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Particulate Matter Very small, or fine, particles are released into the air around us—or are created—by emissions from many natural and manmade sources, including power plants. There are hundreds of types and sources of fine particles. While electric utilities remove more than 99 percent of direct fine particle emissions produced by their power plants, reactions in the atmosphere involving emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) generate sulfates and nitrates, two of the many types of fine particulate matter. Air Quality Standards for PMIn 1997, the U.S. Environmental Protection Agency (EPA) revised the National Ambient Air Quality Standards (NAAQS) for particles to create new fine particle (PM2.5) standards—15 micrograms per cubic meter for an annual average and 65 micrograms per cubic meter for a 24-hour average. Even as states are now preparing implementation plans to meet the 1997 standards (with deadlines to attain the standards by 2010), EPA recently revised the daily standard again. In September 2006, EPA tightened the daily standard from 65 to 35 micrograms per cubic meter; however, EPA did not find compelling evidence to support a change to the annual standard of 15 micrograms per cubic meter. Existing air quality improvement programs are expected to bring most of the country into compliance with the 1997 standards by 2010. In April 2010, EPA will make final determinations on those parts of the country that do not meet the September 2006 standard, and states will finalize plans with EPA in 2013 to meet the new standard in 2015. Power Plants Are Reducing EmissionsPower plants and other industrial sources have been making dramatic reductions in emissions for decades, while supplying the nation’s ever-increasing demand for energy and consumer products. National power plant SO2 and NOx emissions have been reduced by more than 40 percent since 1980. What’s more, new rules issued by the EPA—including the Clean Air Interstate Rule (CAIR), Clean Air Mercury Rule (CAMR), and Clean Air Visibility Rule (CAVR)—will continue to improve air quality. The electric power sector is on track to reduce its SO2 and NOx emission rates (measured in pounds per megawatt hour) by more than 90 percent (compared to 1980 levels) upon implementation of EPA’s CAIR, CAMR, and CAVR. Find out more about our improving air quality. Better Science Is Needed To Set Appropriate PM StandardsImposing stricter regulations for fine particulate matter will not necessarily produce additional health benefits beyond those achieved through the current standards, but will further exacerbate energy prices and prove burdensome to local economies. In fact, EPA’s September 2006 rule is estimated to have an annual price tag of tens of billions of dollars. Even if it is assumed that current concentrations of fine particulate matter in the ambient air contribute to adverse health effects, it has not been established that emissions from power plants generate the particles of concern. EPA’s own Office of Inspector General and the National Academy of Sciences, among others, have found that more research is needed to determine the specific types of particulate matter responsible for health concerns so that EPA can set meaningful standards and implement air quality programs with tangible benefits. Resources
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– Learn more about particulate matter, how electric utilities are improving air quality, and the issues that must be considered before implementing new standards.