Spring Sparks Change in the Arctic Organic Aerosol Population

Organic aerosols (OA) play a crucial role in the Arctic's climate, yet their origins and properties remain poorly understood. Using aerosol mass spectrometry from two central Arctic expeditions (2018 and 2020), we identified six OA types and revealed how their sources shift from spring to summer. As sunlight returns after the polar night, secondary oxygenated OA formed from photo-oxidised volatile organic compounds dominate the central Arctic OA population. Later, marine OA from the marginal ice zone become more prominent, while the influence of long-range transported anthropogenic influence declines. These seasonal changes alter aerosol physicochemical properties (size, composition, and OA oxidation state), and hence their cloud-forming potential. Our results show that the Arctic spring atmosphere acts as an active photochemical reactor, shaping the composition and climate relevance of OA.

Reference: Heutte, B., Angot, H., Chen, G.I., et al. (2025). Sources and composition of organic aerosols in the central Arctic during spring and summer. Environ. Sci. Technol., 59 (41), 21924-21940. https://doi.org/10.1021/acs.est.5c09788