Proper management of air resources is vital to maintaining the wilderness character of an area. Air pollution can affect natural resources and has caused injury to vegetation, bioaccumulation of mercury in fish, eutrophication of coastal ecosystems and visibility impairment in U.S. Fish and Wildlife Service (FWS) wilderness areas. Sources of air pollution include power plants, incinerators, industry, automobiles, dust and fires. Emissions from these sources can be transported long distances and affect areas otherwise considered to be pristine. The FWS uses a combination of monitoring, special studies, participation in the regulatory process and review of new sources of air pollution in its air quality management strategy.