Multi-year Analyses Reveal Different Trends, Sources, and Implications for Source-Related Human Health Risks of Atmospheric Polycyclic Aromatic Hydrocarbons in the Canadian Great Lakes Basin

Polycyclic aromatic hydrocarbons (PAHs) are of high concern to public health due their carcinogenic and mutagenic properties. Here, we present the first comprehensive quantitative analysis sources, potential source regions according sectors source-related human risks multi-year atmospheric measurements PAHs in Canadian Great Lakes Basin (GLB). The highest PAH concentrations were observed at a rural residential site (Egbert), followed by two regionally representative remote sites [Point Petre (PPT) Burnt Island]. levels most GLB atmosphere significantly decreased between 1997 2017, broadly consistent with decreasing trends anthropogenic emissions. Coal, liquid fossil fuel, biomass burning common sources. for identified south or southwest sampling sites. Risk assessment suggests associated inhalation PAHs. On positive note, from coal combustion, fuel petrogenic sources PPT decreased, directly demonstrating success emission control reducing impacts. In contrast, risk forest fire-related emissions may play an increasing role future climate change.