Dimethyl sulfide oxidation in the polluted marine boundary layer : a zero dimensional model study

A comprehensive DMS oxidation reaction mechanism was added to a chemical box model (Model of Chemistry Considering Aerosols - MOCCA) to investigate how atmospheric sulfate levels are affected by pollution in the marine boundary layer. The interaction of a remote air mass with a polluted coastal air mass containing elevated NOx, alkane, and alkene levels was simulated for a mid-latitude region of the Northern Hemisphere. Model runs from different settings were compared with respect to species concentrations, branching ratios, and product yields. Results showed moderate decreases in gas phase DMS, DMSO, DMSO2, and MSA concentrations, and increases of approximately 7% and 100% for SO2 and H2SO4 , respectively. A sensitivity analysis was completed to determine how variations in temperature, DMS emission, NO emission, aerosol characterization, accommodation coefficients, PAN reactions, and a background SO2 emission influence the results