Implementation of the Revoked 1997 8-Hour Ozone National Ambient Air Quality Standards; Updates to 40 CFR Part 52 for Areas That Attained by the Attainment Date

The Environmental Protection Agency (EPA) is updating part 52 of title 40, chapter 1 of the Code of Federal Regulations (CFR) to codify its findings that nine areas in four states attained the revoked 1997 8-hour ozone National Ambient Air Quality Standards (herein referred to as the 1997 ozone NAAQS) by the applicable attainment dates. In February 2019, EPA Regional Offices sent letters to the affected states to communicate the EPA's findings. The areas that timely attained the standards include the Buffalo-Niagara Falls area, and the Jefferson County, Poughkeepsie and Jamestown areas in the state of New York; the Shoreline Sheboygan County and Inland Sheboygan County areas in Wisconsin; the Denver-Boulder-Greeley-Ft. Collins-Loveland area in Colorado; and the San Francisco Bay and Ventura County areas in California. Publishing these determinations in part 52 will document for the public and state air agencies that these areas attained the standards by the applicable attainment dates and are therefore not subject to anti-backsliding consequences for failure to timely attain the standards.