EPA Issues New SO2 Guidelines

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The U.S. Environmental Protection Agency (EPA) issued new standards for sulfur dioxide (SO2) yesterday in a ruling that is likely to raise costs for some utility companies, according to an Associated Press report.

The new guidelines lower the level of SO2 exposure that the EPA considers safe for the first time since the agency began regulating the gas in 1971. According to the EPA, exposure to SO2 can aggravate asthma and cause other respiratory difficulties. People with asthma, children, and the elderly are especially vulnerable to the effects of SO2. The EPA estimated the new rules will prevent 2,300 to 5,900 premature deaths and 54,000 asthma attacks a year. The estimated cost in 2020 to fully implement this standard is approximately $1.5 billion.

According to the AP report, the ruling could mean utilities will take some of their coal plants offline rather than invest in new emissions scrubbing equipment. Progress Energy has said it intends to close 11 plants in North Carolina that are more than 50 years old, because the company believes it will not be cost effective to bring them in line with the new requirements.

Duke Energy was recently forced to pay $93 million in a court settlement for violations of the EPA’s Clean Air Act as the result of SO2 emissions at its coal plant in New Albany, IN.

The American Lung Association (ALA) and Clean Air Watch applauded the move, which they say will help protect communities near coal-fired power plants, industrial boilers, petroleum refineries, metal processing plants and diesel exhaust, although according to a report in the Miami Herald the new standard is less strict than the ALA had advocated. The ALA had previously sued the EPA to force it to focus attention on SO2 levels.

The Herald quoted a spokesman for the Edison Electric Institute, a utility industry association that had fought the new regulations, who described the new rules as “a very stringent standard,” though it was too early to estimate how many plants would require new scrubbing equipment.

The new guideline sets the one-hour SO2 health standard at 75 parts per billion (ppb), a level designed to protect against short-term exposures ranging from five minutes to 24 hours. The EPA is revoking the current 24-hour and annual SO2 health standards because it says evidence indicates that short-term exposures are of greatest concern and the existing standards would not provide additional health benefits.

The EPA is also changing the monitoring requirements for SO2. The new requirements assure that monitors will be placed where SO2 emissions impact populated areas. Any new monitors required by this rule must begin operating no later than Jan. 1, 2013. EPA is expecting to use modeling as well as monitoring to determine compliance with the new standard.

Annual average SO2 concentrations have decreased by 71 percent since 1980, according to the EPA.

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