New air pollution control initiatives aimed at protecting public health from smog and soot would also save the Chesapeake region more than $360 million in Bay cleanup costs while also providing billions of dollars in benefits to other coastal water bodies, according to a new report.

Without reductions in nitrogen oxide emissions that will result from new air pollution control efforts, the new EPA report assumes that states would have to seek even more pollution reductions from farmers, homeowners, city stormwater systems and others who contribute to the nitrogen-laden runoff that fouls the Bay and other coastal waters.

"Absent these air rules, communities surrounding the Chesapeake will have to spend much more money to achieve and maintain a healthy Bay," said Dwight Atkinson, director of the multimedia strategies and analysis division of the EPA's Office of Policy, Planning and Evaluation, who directed the study.

Ultimately, figures in the report indicate that when new air pollution control strategies are fully implemented-some time more than a decade away-they will prevent nearly 17 million pounds of nitrogen a year from entering the Chesapeake. That is about three times the amount that enters from the Patuxent River, or about the same as what enters the Bay from the York and Rappahannock rivers combined.

The report, "Benefits of Reducing Deposition of Atmospheric Nitrogen in Estuarine and Coastal Waters," was one of a series of documents prepared to support the EPA's regulatory impact analysis for its controversial new air quality standards for ground level ozone and tiny soot particles.

The report is thought to be the first time that benefits to water quality were ever quantified to support a federal air pollution rule. However, air quality standards are set to protect human health, and the EPA expects that the bulk of the benefits from its action will be fewer illnesses and deaths stemming from air pollution. Still, the fact that the study was undertaken reflects the growing awareness that pollution spewed into the air may ultimately contribute to water quality problems when it falls back to Earth.

Some officials caution that the report is only a "first cut" at measuring the value of air pollution reductions on water bodies, and that the figures may change over time as better information about the impact of air pollution on water quality becomes available.

The Bay Program has estimated that about a quarter of all the nitrogen entering the Chesapeake comes from the air. While some of that occurs naturally, it mostly stems from air pollution-largely the combustion of fossil fuels in everything from power plants to automobiles, which produces nitrogen oxides as a byproduct.

In the atmosphere, nitrogen oxides (NOx) are transformed into nitrate and nitric acid-a form of "acid rain"-which can travel hundreds of miles after they are emitted. Both are forms of nitrogen which, along with phosphorus, is targeted for nutrient reduction efforts in the Chesapeake Bay.

Because there are so many sources of nitrogen oxides-and the burning of fossil fuels has increased as people have driven their cars more and used more energy-NOx emissions have gradually increased over the years, even as many other air pollutants have declined.

But two actions this year aimed at protecting human health from air pollution would dramatically change that. The efforts focus on NOx because it is a major cause of ground-level ozone pollution, the key component of summertime smog, which blankets many cities and is linked to respiratory problems.

Past efforts to bring cities into compliance with federal ozone standards have come up short in some places because much of the NOx contributing to the problem has drifted in from hundreds of miles away, often from other states. The problem is particularly acute for East Coast cities from Washington D.C. to Portland, ME.

To resolve that issue, the federal government and a group of 37 states two years ago formed the Ozone Transport Assessment Group to study long-range NOx transport.

This summer, OTAG released recommendations for NOx emission reductions that would help keep upwind states from causing downwind pollution problems. The EPA is expected to begin implementing those recommendations this fall.

Those recommendations included NOx emission reductions of up to 85 percent for some pollution sources, including many major Midwest power plants which contribute both to smog problems in the East and nitrogen deposition on the Bay and in its watershed.

When implemented, the OTAG recommendations are expected to bring most places into compliance with the existing ozone standard.

Meanwhile, the EPA has set new, strict air quality standards for ozone and for tiny bits of soot, known as particulates. Meeting those standards-approved by the Clinton Administration in July-would require further NOx reductions beyond those recommended by OTAG.

The EPA report estimated that NOx emission reductions required as part of the OTAG agreement would reduce the amount of nitrogen entering the Bay by about 13.8 million pounds a year.

