EPA’s science advisers disappointed by proposed PM standards
In an unprecedented move, the Clean Air Scientific Advisory Committee asks EPA to rethink its proposed rules.
Under a set of standards [1.5MB PDF] published in January, the U.S. EPA is proposing to reduce allowable levels of particulate matter (PM) found in the air people breathe, but not by as much as its Clean Air Scientific Advisory Committee (CASAC) recommended. In an unusual move, CASAC members criticized the proposed rule, saying it would not be sufficiently protective. The committee plans to send a letter to EPA Administrator Steve Johnson explaining the scientific rationale underlying its recommendations and calling for a tighter rule.
Numerous studies have associated fine particles, PM less than 2.5 micrometers in diameter (PM2.5), with a variety of respiratory and cardiovascular problems, ranging from aggravated asthma to irregular heartbeats, heart attacks, and premature death in people with heart or lung disease, according to EPA. Consequently, the agency’s proposed air-quality standard revisions would lower the daily PM2.5 standard nearly 50% from 65 to 35 micrograms per cubic meter (µg/m3) to protect the public from short-term exposure to high PM2.5 levels. The annual PM2.5 standard would remain the same. In addition, the daily coarse-particle standard for PM between 10 and 2.5 micrometers in diameter (PM10–2.5) would be lowered from 150 to 70 µg/m3. The proposal would exempt the agricultural and mining sectors from having to comply.
However, EPA’s CASAC recommended [1.4MB PDF] a lower annual PM2.5 standard and didn’t specify any exemptions. This is the first time an EPA administrator has chosen not to completely follow CASAC’s advice, according to an agency official and others. “To my knowledge, this is the first time CASAC has ever felt the need to come back to the agency [to provide additional advice and recommendations] once we are at the proposed-standard stage,” the CASAC official says. Panel members held a teleconference meeting in February to discuss how to respond.
During the February phone call, Bart Ostro, chief of the California EPA’s Air Pollution Epidemiology Unit, who does not sit on CASAC, highlighted last-minute edits to the rules by the White House Office of Management and Budget (OMB) and others that he asserted “circumvent the entire peer-review process.” Ostro added, “Many of the [OMB] statements overstate the uncertainty [of health-effects studies] and misrepresent the scientific consensus.”
Deborah Shprentz, a consultant to the American Lung Association, testified that more than 100 leading air-quality scientists and physicians called on EPA in a December 2005 letter to propose substantially more protective PM standards. “Please stick to your guns,” she added. “Lowering the annual fine-particle standard as recommended by this committee is vitally important.”
Various industry groups argue against changing the standards at all, just as they did when EPA tightened the PM rules in 1997. “There are a lot of questions out there that haven’t been adequately addressed,” says Dan Riedinger, spokesperson for the Edison Electric Institute, which represents electric utilities. “Any action at this time to further tighten the standard when we haven’t even begun complying with the current standard set in 1997 is premature.”
John Millett, an EPA spokesperson, says the agency is not yet done with the proposal. “We’ll consider all the [public] comments we get,” including those from CASAC, he says. EPA is required to finalize the rule by September.
