Evidence That Low Exposures to Particulate Matter Pose Health Risks Continues to Accumulate — Will Administrator Wheeler Listen?

EPA’s Office of Air Quality Planning and Standards has issued its final “Policy Assessment for the Review of the National Ambient Air Quality Standards for Particulate Matter.” The Policy Assessment comes with the standard disclaimer that its “findings and conclusions are those of the authors and do not necessarily reflect the views of EPA.” Sadly, truer words were never spoken.

Those following this issue know that, in response to the draft PA, a majority of EPA’s Clean Air Science Advisory Committee concluded that available evidence does not warrant tightening the primary PM2.5 standard. Since this is a blog post, I’ll give the short version – Tony Cox, the CASAC chair, doesn’t appear to believe that epidemiology provides a basis for setting NAAQS.

The staff of the EPA Office of Air Quality Planning and Standards was not impressed. Although written in dry academic prose, the final PA’s response to CASAC can be boiled down to “You have got to be effing kidding me.” The purpose of the NAAQS is of course to set a standard that is “requisite to protect the public health” “with an adequate margin of safety.” On that score, the PA states that:

when air quality in the 47 study areas is adjusted to simulate just meeting the current standards, the risk assessment estimates from about 16,000 to 17,000 PM2.5-related deaths from ischemic heart disease in a single year.

Does that sound like an “adequate margin of safety” to you? Oh, and by the way, the current roster of CASAC members contains no statisticians or epidemiologists and EPA disbanded the panel with special expertise in PM that used to advise CASAC on the PM NAAQS.

Since the courts have traditionally looked to CASAC for evidence that EPA has acted reasonably in setting NAAQS, judicial review is going to be interesting if EPA decides not to tighten the PM2.5 standard and relies on CASAC’s views to do so, but states and NGOs challenge EPA’s failure to tighten the standard and provide a mountain of evidence that CASAC has lost its collective mind.