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Colorado Proposes Revised 8-Hour Ozone Standard Implementation Schedule; Denver Metro Designation Likely to “Bump Up” from Marginal to Moderate Attainment Come January 2016

June 30, 2015

EPA issued its proposed rule to the 8-hour ozone NAAQs on December 17, 2014, indicating that it may lower the allowable levels of ozone to a range between .065 and .070 ppm; this is a significant tightening of the standard from the current level of .075 ppm. The final rule is expected in October 2015.