10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Oxidation of Polycyclic Aromatic Hydrocarbons in Secondary Organic Aerosol Particles
AMBER KRAMER, Kaitlyn J. Suski, Alla Zelenyuk, Staci L. Simonich, David Bell, Oregon State University
Abstract Number: 955 Working Group: Aerosol Chemistry
Abstract Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants which are transported globally on fine particulate matter (PM2.5). Secondary organic aerosols (SOA) are formed through atmospheric reactions of natural biogenic volatile organic compounds, making up a large fraction of PM2.5. Global SOA particle mass has been shown to be increasing due to anthropogenic activity, and have been shown to trap and transport PAHs. SOA particles consist of highly oxidized organic compounds as well as reactive oxygen species. These reactive oxygen species have the potential to react with other organic components such as PAHs. In controlled laboratory experiments, ozone reacted α-pinene SOA was produced with four individual gas phase PAHs present: phenanthrene, dibenzothiophene, pyrene, and benz(a)anthracene. Particles were monitored for changes in physical characteristics, exposed to ozone, and observed over time. Filters of SOA particles were collected and analyzed using gas chromatography mass spectrometry for PAHs and PAH oxidation products. Oxidation products of the experimental PAHs were observed to be in equal concentrations with the parent compound put into the system. The PAH chemistry was observed to change when particles were exposed to 6-10 ppm ozone, using a potential aerosol mass (PAM) oxidation chamber, as well as when particles were analyzed after sitting undisturbed in the reaction chamber for two hours. Data indicates SOA particles are dynamic with continuing chemical reactions occurring.