Atmospheric Oxidation of Biogenic Sulfur Compounds

Biogenic sulfur compounds such as dimethyl sulfide are emitted by marine phytoplankton and undergo complex oxidation pathways in the atmosphere. Reactions with hydroxyl radicals initiate a cascade of intermediates including methylsulfonyl radicals and peroxy species, leading to the rapid formation of sulfuric acid and methanesulfonic acid. These oxidation products nucleate new aerosol particles and contribute to cloud condensation nuclei, thereby modulating radiative forcing and cloud microphysics. The balance between gas-phase and multiphase chemistry in marine and continental atmospheres determines the spatial distribution of biogenic sulfate, its seasonal variability and climatic impact. Recent advances have identified direct routes to sulfuric acid formation from reduced-sulfur precursors and quantified the contribution of biogenic oxidation to global aerosol budgets, underscoring its role in climate feedbacks and air quality.

Research from Nature Portfolio

Recent studies have demonstrated immediate production of sulfuric acid from the hydroxyl-initiated oxidation of organic reduced-sulfur compounds in marine air. Observations reveal key intermediates—methylsulfonyl radicals and their peroxy derivatives—driving rapid gas-phase conversion to sulfuric acid. Modelling under pristine marine conditions suggests that oxidation of these organosulfur vapours can account for nearly half of new gas-phase sulfuric acid formation, refining global aerosol nucleation estimates and highlighting an unexpected direct source of biogenic sulfate.

Atmospheric Oxidation of Biogenic Sulfur Compounds publication trend

The graph below shows the total number of articles in atmospheric oxidation of biogenic sulfur compounds across all publications each year (not limited to Nature Index journals).

Technical terms

Dimethyl sulfide (DMS): A volatile organosulfur compound emitted by marine phytoplankton that serves as a primary biogenic sulfur precursor in the atmosphere.

Hydroxyl radical (OH): A highly reactive atmospheric radical that initiates oxidation of volatile compounds, critical for biogenic sulfur conversion.

Methylsulfonyl radical (CH3SO2): A reactive intermediate formed during the oxidation of reduced-sulfur compounds, leading to sulfuric acid production.

Peroxy radical (e.g. CH3SO2OO): An oxygen-containing intermediate that facilitates rapid gas-phase conversion to acids.

Sulfuric acid (H2SO4): A key atmospheric nucleating agent formed from biogenic and anthropogenic sulfur, central to new particle formation.

Methanesulfonic acid (MSA): A lower-volatility product of DMS oxidation that contributes to aerosol growth and cloud condensation nuclei.

References

1. Direct sulfuric acid formation from the gas-phase oxidation of reduced-sulfur compounds. Nature Communications (2023).
2. Gas‐Phase Formation of Sulfurous Acid (H2SO3) in the Atmosphere. Angewandte Chemie International Edition (2024).
3. IPB-MSA&SO4: a daily 0.25° resolution dataset of in situ-produced biogenic methanesulfonic acid and sulfate over the North Atlantic during 1998–2022 based on machine learning. Earth System Science Data (2024).
4. High Gas-Phase Methanesulfonic Acid Production in the OH-Initiated Oxidation of Dimethyl Sulfide at Low Temperatures. Environmental Science and Technology (2022).