Air quality site reports provide information about when, where and what the National Park Service (NPS) has monitored. The focus of this database is on NPS monitors, thus we do not list all monitoring on a state or a network level because only sites in conjunction with parks are in the database.

Since the late 1970's, the NPS has monitored visibility, ambient levels of fine particles, ozone, sulfur dioxide, wet deposition, and meteorology. Visibility, including scene photography, optical conditions, and fine particles, is monitored as part of the Interagency Monitoring of Protected Visual Environments (IMPROVE), which is a cooperative national program operated by the U.S. Environmental Protection Agency (EPA), NPS, and other federal land management and state air pollution control agencies.

Wet Deposition is monitored through the NPS participation in the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). The NTN collects weekly precipitation samples that are analyzed for cations (hydrogen, calcium, sodium, magnesium, potassium, and ammonium) and anions (sulfate, nitrate, and chloride). The Mercury Deposition Network (MDN), part of the NADP, also collects weekly precipitation samples that are analyzed for mercury.

The National Park Service measures levels of ozone, sulfur dioxide, and meteorological parameters plus dry deposition in concert with the EPA Clean Air Status and Trends Network (CASTNet). Passive ozone sampling and portable ozone monitoring by NPS are now included in the database.

Monitoring History Database Last Updated: October 31, 2008

For additional information contact John Ray, NPS Air Resources Division, Denver, CO (303-969-2820).