Air Quality

Mountains near and far, eventually disappearing completely into heavy haze
Haze hangs over Skyland Resort and the mountains beyond in Shenandoah National Park.

NPS / Katy Cain

Importance and Issues

Air quality can affect human and ecosystem health. The Clean Air Act of 1970 set out to preserve, protect and enhance air quality in the country, and in 1977 amended the act to include all NPS units greater than 6,000 acres as Class I areas receiving the greatest level of protection. Only Shenandoah National Park in the Mid-Atlantic Network (MIDN) is a Class I park, but all parks in the network will benefit from improved air quality.

Park managers will benefit from knowing the type and extent of various air pollutants in order to evaluate their impacts on park resources. The NPS Air Resources Division (ARD) administers an Air Monitoring Program that provides current air quality conditions and assesses long-term trends in pollutants that affect national park resources. The data comes from a variety of sources including monitoring stations in parks and a number of interagency programs.

Monitoring Objectives

  1. Document the annual status of and trends in atmospheric ozone concentrations in MIDN parks using metrics that are relevant to human health (e.g., 8-hour average) and plant response (e.g., W126 index).
  2. Document the annual status of and trends in visibility in MIDN parks.
  3. Document the annual status of and trends in wet deposition of ammonium, nitrate, sulfate, nitrogen, sulfur, and mercury in MIDN parks.

Resource briefs are short PDFs summarizing our monitoring programs or results.

Source: Data Store Saved Search 677. To search for additional information, visit the Data Store.

Periodically, we publish reports that describe what we are learning in the field. These monitoring reports are more in-depth than resource briefs and include data analysis and a discussion of our findings. 

Source: Data Store Saved Search 3459. To search for additional information, visit the Data Store.

Protocols describe how we monitor. They include a descriptive narrative of what we monitor and why, our field methods, how we analyze and manage our data, and more. All of our protocols are peer reviewed.

Visibility Monitoring Standard Operating Procedures (IMPROVE - Interagency Monitoring of Protected Visual Environments)

Source: Data Store Saved Search 3460. To search for additional information, visit the Data Store.

Last updated: December 17, 2020

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