Print PageThe National Park Service (NPS) has an “affirmative responsibility” to protect air quality sensitive resources in parks, including lakes and streams, soils, vegetation, and wildlife. Yet NPS has no regulatory authority over air pollution sources, which are predominantly located outside of parks. How, then, can NPS effectively protect resources in over 270 parks from the adverse effects of air pollution, including acidification of lakes and streams, nutrient nitrogen effects to biodiversity, and ozone injury to vegetation?
Results/Conclusions
NPS has developed an approach that 1) identifies resources most at risk, 2) targets at-risk resources for empirical field studies or ecosystem modeling to evaluate and, where possible, quantify ecosystem response, and 3) uses resulting information to participate in the review of permit applications for new sources of air pollution and the review of national air quality standards. Various methods have been used to identify resources most at risk. To assess the risk to vegetation from ozone, we examined cumulative ozone exposure and soil moisture during the growing season and sensitive plant species present in a park. On the basis of these factors, parks were rated at high, medium, or low risk for visible foliar injury from ozone. For ecosystems and resources at risk from acidification or nutrient nitrogen enrichment, GIS tools were used to evaluate pollutant exposure, inherent ecosystem sensitivity, and park protection mandates. In the acidification assessment we used data on nitrogen and sulfur emissions and deposition, locations of acid-sensitive resources including high-elevation remote lakes, headwater streams, base-poor soils, and red spruce and sugar maple forests, and locations of Class I parks and wilderness areas. In the nutrient nitrogen risk assessment we used data on nitrogen emissions and deposition, nutrient-sensitive resources including remote high-elevation lakes, alpine, arctic, meadow, arid, and semi-arid terrestrial ecosystems, and wetland ecosystems, and locations of Class I parks and wilderness areas. GIS models were then used to rank parks according to their relative risk from acidification or nutrient nitrogen enrichment. The results of these assessments have been used to prioritize research needs and determine where to conduct dose-response experiments or ecosystem modeling to quantify ecosystem effects from air pollution. Quantitative ecosystem response information has been increasingly useful in setting park management goals, reviewing and commenting on permit applications for new sources of air pollution, and advising EPA on the adequacy of air quality standards.
