The Fix Is In: On Ozone NAAQS, EPA Relies on EPA Science

by William Yeatman on May 13, 2014

in Blog, Features

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On Monday, in draft comments to EPA’s “Second Draft Policy Assessment for the Review of the Ozone National Ambient Air Quality Standards,” the Clean Air Scientific Advisory Committee (CASAC) endorsed the agency’s decision to set the lower bound of a national ozone standard at 60 parts per billion.

CASAC’s  finding could have terrible consequences for the U.S. economy. As I’ve explained in a previous post, the D.C. Circuit Court gives controlling weight to CASAC’s assertions. As such, these draft comments legitimize an ozone standard—i.e., one set at 60 ppb—that EPA estimates would cost $90 billion annually. Such a standard would plunge 97% of the country into “non-attainment,” which triggers ultra-stringent controls.

Given the stakes, you’d think EPA and CASAC would rely on only the latest, most independent science, right? Alas, that isn’t the case. Instead, all of the clinical studies cited by CASAC in support of the 60 ppb standard were created by the EPA—the organization that proposed the limit. Thus, the science on which the economy’s fate hinges suffers from a troubling absence of independence. Moreover, all of the non-EPA literature (on health impacts of 60 ppb ozone) cited by CASAC does NOT support a 60 ppb standard. This dichotomy is further disconcerting.

Here’s precisely what CASAC said:

“The CASAC concurs that 60 ppb is an appropriate and justifiable scientifically based lower bound for a revised primary standard. This is based upon findings of adverse effects, including clinically significant lung function decrements and airway inflammation, after exposures to 60 ppb ozone in healthy adults with moderate exertion (Adams 2006; Schelegle et al. 2009; Brown, 2008; Kim et al., 2011), with limited evidence of adverse effects below 60 ppb.”

I formatted the list of scientific articles that buttress CASAC’s conclusions. Let’s take a brief look at this research, one by one.

The report did NOT find a statistical difference in health between exercising in filtered air and in 60 ppb ozone.

  • Schelegle et al. (2009) “6.6-Hour Inhalation of Ozone Concentrations from 60 to 87 Parts per Billion in Healthy Humans,” American journal of Respiratory and Critical Care Medicine, v. 180 pp 265-272

The report did NOT find a statistical difference in health between exercising in filtered air and in 60 ppb ozone.

Using different, less “conservative” statistical tests (i.e., more likely to produce a significant result), this paper re-analyzed the data from Adams (2006), and, upon further review, found that there was “a biologically small but highly statistically significant decrease” in lung function when exercising in 60 ppb relative to exercising in filtered air. Same data, different statistics, different results. [This calls to mind Twain's famous observation regarding the nature of statistics]

Found statistically significant difference in lung function between exercising in clean air and 60 ppb. Notably the observed magnitude of the statistically significant effect of ozone on lung function was less in the Kim et al. (2011) study than for either the Adams (2006) or Schelegle et al. (2009) study, even though neither of these latter two studies found a statistically significant impact.

To recap: There are four clinical studies that address the health impact of ozone on lung function at ambient air levels of 60 ppb. Two of them—Adams (2006) and Schelegle et al. (2009)—did NOT find a statistical difference in lung function between exercising in filtered air and in 60 ppb ozone. And two studies—Brown et al. (2008) and Kim et al. (2011)–did find a statistical difference in lung function between exercising in filtered air and in 60 ppb ozone.

In fact, these latter two studies share something else in common: They were both produced by the EPA! The two lead authors of Brown et al. (2008) worked at EPA’s National Center for Environmental Assessment; the study, moreover, was funded by an EPA grant. And seven of the ten authors of Kim et al. (2011), including the lead researcher, work at EPA’s National Health and Environmental Effects Research Laboratory.

Thus, the science underlying what could be the most expensive regulation, ever, emanates solely from the very organization that would propose the regulation to begin with.

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