Laboratory yields of hydroperoxymethyl thioformate, sulfur dioxide, carbonyl sulfide from the low NOx oxidation of dimethyl sulfide
Abstract
Dimethyl sulfide (DMS), emitted from the surface ocean, contributes to aerosol particle formation and growth in the pristine marine atmosphere. DMS is primarily oxidized by the hydroxyl radical ultimately forming methane sulfonic acid and sulfuric acid. Current models of atmospheric sulfur chemistry often assume that 0.7% of DMS emitted from the ocean is oxidized to carbonyl sulfide (OCS), an abundant trace gas that contributes to the stratospheric sulfate aerosol load. The OCS branching fraction was originally determined in a quartz-glass photoreactor conducted under high RO2 and NOx concentrations that are not representative of the marine boundary layer. Recently, a ubiquitous autoxidation product of the OH-initiated H-abstraction of DMS, hydroperoxymethyl thioformate (HPMTF), has been detected in the marine environment. The ubiquity of HPMTF and its formation under low RO2 and NOx environments leads us to reexamine DMS oxidation product yields with a focus on HPTMF oxidation as a potential pathway to OCS formation. Here, we report the yield of HPMTF, SO2 and OCS from OH-initiated oxidation of DMS conducted under conditions representative of the marine boundary layer. The HPTMF experiments were performed in a dark environmental chamber using alkene ozonolysis as the primary source of OH generation under NOx free conditions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMA082...07J
- Keywords:
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- 0317 Chemical kinetic and photochemical properties;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0345 Pollution: urban and regional;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 3339 Ocean/atmosphere interactions;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES