Yellowstone National Park Air Quality Information
Overview
A variety of regional air pollution sources affect air quality in Yellowstone NP, including electric utility power plants, oil and gas processing, coalbed methane wells, industrial fossil-fuel combustion, and agriculture. Local sources of air pollution include automobiles, snowmobiles, and wildland fires.
The air quality related values (AQRVs) of Yellowstone NP are those resources that are potentially sensitive to air pollution and include visibility, water quality, soils, vegetation, and wildlife.
Visibility is a very sensitive AQRV in Yellowstone NP. Although visibility in the park is still superior to that in many parts of the country, visibility in the park is often impaired by light-scattering pollutants (haze). The U.S. Environmental Protection Agency’s Regional Haze regulations require States to establish goals for each Class I air quality area to improve visibility on the haziest days and ensure no degradation occurs on the clearest days. As part of the Interagency Monitoring of Protected Visual Environments (IMPROVE) network, visibility in Yellowstone NP has been monitored using an aerosol sampler (1988-present), a transmissometer (1989-1993), a nephelometer (2002-present) and an automatic 35mm camera (1981-1982; 1986-1995; 2002-2003).
Certain headwater lakes in Yellowstone NP are potentially sensitive to atmospheric deposition of sulfur and nitrogen compounds because of their low acid neutralizing capacity. Their snowmelt-dominated hydrology makes them vulnerable to episodic acidification in the spring, and possibly chronic acidification. High-elevation soils may also be poorly buffered and sensitive to acidification.
Soils and vegetation in the park may be sensitive to nutrient enrichment from nitrogen deposition. In some parts of the country, including other high-elevation ecosystems in the Rockies, nitrogen deposition has altered soil nutrient cycling and vegetation species composition; native plants that have evolved under nitrogen-poor conditions have been replaced by invasive species that are able to take advantage of increased nitrogen levels.
Estimates of total atmospheric deposition can be made by adding wet and dry deposition. Wet deposition has been monitored in Yellowstone NP since 1980 as part of the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). The site ID is WY08. Dry deposition has been estimated for Yellowstone NP (site YEL408) since 1996 as part of the Clean Air Status and Trends Networks (CASTNet).
Mercury in rainfall is monitored in the park as part of the Mercury Deposition Program (2002-present). Both distant industrial sources and local geothermal sources contribute to mercury deposition in Yellowstone NP.
Several plant species that occur in Yellowstone NP, including Rhustrilobata (skunkbush) and Populus tremuloides (quaking aspen) are known to be sensitive to ozone. Ozone has been monitored with a continuous analyzer from 1987- present in the park. Data indicate that ozone concentrations and doses are not currently at levels known to cause injury to vegetation. No systematic surveys to assess vegetation injury have been performed in the park.
Additional information on in-park emissions at Yellowstone NP is available in 2000 Air Emission Inventory-Yellowstone National Park (March 2003).
Additional information relative to air quality and air quality related values at Yellowstone NP is available in D. Peterson et al. 1998. Assessment of Air Quality and Air Pollutant Impacts in National Parks of the Rocky Mountains and Northern Great Plains. National Park Service. Denver, CO.