THE TROPOSPHERIC OXIDATION OF DIMETHYL SULFIDE - A NEW SOURCE OF CARBONYL SULFIDE

In laboratory investigations of the gas-phase OH initiated oxidation o f dimethyl sulfide (DMS: CH3SCH3) at room temperature the formation of SO2, dimethyl sulfoxide (DMSO: CH3SOCH3), and OCS have been observed. A yield of 0.7 +/- 0.2 % S was measured for OCS. These new results re present a hitherto unknown and quite considerable in situ atmospheric source of OCS. Based on the global DMS source strength as given in the literature and provided that the results from the laboratory study ar e valid under atmospheric conditions we estimate a contribution in the range 0.10 to 0.28 Tg (OCS) yr-1 from the gas-phase atmospheric photo oxidation of DMS to the global OCS budget.