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State Implementation Plan (SIP) - 2015 Eight-hour Ozone Standard, Moderate Ozone Planning

On August 3, 2018, U.S. EPA designated three areas in Ohio as “marginal nonattainment” for the 2015 ozone National Ambient Air Quality Standard (NAAQS): Cincinnati, Cleveland and Columbus. Under section 182(a) of the Clean Air Act Amendments, marginal areas have up to three years from designation to attain the standard (August 3, 2021). The Columbus area attained the standard and was redesignated to attainment on August 21, 2019.

The Cincinnati and Cleveland areas did not meet the ozone standard by the end of the 2020 ozone season (October 31). On April 13, 2022 (87 FR 21842), U.S. EPA proposed to “bump-up” these areas to moderate nonattainment. A bump-up from marginal to moderate nonattainment triggers additional requirements under Clean Air Act (CAA). On June 13, 2022, Ohio EPA provided comments to U.S. EPA (Comments on Attainment Demonstration and Area  Reclassifications) on the proposed bump-up. Effective November 7, 2022 (87 FR 60897), U.S. EPA bumped-up the Cleveland area to moderate nonattainment. Ohio EPA is currently planning for the bump-up. Information and resources will be provided here as they are developed. 

On June 9, 2022 (87 FR 35104), U.S. EPA approved the final redesignation request and maintenance plan for the Ohio portion of the Cincinnati, OH-KY area to be classified as attainment for the 2015 ozone standard based upon 2019-2021 ozone monitoring data. A copy of Ohio's redesignation request and U.S., EPA's final approval can be found on Ohio's State Implementation Plan (SIP) - 2015 Eight-hour Ozone Standard webpage. Since the redesignation was finalized before U.S. EPA’s final action, the Ohio portion of the Cincinnati nonattainment area was not included in the bump-up to moderate nonattainment.

Contact Information

For questions or additional information, contact Holly Kaloz at holly.kaloz@epa.ohio.gov or (614) 644-3632.


Exceptional Event Demonstration

On April 13, 2021, Ohio EPA submitted to U.S. EPA an Exceptional Events demonstration which, if approved by U.S. EPA, may allow the Cincinnati area to be eligible for a one-year extension to the attainment date. The demonstration is available on Ohio's State Implementation Plan Website.

In order for the Exceptional Events demonstration to be approvable, U.S. EPA requires a very detailed and rigorous technical analysis, in accordance with U.S. EPA rule and guidance (available at https://www.epa.gov/air-quality-analysis/final-2016-exceptional-events-rule-supporting-guidance-documents-updated-faqs).

On November 4, 2021, U.S. EPA issued a nonconcurrence letter and a technical support document.

LADCO Projects

Ohio EPA in collaboration with the Lake Michigan Air Directors Consortium (LADCO) and nearby states are engaging in several projects to evaluate potential control measures and update technical information to be used in future decision making.


Ohio EPA rulemakings to adopt/update requirements as required under the CAA or as necessary to attain the 2015 ozone standard will be posted on Ohio EPA’s rulemaking site.

To date, these rulemakings include:

State Implementation Plan (SIP) Submittals

Proposed “Good Neighbor” Federal Implementation Plan for the 2015 Ozone Standard

On April 6, 2022 (87 FR 20036), U.S. EPA proposed a Federal Implementation Plan (FIP) to address regional ozone transport for the 2015 Ozone National Ambient Air Quality Standards (NAAQS). The proposed FIP is often referred to as a “Good Neighbor” FIP or “Transport Rule”. On June 13, 2022, Ohio EPA provided comments to U.S. EPA  (Comments on Proposed Federal Implementation Plan (FIP)) on the proposed FIP.

Subscribe for Updates

Ohio EPA has listServ/electronic mailing lists for parties interested in receiving notifications on rulemakings and State Implementation Plan (SIP) actions. To sign up for these mailing lists:

Create a Customer Support Center Account
How to subscribe for updates and training opportunities through Ohio EPA’s Customer Support Center. Ready to create your account? Click on the link below.

  • Open Ohio EPA's main webpage at: epa.ohio.gov
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