Approval and Promulgation of Air Quality Implementation Plans; Indiana; Infrastructure SIP Requirements for the 2008 Ozone National Ambient Air Quality Standards (NAAQS)

The Environmental Protection Agency (EPA) is taking final action to approve elements of a state implementation plan (SIP) submission by Indiana regarding the infrastructure requirements of sections 110(a)(1) and (2) of the Clean Air Act (CAA) for the 2008 ozone national ambient air quality standards (NAAQS). The infrastructure requirements are designed to ensure that the structural components of each state's air quality management program are adequate to meet the state's responsibilities under the CAA. The proposed rulemaking associated with this final action was published on August 19, 2013, and EPA received two comment letters during the comment period, which ended on September 18, 2013. The concerns raised in these letters, as well as EPA's responses, will be addressed in this final action.