Abundance and Gas-Particle Partitioning of Inorganic Bromine in the Remote Atmosphere

DONGWOOK KIM, Pedro Campuzano-Jost, Benjamin A. Nault, Jason Schroder, Douglas A. Day, Michael Cubison, Jack Dibb, Patrick Veres, J. Andrew Neuman, Jin Liao, Greg Huey, Yuk Chun Chan, Lyatt Jaegle, Alan Fried, Thomas Ryerson, Andrew Weinheimer, Glenn Diskin, Eric Apel, Rebecca Hornbrook, Alan Hills, Donald Blake, Rainer M. Volkamer, Jose Jimenez, CIRES & University of Colorado Boulder

     Abstract Number: 510
     Working Group: Aerosol Chemistry

Abstract
Halogens play important roles in the ozone chemistry in both the stratosphere and troposphere. Bromine can also affect the deposition rate of mercury from the atmosphere. In the particulate phase, halogens can react directly with ozone and could serve as reservoirs for gas-phase reactive halogen species. However, quantitative measurements of particulate halogens on a global scale over remote areas are rare, especially in the upper troposphere and the lower stratosphere. Here we report particulate bromine measurements with the customized University of Colorado Aerodyne high-resolution aerosol mass spectrometer (CU-HR-AMS) together with gas-phase inorganic bromine from multiple aircraft campaigns, including the NASA ATom and ARCTAS missions. We also discuss 1) the AMS response to particulate halogens and details of the quantification method, 2) the total inorganic bromine gas budget estimated by a box model, 3) potential sources of bromine in the free troposphere and polar regions and their implications for ozone chemistry, and 4) the evaluation of bromine from the current GEOS-Chem model. Preliminary results suggest that 1) most particle-phase bromine in the remote atmosphere is likely in bromide form. 2) Particle phase fraction can reach up to ~50 % in the upper free troposphere. 3) Biomass burning and anthropogenic emissions could be important sources of atmospheric bromine. 4) GEOS-Chem needs a better representation of particulate bromine. These results will provide valuable constraints on the bromine budget and chemistry in chemical transport models.