The Clean Air Scientific Advisory Committee (CASAC) of the U.S. Environmental Protection Agency (EPA) determined air quality standards for fine particulate matter are sufficiently protective of the public health and do not need to be tightened further.
The committee voted four to two to advise EPA Administrator Andrew Wheeler the standards for particles no larger than 2.5 microns (PM 2.5) in the air are effective at their current level.
Outdoor sources of particulate matter include car, bus, truck, and off-road vehicle exhausts, power plants, and other machinery and operations that burn fossil fuels or wood for energy. Indoor sources of PM 2.5 include candles, cooking, oil lamps, tobacco smoke, fireplaces, and oil-burning space heaters.
Standards Evolved
The EPA first established national ambient air quality standards (NAAQS) for particulate matter in 1971, shortly after passage of the Clean Air Act (CAA) in 1970. In 1987, EPA began regulating “inhalable particles” no larger than 10 microns (PM 10).
EPA initially set the annual average standard for PM 10 at 65 micrograms per cubic meter (ug/m3), lowering it to 50 ug/m3 in 1997. In September 2006, EPA revoked the annual standard entirely, saying it lacked evidence establishing a link between long-term exposure to coarse particles and health problems. EPA now enforces a 24-hour standard of 150 ug/m3 for PM 10.
Also in 1997, the EPA issued a finding that fine particulates (PM 2.5) pose a greater threat to human health than the coarser particles, initially setting air quality exposure limits at 15 ug/m3 (annually). After various court battles challenging EPA’s standards, the agency tightened the annual standard to 12 ug/m3 in 2012.
Declined to Tighten
As part of a periodic review required by the CAA to determine whether air quality standards for regulated pollutants are still considered protective of human health and the environment in the light of emerging science, the EPA asked its CASAC to determine whether the PM 2.5 standards needed tightening.
Two-thirds of the members of the CASAC concluded the standards did not need to be made more stringent. That angered many environmental activist groups that had been lobbying for stricter standards and claiming even very low concentrations of these particles are deadly.
During the public comment period and at hearings, several scientists argued even the current air quality standards for fine particulate matter are excessive because there is no evidence PM 2.5 is lethal or even harmful to humans.
Ethical Lapses Exposed
Claims EPA used poorly designed scientific studies to justify lowering allowable PM 2.5 standards in 2012 were fleshed out in a lawsuit filed that year by Steve Milloy, publisher of JunkScience.com and a policy advisor to The Heartland Institute, which publishes Environment & Climate News.
Milloy’s lawsuit said EPA illegally experimented on human subjects by exposing them in laboratory tests to what the agency claimed to be super-lethal doses of fine particulate matter.
“EPA admitted to the court its PM epidemiology was just mere statistics and insufficient by itself to conclude PM kills,” Milloy told Environment & Climate News. “EPA lawyers told the court that the agency undertook the human experiments because the epidemiology was inadequate.
“Despite exposing hundreds of elderly and sick people to extremely high levels of particulates, levels it had previously claimed were potentially deadly, EPA did not report a single adverse effect—not one—so the clinical experiments provided no biological evidence to support EPA’s claim of harm from PM 2.5,” Milloy said.
Research Flaws Found
EPA’s PM 2.5 standards were based on flawed research conducted with the help of the American
Cancer Society, which purportedly showed an association between PM 2.5 and total mortality, says retired University of California at Los Angeles School of Public Health researcher James Enstrom, Ph.D.
“No significant relationship between PM 2.5 and total mortality in the 1982 American Cancer Society Cancer Prevention Study I (CPS) cohort was found when the best available PM 2.5 data were used,” said Enstrom. “A 1995 analysis found a positive relationship only by the selective use of CPS II and PM 2.5 data.
“Independent analyses of underlying data raise serious doubts about the CPS II epidemiologic evidence supporting the PM 2.5 NAAQS and provide strong justification for further independent analysis of the CPS II data,” Enstrom said.
Waiting for Evidence
The EPA needs better research to show harm before a majority of CASAC believes the agency can justify tightening the PM 2.5 standards, says Dr. Sabine Lange, Ph.D., a member of CASAC and the Toxicology Section Manager at the Texas Commission on Environmental Quality, who voted to leave the current standards in place.
“EPA needs to provide specific details about how studies were chosen for this review,” said Lange. “In the absence of this information it is very difficult to determine whether a comprehensive, unbiased review has been completed.”
The nation’s air quality has improved dramatically over the past 50 years and is at safe levels of all regulated pollutants today, says Dr. John Dale Dunn, an emergency room physician and attorney.
“None of the criteria air pollutants are harmful or lethal at the current ambient levels,” said Dunn. “The safe levels are only a slight modification of the ambient levels that existed when the EPA went nuts and started pushing regulations based on no good health effects research at all.
“The regulations imposed in recent years are nothing more than a political measure of the influence environmentalists have with EPA bureaucrats,” Dunn said. “The EPA is staffed with a pack of liars and cheats on science whose misconduct goes back five decades.”
Duggan Flanakin ([email protected]) writes from Austin, Texas.
