State Implementation Plan (SIP) - Interstate Transport

Section 110(a)(2)(D)(i) of the federal Clean Air Act, known as the "good neighbor" provision, requires states to demonstrate to U.S. EPA that emissions from one state do not adversely affect another state. Specifically, the act prohibits any source or other type of emissions activity within the state from emitting any air pollutant in amounts which will:

(i) contribute significantly to nonattainment in, or interfere with maintenance by, any other state with respect to any National Ambient Air Quality Standard (NAAQS), or

(ii) interfere with measures required to be included in the applicable implementation plan for any other state to prevent significant deterioration of air quality or to protect visibility.

On May 12, 2005, U.S. EPA issued the Clean Air Interstate Rule (CAIR) aimed to address the interstate transport of pollutants that contributed significantly to downwind nonattainment of the PM 2.5 and eight-hour ozone NAAQS established in July 1997. These pollutants react in the atmosphere to form fine particles and ground-level ozone and are transported long distances, making it difficult for other states to achieve national clean air standards.

In July 2008, the D.C. Circuit Court vacated CAIR, and subsequently, in December 2008, the court remanded these rules without vacating them. The CAIR requirements are in place and CAIR regional control programs are operating while U.S. EPA works to respond to the remand.

On August 2, 2010, U.S. EPA proposed the Transport Rule which would replace CAIR. Specifically, this proposal would require significant reductions in sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions that cross state lines. Emissions reductions of SO2 and NOx will be required in 2012 – within one year after the rule is scheduled to be finalized. Additional reductions of SO2 would occur again in 2014. Nationally, it is expected this rule will reduce power plant SO2 emissions by 71 percent over 2005 levels. Power plant NOx emissions would drop by 52 percent.

On Oct. 1, 2010, Ohio EPA submitted comments on the proposed Transport Rule:

• Comments
• Supplement

On Sept. 1, 2010, U.S. EPA issued a Notice of Data Availability (NODA). The NODA provided supplemental data regarding the proposed Transport Rule including, among other things, an updated version of the power sector modeling platform that U.S. EPA proposes to use to support the final rule.

On Oct. 15, 2010, Ohio EPA submitted comments on the Transport Rule NODA:

• Comments

On Oct. 27, 2010, U.S. EPA issued a second NODA. The second NODA provided supplemental data regarding the proposed Transport Rule including updated emissions inventory data for 2005, 2012 and 2014 for several stationary and mobile source inventory components. The data revisions reflect new approaches to calculating emissions inventories for specific source categories and related new information and models that have become available since the emissions data were developed and modeled for the proposed Transport Rule. Ohio EPA did not submit comments on the second NODA.

On Jan. 7, 2011, U.S. EPA issued a third NODA . The third NODA provided supplemental data regarding the proposed Transport Rule including two alternative methodologies for allocating unit level SO2 and NOx emissions and data supporting those calculations. This NODA also included new provisions for states to submit SIP providing for state allocation of allowances in the proposed Transport Rule trading programs.

On Feb. 3, 2011, Ohio EPA submitted comments on the third Transport Rule NODA:

• Comments

U.S. EPA intends to finalize this proposed rule in July 2011. Although this rule is expected to get larger emission reductions more quickly than CAIR required, U.S. EPA believes additional emissions reductions will be needed to help states attain current and future air quality standards. Therefore, each time the NAAQS are re-evaluated, U.S. EPA intends to evaluate whether new emission reductions will be required from upwind states. U.S. EPA has already begun the work necessary to apply the proposed template to the upcoming 2010 ozone standard. U.S. EPA plans to propose a Transport Rule to address that 2010 ozone standard in 2011 and finalize it in 2012. 

Additional information about U.S. EPA actions regarding interstate transport can be found at:


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