Glacier National Park Air Quality Information
Overview
Air pollutant emissions near Glacier NP are low. In Montana, the largest sources near the park are Plum Creek Manufacturing, Columbia Falls, with emissions of particulate matter (PM10) and nitrogen oxides and Columbia Falls Aluminum Company (CFAC), 10 km south of the park near Columbia Falls, which emits PM10, sulfur dioxide, and fluoride. East of the Continental Divide, oil and gas processing plants along the east front in Alberta are the largest point sources near the park emitting SO2 and NO2. Other local sources include wind-blown dust and agricultural, slash, prescribed, and wood stove burning. Regional sources of air pollution include electric utility power plants, oil and gas processing, industrial fossil-fuel combustion, and agriculture. Wildland fires also contribute significantly to air pollution at certain times of the year.
The air quality related values (AQRVs) of Glacier 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 Glacier NP. Although visibility in the park is still superior to that in many parts of the country, visibility in the park is sometimes 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 Glacier NP has been monitored using an aerosol sampler (1988-present), a transmissometer (1988-present), and an automatic 35mm camera (1983-1995). An analysis of 1990-1999 data indicates that visibility in the area is improving. However, that trend could be reversed by increased oil and gas development and increased coal burning for power production in western States.
High-elevation, headwater lakes in Glacier NP are potentially sensitive to atmospheric deposition of sulfur and nitrogen compounds. These lakes are situated on relatively inert bedrock, receive little glacial runoff, and therefore have low acid neutralizing capacity. Their snowmelt-dominated hydrology makes them vulnerable to episodic acidification in the spring, and possibly chronic acidification. Most lakes in Glacier NP have relatively high buffering capacity, receiving sufficient base cations from glacial runoff and sedimentary bedrock.
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 Glacier NP since 1980 as part of the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). The site ID is MT05. Dry deposition has been estimated for Glacier NP (site GLR468) since 1995 as part of the Clean Air Status and Trends Networks (CASTNet). Wet deposition predominates; data indicate that, for the period 1999-2001, wet deposition contributed over 80 percent of total inorganic nitrogen deposition and about 75 percent of total sulfur deposition in Glacier NP. Although deposition rates for nitrogen and sulfur are relatively low, they are elevated above natural deposition rates. Trend data for wet deposition from 1993-2003 indicate that although deposition of sulfate decreased during that period, deposition of nitrate increased.
Mercury in rainfall is monitored in the park as part of the Mercury Deposition Program (2003-present). Mercury and organic contaminants are also measured in snow, water, sediment, and biota in Glacier NP as part of the Western Airborne Contaminants Assessment Project.
Several plant species that occur in Glacier NP, including Salix scouleriana (Scouler’s willow) and Populus tremuloides (quaking aspen) are known to be sensitive to ozone. Ozone has been monitored with a continuous analyzer from 1992- present in the park. Data indicate that ozone concentrations and doses are very low in the park and not likely to cause injury to vegetation.
Fluoride emissions from the Columbia Falls Aluminum Company prompted concerns about fluoride toxicity to vegetation, and subsequently grazing animals, in the late 1960’s. Fluoride in ambient air and vegetation has been monitored in the park since that time. There have been significant fluoride emission reductions at the smelter and subsequent reductions in fluoride in the park.
UV-B radiation has been monitored in the Park since 1997 as part of the Department of Agriculture’s UV-B Monitoring Program. As stratospheric ozone levels decline, increases in UV exposure are possible. Increased exposure to ultraviolet radiation has negative implications for human health and plant productivity.
In 2003, Glacier NP added a Climate Reference Network (CRN) site at St. Mary. The CRN will provide data on precipitation and temperature that can be used to detect climate change.
Additional information on in-park emissions at Glacier NP is available in 2000 Air Emissions Inventory- Glacier National Park (August 2002).
Additional information relative to air quality and air quality related values at Glacier 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.