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Clean Air Interstate Rule

On March 10, 2005, the United States Environmental Protection Agency (EPA) issued the Clean Air Interstate Rule (CAIR) that was designed to address power plant pollution that drifts from one state to another. A cap and trade system was used to reduce the target pollutants: sulfur dioxide and nitrogen oxides.

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CAIR State Implementation Plan (SIP) Revision and Rule

CAIR SIP Revision

30 TAC Chapter 101, Subchapter H, Division 7 CAIR Rule Revision

General Information on CAIR

Note: On July 6, 2011, the EPA finalized a rule intended to replace CAIR, called the Cross-State Air Pollution Rule (CSAPR), requiring 28 eastern states to reduce EGU emissions that contribute to ozone and PM2.5 pollution in other states. Texas was included in CSAPR for the 1997 ozone and 1997 PM2.5 NAAQS. For more information on the latest CSAPR actions, visit the CSAPR webpage.

On March 10, 2005, the EPA signed CAIR. The final rule was subsequently published in the Federal Register on May 12, 2005. The rule required 28 states and the District of Columbia to achieve specified emission reductions for new and existing electric generating units (EGUs). States had the option to use one of two methods of compliance: (1) meet the state's emission budget by requiring EGUs to participate in an interstate cap and trade system, administered by the EPA, that caps emissions in two stages; or (2) meet an individual state emission budget through measures of the state's choosing. In 2005, the 79th Texas Legislature (Regular Session) passed HB 2481, which required Texas to adopt portions of the rule by reference and stipulated specifications for allowances and set-asides for nitrogen oxide (NOX) emissions. Therefore, Texas was participating in the EPA-administered interstate cap and trade program.

CAIR consisted of two phases for reductions in NOX and sulfur dioxide (SO2). Phase I for NOX was to run from 2009 through 2014; Texas' NOX budget amounted to 181,014 tons annually. Phase II was set to begin in 2015 and continue indefinitely; Texas' NOX budget would be 150,845 tons annually.

SO2 budgets were based on Title IV allocations with annual state budgets for 2010 through 2014 (Phase I) based on a 50% reduction for all units in the affected state. The Texas budget for Phase I was 320,946 tons annually. In 2015 and beyond, Phase II budgets were to be based on a 65% reduction of Title IV allowances allocated to units in the affected state for SO2 controls. The Texas budget for Phase II would be 224,662 tons annually. SO2 allocations were distributed by the EPA through the Acid Rain Program . EGUs that were required to participate in the CAIR program, but were non-Acid Rain units, were required to acquire SO2 allowances.

The EPA modeled 37 states, including Texas, for their fine particulate matter (PM2.5) contribution using the Community Multiscale Air Quality Model. A criterion of 0.2 micrograms per cubic meter (µg/m3) was used for determining whether SO2 and NOx emissions in a state made a significant contribution to PM2.5 nonattainment in another state. State-by-state zero-out modeling was then used to quantify the state's contribution for SO2 and NOX. The EPA's modeling demonstrated that Texas contributed 0.29 µg/m3 with two downwind linkages - Madison and St. Clair, Illinois. For ozone, 31 states in the eastern United States were modeled. Since Texas was not included in the modeling exercise, there was no determination that Texas contributed to ozone nonattainment in another state.

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Related Links

Texas Statutes

EPA's CAIR Information

EPA's Clean Air Mercury Rule (CAMR) Information

Other Information

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