AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Influence of Agricultural Emissions and the Chesapeake Bay on Urban Aerosol Chemistry in Baltimore, Maryland
MICHAEL BATTAGLIA JR., Nicholas Balasus, Kat Ball, Ruben Delgado, Christopher Hennigan, University of Maryland, Baltimore County
Abstract Number: 138 Working Group: Remote and Regional Atmospheric Aerosol
Abstract As part of the NASA OWLETS-2 field campaign, we characterized aerosol composition and gas-phase ammonia concentrations at an urban land-water transition site located in the upper Chesapeake Bay. Several intense pollution episodes were captured throughout the course of the campaign, with daytime aerosol nitrate concentrations much higher (> 5 µg m-3) than is typically observed in the eastern U.S. during summer. The ISORROPIA-II aerosol thermodynamic equilibrium model was utilized to compute aerosol pH, aerosol liquid water (ALW) and ammonia gas-particle partitioning. These predictions were paired with HYSPLIT back trajectory modeling predictions to identify source origin and transport times during these periods. The results indicate significant ammonia contributions from poultry farms on Maryland’s Eastern Shore and dairy farms in southeastern Pennsylvania. Ammonia concentrations showed a distinct diurnal profile but were consistently high throughout the study (mean ~4 µg m-3), suggesting the importance of emissions from both agricultural regions. The HU-Beltsville CASTNET site was used as inland site for comparison of the observed trends. These results are likely to have broad implications on aerosol chemistry in regions with diverse and meteorologically-driven changes in source influences, as well as for pollution control strategies in coastal urban areas.