Articles | Volume 4, issue 11/12
Atmos. Chem. Phys., 4, 2481–2497, 2004
Atmos. Chem. Phys., 4, 2481–2497, 2004

  08 Dec 2004

08 Dec 2004

Impact of reactive bromine chemistry in the troposphere

R. von Glasow2,1, R. von Kuhlmann3,4, M. G. Lawrence3, U. Platt2, and P. J. Crutzen3,2 R. von Glasow et al.
  • 1Institute for Environmental Physics, Universität Heidelberg, Germany
  • 2Center for Atmospheric Sciences, Scripps Institution of Oceanography, University of California, San Diego, USA
  • 3Atmospheric Chemistry Division, Max-Planck-Institut für Chemie, Mainz, Germany
  • 4now at: German Aerospace Center (DLR), Bonn-Oberkassel, Germany

Abstract. Recently several field campaigns and satellite observations have found strong indications for the presence of bromine oxide (BrO) in the free troposphere. Using a global atmospheric chemistry transport model we show that BrO mixing ratios of a few tenths to 2 pmol mol-1 lead to a reduction in the zonal mean O3 mixing ratio of up to 18% in widespread areas and regionally up to 40% compared to a model run without bromine chemistry. A lower limit approach for the marine boundary layer, that does not explicitly include the release of halogens from sea salt aerosol, shows that for dimethyl sulfide (DMS) the effect is even larger, with up to 60% reduction of its tropospheric column. This is accompanied by dramatic changes in DMS oxidation pathways, reducing its cooling effect on climate. In addition there are changes in the HO2:OH ratio that also affect NOx and PAN. These results imply that potentially significant strong sinks for O3 and DMS have so far been ignored in many studies of the chemistry of the troposphere.

Final-revised paper