Poor air quality and deposition of pollution compounds have serious detrimental effects on native ecosystems.  Air pollution and deposition are known to contribute to invasion of weedy exotic plant species, decline in native shrub populations, and poor growth in many tree species.  Class I wilderness areas are one of the few landscapes where land managers have some control over factors influencing air quality.  Through the Clean Air Act, land managers have the responsibility for “Prevention of Significant Deterioration” of natural resources by new pollution sources.  However, determination of significant deterioration requires monitoring data, especially information on the existing condition and current air quality parameters within the wilderness boundaries.

The National Atmospheric Deposition Program (NADP) has coordinated wet deposition monitoring for more than 35 years.  NADP is the “go-to” resource for measurements of the acid and nutrient content in the nation’s rain.  With over 250 locations in rural and remote locations across the country, data from the NADP networks is widely used by researchers, land managers, and policy makers to understand the effects of air pollution on native ecosystems and natural resources, and to establish goals for emission restrictions.   Many of the NADP sites were established and are operated by the Forest Service, National Parks Service, Bureau of Land Management, Fish and Wildlife, among other state and federal land managers.  The Forest Service frequently relies on NADP data for natural resource assessments. The question arose: Which specific monitoring locations were most appropriate for assessing air quality and deposition at a specific Class I Wilderness area?

A GIS-based study was conducted to identify the proximity of NADP monitoring stations to each of the 88 Class I areas managed by the Forest Service.  The results demonstrated that 17 Class I areas have adequate monitoring within the recommended 20km distance from the boundary.  An additional 36 Class I areas have data available from NADP stations between 20km to 50km from the boundaries, but because most wilderness areas are located in mountains with complex terrain, monitoring data from locations greater that 20km may not reflect the conditions within the wilderness boundaries.  The results of this study highlighted a serious lack of deposition data for most Class I wilderness areas managed by the Forest Service.