Dimethyl Sulfide and Dimethyl Sulfoxide and Their Oxidation in the Atmosphere

Abstract

Sulfur plays an important role in both the tropospheric and stratospheric budget of atmospheric gases and investigations of the atmospheric sulfur cycle has been a subject of intense scientific interest for many years. In industrialized regions such as the USA and most of Europe, anthropogenic sulfur emissions (mainly comprised of SO2) exceed natural emissions by about one order of magnitude. On a global scale biogenic emissions become important with contributions to the sulfur budget of 15-20% and 50-60% in the Northern and Southern Hemispheres, respectively. On a global scale biogenic emissions become important with contributions to the sulfur budget of 15-20% and 50-60% in the Northern and Southern Hemispheres, respectively. Of the biogenic contribution one compound, namely dimethyl sulfide (DMS: CH3SCH3), constitutes approximately 50% of the emissions. The present review concentrates to a large extent on reviewing the new data associated with DMS and DMSO. Further, in the interest of brevity the approach taken in writing the review on the kinetics and mechanistic aspects of the oxidation of the sulfur compounds has been to write a brief synopsis of the situation prior to 1997 and then to update this knowledge by inclusion of the information from recent publications followed by an appraisal of the new situation.