Last week, the D.C. Circuit upheld EPA’s 2008 ozone standard of 75 ppb, although it remanded the agency’s decision to set a secondary standard at exactly the same level. It may seem strange for the court to take five years to issue its decision on these ozone standards, but the court was marking time while EPA proposed to lower the standard to between 60 and 70 ppb, only to have that proposal rejected by the White House in light of plans to re-evaluate the standard whole cloth in 2013.
Now that it is 2013, a new proposal is expected by the end of the year, which may render the court’s recent decision of little practical effect, since EPA may soon replace the 2008 ozone standard. However, the fact that the court endorsed EPA’s ozone standard in spite of the fact that it was set higher than recommended by the Clean Air Scientific Advisory Committee (CASAC) could have implications for future revisions of national air quality standards, including the new ozone standard expected in a few months. A copy of the court’s decision is available here: Mississippi v. EPA.