On Tuesday, the District of Columbia Court of Appeals vacated EPA’s “Close-Out Rule,” which basically concluded that upwind states contributing to exceedances of the National Ambient Air Quality Standard for ozone in downwind states did not have to undertake any additional actions to reduce their contribution to downwind state ozone concentrations. The decision was inevitable following last month’s decision in Wisconsin v. EPA, in which the D.C. Circuit ruled that upwind states must eliminate any substantial contribution to downwind NAAQS exceedances by the same deadline faced by those downwind states to meet the ozone NAAQS.

As the Court noted in yesterday’s decision:

EPA acknowledges [that] the Close-Out Rule “relied upon the same statutory interpretation of the Good Neighbor Provision” that we rejected in Wisconsin. Thus, the agency’s defense of the Close-Out Rule in these cases is foreclosed.

While EPA has informed the Court that it might seek rehearing or rehearing en banc in Wisconsin v. EPA, for now EPA is in the position of figuring out how to require upwind states to eliminate significant contributions to downwind ozone NAAQS exceedances by 2021. I think that the decisions in both Wisconsin v. EPA and New York v. EPA are correct, but they certainly highlight significant flaws with the Clean Air Act’s NAAQS provisions. Does anyone think that such reductions will happen by 2021? Let’s remember that we’re still talking about how to attain an ozone standard, 0.075 ppm, that was lowered in 2015 to 0.070 ppm.

As I have said in other contexts, if we had a working legislative body, the dysfunctional NAAQS process would have been fixed by now.