Implementation of the 2015 National Ambient Air Quality Standards (NAAQS) for Ozone: Final Nonattainment Area Classifications Approach
On March 1, 2018, the U.S. Environmental Protection Agency issued a final rule establishing the air quality thresholds that define each of the five Clean Air Act classifications for areas designated nonattainment for the 2015 National Ambient Air Quality Standards (NAAQS) for ground-level ozone; and establishing the attainment deadline associated with each classification. The EPA revised both the health-based and welfare-based standards for ozone on October 1, 2015.