Methanethiol abundance and oxidation in a polluted marine atmosphere

Charel Wohl; Grant L. Forster; Pete M. Edwards; Parvadha Suntharalingam; David E. Oram

doi:10.1029/2025GL114929

Methanethiol abundance and oxidation in a polluted marine atmosphere

Charel Wohl, Grant L. Forster, Pete M. Edwards, Parvadha Suntharalingam, David E. Oram

Research output: Contribution to journal › Article › peer-review

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.

Original language	English
Article number	e2025GL114929
Journal	Geophysical Research Letters
Volume	52
Issue number	8
DOIs	https://doi.org/10.1029/2025GL114929
Publication status	Published - 28 Apr 2025

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10.1029/2025GL114929Licence: CC BY

Wohl_etal_2025_GeophysicalResearchLettersFinal published version, 1.79 MBLicence: CC BY

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025GL114929Licence: CC BY

1 Finished
1 Active

ConstrAining the RolE of Sulfur in the earth system (CARES)
Oram, D.
Natural Environment Research Council
1/09/23 → 31/08/27
Project: Research
Proton Transfer Reaction – Time of Flight Mass Spectrometer (PTR-ToF-MS) for aircraft and ground-based applications.
Oram, D., Kaiser, J., Reeves, C. & Forster, G.
Natural Environment Research Council
1/10/19 → 31/12/21
Project: Research

Cite this

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title = "Methanethiol abundance and oxidation in a polluted marine atmosphere",

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.",

author = "Charel Wohl and Forster, {Grant L.} and Edwards, {Pete M.} and Parvadha Suntharalingam and Oram, {David E.}",

note = "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).",

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AU - Wohl, Charel

AU - Forster, Grant L.

AU - Edwards, Pete M.

AU - Suntharalingam, Parvadha

AU - Oram, David E.

N1 - 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).

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Y1 - 2025/4/28

N2 - 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.

AB - 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.

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DO - 10.1029/2025GL114929

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JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 8

M1 - e2025GL114929

ER -

Methanethiol abundance and oxidation in a polluted marine atmosphere

Abstract

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Projects

ConstrAining the RolE of Sulfur in the earth system (CARES)

Proton Transfer Reaction – Time of Flight Mass Spectrometer (PTR-ToF-MS) for aircraft and ground-based applications.

Cite this