| Abstract
| - Atmospheric polycyclic aromatic hydrocarbon (PAHs)concentrations were measured in both the vapor andparticle phases at seven sites near the Great Lakes as apart of the Integrated Atmospheric Deposition Network. Lowermolecular weight PAHs, including fluorene, phenanthrene,fluoranthrene, and pyrene, were dominant in the vaporphase, and higher molecular weight PAHs, including chrysene,benzo[a]pyrene, and coronene, were dominant in theparticle phase. The highest PAH concentrations in boththe vapor and particle phases were observed in Chicagofollowed by the semiurban site at Sturgeon Point, NY. Thespatial difference of PAH concentrations can be explainedby the local population density. Long-term decreasing trendsof most PAH concentrations were observed in both thevapor and particle phases at Chicago, with half-lives rangingfrom 3−10 years in the vapor phase and 5−15 years inthe particle phase. At Eagle Harbor, Sleeping Bear Dunes,and Sturgeon Point, total PAH concentrations in thevapor phase showed significant, but slow, long-termdecreasing trends. At the Sturgeon Point site, which wasimpacted by a nearby city, particle-phase PAH concentrations also declined. However, most particle-phase PAHconcentrations did not show significant long-termdecreasing trends at the remote sites. Seasonal trendswere also observed for particle-phase PAH concentrations,which were higher in the winter and lower in the summer.
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