Recognizing the value of the fresh mountain air of the North Cascades, Congress designated North Cascades National Park as a Class I area, affording it the highest degree of air quality protection. Unfortunately, the park lies in the path of prevailing westerly winds blowing from rapidly growing urban-industrial and agricultural areas in Puget Sound. The mark of humankind's activity can be found everywhere within the park. Windborne pollutants are deposited on glaciers in the park via precipitation. As the ice melts, water carries the pollutants into the food chain, moving from tiny aquatic insects called macroinvertebrates to fish to land mammals and eventually even back to humans.
Consequently, park managers are cooperatively involved with the US Geological Survey, the National Park Service's Air Resources Division and others to assess air pollution impacts and protect air quality related resources. The air resources management program at North Cascades includes monitoring, research and data dissemination. Pollutants such as particulate matter, ozone, acid deposition, mercury and pesticides have been monitored in the park. The park and cooperators have also studied the impact of those pollutants on visibility, water quality, vegetation and wildlife. Data are used to inform management strategies and regulatory activities that affect park air quality.