Description
Summary:The Arctic atmosphere is subject to a wide range of local and remote sources of air pollution, which can affect local Arctic communities, contribute to Arctic warming, and cause harm to sensitive Arctic ecosystems. Despite the remote location, the Arctic surface displays characteristic enhancement of air pollutant concentrations during winter and spring known as Arctic Haze. This haze is sourced from long-range transport of pollutants from lower latitudes. During summer, less efficient transport and more efficient pollutant removal leads to lower anthropogenic influence, but increased abundances of naturally-sourced pollutants, including smoke emissions from high latitude wildfires. Long-range transport to the Arctic follows well established pathways, which are determined by dominant meteorological features of the high latitude northern hemisphere. Although poorly constrained at present, local emissions of air pollutants also make important contributions in populated regions, particularly in winter when severe surface-based inversions cause trapping of pollutants close to the surface. Processes controlling secondary pollutant formation under cold, dark conditions are poorly understood at present, and potential novel pathways for oxidant formation and precursor oxidation are under investigation. Impacts of Arctic air pollutants on health may be exacerbated by heavy organic aerosol loadings, and poor underlying health in some local communities. The future evolution of Arctic air pollution will be tightly coupled to both environmental and socioeconomic drivers that will determine Arctic development. Projected reductions of air pollution emissions due to air quality and climate mitigation strategies at lower latitudes are likely to produce warming in the Arctic over the near-term, due to sharp reductions in cooling aerosols.