Correspondence Search

National Park Service correspondence available through this search page includes letters and reports concerning the Prevention of Significant Deterioration permit review program, air quality regulation development, and related air quality guidance. Correspondence dated January 1, 2003 or later is available.

To search for documents of interest, enter words and phrases separated by commas. You can also use the words 'and', 'or' (a comma implies or) and 'not' to help further define your search. See the example searches below for more information.

Search Example 1: Mammoth Cave National Park - provides a list of every document that contains the phrase 'Mammoth Cave National Park'.

Search Example 2: april * 2003, may * 2003 - provides a list of every document that contains a date within April 2003 or a date within May 2003.

Search Example 3: "April 23, 2003" - provides a list of every document that contains 'April 23, 2003'.

Search Example 4: visibility and deposition - provides a list of every document that contains both 'visibility' and 'deposition'.