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Ground-level Ozone

Ozone Implementation - Programs and Requirements for Reducing Ground Level Ozone

EPA establishes national ambient air quality standards (NAAQS) for ground level ozone (O3) and other criteria pollutants.  EPA works with partners at state, local, and tribal levels to meet these standards.

Under the Clean Air Act (CAA), as amended in 1990, each state must develop a plan describing how it will attain and maintain the NAAQS.  In other words, how it plans to clean up polluted areas and keep them clean.  This plan is called the State Implementation Plan (SIP) and is required under Section 110 of the CAA (40 CFR Part 51, Subparts F & G).  In general, the SIP is a collection of programs (monitoring, modeling, emission inventories, control strategies, etc) and documents (policies and rules) that the state uses to attain and maintain the NAAQS.  A state must engage the public in approving its plan prior to sending it to EPA for approval.

In some cases where the EPA fails to approve a SIP, the Agency can issue and enforce a Federal Implementation Plan (FIP) to ensure attainment and maintenance of the NAAQS.

More information
Implementation Rule for the 1997 8-hour Ozone Standard
Ozone Designations
Ozone Standards
Regulatory Actions


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