Air Quality in National Parks: Annual Performance and Progress Report, 2009

摘要

The National Park Service (NPS) measures progress toward improving park air quality by examining trends for key air quality indicators, including: visibility which affects how well and how far visitors can see; ozone which affects human health and native vegetation; and atmospheric deposition which affects ecological health through acidification and fertilization of soil and surface waters. The NPS monitors one or more of these indicators in 57 park units, and there are sufficient data to assess conditions and trends in all of these parks. In addition, many state and local air quality monitoring stations are located near enough to parks that the data they collect are considered reasonably representative of park air quality. As a result, air quality conditions and trends have been calculated for 195 monitoring locations representing 241 park units.