AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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On the Role of NOx in Biomass Burning Plumes: A Box Model Perspective
QIAOYUN PENG, Brett Palm, Sam Hall, Eric Apel, Rebecca Hornbrook, Alex Jarnot, Nicola Blake, Frank Flocke, Emily Fischer, Joel A. Thornton, University of Washington, Seattle, WA
Abstract Number: 755 Working Group: Biomass Combustion: Emissions, Chemistry, Air Quality, Climate, and Human Health
Abstract With large primary emissions of nitrogen-containing compounds, important nitrogen chemistry takes place in thick wildfire plumes that impacts the formation of secondary organic and inorganic aerosol. The importance and effects of reactive nitrogen chemistry on biomass burning aerosol evolution were examined using airborne measurements over western U.S. during the Wildfire Experiment for Cloud chemistry, Aerosol absorption and Nitrogen (WE-CAN) Campaign in summer 2018. We employed in situ fresh smoke measurements together with a 0-D photochemical box model to evaluate the extent of NO3–VOC chemistry compared to OH-initiated oxidation in wildfire plume evolution, as well as SOA formation potential and contribution to inorganic particulate nitrate. With abundant sources of NO2, O3, VOCs and sufficiently dark plume center, daytime NO3-initiated oxidation becomes important due to high NO3 production rates in young fire smoke, which accelerates the formation of SOA. Our results suggest that neglecting or omitting NO3 chemistry in photochemical simulations of thick smoke plumes may lead to significant underestimation in the concentration of both organic and inorganic nitrates, which have been observed to form a substantial portion of atmospheric aerosol.