ABSTRACT
Emissions into the atmosphere of a wide range of substances can impact sensitive resources in national parks at downwind locations. The air pollutants of concern for this book include gases and particles containing sulfur (S), nitrogen (N), mercury (Hg), and other metals; pesticides and other organic compounds; ozone; and particles that reduce visibility. Emissions sources are varied and in particular include power plants, industrial facilities, motor vehicles, incinerators, agriculture, re, oil and gas development, and other human-caused and natural sources. Air pollutants can cause or contribute to numerous adverse environmental impacts. These include acidication of soil and water; nutrient over-enrichment (eutrophication) of terrestrial and aquatic ecosystems; biomagnication (increase in concentration within the food web) and toxicity of contaminants; inhibition of plant health, growth, or reproduction; changes in species composition (which species occur at a given location) and abundance; and visibility degradation caused by haze.
