Air Plan Approval; Connecticut; Infrastructure State Implementation Plan Requirements; Prevention of Significant Deterioration Permit Program Revisions

The Environmental Protection Agency (EPA) is proposing to approve elements of a State Implementation Plan (SIP) submission from Connecticut regarding the infrastructure requirements of the Clean Air Act (CAA or Act) for the 2012 fine particle (PM 2.5 ) National Ambient Air Quality Standards (NAAQS), and a SIP submission addressing interstate transport requirements of the CAA for the 2006 PM 2.5  NAAQS. In addition, we are proposing to approve one statute included in the SIP for the 2012 PM 2.5  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 EPA is also proposing to approve revisions to the SIP submitted by Connecticut on October 18, 2017, satisfying Connecticut's earlier commitment to adopt and submit provisions that meet certain requirements of the federal Prevention of Significant Deterioration (PSD) permit program. In addition, we are proposing to convert the June 3, 2016 conditional approval for elements of Connecticut's infrastructure SIP regarding PSD requirements to treat nitrogen oxides (NO X ) as a precursor to ozone and to establish a minor source baseline date for PM 2.5  emissions. This action is being taken under the Clean Air Act.