The Environmental Protection Agency (EPA) is approving a State Implementation Plan (SIP) revision submitted by the State of New Hampshire that addresses the infrastructure requirements of the Clean Air Act (CAA or Act), excluding the interstate transport provisions, for the 2015 ozone National Ambient Air Quality Standards (NAAQS). We are also granting the state an exemption from the infrastructure SIP contingency plan obligation for ozone and are conditionally approving several elements of New Hampshire's submittal relating to air-quality modeling requirements. In addition, we are correcting errors in our previous approval of an infrastructure SIP submission from New Hampshire for the 2012 PM<INF>2.5</INF> NAAQS and conditionally approving several elements of that submittal. The infrastructure requirements are designed to ensure that the structural components of each state's air-quality management program, including provisions prohibiting emissions that will have certain adverse air-quality effects in other states, are adequate to meet the state's responsibilities under the CAA. This action is being taken in accordance with the Clean Air Act.