Secondary organic aerosol (SOA) generated from the high-NOx photooxidation of isoprene was dissolved in water and irradiated with ? > 290 nm light to simulate direct photolytic processing of organics in atmospheric water droplets. High-resolution mass spectrometry was used to characterize the composition at four time intervals (0, 1, 2, and 4 h). Photolysis resulted in the decomposition of high molecular weight (MW) oligomers, reducing the average length of organics by 2 carbon units. Approximately 65% by count of SOA molecules decomposed during photolysis, accompanied by the formation of new products. An average of 30 % of the organic mass was modified after 4 h of direct photolysis. In contrast, only a small fraction of the mass (
Revised: July 26, 2012 |
Published: May 17, 2012
Citation
Nguyen T.B., A. Laskin, J. Laskin, and S. Nizkorodov. 2012.Direct Aqueous Photochemistry of Isoprene High-NOx Secondary Organic Aerosol.Physical Chemistry Chemical Physics. PCCP 14, no. 27:9702-9714.PNNL-SA-89184.doi:10.1039/c2cp40944e