Air Plan Approval; ID, Pinehurst PM10

On September 29, 2017, the Idaho Department of Environmental Quality (IDEQ) submitted a redesignation request and limited maintenance plan (LMP) for particulate matter with an aerodynamic diameter less than or equal to ten micrometers (PM10) for the PM10 National Ambient Air Quality Standard (NAAQS) developed for the Pinehurst PM10 Nonattainment Area (NAA) and Pinehurst PM10 Expansion Nonattainment Area (NAA). The redesignation request asserts that the area meets the Clean Air Act (CAA) requirements for redesignation identified in section 107(d)(3)(E). This limited maintenance plan for these contiguous nonattainment areas addresses maintenance of the PM10 standard for a ten-year period beyond redesignation. The Environmental Protection Agency (EPA) proposes to approve this IDEQ Implementation Plan (SIP) revision. The EPA also proposes to approve the September 15, 2013, high wind exceptional event at the Pinehurst monitoring station. Additionally, the EPA is proposing to approve the emissions inventory for the West Silver Valley annual PM2.5 NAA.