Section 52.350 - Control strategy: Ozone(a) Revisions to the Colorado State Implementation Plan, 1-hour ozone NAAQS Redesignation Request and Maintenance Plan for Denver entitled "Ozone Redesignation Request and Maintenance Plan for the Denver Metropolitan Area,'excluding Chapter 1 and Appendix B, as adopted by the Colorado Air Quality Control Commission on January 11, 2001, State effective March 4, 2001, and submitted by the Governor on May 7, 2001.(b) Revisions to the Colorado State Implementation Plan, 8-hour ozone NAAQS Early Action Compact plan for the metropolitan Denver area entitled "Early Action Compact Ozone Action Plan," excluding sections entitled "Introduction" and "Ozone Monitoring Information," as adopted by the Colorado Air Quality Control Commission on March 12, 2004, and submitted by the Governor to us on July 21, 2004.(c) Revisions to the Colorado State Implementation Plan for the 1997 8-hour ozone NAAQS entitled "Denver Metro Area & North Front Range 8-Hour Ozone Attainment Plan," excluding the last paragraph on page IV-1, the first paragraph on page IV-2, the words "federally enforceable" in the second to last paragraph on page V-6, and the reference to Attachment A in the Table of Contents and on page IV-3, as adopted by the Colorado Air Quality Control Commission on December 12, 2008, and submitted by the Governor to EPA on June 18, 2009.(d) Determination of attainment by the attainment date for the revoked 1997 8-hour ozone National Ambient Air Quality Standards (NAAQS). Effective August 30, 2021. On November 13, 2020, the EPA determined that Denver-Boulder-Greeley-Ft. Collins-Loveland, CO, attained the revoked 1997 8-hour ozone NAAQS by the applicable attainment date of November 20, 2010. The determination was based upon complete quality-assured and certified data for the three calendar years 2007-2009. 66 FR 47092 , Sept. 11, 2001, as amended at 70 FR 48654 , Aug. 19, 2005; 76 FR 47451 , Aug. 5, 2011; 86 FR 40787 , July 29, 2021