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Air Quality

Air Pollutants - Particulate Matter (PM) - Standards & Requirements

National Ambient Air Quality Standards for Particulate Matter

Since the first PM National Ambient Air Quality Standard (NAAQS, or standard) was established in 1971, the U.S. Environmental Protection Agency (EPA) has revised them several times. Using the tabs and links below you can find information on the current PM standard and regulatory actions, as well as a detailed history of the current and previous PM standards.

1971 National Ambient Air Quality Standard for PM (April 30, 1971) (Revoked)

  Averaging Time Level (Micrograms per cubic meter)
Total Suspended Particles (TSP) 24-hour 1 260 (primary)
150 (secondary)
Annual 2 75

1 To meet this standard, no monitor in an area can exceed 260 or 150 micrograms per cubic meter more than once per year.

2 To meet this standard, the annual average TSP levels in an area cannot exceed 75 micrograms per cubic meter.

History of the 1971 PM Standard

July 1, 1987 EPA published the 1987 PM standard (52 FR 24634). This standard revoked the 1971 Total Suspended Particulate TSP standards.
April 30, 1971 EPA published the first PM standard (36 FR 8186).

Additional Resources

For more information please contact the Bureau of Air Quality at (803) 898-4123 or by email.