Air Quality and Snow Chemistry at a Snowmobile
Staging Area in a Rocky Mountain Subalpine Forest

Summary: A pilot study will be conducted at a snowmobile staging area to examine air quality at the site. Nitrogen oxides, carbon monoxide, and particulate matter will be monitored. Weekend and weekday data will be compared. Automated counters will be examined as a method to quantify snowmobiles present at the site. Water chemistry will be determined from snow samples collected under and away from a snowmobile trail. Vegetation and soils will also be examined across snowmobile trails.

Introduction: This study will examine air and snow water quality characteristics at the Medicine Bow National Forest Green Rock Picnic Area, a winter closure point and turnaround for Wyoming State Highway 130, 26 miles west of Laramie, Wyoming. A winter trailhead and parking area is located here where snowmobiles are unloaded, fueled, started, and warmed before excursions are begun. Use of this site by snowmobilers is particularly high on weekends, and use has increased over the past several years. It is expected that snowmobile use may continue to increase in the Snowy Range of Wyoming.

Objectives of the study are: 1) To monitor the meteorology, nitrogen oxides, carbon monoxide, and particulate matter in ambient air at a snowmobile staging area. 2) To examine methods to determine snowmobile counts. 3) To examine variability in snow chemistry in and near a snowmobile trail. 4) To compare vegetation and soil characteristics under and away from a snowmobile trail.

Methods: Standard meteorological instrumentation and air quality monitors will be installed in a small building near the Green Rock Picnic Area trailhead at the winter closure of Wyoming State Highway 130. Meteorological instruments will measure wind speed, wind direction, temperature, and relative humidity. Air quality monitors will measure nitrogen oxides, carbon monoxide, and particulate matter. Air quality data will be compared for weekend and weekday differences. Post-winter measurements will continue after snowmelt to determine weekday and weekend differences without the presence of snowmobiles.

Automatic infrared and/or video counters will be tested to detect and count snowmobile passage. Automated counters will be checked intermittently by comparing with hand counts by volunteers.

Snow samples will be collected at a site along a snowmobile trail for chemical analysis. The samples will be weighed to determine snow water equivalent and transferred to the lab for chemical analysis. Snow samples will be collected during late January and during late April to early May, to capture the early and late season snowpack.

Vegetation will be examined at the end of the melt season. Soil water chemistry and soil density will also be measured at each site. A paired sample test will be used to compare vegetation and soil characteristics between trail and non-trail sites.

After the initial year of preliminary data from this pilot study, the study could be expanded to include data from an additional site with low snowmobile use. This will allow comparison of low use sites with the high use site, information not available from this initial study. The results of this pilot study will relate only to the Green Rock Picnic Area site, with no extrapolation possible regarding air quality at other sites.

Participants in the study:
USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO
USDA Forest Service, Rocky Mountain Region, Air Resources Division, Denver, CO
USDA Forest Service, Medicine Bow/Routt National Forests, Laramie, WY
US DOI, Geological Survey, Biological Resources Division, Fort Collins, CO
US DOI, Bureau of Land Management, Cheyenne, WY
US Environmental Protection Agency, Region VIII, Denver, CO
University of Wyoming, Department of Renewable Resources, Laramie, WY
Wyoming Department of State Parks, Snowmobile Trails Program, Cheyenne, WY
Wyoming Department of Environmental Quality, Air Quality Division, Cheyenne, WY
Wyoming State Snowmobile Association

For further information contact:
Dr. Robert Musselman
USDA Forest Service
Rocky Mountain Research Station
240 West Prospect Road
Fort Collins, CO 80526
Phone: 970-498-1239
Email: rmusselman@fs.fed.us