EPA Issues New Plan to Limit Soot
Critics say the revised standard is too weak to properly protect the public from health dangers caused by breathing particulates.
By Miguel Bustillo and Marla Cone
Times Staff Writers
December 21, 2005
Federal air quality officials on Tuesday proposed tighter limits on a pollutant especially prevalent in the Los Angeles region, but environmentalists and some scientists said the changes would do little to prevent thousands of Americans from dying prematurely from breathing the tiny particles of soot.
The U.S. Environmental Protection Agency's proposed new standards for fine particulate matter are substantially weaker than what the agency's own staffers and a scientific advisory panel recommended after reviewing about 2,000 new studies on the pollutant's health effects.
Many environmental scientists say there is overwhelming evidence that particulates are making people susceptible to heart disease and triggering deadly heart attacks, asthma attacks and strokes in those who already have cardiac or respiratory diseases.
On the day the EPA's proposal was announced, scientists reported new research offering some of the most compelling evidence yet that long-term exposure to particulates at levels that satisfy federal health standards causes heart disease.
In a study published Tuesday in the Journal of the American Medical Assn., lab mice developed clogged arteries when they breathed amounts of particulates that are commonly found throughout the Los Angeles region and other urban areas. Heart disease was particularly severe in mice fed a high-fat diet, though all mice that breathed the fine particles developed more plaque in their arteries than those breathing purified air.
The Los Angeles Basin, especially the Riverside area, has the worst particulate pollution in the nation, largely due to exhaust from trucks and other diesel-powered vehicles.
Even coastal areas of the Los Angeles region regularly exceed the particulate levels that caused heart disease in the mice.
The EPA's proposed rules, which would take effect next year, target fine particles of 2.5 micrometers — roughly onethirtieth the diameter of a human hair. Current standards adopted in 1997 that limit annual average concentrations to 15 micrograms per cubic meter of air would remain intact. But standards limiting daily concentrations would be tightened from 65 micrograms to 35 micrograms.
In June, the EPA's Clean Air Scientific Advisory Committee recommended stronger fine-particulate standards than those the agency wound up proposing: a daily limit of 35 to 30 micrograms and an annual limit of 14 to 13 micrograms.
EPA officials estimated Tuesday that 191 counties around the country would be in violation of the new standards, up from 116 that violate existing limits. Nearly all of Southern California is already in violation. In Riverside, the pollution reached a daily peak of 93.8 micrograms per cubic meter of air in 2004 — almost three times the amount that would be allowed under the new proposal.
Under the new standards, EPA staff estimated that 1,265 Los Angeles residents would still die prematurely every year from prolonged exposure to particle-laden air. Under the current standard, 1,507 would die earlier than normal.
Nevertheless, EPA Administrator Stephen L. Johnson said Tuesday that the total body of scientific evidence does not clearly support a standard tougher than the one the agency has proposed.
"What I need to consider is, is there a clear basis, or clear evidence, to make a decision, and this choice requires an interpretation of the evidence," Johnson said.
Environmental and public health organizations, which had sued the EPA to force a revision of fine-particle rules based on updated science as required by law, immediately condemned the agency's new rules, calling them far too weak and an early Christmas present to polluting industries.
"This may be the most important decision that the Bush administration makes on air pollution, but the White House has chosen to disregard its own science advisors under pressure from the electric-power industry and other special interests," said Emily Figdor of the U.S. Public Interest Research Group.
Industry organizations opposed the change, contending that they already have made substantial cuts in particulate emissions from industrial plants and vehicles.
"New particulate matter standards may be premature in that EPA and the states are just now implementing the revisions from 1997," the Electric Reliability Coordinating Council, a group representing coal-fired power plants, said in a statement. "It is hard to see the justification for ratcheting the national particulate matter standard lower at this point."
Counties are supposed to clean up particle pollution by 2015 or face federal penalties, including possibly losing transportation money.
"It will be a significant challenge in Southern California … but we should not allow difficulty to set the bar," said Barry Wallerstein, executive officer of the South Coast Air Quality Management District, the region's main air pollution regulator. "We should set the bar wherever it needs to be to protect public health."
Though the Los Angeles region has made great progress in reducing some types of air pollution — most notably ozone, the main ingredient of smog — improvement has been slower with particulates. That is due in large part to the steady growth of cargo shipments in the region, particularly at the twin ports of Los Angeles and Long Beach, and the diesel exhaust emitted by ships, loading machinery, and truck and rail traffic in and around the ports.
Experts have estimated that particulate pollution may cause thousands of deaths per year in the United States from heart attacks, strokes, asthma attacks and other respiratory diseases. Dozens of studies around the world have documented increased hospitalization and death rates among people with heart and lung diseases on days when particulate levels rose.
The research released Tuesday suggests that long-term, chronic exposure can be dangerous too, with years of exposure making people susceptible to developing cardiovascular disease.
The scientists, from the New York University School of Medicine, Mount Sinai School of Medicine and University of Michigan, said they found a clear cause and effect between breathing particulates and atherosclerosis, the hardening and clogging of blood vessels. Long-term exposure to the microscopic bits of soot and smoke spewed by vehicles and industries causes immune cells to build up and inflame vital arteries, they reported.
For six months, mice that were bred to be susceptible to developing cardiovascular disease breathed air containing 15 micrograms of fine particles per cubic meter, the same as the federal standard. Last year, most of Los Angeles, Orange, Riverside and San Bernardino counties averaged 16 to 22 micrograms.
Overall, the mice that breathed the polluted air fared worse in an array of cardiovascular tests than those that breathed filtered, particulate-free air. But mice that were fed a high-fat diet showed even more dramatic effects.
On normal diets, aortas of the exposed mice were 19.2% filled with plaque, compared with 13.2% for those breathing the particulate-free air. Among those fed high-fat diets, the exposed mice had arteries that were 41.5% obstructed by plaque, compared with 26.2% for the mice breathing the filtered air.
Eating a high-fat diet and breathing particulate pollution in places such as Los Angeles "is a really bad combination," said Dr. Nino Kuenzli, a USC associate professor and environmental epidemiologist. Last year Kuenzli reported similar findings in people living in the Los Angeles region. Those who lived in areas with the highest particulate levels had more constricted arteries.
The mouse study is "very important because it confirms that the type of air pollution we inhale on an everyday basis has definite effects and it occurs at levels we accept as a given," Kuenzli said.
"It is very clear that we do not have standards yet that would protect everyone's health," he added. "That is the opinion probably of the vast majority of scientists."
Copyright 2005 Los Angeles Times
...and the real polluters skate once again.