Updated

After years of legal wrangling, the government is poised to issue new rules on where and how to comply with tougher air quality standards that will affect the cleanup of smog in dozens of states.

Some 470 counties in 31 states could be targeted by the Environmental Protection Agency (search) regulations designed to reduce unhealthy levels of ground-level ozone (search) or smog.

The EPA is also proposing other rules to improve views and air quality in national parks and wilderness areas. Both announcements, scheduled Thursday, are the result of court settlements with environmental groups.

"When we are finished, our entire nation will have cleaner air," Mike Leavitt, head of the EPA, said in a speech Wednesday.

EPA is requiring states to implement tougher ozone standards that will result in more vehicle inspections and maintenance, cleaner-burning gasoline, better transportation planning and improvements at coal-burning power plants and other industrial facilities.

The new ozone standards, crafted by the Bush EPA after being initiated under the Clinton administration, are intended to reduce smog from ozone produced by paint and gasoline vapors combining at ground levels with nitrogen oxides (search) from fossil fuel burning. Heat and sunlight turn it into smog.

Southern California, Great Lakes states and the Northeast corridor from Washington, D.C., to New York City, western Pennsylvania and parts of Tennessee, Alabama and Georgia are expected to be most out of compliance with the 1997 standards, according to recent EPA air quality monitoring data.

Two years ago, about 10 million people in dozens of metropolitan areas began trying voluntarily to meet the standards, buying more time to comply in the long run, Leavitt said.

"Let me also be clear that clean air progress requires more than voluntary agreements," said Leavitt, a former Utah governor. "A strong national approach is needed because many states believe they could take all the cars off their roads, clean up the power plants and close factories in their state, and they will still fail to reach attainment."

Leavitt said roughly 2,700 counties do meet the standards, as do 19 states: Alaska, Colorado, Florida, Hawaii, Idaho, Iowa, Kansas, Minnesota, Mississippi, Nebraska, Nevada, North Dakota, Oklahoma, Oregon, South Dakota, Utah, Vermont, Washington and Wyoming.

The standards allow less ozone in the air, from 120 parts per billion down to 85, and require more hours of sampling.

They were delayed from taking effect for four years because of failed court challenges by the trucking, manufacturing and business groups as well as by the states of Michigan, Ohio and West Virginia.

The Supreme Court upheld the standards in February 2001. Environmental and public health groups such as the American Lung Association (search) and Environmental Defense (search) sued to force government into action.

Leavitt was under a court-ordered deadline Thursday to release the list of non-complying counties and the categories they fall in, which determine the corrective measures and time frames to accomplish cleanups.

EPA also is proposing that states impose new limits on air pollution from power plants and other sources of emissions, which drift hundreds of miles and cause haze and visibility problems in remote areas.

That proposal results from a lawsuit by Environmental Defense to enforce Clean Air Act (search) goals for improving visibility in 155 national parks and wilderness areas, and in the Roosevelt Campobello International Park near Lubec, Maine, overseen by a U.S.-Canada commission.

Some of the parks affected include Acadia in Maine, Glacier in Montana, Grand Canyon in Arizona, Great Smoky Mountains in Tennessee and North Carolina, Shenandoah in Virginia, Yellowstone in Wyoming, Montana and Idaho, and Sequoia and Yosemite in California.

"There's an urgent need for EPA to clean up the pollution from power plant smokestacks that cast a veil of haze over our national parks and harms public health," said Vickie Patton, a senior attorney in Boulder, Colo., for the environmental group.