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EPA Proposal Addresses “Good Neighbor” Obligations for 2008 Ozone Standard

Eastern States on Track to Meet 2008 Ozone Standards

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WASHINGTON — The U.S. Environmental Protection Agency (EPA) is proposing to determine that the 2016 Cross State Air Pollution Rule (CSAPR) Update satisfies “good neighbor” obligations in the 2008 National Ambient Air Quality Standards (NAAQS) for ground-level ozone. The “good neighbor” (or “interstate transport”) provision requires upwind states to control their emissions so as not to cause air quality problems in downwind states.

This proposal is intended to provide certainty to states across the country. Instead of imposing additional top-down regulations, this action analyzes air quality trends and modeling that show states in the CSAPR Update region will meet the 2008 ozone NAAQS after the CSAPR Update is fully implemented, and additional upwind reductions are not required.

Based on progress in reducing concentrations and precursor emissions of ozone, this proposed action will close out the CSAPR approach to ‘good neighbor’ obligations, which has involved the imposition of federal implementation plans and lingering uncertainty for our state partners,” said EPA Office of Air and Radiation Assistant Administrator Bill Wehrum. “Starting this year, we expect states to step up to address these interstate obligations and EPA has identified technical tools and flexibilities to facilitate these plans.”

The latest EPA air quality data and modeling predict that by 2023 there will be no remaining nonattainment or maintenance areas for the 2008 Ozone NAAQS in the CSAPR Update region, which encompasses most of the eastern United States. Once the 2016 CSAPR Update is fully implemented, upwind states in this region are not expected to contribute significantly to nonattainment or interfere with maintenance of 2008 ozone standards in any downwind state.

Under today’s proposal, EPA and these 20 states would have no obligation to establish additional requirements for sources to further reduce transported ozone pollution to meet the 2008 ozone NAAQS.

EPA is proposing minor, clerical revisions to the existing CSAPR Update regulations to reflect the Agency’s proposed determination that the Federal Implementation Plans (FIPs) in place for the covered states fully address the Clean Air Act’s “good neighbor” provisions for the 2008 ozone NAAQS. The proposal would apply to states currently subject to CSAPR Update FIPs, as well as any states for which EPA has approved replacement of CSAPR Update FIPs with CSAPR Update State Implementation Plans (SIPs).

Earlier this year, EPA provided more information, including updated modeling and a list of potential flexibilities, to help states to develop their “good neighbor” state plans under the 2015 ozone NAAQS, which are due in October 2018.

EPA will take comment on today’s proposed action for 45 days after publication in the Federal Register. For more information on today’s announcement and information on how to comment, go to:


“Good neighbor” obligations under the Clean Air Act (CAA) require upwind states to reduce pollution that could significantly contribute to downwind states’ inability to attain and maintain the National Ambient Air Quality Standards (NAAQS). See 42 U.S.C. § 110(a)(2)(D)(i)(I).

Under the CAA, each state is required to submit a State Implementation Plan (SIP) that provides for the implementation, maintenance, and enforcement of each NAAQS to EPA. Each state must make this new SIP submission within 3 years after EPA issues a new or revised NAAQS.  A key CAA requirement for these SIPs is that they must assure that emissions in upwind states do not contribute significantly to problems with attainment or maintenance of the NAAQS in downwind states (known as the “good neighbor” or “interstate transport” provision). If a state does not submit a good neighbor SIP, or if the EPA disapproves the SIP, EPA must issue a Federal Implementation Plan (FIP).