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Primary aerosols play a critical role in polar climate systems, influencing cloud formation, precipitation, radiative balance, and surface energy budgets. This paper provides a comprehensive synthesis of primary aerosol sources, transformation and removal processes, and broader atmospheric impacts in polar regions, emphasizing their links to ocean and sea ice biogeochemistry. These aerosols (including sea salt, primary organic aerosol, and primary biological aerosol particles) originate from marine and cryospheric environments and are emitted through physical processes, such as wave breaking, bubble bursting, and blowing snow. Emission sources include seawater, sea ice, snow, and freshwater from river discharge and glacial runoff. Once airborne, these particles can serve as a chemical reservoir, influencing atmospheric composition and reactivity, and as seeds for cloud droplet and ice crystal formation, influencing cloud microphysics and polar climate. Despite their importance, many of the processes governing primary aerosol emissions and transformations remain poorly constrained. The most pressing knowledge gaps pertain to emission processes, limited spatiotemporal observational coverage, instrumentation constraints, parameterization development, and the integration of interdisciplinary expertise. To improve our understanding of primary aerosol drivers and their response to climate, future research efforts should prioritize strategically coordinated and cross-disciplinary process studies, advancements in measurement technologies and coverage, and close collaboration between modelers and observational scientists to inform and refine model parameterizations. As polar regions continue to undergo profound changes marked by increased precipitation, reduced sea and land ice, freshening oceans, and shifting ecosystem dynamics, characterizing present-day primary aerosol populations is vital. Improved understanding will be essential for anticipating future changes in aerosol-radiation and aerosol-cloud interactions and their implications for polar and global climate systems.

Changing Arctic climate conditions have accelerated sea ice retreat, altering ocean–atmosphere interactions and marine ecosystems. Reduced sea ice cover likely enhances emissions of primary marine organic aerosol (PMOA) through bubble bursting, with implications for aerosol–cloud interactions. This study examines the emission patterns, seasonality, and historical trends of key PMOA species (dissolved carboxylic acidic containing polysaccharides, PCHO; dissolved combined amino acids, DCAA; polar lipids, PL) within the Arctic from 1990 to 2019. Surface ocean concentrations of marine biomolecules, derived from a biogeochemistry model used in the ECHAM-HAM aerosol–climate model, exhibit pronounced seasonal cycles. PMOA emissions show strong variability, driven by marine productivity and sea-salt emissions, with maxima from May to September. Total PMOA emissions increased by about 12 %, and the burden rose by 4 % between 1990–2004 and 2005–2019. A 30 year summer trend (July–September) indicates a rapid decline in sea ice, accompanied by increasing concentrations of organic groups in inner-Arctic waters. Positive PMOA emission anomalies have become more frequent over the past 15 years, and total PMOA production has increased by 0.8 % yr−1 since 1990. Differences among biomolecular types persist, with PCHO showing the strongest increases in both emissions (1.3 % yr−1) and aerosol concentrations (0.8 % yr−1).

Primary marine organic aerosol (PMOA) contributes significantly to the aerosol loading over remote oceanic regions, where sea spray dominates aerosol production in the lower troposphere, and plays an important role in aerosol–cloud–climate interactions. The sea–atmosphere transfer of organic components depends on their abundance at the ocean surface and their physicochemical characteristics. We introduce a novel approach for representing the ocean concentration of the most abundant organic groups in seawater that are relevant for aerosols. By apportioning the phytoplankton-exuded dissolved organic carbon, modelled in the biogeochemistry model FESOM2.1–REcoM3, three biomolecule groups are computed (dissolved carboxylic acidic containing polysaccharides (PCHO), dissolved combined amino acids (DCAA), and polar lipids (PL)). The transfer of these marine groups to the atmosphere is represented by the OCEANFILMS (Organic Compounds from Ecosystems to Aerosols: Natural Films and Interfaces via Langmuir Molecular Surfactants) parameterization which is implemented in the aerosol–climate model ECHAM6.3–HAM2.3 to represent the emission and transport processes in the atmosphere. The concentration of biomolecules in the ocean serves as the bottom boundary condition for the PMOA simulation within the aerosol model. Among the simulated organic groups in seawater, modelled PCHO is the most prevalent, followed by DCAA and PL. Conversely, PL contributes the most to the organic matter in aerosols, given the high air–seawater affinity of lipids compared to the other groups. Biomolecules exhibit minor variations in equatorial waters, whereas strong seasonal patterns are observed towards the polar regions. The global aerosol model simulations indicate that PMOA emission fluxes are primarily influenced by marine biological activity and surface wind conditions. Based on the most comprehensive evaluation to date, the computed levels of biomolecules in the ocean and species-resolved PMOA concentrations are compared with ground-based measurements across the globe. The comparison shows a reasonably good agreement, given the uncertainties in model assumptions and measurements. Model biases in the representation of the marine organic aerosol groups are caused by uncertainties in the aerosol-process representation and the simulated sea salt concentrations. A comparison with a set of long-range in situ aircraft measurements indicates that by including PMOA in the model, the representation of organic aerosols in the southern oceans is significantly improved.