The report said that the additional air pollution reductions needed to achieve the new air quality standards would cut the amount of nitrogen entering the Bay by nearly 3 million additional pounds annually.

For comparison, the Bay states are presently trying to reduce the amount of nitrogen entering the Chesapeake by 74 million pounds (from 1985 levels) by the year 2000.

Reductions from the new air pollution control efforts, for the most part, would not help achieve that goal because most will not occur until after the turn of the century. But air pollution controls could play an important role in maintaining the reduced nutrient levels after 2000, which is another Bay program goal.

"There are many who have said for years that the Clean Air Act could be a major weapon in dealing with our problems of holding the line after the year 2000, and it sounds as though there is at least some evidence in this report that the people who believe that are correct," said Bill Matuszeski, director of the EPA's Chesapeake Bay Program Office in Annapolis.

When fully implemented, the report indicates that the Bay region could save hundreds of millions of dollars in spending on additional nutrient control efforts or-at the least-help to offset the the additional nitrogen that would be produced by a growing population in the watershed. The capital cost of keeping a pound of nitrogen out of the Bay presently ranges from less than a dollar a pound for efforts such as changing certain agriculture fertilization practices to about $150 per pound for retrofitting stormwater runoff system in already developed urban areas.

But low-cost options alone will not meet the nutrient reduction goal and maintain those levels after the turn of the century. When a team of experts assembled for the report devised the most likely mix of traditional pollution control techniques, the average cost of preventing a pound of nitrogen from entering the Bay was $21.82.

That means the value of the OTAG reductions to the Bay would be about $300 million in capital costs, and the value of additional pollution reductions achieved through the new air standards is another $64 million in capital costs. Also avoided would be the cost of operating and maintaining those runoff controls, which would amount to about 3 percent of the capital cost annually, or about $11 million a year.

Authors of the report say those figures probably understate the benefit because as time goes by, most of the low-cost control options will be "used up," leaving only more expensive options available.

"It's probably at least 50 percent more conservative than the total costs are likely to be," said Eric Slaughter, of the EPA's Office of Wetlands, Oceans and Watersheds, who worked on the report.

For other coastal areas, benefits will total in the billions of dollars, according to the study, which examined 11 East and Gulf coast estuaries besides the Bay. Overall, they estimated that OTAG actions would be worth about $2.1 billion for those water bodies, with the new clean air standards worth an additional $428 million.

The report's authors say those figures underestimate total benefits because not all estuaries were examined, nor were impacts on the Gulf of Mexico.

The cost estimates were made for the year 2010, when it is estimated that most of new pollution controls on industries and power plants, cleaner running cars and other actions needed to meet the new clean air initiatives will be in place.

Benefits to the Bay and other water bodies could be even greater, though, as the report assumes that many reductions will take place only during a five-month period during summer months when ozone pollution is a problem. If the reductions were made year round, as some have advocated, benefits to the Bay and other coastal waters would be even greater.

"The problem in the Bay isn't just during the summer," Matuszeski said.

Nitrogen is a major concern for the Bay and other coastal waters because excess amounts can stimulate algae blooms, which affect water quality. Unlike the easier-to-control phosphorus, which primarily affects algae in fresh water, nitrogen stimulates algae growth in salt water.

Algae blooms cloud the water and prevent the growth of underwater grasses that provide food and habitat for crabs, fish, waterfowl and other species. When the algae die, they sink to the bottom of the Bay and decompose in a process that depletes the water of oxygen needed by fish and other water-dwelling species.

Efforts to control nitrogen in the Bay have proven difficult, and the Bay states are currently behind schedule in meeting their nitrogen reduction objective, though it appears they will meet their phosphorus reduction goal.

Copies of the report, "Benefits of Reducing Deposition of Atmospheric Nitrogen in Estuarine and Coastal Waters," are available by contacting Eric Slaughter, of the EPA's Office of Wetlands, Oceans and Watersheds. E-mail: Fax: 202-260-9960.