Quantification of Anthropogenic and Pyrogenic Particulate Bromine by Aerodyne Aerosol Mass Spectrometer (AMS)

DONGWOOK KIM, Pedro Campuzano-Jost, Hongyu Guo, Benjamin A. Nault, Douglas A. Day, Melinda Schueneman, Jason Schroder, Josh DiGangi, Sally Pusede, Glenn Diskin, Donald Blake, Jack Dibb, Rainer Volkamer, Jose-Luis Jimenez, University of Colorado, Boulder

     Abstract Number: 407
     Working Group: Remote and Regional Atmospheric Aerosol

Abstract
Gas-phase bromine is important for ozone chemistry in both the troposphere and the stratosphere. Recent studies have shown that reactive bromine species could worsen air quality in urban areas by enhancing O₃, secondary organic aerosols, and nitrate formation. Particulate bromine can be a reservoir for reactive bromines in the atmosphere. However, due to a lack of measurements with high sensitivity and fast time resolution, concentration and sources of particulate bromine are currently not well-constrained in chemical transport models (CTMs). Current emission inventories used in CTMs assume that bromine is predominantly emitted from marine sources. We have retrieved new submicron particulate bromine data products from the highly customized CU-Boulder Aerodyne Aerosol Mass Spectrometer (AMS) measurements. The specificity of the AMS response to particulate bromine and its good agreement with filter-based bromide measurements is demonstrated. We present particulate bromine measurements for urban, remote, and wildfire-impacted airmasses sampled during the KORUS-AQ, TI³GER, and FIREX-AQ aircraft campaigns. We have identified sources that were previously not well recognized. The measurements suggest primary emission of particulate bromine from anthropogenic and pyrogenic sources, based on the strong correlation with combustion tracers. We find that particulate bromine could be the major form of bromine emission from US wildfires, larger than more commonly measured gas-phase species. Anthropogenic particulate bromine emissions in highly polluted Asian urban areas are identified and likely to affect urban air quality. We also discuss the contribution of anthropogenic and pyrogenic bromine sources to the global bromine budget based on the bromine-to-CO emission ratios.