A federal court ruling in July that tossed out an EPA rule to reduce smog and soot pollution in the Eastern United States means the Bay Program will likely miss one of the few 2010 nutrient reduction goals it had been expected to achieve.

The U.S. Court of Appeals for the District of Columbia concluded that the Clean Air Interstate Rule, which would have required sharp reductions of sulfur dioxide and nitrogen oxide emissions, was "fundamentally flawed."

At a July 30 Congressional hearing, Benjamin Grumbles, EPA assistant administrator for water, warned in written testimony that the decision would likely have "serious and adverse impacts to the health of the Bay."

"The Bay jurisdictions were relying on the CAIR rule to significantly reduce nitrogen emissions by 2010," he said.

When the EPA and states set nitrogen reduction goals for the Bay in 2003, they counted on achieving 8 million of the needed 100-million-pound nitrogen reduction from the rule, which was then in development.

The rule would have cut sulfur dioxide emissions from power plants by 70 percent and nitrogen oxide emissions by more than 60 percent by 2015, with most of the reductions coming by 2010.

Those reductions were expected to begin taking effect next year, and result in an 8-million-pound nitrogen reduction to the Bay by 2010-making it one of the few 2010 reduction goals that would be achieved. Additional reductions were expected in subsequent years.

Lewis Linker, modeling coordinator for the EPA's Chesapeake Bay Office, said the region would still see a portion of those reductions because some states, such as Maryland, Pennsylvania and New York, had already taken legislative or regulatory actions that would achieve, or go beyond, emission cuts required by CAIR.

However, the Bay states generate only about half of the nitrogen oxides that result in nitrogen deposition on the Chesapeake's 64,000-square-mile watershed. The rest originates from upwind areas.

"CAIR was absolutely a step forward," Linker said. "It's sorry to have that taken away from us."

CAIR would have used a cap-and-trade program to slash nitrogen oxide and sulfur dioxide emissions from power plants in 28 Eastern states and the District of Columbia.

North Carolina challenged the rule, arguing that the trading provisions would allow some power plants to pollute more by purchasing credits from cleaner plants operating elsewhere. As a result, it argued pollution from some plants could actually increase soot in smog in North Carolina.

The court agreed with North Carolina's arguments, saying the rule was flawed because its cap system did not give enough consideration to state-specific emissions and needed reductions. The court said the rule had "more than several fatal flaws" and that "no amount of tinkering" could save it.

CAIR was developed as a response to years of meetings among state and federal agencies aimed at trying to resolve lingering air quality problems in the mid-Atlantic and Northeast, where pollution from outside areas is a major contributor to local air quality problems. Without upwind reductions, those areas cannot meet air quality standards.

As a result, some action to replace CAIR is considered inevitable, although it may take legislation from Congress, which is unlikely to happen before next year at the earliest.

Many utilities had already begun work to install upgrades, and in August, a bipartisan group of senators urged them to continue that work as Congress explores legislative options. They included Sens. Tom Carper, D-DE, Lamar Alexander, R-TN, Judd Gregg, R-NH, and Bernie Sanders, I-VT.

"We are exploring legislative options to restore the clean air benefits that would have resulted from CAIR," they wrote to utilities. "However, we are concerned that during the time it takes to draft and pass legislation, millions of Americans in the Eastern United States will be exposed to harmful pollutants that otherwise would have been eliminated by CAIR."

The lawmakers added that they are "confident that Congress and the administration will require power plant emission reductions a least as stringent as CAIR, and likely stronger."

Air pollution is estimated to contribute about a quarter of the nitrogen that reaches the Chesapeake Bay each year. A bit more than half of that stems from nitrogen oxide emissions from power plants, vehicles, ships and other sources that burn fossil fuels. The rest stems from ammonia emissions, which largely originate from agriculture.