Particle Pollution (PM2.5) Designation History EPA letter to Governor Pat McCrory on final PM 2.5 designations, Dec. 18, 2014 EPA letter to Governor Pat McCrory on PM 2.5 Designations, Aug. 19, 2014 North Carolina's Recommendations for Air Quality Designations for the 2012 Revised Annual PM2.5 Standard - Letter from DENR Secretary John Skvarla to EPA (Dec. 13, 2013) PM2.5 Nonattainment Areas in North Carolina Letter from DENR Secretary Bill Ross to USEPA about Proposed PM2.5 Designations (Sept. 8, 2004) Letter from Gov. Mike Easley to USEPA Administrator Michael Leavitt regarding PM2.5 Nonattainment Designations (Sept. 9, 2004) North Carolina PM2.5 Design Values