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Aerosol from Organic Nitrogen in the Southeast United States
Citation:
Pye, H., D. Luecken, K. Baker, J. Bash, Bill Hutzell, D. Schwede, L. Xu, N. Ng, B. Ayres, K. Baumann, W. Carter, E. Edgerton, J. Fry, AND P. Shepson. Aerosol from Organic Nitrogen in the Southeast United States. CMAS Conference, Chapel Hill, NC, October 05 - 07, 2015.
Impact/Purpose:
The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) conducts research in support of EPA’s mission to protect human health and the environment. AMAD’s research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the Nation’s air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
Description:
Biogenic volatile organic compounds (BVOCs) contribute significantly to organic aerosol in the southeastern United States. During the Southern Oxidant and Aerosol Study (SOAS), a portion of ambient organic aerosol was attributed to isoprene oxidation and organic nitrogen from BVOC reaction with nitrate radicals. In this work, we compare observed values of biogenic aerosol with CMAQ v5.1 and updated model representations. We show that monoterpenes are predicted to account for the majority of particle-phase organic nitrates in Centreville, AL during SOAS, and a new mechanistic representation of particle-phase organic nitrates produce more organic aerosol than standard CMAQ v5.1. Hydrolysis of particle-phase organic nitrates decreases gas-phase alkyl nitrates, increases modeled HNO3 and organic aerosol, but does not substantially increase particle nitrogen.
