Synergistic effects of oceanic dimethyl sulfide emissions and atmospheric oxidants on new particle formation in the Arctic.

The direct confirmation of the cause-and-effect association between biogenic DMS emissions and the formation of DMS-derived aerosols is challenging because of the complex atmospheric processes involved. Here, we used decade-long field observations and a source-receptor model to pinpoint the key processes controlling the formation of biogenic sulfur aerosols in the Arctic. Our results revealed strong relationships between DMS, MSA, and subsequent new particle formation events during the phytoplankton growing periods. Notably, the efficiency of converting DMS into sulfur particles exhibited substantial variability across various ocean-ice regimes and seasons, depending on atmospheric OH and BrO levels driven by solar radiation and first-year sea ice, respectively. As the Arctic Ocean warms, phytoplankton blooms and the extent of younger sea ice intensifies, leading to increased emissions of DMS and its oxidants into the atmosphere. These combined factors could accelerate biogenic sulfur particle formation, thereby influencing cloud properties and radiative impacts in a warming Arctic.