EC-02. Sulfate and carbonyl sulfide production from aqueous processing of dimethyl sulfide oxidation products

Abstract
The oxidation products of dimethyl sulfide (DMS) contribute to the production and growth of cloud condensation nuclei (CCN) in the marine boundary layer. Laboratory and field measurements have demonstrated that DMS is oxidized by OH radicals to the stable intermediate hydroperoxymethyl thioformate (HPMTF), which is both globally ubiquitous and efficiently lost to multiphase processes in the marine atmosphere. Currently, the condensed phase chemistry included in chemical transport models relies on the assumption that HPMTF is irreversibly lost to atmospheric surfaces arresting carbonyl sulfide (OCS) production and forming sulfate at unit yield. At present, there are no experimental measurements of the connection between sulfate and carbonyl sulfide production from the aqueous processing of HPMTF. Using a custom-built bubbler apparatus combined with chemical ionization mass spectrometry (CIMS), a OCS analyzer and ion chromatography, we report the yield of OCS and sulfate. While we did not directly observe the condensed-phase mechanisms of HPMTF in this experiment, the relative yields of OCS and sulfate provide mechanistic insight on the hydrolysis mechanism of HPMTF.