Methanethiol abundance and oxidation in a polluted marine atmosphere

Wohl, Charel, Forster, Grant L., Edwards, Pete M., Suntharalingam, Parvadha and Oram, David E. (2025) Methanethiol abundance and oxidation in a polluted marine atmosphere. Geophysical Research Letters, 52 (8). ISSN 0094-8276

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Abstract

Biological activity in the surface ocean leads to emissions of methanethiol (MeSH) and dimethyl sulfide (DMS). Measurements of MeSH in the marine atmosphere are sparse and the impact of NOx pollution on MeSH oxidation remains unexplored. We present measurements of MeSH and DMS at a coastal site with NOx up to 24.3 ppb in the United Kingdom during May and June. Winds coming from the seaward (northerly) direction showed a median (25th quantiles) MeSH mixing ratio of 15.7 (7.9–26.9) ppt. The measurements reveal significantly lower MeSH during daytime. Atmospheric box model calculations suggest that ∼25% of the MeSH oxidation is initiated by NO3 at this site and that NOx pollution can reduce the SO2 yield from MeSH. This work is further evidence for the prevalence of MeSH and illustrates the impact of NOx pollution on MeSH oxidation with associated implications for its role in aerosol-cloud processes, and climate.

Item Type:	Article
Additional Information:	Data Availability Statement: DMS and MeSH mixing ratio data and associated meteorological and trace gas measurements are archived at Wohl (2025). Funding information: This work has been supported by the National Centre of Atmospheric Science through the FAAM Mid-Life upgrade. We thank the Atmospheric Measurement and Observation Facility (AMOF), part of the National Centre for Atmospheric Science (NCAS), for its support for the Weybourne Atmospheric Observatory. We thank Alex Etchells (UEA, ITCS) for IT support at WAO and Lorrie Jacob (University of Cambridge) for helpful discussions surrounding the MCM box modeling. The work was supported by the UK Natural Environment Research Council (NERC) CARES project (ConstrAining the RolE of Sulfur in the earth system), NE/W009307/1 and the UK National Center for Atmospheric Sciences (FAAM mid-life upgrade project). The Vocus instrument was funded through a NERC Capital Equipment award (NE/T009020/1).
Uncontrolled Keywords:	sdg 13 - climate action,sdg 14 - life below water ,/dk/atira/pure/sustainabledevelopmentgoals/climate_action
Faculty \ School:	Faculty of Science > School of Environmental Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups:	Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Related URLs:	https://agupubs.onlinelibrary.wiley.com/...
Depositing User:	LivePure Connector
Date Deposited:	06 May 2025 11:30
Last Modified:	12 May 2025 00:11
URI:	https://ueaeprints.uea.ac.uk/id/eprint/99188
DOI:	10.1029/2025GL114929

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