Air Quality

Even at relatively low levels, such as those found in the Greater Yellowstone, air pollution and deposition can leach nutrients from soil, injure vegetation, and acidify and fertilize lakes and streams. The Clean Air Act Amendments of 1977 designated Yellowstone and Grand Teton national parks among the 156 national parks and wilderness areas that are Class I airsheds, requiring the most stringent air quality protection within and around their boundaries. Strong winds tend to disperse pollutants, but the physical characteristics of high-elevation basins, such as thin and rocky soils, sparse vegetation, short growing seasons, and snowmelt-dominated hydrology, make them more susceptible to changes due to acid deposition and nutrient enrichment from nitrogen deposition. Air pollution sources in the Greater Yellowstone include energy development in southwest Wyoming and agricultural air emissions in southern Idaho.

Updated 3/19/09