You may have read in a recent Federal Register that the EPA is proposing to grant a one-year extension before classifying the Denver Metro North Front Range (DMNFR) ozone nonattainment area (NAA) from moderate to serious. This is based on 2017 being a "clean" year with no exceedances of the 8-hour 2008 ozone standard after removing "exceptional events". This extension was anticipated, and the publication in Register provides confirmation. Based on 2018 monitor data, it's likely that the area will be reclassified to "serious" as early as January 1, 2020.
For assistance with your air permitting needs, contact the Denver office by calling (720) 638-7647 or the Trinity office nearest you by calling (800) 229-6655 for more information.