New Parameterizations for Understanding Secondary Organic Aerosol Formation from Isoprene under Anthropogenic Influence

Monday, 14 December 2015: 11:00
3004 (Moscone West)
Lindsay Yee1, Gabriel A Isaacman-VanWertz1, Rebecca Ann Wernis1, Nathan M Kreisberg2, Suzane S de Sá3, Scot T Martin4, Lizabeth Alexander5, Brett B Palm6, Weiwei Hu6, Pedro Campuzano Jost7, Douglas A Day8, Jose L Jimenez9, Paulo Artaxo10, Antonio O Manzi11, Rodrigo Augusto Ferreira de Souza12, Susanne V Hering2, Allen H Goldstein1 and The GoAmazon Team, (1)University of California Berkeley, Berkeley, CA, United States, (2)Aerosol Dynamics Inc., Berkeley, CA, United States, (3)Harvard University, School of Engineering and Applied Sciences, Cambridge, MA, United States, (4)Harvard University, Cambridge, MA, United States, (5)Pacific Northwest National Laboratory, Environmental Molecular Sciences Laboratory, Richland, WA, United States, (6)University of Colorado at Boulder, Boulder, CO, United States, (7)University of Colorado Boulder, Boulder, CO, United States, (8)CIRES, Boulder, CO, United States, (9)University of Colorado at Boulder, Dept. of Chemistry and Biochemistry, Boulder, CO, United States, (10)USP University of Sao Paulo, São Paulo, Brazil, (11)National Institute for Amazon Research (INPA), Manaus, AM, Brazil, (12)Organization Not Listed, Washington, DC, United States
Several studies have focused on elucidating the chemical mechanisms responsible for isoprene photochemistry leading to secondary organic aerosol (SOA) formation. While isoprene oxidation is the source of a large fraction of the organic mass in biogenic SOA formation over forested regions, few ambient measurements of the isoprene-derived products exist at sufficient time-resolution to fully parameterize the dynamic reactions in the particle phase. We deployed the Semi-Volatile Thermal desorption Aerosol Gas chromatograph (SV-TAG) during the Southern Oxidant and Aerosol Study (SOAS) in the Southeastern U.S. in summer 2013 and during the wet and dry seasons of the Green Ocean Amazon experiment (GoAmazon 2014/5) in central Amazonia. Both field campaigns were located in isoprene-rich forested regions under the varying influence of anthropogenic pollution. We measured oxidation products at the molecular level, including 2-methyl tetrols, C5-alkene triols, and 2-methyl glyceric acid in the gas and particle phases at hourly time resolution. Using supporting measurements of particle composition (e.g. sulfate) and modelled liquid water content, we compare the relative contribution of these tracers to the particle-phase across these regions and explore possible parameterizations that can be used for modeling SOA formation from isoprene.