Snowpack chemistry as an indicator of pollutant emission levels from motorized winter vehicles in Yellowstong National Park

TitleSnowpack chemistry as an indicator of pollutant emission levels from motorized winter vehicles in Yellowstong National Park
Publication TypeConference Proceedings
Year of Conference1997
AuthorsIngersoll, G., Turk J., McClure C., Lawlor S., Clow D. W., and Mast A.
Conference Name65th Annual Western Snow Conference
Series TitleProceedings of the 65th Annual Western Snow Conference
Date PublishedMay 1997
PublisherWestern Snow Conference
Conference LocationBanff, Alberta
KeywordsNitrates, Oversnow vehicles, Pollutants, Snowmobiles

Wintertime visitors to Yellowstone National Park, Wyoming, consider scenery, wildlife, and clean air as three important qualities of their experience in the Park. Because the majority of winter visitors tour Yellowstone by motorized winter vehicles, and winter visitation has increased nearly tenfold since 1968, the effects of vehicle use are a growing concern for resource managers. The extent of effects on air quality and ecosystem health from increasing vehicular emissions throughout the Park is not fully understood. Snowpack chemistry provides a composite record of atmospheric deposition of airborne pollutants throughout winter. Pollutant levels from vehicular emissions inside the Park were characterized by snowmelt-chemical data from three sites at a variety of high- and low-traffic locations. At each site snow samples representing most of the annual snowpack were collected at an off-road site 20 m to 100 m from motorized-traffic routes, and at a site directly in snow-packed roadways used by over-snow vehicles. Snowmelt chemistries were compared between these three pairs of samples collected in-road and off-road to determine whether concentrations decreased with distance from the source. Concentrations of ammonium, nitrate, and sulfate in snowmelt positively correlated with vehicle usage. Ammonium and sulfate levels were consistently higher for the in-road snow compared to off-road snow for each pair of sites, but nitrate concentrations did not decrease within a distance of 100 m from the emission source. This method demonstrates that snowpack chemistry can be used as a quantifiable indicator of airborne pollutants from vehicular traffic. A correlation was shown between pollutant levels and vehicle traffic. Additional results indicate the nitrate ion may be used to distinguish between local and regional emissions sources.