New EPA smog standards proposed yesterday may affect the Pittsburgh region when they are finalized in March.

The greater Pittsburgh metro region, which in recent years has struggled to meet regulations, was just about to declare itself in compliance with the old standard, said Roger Westman, manager of the air quality program at the Allegheny County Health Department. Mr. Westman hadn't yet reviewed the new EPA proposal, but he said the regulations would almost certainly put the area right back out of compliance.

The EPA has been under pressure to tighten smog regulations for several years. It last revised standards in 1997, and recent research has strengthened the case that even low levels of exposure are unhealthy.

The new proposal would strengthen regulation of ground-level ozone--a primary component of smog--from the currently accepted level of 0.084 parts per million in the atmosphere over an eight-hour period to between 0.070 and 0.075 parts per million.

"Based upon the current science, I have concluded that the current standard is insufficient to protect public health," EPA Administrator Stephen L. Johnson told reporters yesterday during a conference call.

It can take years to reduce pollution, and states wouldn't be expected to immediately comply with the regulations when they are finalized next March. Instead, environmental agencies create three- to five-year plans that are vetted by the EPA.

These plans include a variety of methods, such as tighter regulations on industry pollution and modified vehicle emissions programs.

But Ron Ruman, spokesman for the Pennsylvania Department of Environmental Protection, cautioned that the EPA proposal is just that -- a proposal. "Right now, it's a little tough to say what it means" for the state, he said. When the final standards are issued next spring, state agencies will better be able to react.

The new regulations are tighter than the old ones, but some scientists, environmentalists and politicians have criticized the proposed regulations for not going far enough.

The Clean Air Scientific Advisory Committee, an EPA panel composed of independent experts, had recommended that regulations be tightened to between 0.060 and 0.070 parts per million. Not only did the EPA not enter that range, but its proposal also leaves the door open to keeping the current standards.

"How is it that they can, with a straight face, take comment about the current standard?" asked William Becker, executive director of the National Association of Clean Air Agencies. "The EPA is acknowledging that the current standard is inadequate to protect public health," he noted, but is leaving the door open to comment on it anyway.

"The mandate of the EPA is to protect public health with an adequate safety threshold," he said -- without regard to the cost it would take to enforce its regulations.

"The only plausible explanation is that this is not the EPA administrator talking, that this is pressure from the White House to ignore not just the committee, but also common sense by seeking comment on the current standards," Mr. Becker said.

The new regulations are "a middle ground," admits Dr. Rogene Henderson, who chaired the EPA panel that recommended the stricter standards. "I admit that I was fearful that the administrator would come out in favor of keeping the current standard."

Her fears may have been fueled in part by the EPA's decision in September to release particulate regulations that were significantly more lax than those her committee had recommended.