EPA's Ozone NAAQS Largely Survives: CASAC Still Rules

The D.C. Circuit today largely upheld EPA's 2015 revisions to the National Ambient Air Quality Standard for ozone. I'm not much of a prognosticator, but I pretty much called this one years ago. The Court was never going to require EPA to consider costs in setting the NAAQS – not a surprise, given that the Supreme Court concluded in Whitman v. American Trucking Association that the CAA:

Nor was it going to rule that EPA should have taken background ozone concentrations into account in setting the NAAQS. As the Court recognized, the statute allows EPA to address background issues in implementing the NAAQS, but implementation issues are irrelevant to setting the NAAQS at the level, "allowing an adequate margin of safety, [that] are requisite to protect the public health."