For more information about National Park Service air resources, please visit http://www.nature.nps.gov/air/.
Yellowstone Winter Vehicle Use and Air Quality
During the late 1990′s the volume of snowmobile traffic in Yellowstone NP had increased to point that the air quality was being affected. The park put into effect a temporary Winter Use Plan that set a Best Available Technology (BAT) limit on snowmobiles and limited their numbers. Air quality monitoring and several specific studies on snowmobile and snowcoach emissions were initiated to better understand the situation. The Air Resources Division has helped with several of the Yellowstone special studies
Air quality monitoring at Yellowstone
Early monitoring at Yellowstone was short-term to assess if there was a problem of winter air quality for staff and visitors. More recently, continuous winter monitoring has been used. The table below lists the winter air quality reports.
Emissions studies of winter vehicles
In partnership with researchers at the University of Denver, several studies to remotely and directly measure vehicle emissions have been conducted. Some of the results are given in the table and bar chart below:
Data |
Mean grams/gala,b |
Mean g/mile |
Estimated |
||||||
|---|---|---|---|---|---|---|---|---|---|
CO |
HC |
NOx |
CO |
HC |
NOx |
CO |
HC |
NOx |
|
| 1999 Mean 2-stroke Snowmobile | 1100 | 1400 | NA | (85) | (110) | NA | 71 | 92 | NA |
| 2005 Mean 4-stroke Ski Doo Fleet | 1400 | 110 | 6.6 | (78) | (6.1) | (0.4) | 60 | 4.7 | 0.3 |
| 2005 Mean 4-stroke Snowmobiles | 670 | 80 | 64 | (37) | (4.4) | (3.6) | 28 | 3.4 | 3.4 |
| 2005 Mean 4-stroke Arctic Cat Fleet | 570 | 72 | 78 | (32) | (4) | (4.3) | 25 | 3.1 | 3.3 |
| 2005 Highest Emissions Snowcoach* | 2200 | 180 | 27 | 630 | 50 | 7.7 | 74 | 5.9 | 0.9 |
| 2005 Mean Snowcoach | 1000 | 37 | 71 | 300 | 10 | 24 | 35 | 1.2 | 2.8 |
| 2005 Lowest Emissions Snowcoachf | 36 | 6.5 | 9.1 | 5.3 | 1 | 1.4 | 0.6 | 0.1 | 0.2 |
| a grams/gallons calculations for the snowmobiles assume a fuel density of 726 g/l. b Snowmobile NO emissions have been converted to NO2. c Snowmobile g/mile estimates use 13 mpg for 2-strokes and 18 mpg for 4-strokes. d Data obtained from the National Park Service Public Use Statistics Office. e Xanterra coach 709, vintage Bombardier with carbureted engine. f Alpen Guides Delacy, vintage Bombardier converted to a modern fule injected engine with exhaust after treatment. |
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Summary table from: Bishop et al., In-use Emission Measurements of Snowmobiles and Snowcoaches, 2006.
Reports and publications
- Ray, J. D., G. Bishop, B. G. Schuchmann, C. Frey, G. Sandhu, and B. Graver. 2013. Yellowstone
over-snow vehicle emission tests – 2012: Summary vehicle data and fleet estimates for
modeling (pdf, 979 KB). Natural Resource Technical Report NPS/NRSS/ARD/NRTR–2013/661. National
Park Service, Denver, Colorado. - Bishop, Gary A., Ryan Stadtmuller, Donald H. Stedman, and John D. Ray. August, 2009. Portable Emission Measurements of Yellowstone Park
Snowcoaches and Snowmobiles. Journal of the Air & Waste Management Association 59:936–942. Abstract (pdf, 63 KB), Article (pdf, 689 KB).
This paper was first published in August 2009 in the Journal of the Air & Waste Management Association. Copyright 2009. Air & Waste Management Association. - Bishop, Gary A., Ryan Stadtmuller, Donald H. Stedman, and John D. Ray. January 2007. Portable Emission Measurements of Snowcoaches and Snowmobiles in Yellowstone National Park; Final Report to NPS (pdf, 3 MB). University of Denver, Denver, CO.
- Bishop, Gary A., Daniel S. Burgard, Thomas R. Dalton, and Donald H. Stedman. January 2006. In-use Emission Measurements of Snowmobiles and Snowcoaches in Yellowstone National Park; Final Report to NPS. University of Denver, Denver, CO. Executive summary (pdf, 84 KB) Contents page (pdf, 69 KB) Full Report (pdf, 8.01 MB) Presentation (pdf, .78 MB)
- Bishop, Gary A., Daniel S. Burgard, Thomas R. Dalton, Donald H. Stedman, and John D. Ray. April 15, 2006. Motor-Vehicle Emissions in Yellowstone National Park, Environmental Science & Technology, p. 2505.
[Article (pdf, 411 KB)] - Bishop, Gary A., Jerome A. Morris, and Donald H. Stedman. 2001. Snowmobile Contributions to Mobile Source Emissions in Yellowstone National Park, Environmental Science & Technology, VOL. 35:14, p. 2874. [Article (pdf, 218 KB)]
- Bishop, Gary A., Donald H. Stedman, Mary Hektner, and John D. Ray. 1999. An In-Use Snowmobile Emission Survey in Yellowstone National Park, Environmental Science & Technology, VOL. 33:21, p.3824.
[Article (pdf, 43 KB)]
Other Studies
- August 2012, Measurement of Fuel Use and Emissions of Over-Snow Vehicles at Yellowstone National Park (pdf, 1.12 MB), by C. H. Frey, G. Sandhu, B. Graver, and J. Hu of North Carolina State University.
- 2004-2005 Yellowstone NP Snowmobile Emission Report, Gary Bishop and Don Stedman, University of Denver (pdf, 1.6 MB)
- 2004-2005 Yellowstone NP Snowmobile Emission Report (pdf, 1.6 MB)
- Air Quality Concerns Related to Snowmobile Usage in National Parks, NPS (2000) (pdf, 38.1 MB)
Related Links
Last Updated: February 11, 2013
