The dimethyl sulfide reaction with atomic chlorine and its implications for the budget of methyl chloride

Abstract

DMS is produced in large quantities by natural oceanic processes. Its chemistry and emissions have been postulated to play a role in the radiative balance of the atmosphere. While its reactions with OH and NO3 radicals are well known, the reaction with chlorine atoms in the marine boundary layer has also been suggested recently. If this produces CH3Cl, it would contribute to the global budget of this naturally occuring halocarbon. Experiments were carried out to measure the yield of CH3Cl in the Cl+DMS reaction. CH3Cl was indeed formed in this reaction in laboratory experiments at 1 atm. and 298 K, with a small yield of (1.34±0.07) × 10−3. This yield is sufficiently small that the contribution to the global CH3Cl budget is estimated to be ≤2% and it is unlikely to be responsible for the anomalously high CH3Cl concentrations measured recently over the Labrador Sea.