As Maryland and much of the Northeast suffered through unhealthy air quality Tuesday, the Environmental Protection Agency proposed new curbs on power plant pollution that drifts from the Midwest across the eastern United States.
EPA's "transport rule" would target power plant emissions in 31 states and the District of Columbia, aiming to reduce smog and soot pollution that is tied to premature deaths, asthma, heart attacks and other health problems.
The rule was drawn up to replace an interstate air pollution regulation adopted by the Bush administration in 2005, which a federal court ordered the EPA to redo two years ago. It is expected to reduce emissions of sulfur dioxide by 71 percent by 2014 and of nitrogen oxide by 52 percent. The two pollutants form fine particulate or soot pollution and ground-level ozone, or smog, which are linked to widespread health problems, including missed school and work.
"This enables the Clean Air Act to work as intended," said Gina McCarthy, the assistant EPA administrator. "It'll help downwind states attain health-based standards."
Jay Apperson, spokesman for the Maryland Department of the Environment, said the EPA action should help clean the state's air, since officials estimate that up to 70 percent of the ozone detected in Maryland drifts here from other places.
The EPA analysis said the curbs would help eliminate unhealthful levels of fine particulate or soot pollution in Baltimore by 2014 and would help keep ozone pollution from slipping back into unhealthful levels in Anne Arundel County. But Apperson said that the EPA was relying on old information and that both areas now meet federal air-quality standards.
Maryland's Healthy Air Act, adopted in 2006, requires the state's power plants to reduce sulfur dioxide by 85 percent and sulfur dioxide by 75 percent, Apperson said.
However, further reducing emissions by power plants in other states should help Maryland improve its air quality, Apperson said. The EPA had announced earlier this year that it plans to lower the threshold for safe exposure to ground-level ozone, saying that research indicates harmful effects at lower levels than the current standard allows. EPA officials said the agency probably would call for further emissions cuts in 2012.
Environmentalists applauded the EPA move, but said more action is needed to prevent health problems caused by air pollution.
"You couldn't find a day more appropriate to say we need to do more to clean up the air," said Frank O'Donnell of Clean Air Watch in Washington.
While Maryland's air quality has improved, it still experiences periods of harmful smog. On Tuesday, ozone in Maryland reached "Code Red" levels for the second straight day, bad enough that experts urge that everyone — not just people with breathing or heart problems — stay indoors. The "Code Red" level was measured in Davidsonville in Anne Arundel County. "Code Orange" levels were detected in five other places, including Essex and Edgewood, with children and sensitive individuals urged to limit time outdoors.
But an industry lobbyist warned that the proposed rule risks power brownouts in the East.
Scott Segal, a lawyer with Bracewell-Guiliani in Washington, said the new rule is "significantly more stringent" than the one produced by the Bush administration. He contended that it would raise the cost of generating power and could prompt some plants to close.
McCarthy said she did not expect power companies to close plants rather than upgrade them to meet stricter emissions limits.
The regulation proposes allowing companies to buy and trade emissions credits, though there is less latitude than under the Bush rule. The EPA estimates health and lost-work benefits at $120 billion, including tens of thousands fewer premature deaths and heart attacks, which the agency says far outweighs the projected compliance costs of $2.8 billion.
But McCarthy said she expects that the proposed regulation will be challenged in court once it's finalized, which would occur after a 60-day period for comment.