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Under the Clean Air Act Amendments of 1977, EPA is required to review and if appropriate revise the air quality criteria for the primary (health-based) and secondary (welfare-based) national ambient air quality standards (NAAQS) every 5 years. On December 31, 2020, EPA published a final decision retaining the ozone (O3) NAAQS, which was the subject of petitions for reconsideration as well as petitions for judicial review. Consistent with Executive Order 13990, Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis,” signed by President Biden on January 20, 2021, EPA undertook a review of the December 2020 decision. Based on that review, EPA has decided to undertake a reconsideration of the December 31, 2020 decision. As part of this reconsideration, EPA developed draft policy assessments for the reconsideration and sought the advice of the Clean Air Scientific Advisory Committee (CASAC) and a newly-constituted expert O3 panel. After carefully considering advice provided by the CASAC in the reconsideration process, EPA is initiating a new review of the O3 NAAQS and the underlying air quality criteria, and EPA will incorporate the ongoing reconsideration into that review. A Call for Information for the new review was published in the Federal Register , and in that review, EPA held a public science and policy workshop in May 2024 to gather input from the scientific community and the public, a summer release of the proceedings of the workshop and a fall 2024 release of the Integrated Review Plan, Volume 2 to guide the new review and development of the Integrated Science Assessment for the new review.