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Yellowstone Winter Vehicle Use and Air Quality

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An old Bombardier snowcoach being tested for emissions at Yellowstone National Park, Wyoming. Photo: J. Ray

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.

Year

NPS Report

Data Transmittal Report

2009 – 2011 Winter air quality in Yellowstone National Park: 2009-2011. (pdf, 897 KB) Natural Resource Technical Report. Air Resources Division. John Ray, February 2012. Winter Use Air Quality Study at Yellowstone National Park, Winter 2009-2010. Contractor Report
(pdf, 888 KB)
2008 – 2009 Winter air quality in Yellowstone National Park: 2008-2009. (pdf, 279 KB) Natural Resource Technical Report. Air Resources Division. John Ray, February 2010. Winter Use Air Quality Study at Yellowstone National Park, Winter 2008-2009. Contractor Report
(pdf, 696 KB)
2007 – 2008 Winter Air Quality in Yellowstone National Park, 2007-2008. (pdf, 800 KB) Natural Resource Technical Report, Air Resources Division. John Ray, November 2008. Winter Use Air Quality Study at Yellowstone National Park, Winter 2007-2008. Contractor Report
(pdf, 2.1 MB)
2006 – 2007 Yellowstone Winter Air Quality, 2006-2007.(pdf, 2.4 MB) Final NPS Air Resources Division Report. John Ray, July, 2007. Winter Air Quality Monitoring at Yellowstone National Park, Winter 2006-2007. Contractor Report
(pdf, 800 KB)
2005 – 2006 Yellowstone Winter Air Quality Study, 2005-2006. (pdf, 3.4MB) NPS Air Resources Division Report. John Ray, Feb., 2007.  
2004 – 2005 Yellowstone Winter Air Quality Study, 2004-2005, NPS Air Resources Division Report (pdf, 1.6 MB), John Ray, 2005.
Presentation (pdf, 600 KB)
Winter Air Quality Monitoring at Yellowstone National Parks, Winter 2004-2005. Contractor Report
(pdf, 1.5 MB)
2003 – 2004 Yellowstone Winter Study, 2003-2004 – Overview (pdf, 125 KB)
ARD report (pdf, 536 KB), John Ray, March, 2005.
Winter Air Quality Monitoring at Yellowstone National Parks, Winter 2003-2004. Contractor Report
(pdf, 2.3 MB)
2002 – 2003 Yellowstone Winter Air Quality, 2002-2003 Air Resources Division quick summary (pdf, 28 KB), John Ray, July 2003. Winter Air Quality Monitoring at Yellowstone and Grand Teton National Parks, Winter 2002-2003. Contractor Report (pdf, 38.1 MB)   
Appendix A
(pdf, 841 KB)  
Appendix B
(pdf, 700 KB)

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:

Table 16. Estimated gram/mile/person emissions for Yellowstone winter transportation options

Data

Mean grams/gala,b

Mean g/mile
(Estimated g/mile)c

Estimated
g/mile/persond

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.

Summary table from: Bishop et al., In-use Emission Measurements of Snowmobiles and Snowcoaches, 2006.


snowcoach emissions graph
Snowcoach emissions were found to vary over a wide range at Yellowstone NP

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



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Last Updated: February 11, 2013