The Environmental Protection Agency is clamping down on power plant pollution in more than 20 states, including Minnesota, that contributes to unhealthy air downwind.

EPA Administrator Lisa Jackson announced Thursday a plan to reduce smokestack pollution causing smog and soot in downwind states -- where it combines with local air contaminants, making it impossible for those states to meet air quality standards on their own.

The rule differs from one proposed by the Obama administration in July. Jackson said the regulation would ensure no community has to bear the burden of polluters in another state. She said just because pollution drifts far from a power plant "doesn't mean pollution is no longer that plant's responsibility."

Minnesota's air is not substantially affected by plants in other states. But pollutants from power plants here move east and dirty the air in Wisconsin and Chicago, according to the EPA. It is one of 21 states required to reduce both sulfide dioxide and nitrogen oxide.

"Those are places that can't meet air quality standards in part because we are not being a good neighbor," said J. Drake Hamilton, science policy director for Fresh Energy, a Minnesota environmental advocacy group.

Jackson said the changes were based on new air quality data.

Critics called it another step by the Obama administration to crack down on coal-fired power plants. The regulation is one of several expected from the EPA that would target pollution from the nation's 594 coal-fired power plants, which provide nearly half of the country's electricity -- but also a significant share of its pollution.

While the EPA says the regulations will not cause the power to go out, almost everyone agrees that it will help close down some of the oldest, and dirtiest, coal-fired facilities. At the remaining plants, operators would have to use existing pollution controls more frequently, use lower-sulfur coal, or install additional equipment.

"The EPA is ignoring the cumulative economic damage new regulations will cause," said Steve Miller, president and CEO of the American Coalition for Clean Coal Electricity, a pro-coal industry association. Along with other pending regulations, Miller said they "are among the most expensive ever imposed by the agency."

The rule, which begins going into effect next year, will cost power plant operators $800 million annually, according to EPA estimates.

Minnesota's 32 power plants are already well on their way to achieving the new standards. In 2001 state power companies voluntarily started adding scrubbers and other technologies to reduce pollution, and so are close to the new goals.

"I expect the state will be close if not in compliance," said Mike Cashin, environmental policy manager for Minnesota Power.