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Pinning Down Pollutants in City a Difficult Task

Expert reports on particulate matter and health-related issues.

Alexandria city staff and Dr. Jonathan Levy presented results of a study on the impact of particulate matter from the Mirant Potomac River power plant on city residents.

Approximately 50 people visited The Lyceum to listen to the Harvard School of Public Health professor’s report. For the past several months, there has been debate about the impacts of pollutants from the plant on neighboring residents. The city hired Levy to look into the issue of fine particulate matter since studies have shown that respiratory and cardiovascular health are effected by these emissions.

Levy studied all five Washington area power plants. “We considered both current emissions and what the plants would emit if Best Available Control Technology were used,” Levy said. “Interpretation of these findings is complex. Although much of the PM2.5 [fine particulate matter] in Alexandria would remain if these emission controls were implemented, the Potomac River plant is likely the single largest contributor to PM2.5 in Alexandria.

"It is also clear that emission control decisions must consider regional impacts if total public health benefits are a concern, but must also evaluate local impacts to ensure that populations are not disproportionately impacted. Our findings cannot provide a definitive policy recommendation, in part because we did not consider control costs and did not conduct detailed near-source modeling necessary to fully understand special patterns.

"However, this report provides some information about the relative importance of local and regional power plants for air pollution in Alexandria , which can be used to inform future policy decisions.”

THE FORMAL definition of particulate matter is “any solid or liquid substance suspended in the air.” This includes particles of different sizes and different chemical composition. PM2.5 is the finest of the measurable particulate matter. These small particles are best able to travel to the lower portions of the lung, and would be the most likely to contribute to health effects, according to Levy’s study.

Particulate matter is either emitted directly from a source or created through chemical reactions in the atmosphere. Fly ash or carbon particles from diesel vehicles are examples of the first type while sulfate and nitrate particles are examples of the latter.

According to Levy’s findings, emissions from the area’s five power plants contribute to about 2.3 deaths, .7 cardiovascular hospital admissions and 1.2 pediatric asthma emergency room visits per year in Alexandria.

“There are an average of 800 deaths a year in Alexandria and, like everywhere else in the country, the leading cause of death is heart disease,” said Dr. Charles Konigsberg, the director of the Alexandria Health Department. “Cancer is second and stroke is third. This hasn’t really changed over the past several years.

“Asthma has been on the increase for a number of years and there are many contributing factors, including air pollution. “While we are obviously concerned about any source of pollution, emissions from the Mirant plant are not at the top of the list of health concerns in Alexandria,” he said.

THE POTOMAC RIVER plant began operations in 1949 and uses old coal-burning technology. In the summer of 2003, the plant was cited for exceeding allowable oxides of nitrogen emissions. The Virginia Department of Environmental Quality is currently negotiating a new permit with Mirant and the state’s Attorney General is negotiating a consent decree that would address penalties and mitigation measures.

“We do not want the plant to be permitted to trade environmental credits,” said Mayor William D. Euille.

This practice of “trading credits” is allowed and sometimes even encouraged by the U. S. Environmental Protection Agency. It allows older and “dirtier” plants to purchase environmental credits from newer and “cleaner” plants. The cleaner plants, which exceed required emission standards, can thus earn money by selling their excess credits to allow older plants to continue to operate outside new federally-imposed environmental standards.

“While credit trading is prohibited in the most recent proposed permit for Mirant, some trading might be allowed under the Attorney General’s consent decree,” said Bill Skrabak, the city’s director of environmental quality.

The city is also asking that Mirant be required to install Separate Over Fired Air, an emissions control technology designed to reduce nitrogen oxide emissions, at the plant as part of the new permit. This will reduce these emissions significantly during the summer months when ozone is at its highest.

FEDERAL STANDARDS for particulate matter were only established in 1997. “After that, it takes time to determine whether states and local jurisdictions are meeting those standards,” Skrabak said. “Then, once a determination is made, there has to be a plan to ensure compliance. All of that takes time and we aren’t quite there yet. VDEQ has submitted a state plan for cleaning the air in the state’s non-attainment areas and, as part of that plan, has requested that no credit trading be allowed that doesn’t clean the air in the region. That state plan has been approved by EPA.”

Ultimately, the city wants the plant to be closed. “We understand that there are many steps between saying we want it closed and actually seeing it closed,” said Councilman Paul Smedberg. “We are also aware that it is not the only polluter. Cars and other motor vehicles are, of course, polluting the air every day much more than the plant.”

Levy agreed. “The Potomac River Power plant contributes anywhere from one to four percent of the total ambient small particulate matter. The obvious question is whether this constitutes a significant fraction or not. Although it implies that eliminating the Potomac River power plant would only decrease small particulate matter concentrations by a relatively small percentage, the same argument is likely true for any single source taken in isolation.

"The more important questions are what benefits could be obtained by alternative emission control plans, how those benefits compare across pollution sources, and whether the public health benefits of these emission controls justify the costs,” the report said.

THE CITY HOPES that the costs of the emission controls will lead to closing the plant. “This plant produces a relatively small amount of power,” Skrabak said. “The cost of the new emission control technology and the amount of power produced may lead Mirant to conclude that it is not worth the return on investment.”

There are other concerns, of course. “Mirant sells power to Pepco,” Skrabak said. “It is our understanding that it provides power to parts of northwest D.C. and that there may be some agreement with the Pentagon to provide backup power. You want to have built-in redundancies on the power grid to ensure that if one plant is off-line there will be sufficient back-up to ensure sufficient power. This is a regional question that needs to be considered.”

Euille agreed. “We can certainly state that we want the plant to close,” he said. “However, it is a regional question and one that needs to be discussed as such. We do not expect the plant to be closed tomorrow or even next year and certainly not without plans for how the power that it generates will be replaced.

“In the meantime, we want them to comply with all of the conditions in the new permit,” he said.

Council will review the report on June 9, and will vote on any action that needs to be taken.