SOURCES AND SINKS OF H2SO4 IN THE REMOTE ANTARCTIC MARINE BOUNDARY-LAYER

A steady state analysis of H2SO4 sources and sinks in the Antarctic ma rine boundary layer was performed using measurements from project SCAT E, Sulfur Chemistry in the Antarctic Troposphere Experiment. The calcu lations show that the SO2 levels needed to account for the observed ga s phase H2SO4 ranged from about 17 to 300 parts per trillion by volume (pptv) with an average SO2 concentration of 100 pptv, far more than p revious measurements of SO2 in this region which range between 7 and 1 7 pptv [Berresheim, 1987; Pszenny et al., 1989; P. Quinn, personal com munication, 1996]. Boundary layer oxidation of DMS via an SO2 intermed iate was found to be an insufficient source of H2SO4 in this region. L ikely alternative sources of H2SO4 include oxidation of boundary layer DMDS and vertical entrainment of air from higher altitudes.