Brominated organic species in the Arctic atmosphere

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Abstract
Measurements are reported of four gas‐phase, brominated organic species found in the Arctic atmosphere during March and April 1983. Volume mixing ratios for CH3Br, CH2BrCH2Br, CHBr3, and CH2Br2 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 CH2Br2 (3 to 60 pptv) at 29 ± 6%. Both CH3Br and CH2BrCH2Br (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).