In October 2015, EPA reduced the level of the National Ambient Air Quality Standards (“NAAQS”) for ozone from 75 parts per billion (“ppb”) to 70 ppb. What is happening concerning implementation of those NAAQS?

Although litigation over EPA’s decision to lower the ozone NAAQS remains in abeyance as the Trump Administration continues to consider whether the Agency should reconsider the rule or some part of it, the 2015 standard itself has not been stayed. Thus, the Clean Air Act requires that implementation of the standard proceed. One key step in implementation is promulgation by EPA of a list of areas where the standard is violated, including areas that contribute to standard violations in nearby areas. EPA’s identification of these “nonattainment” areas is a trigger for many of the Act’s control requirements. Continue Reading What’s Up with Air Quality Standards for Ozone?