EC-14. Quantification of anthropogenic and pyrogenic particulate bromine by Aerodyne aerosol mass spectrometer (AMS)

Abstract
Gas-phase bromine chemistry is important for ozone chemistry in both the troposphere and stratosphere over the past few decades. Recent studies have shown that reactive bromine species could worsen air quality in urban areas by enhancing O3, SOA, and nitrate formation. Particulate bromine can be a reservoir for reactive halogens in the atmosphere. However, due to a lack of measurements with high sensitivity and fast time resolution, its concentration and sources have not been well-constrained in chemical transport models. Current emission inventories used in models assume that bromine is predominantly emitted from marine sources. We have identified anthropogenic and pyrogenic sources that are previously not well recognized. We present particulate bromine measurements over urban, remote, and wildfire conditions during the KORUS-AQ, FIREX-AQ, and TI3GER aircraft campaigns. We have retrieved new submicron particulate bromine data products from aerosol mass spectrometry (AMS). The specificity of the AMS response to particulate bromine and its good agreement with other bromide measurements is demonstrated. The measurements suggest primary emission of particulate bromine from anthropogenic and pyrogenic sources, based on the strong correlation with combustion tracers. We found that particulate bromine could be the major form of bromine emission from US wildfires. Also, we discuss the contribution of anthropogenic and pyrogenic bromine sources to the global bromine budget based on the bromine-to-CO emission ratio.