It's a kind of air pollution virtually invisible to the naked eye. But these microscopic specks - one-seventh the width of a human hair - lie at the heart of a new battle over what might be called America's white-glove test for clean air.
Several major environmental groups, backed by scientific studies, say the tiny particles pose a health risk and want better government air-quality standards.
But many industry and state officials are balking, saying new federal rules to rid the air of particulates are unnecessary and would cost billions of dollars with no guaranteed benefit.
Caught in the middle is the US Environmental Protection Agency (EPA) - under court order to decide by next week whether existing standards are adequate.
This dustup could become the first major environmental battle of the 105th Congress and the second Clinton term. It raises fundamental questions like "How clean is clean?" and "What's the ratio of costs to benefits?" It also involves the politically touchy subjects of unfunded federal mandates (laws requiring states to pay for enforcement of US standards) and regulation reform.
The focus here is not the smelly, sky-darkening variety of air pollution, but odorless ozone (a main element in smog) and very fine particles found in dust, soot, and smoke.
"It's too early to tell precisely what the new standards could mean," says Frank O'Donnell, executive director of Clean Air Trust, a coalition of environmental and health groups concerned with pollution.
"But since combustion of fossil fuels is the major source of both ozone and fine particles," he adds, "it is logical to assume that the new standards could lead to cleanup of dirty coal-fired utilities in the Midwest and increase pressure for cleaner diesel trucks and buses, cleaner automobiles and gasoline, and additional controls on refineries, steel mills, and other factories."
Automakers, electric utilities, chemical manufacturers and other industries have united to head off stricter controls.
The National Association of Manufacturers, one of the largest lobbying groups in Washington, recently formed an Air Quality Standards Coalition. According to a recent letter soliciting as much as $100,000 each from large corporations, small businesses, and trade groups, the coalition's purpose is to "mobilize resources [and] lend stature to communications with senior government officials."
The letter warns that "more stringent standards for ozone or particulate matter could lead to pervasive and expensive regulatory control programs...."
Current regulations under the Clean Air Act address particles as small as 10 microns in diameter (about one-seventh the width of a human hair). The EPA is considering a new 2.5-micron standard for particulates. Some scientists say even these very, very tiny particles are a threat to public health.
Using data on 239 American cities provided by the Harvard School of Public Health and other research institutions, the Natural Resources Defense Council in a report issued last May warned of the danger of particulate air pollution.
Responding to this study, EPA administrator Carol Browner said, "A growing body of evidence now suggests that particulate matter poses a serious threat to public health in many American cities and may contribute to premature deaths...." Ms. Browner expressed particular concern for children and the elderly.
But other scientists say the evidence is not strong enough to demand stricter regulations on this form of air pollution. These include members of the EPA's own Clean Air Scientific Advisory Committee, which reported last June that "our understanding of the health effects of [particulates] is far from complete." Members of this independent group could not agree on whether stricter standards were called for.
If the federal government does put new standards in place, it will in effect raise the threshold of compliance - putting more businesses and local governments in violation at a time when steady improvement has meant fewer and fewer "nonattainment" areas under the Clean Air Act's National Ambient Air Quality Standards (NAAQS).
This is a major concern to state governors and members of Congress from industrialized areas. Several governors, other state officials, and regional business councils have urged the Clinton administration not to approve the stricter standards without more scientific proof that they are necessary.
In a letter to President Clinton in July, a group of 90 senators and representatives from states where oil and gas is produced and refined called for "a more flexible regulatory approach ... a bipartisan middle ground that reflects common sense environmental regulation."
At the moment, the proposed revisions to the NAAQS for ozone and particulates are being studied by the White House Office of Management and Budget (OMB), which reviews proposed regulations for their economic and budgetary impact.
In a recent letter to OMB, a lobbyist for the American Automobile Manufacturers Association warned that the implications of the proposed revisions "are potentially enormous for state and local government, and for virtually the entire industrial sector of the economy."
In response to what is seen as a public relations advantage by pro-environment groups, industry representatives have crafted a "grass-roots" effort urging flexible regulations and more state control.
According to a recent report in the National Journal, Citizens for a Sound Economy (funded by organizations like the Chemical Manufacturers Association, the National Association of Manufacturers, and the American Petroleum Institute, and led by a Washington-based lobbyist for a steel corporation) "has launched the first phase of what it hopes will be a $5 million, multi-year campaign aimed at overhauling the nation's environmental regulations to ease the burdens of business."