AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Investigations of the Mixing of Sulfate Aerosols and Isoprene Epoxydiols in Secondary Organic Aerosol Formation Chamber Experiments
THEODORA NAH, Lu Xu, Kymberlee Osborne-Benthaus, S. Meghan White, Stefan France, Nga Lee Ng, City University of Hong Kong
Abstract Number: 843 Working Group: Aerosol Chemistry
Abstract The impacts of inorganic sulfate aerosol mass and mixing conditions on SOA formed from the reactive uptake of trans-β-IEPOX under humid conditions were investigated in this laboratory chamber study. For both highly acidic and less acidic seed aerosols, SOA mass concentrations increased with sulfate mass. Higher SOA mass concentrations were measured in experiments where highly acidic seed aerosols were used. In addition, the SOA mass concentration and composition depended on how IEPOX and sulfate seed aerosols were mixed in the chamber, which was investigated by varying the injection order of sulfate seed aerosols and IEPOX (i.e., injection of IEPOX first vs. injection of seed aerosols first). Higher SOA mass concentrations were measured in experiments where sulfate seed aerosols were introduced into the chamber before IEPOX. This indicated that SOA formed in “seed aerosols first” experiments contained larger quantities of low volatility organic compounds compared to SOA formed in the “IEPOX first” experiments. Overall, these results indicated that IEPOX-derived SOA formed in chamber experiments will depend on the amount of sulfate seed aerosols used and mixing conditions in the chamber.