Approval and Promulgation of Implementation Plans; Iowa; Clean Air Interstate Rule

EPA is taking final action to approve a revision to the Iowa State Implementation Plan (SIP) submitted on August 15, 2006. This revision addresses the requirements of EPA's Clean Air Interstate Rule (CAIR) promulgated on May 12, 2005, and subsequently revised on April 28, 2006, and December 13, 2006. EPA has determined that the SIP revision fully implements the CAIR requirements for Iowa. As a result of this action, EPA will also withdraw, through a separate rulemaking, the CAIR Federal Implementation Plans (FIPs) concerning SO<INF>2</INF>, NO<INF>X</INF> annual, and NO<INF>X</INF> ozone season emissions for Iowa. The CAIR FIPs for all States in the CAIR region were promulgated on April 28, 2006, and subsequently revised on December 13, 2006. CAIR requires States to reduce emissions of sulfur dioxide (SO<INF>2</INF>) and nitrogen oxides (NO<INF>X</INF>) that significantly contribute to, and interfere with maintenance of, the national ambient air quality standards for fine particulates and/or ozone in any downwind state. CAIR establishes State budgets for SO<INF>2</INF> and NO<INF>X</INF> and requires States to submit SIP revisions that implement these budgets in States that EPA concluded did contribute to nonattainment in downwind states. States have the flexibility to choose which control measures to adopt to achieve the budgets, including participating in the EPA-administered cap-and-trade programs. In the SIP revision that EPA is approving today, Iowa has met the CAIR requirements by electing to participate in the EPA- administered cap-and-trade programs addressing SO<INF>2</INF>, NO<INF>X</INF> annual, and NO<INF>X</INF> ozone season emissions.