In a decision that could have broad health and economic implications, the EPA was expected to announce tougher air quality rules in late November that could compel many cities to begin new smog controls.

The proposal was expected to create a more strict federal ozone standard and to further reduce particulate pollution in the air. Both particulate pollution and ozone - a key component of summertime smog - affect human health.

But a stricter ozone standard, in particular, could also benefit the Bay cleanup effort. Nitrogen oxides, which are a major contributor to ozone pollution, are also a major source of nutrient pollution to the Chesapeake. Computer models estimate that more than a quarter of all the nitrogen entering the Bay results from air pollution.

A recent EPA report suggested that reducing pollution to benefit the Bay was cost competitive with some traditional water pollution control techniques, even without considering other benefits - such as reductions in acid rain and protection of human health - derived from the air pollution controls. [See Air, Bay cleanups: 2 for the price of 1, in the November 1996 Bay Journal.]

Even before the new standards were released, though, opponents were criticizing them as a threat to the nation's economy that would do little to benefit public health.

The proposals could cost "many billions of dollars" and more than triple the areas unable to meet federal standards, argues Alan Charles Rawls, an attorney representing the American Automobile Manufacturers Association. "The implications ... are potentially enormous for state and local governments and for virtually the entire industrial sector of the economy."

Yet, many health experts argue that even communities meeting the current federal standards have air that is harmful to children, the elderly and those with lung problems such as asthma.

"The federal standards are not doing the job in protecting the public health, especially among children and the elderly with chronic heart and lung diseases," said Ronald White of the American Lung Association, which, through a lawsuit, forced the EPA to review the standards.

In recent years, state and local officials have struggled to meet the existing standards, forcing factories and auto makers to spend billions of dollars in pollution controls. Even so, many of the nation's largest cities still fall short of meeting the ozone standard. Seventy-four metropolitan areas - down from 98 six years ago - are still not in compliance.

In addition, about 40 areas now do not meet the federal standard for fine dust, or particulates.

The proposal before the EPA would require communities to cut ozone levels by an additional one-third, to 0.08 parts per million cubic feet of air from 0.12 ppm.

The agency also is considering, for the first time, regulating minute particles of dust, down to 2.5 microns in diameter. Current standards apply only to particles of 10 microns or larger. Health experts argue the smaller particles - many of which come from industrial or utility smokestacks - cause the most harm because they lodge deep in the lungs.

Either way, the EPA is under a court order to decide by month's end. Its technical staff has already recommended tightening two of the standards.

Opponents include the National Association of Manufacturers, the American Petroleum Institute and a Utah steel company, long a target of environmental groups because of alleged air pollution in the Utah Valley.

Senior executives of Geneva Steel, including Chairman Joseph Cannon, have been active in developing the industry coalition, which has a $2.2 million war chest. The company also has hired C. Boyden Gray, former Bush administration White House counsel, as a lobbyist.