Air Quality Criteria for Ozone and Related Photochemical Oxidants

The Clean Air Act requires periodic (5-year) update revision of criteria and National Ambient Air Quality Standards (NAAQS) for Ozone. The previous revision of the criteria contained in the Air Quality Criteria Document (AQCD) for Ozone and Related Photochemical Oxidants was completed in 1996 and provided scientific bases for revision of the Ozone NAAQS in 1997. The current update revision started in fiscal year 1999 and resulted in release in January, 2005 of the First External Review Draft (ERD) of the revised Ozone AQCD. This was followed by 90-day public comment period and a CASAC review of the draft in May, 2005. Revisions of the First ERD were completed, which culminated with release of the Second ERD in August, 2005, followed by a 60-day public comment period and a December, 2005 CASAC meeting to review the Second ERD. Revisions to the Second ERD resulted in publication in March 2006 of the Final Ozone Air Quality Criteria Document.