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Visibility

Maps of Protected Areas

Certain national park and wilderness areas across the country are given special protection under the Clean Air Act, including some of our best known parks such as Grand Canyon, Yosemite, and Great Smokies.

Today there are 156 protected areas (see map) designated as mandatory federal "Class I" areas for the purposes of the visibility protection program.

The Federal agencies responsible for managing the 156 mandatory federal Class I areas are shown below:

More on "Class I" areas - Under the Clean Air Act, the "Class I" area designations were given to 158 areas in existence as of August 1977 that met the following criteria:

  • all national parks greater than 6000 acres
  • all national wilderness areas and national memorial parks greater than 5000 acres
  • one international park

In 1980, Bradwell Bay, Florida and Rainbow Lake, Wisconsin were excluded for purposes of visibility protection as federal Class I areas. Today, 156 national park and wilderness areas remain as "Class I" visibility protection areas. "Class I" area designations are also important in evaluating the impacts of new air pollution sources (e.g. factories) on national parks and wilderness areas. Special analyses are required when a proposed new emissions source may impact any of the original 158 Class I areas or new areas designated as Class I by states and Tribes. To date, five Tribal areas (see map) have been designated as "Class I" for new source permitting purposes (PDF) (1pg, 74k), but no additional areas have been added by states.

 

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