Air Plan Approval; ID, West Silver Valley PM2.5

The Environmental Protection Agency (EPA) proposes to determine that the West Silver Valley, Idaho nonattainment area has clean data for the 2012 annual fine particulate matter (PM2.5) National Ambient Air Quality Standard (NAAQS). This proposed clean data determination (CDD) is based upon quality-assured, quality-controlled, and certified ambient air monitoring data showing the area has attained the 2012 PM2.5 NAAQS based on the 2015-2017 data available in the EPA's Air Quality System (AQS) database. The EPA also proposes to take final agency action on the September 2017 wildfire exceptional event at the Pinehurst monitoring station, pursuant to EPA regulations, as having affected PM2.5 and PM10 values. Based on the proposed clean data determination, the EPA is also proposing to determine that the obligation for Idaho to make submissions to meet certain Clean Air Act (CAA or the Act) requirements related to attainment of the NAAQS for this area are not applicable for as long as the area continues to attain the 2012 annual PM2.5 NAAQS.