A METHOD FOR SAMPLING DIMETHYLSULFIDE IN POLLUTED AND REMOTE MARINE ATMOSPHERES

Methods have been developed for the measurement of atmospheric dimethy lsulfide in both polluted and clean marine environments, avoiding samp ling losses due to reactions with atmospheric oxidants. Preconcentrati on of DMS on Molecular Sieve 5A was followed by analysis using gas chr omatography with flame photometric detection. Prolonged contact of pol luted air samples with a potassium iodide-based solution resulted in t otal oxidant destruction. Dimethylsulfide was measured over the Atlant ic Ocean during a cruise between the U.K. and the Antarctic, between O ctober 1992 and January 1993. In equatorial regions (30-degrees-N-30-d egrees-S) the atmospheric DMS concentration ranged from 5 to 90 ng m-3 with an average of 30 ng m-3 . In the polar waters and regions-south of the Falkland Islands concentrations from 5 to 1050 ng m-3 were obse rved with a mean concentration of 120 ng m-3.