Respiratory Specialists Bang the Drum About Soot's Dangers

NEW YORK, Sept. 22 -- The Environmental Protection Agency's new emission standards for soot have drawn scorn from medical societies and public health advocacy groups that predict dire cardiovascular and pulmonary fallout.

They allege that the EPA's new emission standards for soot, also known as fine particulate matter, will jeopardize patients with cardiovascular and pulmonary diseases and other conditions.

"The science is clear," said John E. Heffner, M.D., president of the American Thoracic Society, which is based here. "People develop respiratory disorders and those with existing lung, heart, and other chronic diseases die prematurely because they are exposed to these microscopic pollutants at levels well below those set by the EPA."

"Unfortunately, EPA's standards fail to protect the health of the public, despite the requirement in the Clean Air Act that they must," echoed John L. Kirkwood, president and CEO of the American Lung Association. "Overwhelming evidence shows that millions of people suffer unnecessarily, even face an earlier death, because they breathe this pollution. EPA could have, should have done better."

Fine particulate matter/soot consists of air pollution particles smaller than 2.5 micrometers in diameter (PM_2.5). The particles are primarily generated by incomplete combustion of fuels in cars, power plants, and heavy industry. Microfine particles have a much greater chance of reaching the small airways and the alveoli than do larger particles, according to respiratory specialists.

The new EPA standards issued this week leave in place the decade-old standard of 15 ?g of particles per cubic meter of air averaged out over the course of a year, but decrease the maximum particle concentration considered to be safe over a 24-hour period from 60 to 35 micrograms/m³ .

Yet the ATS, American Lung Association, American Medical Association, public health groups, and scientists within the EPA itself have all called for more stringent limits on fine particulate matter pollution.

The recommended standard would consider as safe a maximum annual average of 12 ?g/m³ , and a maximum 24-hour average of 25 ?g/m³ .

"While almost any improvement in the weak 1997 standards is better than nothing, EPA's modest revisions cannot be justified," Kirkwood said. "Thousands of studies -- most funded by EPA itself -- unmistakably demonstrate that particulate matter is a dangerous air pollutant, endangering life and health at levels well below those announced by EPA."

Exposure to air pollution significantly increases the risk of death in patients with chronic obstructive pulmonary disease (COPD), diabetes, congestive heart failure, and inflammatory diseases, said researchers at the Harvard School of Public Health at this year's annual meeting of the ATS.

Short-term exposure to ultrafine particulate air pollution has also been shown to increase the risk of Medicare-age hospital admissions for cardiovascular and respiratory ailments. Evidence for the health risks of inhaling particles as fine as PM_2.5 came from a database of hospital admissions for 11.5 million Medicare enrollees in 204 U.S. urban counties, wrote Francesca Dominici, Ph.D., of Johns Hopkins in the March 8, 2006, issue of the Journal of the American Medical Association.

In addition, the practice of monitoring air pollution in 24-hour increments may underestimate the health-risks of brief pollution spikes. A comparison of death records from 13 Japanese cities with reports on hour-by-hour air pollution concentrations showed that fatal hemorrhagic strokes among those 65 or older were associated with a spike in air pollution levels about two hours earlier, reported Shin Yamazaki, M.D., of the University of Kyoto, and colleagues this week. That study dealt with particles larger than 2.5 micrometers, however,

"By failing to issue a more stringent standard," said Dr. Heffner, "the EPA is ignoring compelling research, the advice of experts, and the Clean Air Act, which requires the agency to regularly review the scientific data and set standards that protect the public's health. This is particularly egregious, given that its own experts recommended a tighter standard."