Atmospheric DMS and its oxidation products in relation to aerosol growth and formation in the Canadian Arctic

Dimethyl sulfide (DMS), a compound released by phytoplanktons, is the major source of biogenic sulfate in the remote marine atmosphere and has been hypothesized to provide a biological climate feedback that could stabilize the Earth’s temperature in the event of a warming episode (Charlson et al., 1987). Oxidation of atmospheric DMS produces methane sulfonic acid (MSA) and sulfur dioxide (SO2). Sulfur dioxide could eventually oxidize into sulfate, a major component of aerosols that could influence the earth’s radiation balance via direct and indirect aerosol effects. Thus, it is important to determine the influence of DMS on aerosol formation. Measurements of DMS, SO2, aerosol sulfate and methane sulfonate (MS-) were conducted during Fall 2007 and Fall 2008 in the Canadian Arctic as part of the joint Arctic SOLAS-Arcticnet-CFL field campaign. The amount of DMS derived SO2 and sulfate was estimated using stable isotope apportionment techniques. The results provide inputs for modelling DMS oxidation, and determining the effects of its oxidation products on aerosol formation. A box model of DMS oxidation and subsequent aerosol formation from SO2 to sulfate oxidation will be presented in this study. This aims to further understand the possible climatic effects of DMS in the Arctic.