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Sources, Properties, Aging, and Anthropogenic Influences on OA and SOA over the Southeast US and the Amazon duing SOAS, DC3, SEAC4RS, and GoAmazon
Citation:
Jimenez, J., W. Hu, P. Campuzano, S. Thompson, J. Krechmer, B. Palm, Z. Peng, H. Stark, D. Day, A. Ortega, R. Mauldin, F. Lopez-Hilfiker, C. Mohr, J. Thornton, A. Goldstein, G. Isaacman, L. Yee, A. Khan, R. Holzinger, M. Canagaratna, P. Massoli, J. Kimmel, J. Nowak, J. Jayne, D. Worsnop, J. Crounse, J. St Clair, P. Wennberg, T. Nguyen, M. Coggon, J. Seinfeld, S. Simoes de Sa, S. Martin, P. Kim, D. Jacob, W. Brune, J. Offenberg, T. Mikovini, A. Wisthaler, J. Liao, K. Froyd, D. Murphy, I. Pollack, T. Ryerson, J. Lee-Taylor, A. Hodzic, S. Madronich, R. Seco, J. Park, J. Brito, F. Wurm, P. Artaxo, R. Souza, A. Manzi, AND A. Guenther. Sources, Properties, Aging, and Anthropogenic Influences on OA and SOA over the Southeast US and the Amazon duing SOAS, DC3, SEAC4RS, and GoAmazon. American Association for Aerosol Research Annual Meeting, Orlando, FL, October 20 - 24, 2014.
Impact/Purpose:
The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
The SE US and the Amazon have large sources of biogenic VOCs, varying anthropogenic pollution impacts, and often poor organic aerosol (OA) model performance. Recent results on the sources, properties, aging, and impact of anthropogenic pollution on OA and secondary OA (SOA) over these regions will be presented. SOA from IEPOX accounts for 14-17% of the OA on average over the SE US. Higher IEPOX-SOA correlates with air masses of high isoprene, IEPOX, sulfate, acidity, and lower NO. The IEPOX organosulfate accounts for~20% of IEPOX-SOA over the SE US. The AMS ion CsH6GO+ is shown to be a good marker of IEPOX-SOA, while total m/z 82 (as in ACSM) suffers larger interferences. The sinksof IEPOX-SOA via both OH oxidation and evaporation are slow. The low-volatility of IEPOX-SOA contrastswith the small semivolatile molecules that have so far been identified as its components, suggesting the importance of oligomerization. Urban SOA is estimated to account for 25% of the OA in the SE US using two methods based on the GEOS-Chem model and the measured 14C, using recent results that urban SOA is 30% non-fossil, mainly due to cooking emissions.