An overview of Arctic organic aerosols: from composition to cloud feedbacks

As one of the most susceptible components of the global climate system, the Arctic undergoes rapid changes where aerosol properties play a pivotal role in modulating regional radiation budgets and climate feedbacks. Amid intensified Arctic amplification and expanding anthropogenic footprints, the chemical composition, sources, and cloud condensation nuclei activity of Arctic organic aerosols (OA) have emerged as critical research frontiers. This review synthesizes current knowledge on the seasonal dynamics and physicochemical evolution of Arctic OA, with a particular emphasis on secondary organic aerosols formation pathways. We evaluate the complex interplay between indigenous marine biogenic emissions, long-range transported pollutants, and episodic biomass burning. Emerging evidence indicates that the cloud condensation nuclei potential of Arctic OA is fundamentally governed by their molecular-level oxidation state and phase state, which collectively reshape cloud microphysics and radiative forcing. This synthesis underscores the necessity of integrating multiphase chemistry into the aerosol-cloud climate feedback loop to bolster the reliability of climate models in the context of rapid Arctic amplification.