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Summary of Seattle-Tacoma Puget Sound Area 2nd 10-Year Ozone Maintenance Plan


The Seattle-Tacoma Puget Sound Area was redesignated attainment for ozone on November 25, 1996.

Washington submitted an ozone maintenance plan on January 28, 1993, and EPA approved the plan on September 26, 1996 (61 FR 50438 (PDF)(6 pp, 189 K, About PDF)).

Washington submitted a second 10-year CO/ozone maintenance plan on December 17, 2003, and EPA announced its proposed approval of the plan on June 1, 2004 (69 FR 30847 (PDF)(6 pp, 164 K)).

On August 5, 2004, EPA approved the Central Puget Sound Area 2nd 10-year CO/ozone maintenance plan (69 FR 47365 (PDF)(2 pp, 143 K)).


The plan relies on control strategies needed to assure attainment of the National Ambient Air Quality Standards (NAAQS) for ozone. The strategy focuses on vehicle Inspection and Maintenance Program in conjunction with the Federal Motor Vehicle Emissions Improvement Program.


  • WAC 173-422, Motor Vehicle Emission Inspection
  • PSCAA Regulation II

Contingency Measures

  • PSCAA Regulation I, Section 8.06, Outdoor Burning Ozone Contingency Measure
  • PSCAA Regulation II, Section 2.09, Oxygenated Gasoline Carbon Monoxide Contingency Measures and Fee Schedule
  • PSCAA Regulation II, Section 2.10, Gasoline Station Ozone Contingency Measure

EPA Effective Date

September 7, 2004