Approval and Promulgation of Implementation Plans; Iowa; Interstate Transport of Pollution

EPA is revising the Iowa State Implementation Plan (SIP) for the purpose of approving the Iowa Department of Natural Resources' (IDNR) actions to address the "good neighbor" provisions of the Clean Air Act section 110(a)(2)(D)(i). These provisions require each state to submit a SIP that prohibits emissions that adversely affect another state's air quality through interstate transport. IDNR has adequately addressed the four distinct elements related to the impact of interstate transport of air pollutants. These include prohibiting significant contribution to downwind nonattainment of the National Ambient Air Quality Standards (NAAQS), interference with maintenance of the NAAQS, prevention of significant deterioration of air quality, and protection of visibility. The requirements for public notification were also met by IDNR.