SO2 OXIDATION ON SALT PARTICLES - PROCESS ES OF HETEROGENEOUS SULFATEFORMATION IN MARINE ATMOSPHERE

In aerosol systems the various chemical reactions leading to atmospher ic trace gas removal are connected partially with each other but are a lso partially combined with gas phase reactions. Additionally these ch emical conversions are superimposed by mixing and rarefactive processe s. The importance of individual reaction pathways, i. e. the contribut ion of the heterogeneous SO2 oxidation to atmospheric sulfate formatio n, can therefore only be studied with the aid of controlled laboratory experiments. The investigations carried out on the sulfate formation in sea salt and in NaCl aerosols represent a contribution to clarify t he significance of the heterogeneous SO2 oxidation in a marine atmosph ere. The oxidative conversion of SO2 in sea salt aerosols depends on r eaction parameters such as particle concentration, relative humidity, SO2 gas concentration and the presence of other trace gases. For this gas removal process reaction rates were obtained which can exceed the reaction rates of the homogeneous gas phase oxidation as well as those of the oxidation in cloud or fog droplets.