How does deposition of air pollutants affect public health and the health of the Great Waters ecosystems?
A rapidly growing number of atmospheric deposition monitoring and modeling studies confirm that, along with runoff and discharges of pollution into waterways, atmospheric deposition is a significant pathway of pollutant inputs to the Great Waters. These studies show that the contribution of atmospheric deposition to overall pollutant loadings varies greatly by pollutant and location. For example, studies show that atmospheric deposition contributes from less than 5 to 100 percent of dioxins and furans entering the Great Lakes, depending on the location of the monitoring site, and from 2 to 38 percent of the nitrogen load to certain coastal waters. Given this variability in contributions, the improvement of the quality of the Great Waters environments requires an understanding of all of the sources of the pollutants into a waterbody, including runoff from urban areas and farms, discharge from point sources, and seepage from contaminated sediments, as well as atmospheric deposition. Like
