Brominated organic species in the Arctic atmosphere

Measurements are reported of four gas-phase, brominated organic species found in the Arctic atmosphere during March and April 1983. Volume mixing ratios for CH/sub 3/Br, CH/sub 2/BrCH/sub 2/Br, CHBr/sub 3/, and CH/sub 2/Br/sub 2/ were determined by GC/MS analysis from samples taken Arctic wide, including at the geographic North Pole and during a tropopause folding event over Baffin Bay near Thule, Greenland. Methyl bromide mixing ratios were reasonably constant at 11 +- 4 pptv while the other three brominated organics showed a high degree of variability. Bromoform (2 to 46 pptv) was found to be the dominant contributor to gaseous organic bromine to the Arctic troposphere at 38 +- 10% followed by CH/sub 2/Br/sub 2/ (3 to 60 pptv) at 29 +- 6%. Both CH/sub 3/Br and CH/sub 2/BrCH/sub 2/Br (1 to 37 pptv) reservoirs contained less than 20% of the organically bound bromine. Stratospheric samples, taken during a tropopause folding event, showed mixing ratios for all four species at levels high enough to support a stratospheric total volume mixing ratio of 249 pptv Br (888 ngBr/SCM).