Prevalence of Local Emissions in Arctic Carbonaceous Aerosols Revealed by Dual Carbon Isotopes and Atmospheric Transport Modeling

Abstract Carbonaceous aerosols in the Arctic are mainly attributed to long‐range transport from lower latitudes, but direct observational data over the central Arctic Ocean, particularly in summer, remain limited. We present a cruise‐based study conducted during the eighth Xuelong Arctic expedition across the central Arctic Ocean. Using dual carbon isotope analysis (δ 13 C– Δ 14 C), molecular organic composition, and black carbon (BC)‐atmospheric modeling, we provide quantitative insights into the sources of Arctic marine aerosols. Our findings show significant spatial differences in aerosol composition between the North Pacific and Arctic Ocean. Fossil fuel–derived carbon contributes 55.5 ± 17% (0.49 ± 0.39 μg m −3 ) of total carbon in Arctic summer aerosols. While model simulations closely match BC concentrations outside the Arctic Ocean, they underestimate BC levels in the inner Arctic by a factor of two, suggesting gaps in local source representation. These findings emphasize the need for better representation of local emissions, especially from shipping, in models to improve understanding of aerosol‐driven climate effects in the Arctic.