Observation of DMSO and CH3S(O)OH from the gas phase reaction between DMS and OH

Products and mechanisms have been investigated for the reactions between dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) and the hydroxyl radical (OH) in the presence of NO_x. All of the experiments were performed in a 480 L reaction chamber, applying Fourier transform infrared spectroscopy (FT-IR) and ion chromatography as the analytical techniques.In addition to the sulfur containing products that are known to be produced from the gas phase reaction between DMS and OH (SO₂, dimethylsulfone, methylsulfonyl peroxynitrate, methanesulfonic acid, H₂SO₄), DMSO and methanesulfinic acid (CH₃S(O)OH) were also observed as products. Only SO₂, DMSO₂ and methylsulfonyl peroxynitrate were found as sulfur containing products in the reaction between DMSO and OH. Based on these new results we propose a mechanism for the atmospheric oxidation of DMS and DMSO by OH radical.