AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Secondary Organic Aerosol Yields from Isoprene Oxidation under Low-NO Conditions
KELVIN BATES, Rebecca Schwantes, Tran Nguyen, Xuan Zhang, Yuanlong Huang, Richard Flagan, John Seinfeld, Caltech
Abstract Number: 89 Working Group: Aerosol Chemistry
Abstract The oxidation mechanisms of isoprene, in both the gas and particle phases, have been the subject of substantial research in recent years, which has elucidated the importance of a number of previously underappreciated key factors (e.g. radical lifetimes, particle acidity, etc.) in determining the secondary organic aerosol (SOA) composition and yield from isoprene. In the environmental chamber experiments detailed here, we comprehensively study SOA formation from isoprene in a low-NO atmosphere under a wide variety of conditions to determine the dependence of SOA yields on a number of these variables, including temperature, particle salt composition, relative humidity, and particle acidity. In order to avoid excessive particle phase oxidation from H2O2 photolysis in aqueous particles, we use tert-butylhydroperoxide as an oxidant source. We report SOA yields as measured by a differential mobility analyzer, SOA composition as measured by an aerosol mass spectrometer, and gas-phase oxidation products as measured by a CF3O- chemical ionization mass spectrometer, and compare all results to both previously reported isoprene SOA yields and those measured under various high-NO regimes in concurrent experiments.