Tracking Pollution Pathways to the Arctic: Sector and Regional Source Contributions to PAH Deposition Over Three Decades

The Arctic region faces increasing pollution from long-range atmospheric transport of persistent organic pollutants (POPs), with polycyclic aromatic hydrocarbons (PAHs) being a notable threat to marine ecosystems already under pressure from climate change. Despite emission reductions in industrialized nations, understanding the sources, pathways, and temporal evolution of PAH deposition to Arctic and subarctic seas remains critical for effective pollution management and international cooperation. This study presents a comprehensive assessment of priority PAH compounds across Arctic and subarctic marine regions from 1990 to 2021 using the GLEMOS (Global EMEP Multi-media Modeling System) multicompartment chemical dispersion model at 3×3° global resolution. Simulations use emissions from the Global Emission Modeling System (GEMS) inventory, providing spatially and temporally resolved emission estimates across all major source regions. We quantify atmospheric concentrations and total deposition fluxes, providing spatial estimates of contaminant loading to vulnerable polar marine environments over three decades of significant Arctic environmental transformation. The source attribution framework identifies sector-specific and region-specific contributions to Arctic PAH contamination, linking GEMS emission sources in lower latitudes to deposition patterns across Arctic and subarctic receptors. This source-receptor analysis reveals the relative importance of different economic sectors (e.g., residential heating, transportation, industrial processes) and geographic regions in driving Arctic contamination, enabling targeted policy interventions and accountability frameworks. Our results reveal significant spatial heterogeneity in PAH deposition patterns across the Arctic, with distinct hotspots corresponding to dominant atmospheric transport pathways and regional emission intensities. Temporal trends reveal the effectiveness of emission reduction policies in some regions while highlighting emerging concerns from rapidly developing economies. The long-term GLEMOS simulations capture how changing emission profiles, atmospheric circulation patterns, and Arctic physical conditions have influenced contaminant delivery to polar marine systems. By quantifying where Arctic pollution originates and how these patterns have evolved over three decades, this work contributes to the ongoing Arctic Monitoring and Assessment Programme (AMAP) assessment efforts. The findings provide essential information for understanding PAH exposure risks to Arctic marine ecosystems, informing international pollution control agreements, and establishing baseline conditions for future monitoring priorities in this rapidly changing region.