Environmental groups called on Gov. Mike Easley and state legislators yesterday to support their plan for cleaning up the state's air by drastically cutting pollutants from coal-fired power plants.

The plan was released yesterday at a series of press conferences across the state. Its sponsors said it would reduce smog, acid rain and mercury poisoning in fish and improve visibility in the mountains by forcing power companies to cut emissions of key pollutants by as much as 90 percent. The cost of the cuts, if passed on to consumers, would amount to a little more than $4 a year for each household in the state, they said.

"There is no reason to wait to improve air quality," said Michael Shore, an air-quality manager for Environmental Defense. "Now is the time for a plan that protects people, not outdated power plants."

The U.S. Supreme Court, in a related issue, ruled yesterday that the U.S. Environmental Protection Agency can force North Carolina and 21 other states to cut emissions from coal-fired plants that drift across state lines to create smog in other states. The reductions demanded by the EPA will come close to meeting the target for the smog-causing pollutants set by the environmental groups.

North Carolina has acquired something of a reputation as a smoggy place after finishing in the top 10 in a number of national reports on smog. The number of days in which the air in parts of North Carolina was unhealthy to breathe because of smog rose steadily from 25 in 1989 to 65 in 1999.

Ozone, the main ingredient in smog, can make breathing difficult for those with asthma and other types of obstructive lung disease. Chronic exposure can also harm agricultural plants and trees. High ozone levels trigger more than 200,000 asthma attacks in North Carolina each year, said Hope Taylor, a biochemist who heads the Clean Water Fund of North Carolina.

Nitrogen oxides, which react with sunlight to form ozone, and sulfur dioxide also form tiny particles that can clog lungs and lead to serious health effects, including death, she said. More than 1,800 people in the state die prematurely each year because of exposure to the particles, Taylor said.

Those particles have also reduced visibility in the state's mountains by more than 75 percent, said Denise Lee of the Blue Ridge Environmental Defense League.

The 14 coal-fired power plants in the state account for 45 percent of the nitrogen oxides, 82 percent of the sulfur dioxide and 65 percent of the mercury discharged into the state's air. Duke Power Co.'s Belews Creek Steam Station in Stokes County alone spews an average of 83,000 tons of nitrogen oxides into the air each year.

Reducing those emissions by 80 percent to 90 percent from 1998 levels could be done with existing technology, Taylor said. Polluted air, she said, costs the state about $3.5 billion each year in health-care, agricultural and tourism costs, far more than the $449 million it would take to make the reductions.

Getting rid of the pollution won't be that easy or cheap, said Joe Maher, a spokesman for Duke Power. The devices to remove sulfur dioxide, commonly called scrubbers, can cost as much as $100 million for each power-plant boiler, he said, and Duke has 30 coal-fired boilers.

"It's very important that any regulation be a regulation that is firmly grounded in the real world, not just a number that somebody likes," Maher said.

Easley hasn't seen the report, noted Fred Hartman, one of his spokesmen.

Neither has state Sen. Fountain Odom, a Democrat from Mecklenburg County. He is a co-chairman of the Environmental Review Commission, which recommends environmental legislation, and says he drives a hybrid gas-electric car because he's worried about air quality.

"So I'm supportive, but you have to very careful in imposing so many expensive reductions in air emission when the surrounding states aren't doing it," Odom said. "Most of the air pollution in our mountains comes from Tennessee. You could shut us down and not do much to improve air quality in the mountains. You could cripple our own economy."

Meeting the environmental groups' target for nitrogen oxides may not require more regulations. The state's Environmental Management Commission passed rules in the fall that should result in a 75 percent reduction from 1998 levels, Maher said.

The commission passed the rules after the EPA directed North Carolina and other states to reduce emissions that were contributing to pollution in other states. The commission took the action in case the Supreme Court, as it did yesterday, turned down arguments by power companies and seven of the affected states that the EPA had acted improperly.

"The report has a lot of good recommendations in it, and we'll be looking at them closely," said Tom Mather, a spokesman for the N.C. Division of Air Quality. "The rules that the EMC adopted go a long way toward what these groups are asking for."