EPA Scientific Advisory Group Rejects Agency PM Standards

Sep 29: U.S. EPA's Clean Air Scientific Advisory Committee (CASAC), in a strongly critical 3-page letter to Administrator Stephen Johnson, says that the Agency's newly finalized annual PM2.5 standard does not provide an “adequate margin of safety… requisite to protect the public health” which they say is required by the Clean Air Act. Further they say that their recommendations to the Agency "were consistent with the mainstream scientific advice that EPA received from virtually every major medical association and public health organization that provided their input..." On September 21, EPA announced what it said were the "strongest national air quality standards in the country's history" establishing National Ambient Air Quality Standards (NAAQS) for fine and coarse particle particulate matter (PM). Administrator Johnson said at the time, "Regardless of the rhetoric, facts are facts -- today EPA is delivering the most health protective national air standards in U.S. history to all 300-million Americans. As a 26-year EPA scientist, I have spent my career working to hand down a cleaner, healthier environment -- and these stronger air quality standards do just that." [See WIMS 9/21/06]

In stark contrast, the CASAC begins its letter to Johnson saying, "We, the seven members of the Clean Air Scientific Advisory Committee (CASAC or Committee), are writing to express our serious scientific concerns regarding the public health and welfare implications of EPA’s final primary (health effects) and secondary (welfare effects) National Ambient Air Quality Standards (NAAQS) for airborne particulate matter (PM). As you know, the CASAC is mandated by the Clean Air Act to provide scientific advice on the setting of these standards that are intended to protect both public health and public welfare, and in the case of the protection of public health, to do so with 'an adequate margin of safety.' The Committee has conscientiously fulfilled its duty in providing our best scientific advice and recommendations to the Agency. Regrettably, however, EPA’s final rule on the NAAQS for PM does not reflect several important aspects of the CASAC’s advice."

CASAC said it was concerned that EPA did not accept its finding that the annual PM2.5 standard was not protective of human health and did not follow its recommendation for a change in that standard. In emphasized text, the CASAC writes, "...there is clear and convincing scientific evidence that significant adverse human-health effects occur in response to short-term and chronic particulate matter exposures at and below 15 µg/m3, the level of the current annual PM2.5 standard..." CASAC said that in addition to their recommendation, 20 of the 22 members of the CASAC’s Particulate Matter Review Panel that assisted in the review -- including all seven members of the chartered (statutory) Committee -- were in complete agreement. Again in emphasized text, CASAC said, "It is the CASAC’s consensus scientific opinion that the decision to retain without change the annual PM2.5 standard does not provide an 'adequate margin of safety … requisite to protect the public health' (as required by the Clean Air Act), leaving parts of the population of this country at significant risk of adverse health effects from exposure to fine PM. Significantly, we wish to point out that the CASAC’s recommendations were consistent with the mainstream scientific advice that EPA received from virtually every major medical association and public health organization that provided their input to the Agency... Indeed, to our knowledge there is no science, medical or public health group that disagrees with this very important aspect of the CASAC’s recommendations."

Describing another concern with EPA's final PM regulations, CASAC said they were, "completely surprised at the decision in the final PM NAAQS to revert to the use of PM10 the indicator for coarse particles. In our September 15, 2005 letter, the CASAC recommended a new indicator of PM10-2.5, which EPA put forward in its proposed rule for the PM NAAQS... The CASAC wishes to emphasize that continuing to rely on primary standards to protect against all PM-related adverse environmental and welfare effects assures neglect, and will allow substantial continued degradation, of visual air quality over large areas of the country."

In a concluding summary, CASAC says, "...the Agency has rejected the CASAC’s expert scientific advice with regard to lowering the level of the annual primary fine particle (PM2.5) standard and establishing a new coarse particle (PM10-2.5) standard -- both of which are consistent with the recommendations of the nationally-recognized science, medical and public health groups such as those cited above -- and, in addition, EPA has not followed our advice in setting a separate secondary PM2.5 standard. We note that, since the CASAC’s inception in the late 1970s, the Agency has always accepted the Committee’s scientific advice with regard to final NAAQS decisions."

Access the complete CASAC letter (click here). Access the WIMS 9/21/06 article on EPA's PM standards with links to further information posted on the WIMS-eNewsUSA Blog (click here). Access the CASAC PM Review Panel website for extensive background information (click here). [*Air]