine, 516 Rowland Hall, Irvine, CA 92697
Recent work in our laboratory has shown that photochemistry of secondary organic aerosols (SOA) and organic thin films is changed following oxidation. Small gas phase products (e.g., formaldehyde, formic acid) from the reaction of aerosol with UV light in the actinic region were monitored with cavity ringdown spectroscopy (CRDS). This work extends the research on SOA and thin film organic aerosol proxies to larger gas phase products probed via chemical ionization mass spectrometry (CIMS). Higher mass gas phase products are monitored and assigned. Heating of the aerosols releases less volatile products into the gas phase, which are also monitored via CIMS. The ability to monitor products across a wide mass range using both CRDS and CIMS leads to a greater understanding of the photochemical processes within the aerosol. Reaction mechanisms and their implications for photochemical aging of organic aerosols will be discussed.
 

Environmental Interfaces
8:30 AM-12:00 PM, Sunday, 10 September 2006 Sir Francis Drake -- Empire Room, Oral

Division of Colloid & Surface Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006