For the first time in nearly 40 years, EPA is proposing to strengthen the nation’s sulfur dioxide (SO2) air quality standard to protect public health. Power plants and other industrial facilities emit SO2 directly into the air. Exposure to SO2 can aggravate asthma, cause respiratory difficulties, and result in emergency room visits and hospitalization. People with asthma, children, and the elderly are especially vulnerable to SO2’s effects.
“Short-term exposures to peak SO2 levels can have significant health effects – especially for children and the elderly – and leave our families and taxpayers saddled with high health care costs,” said EPA Administrator Lisa P. Jackson. “We’re strengthening clean air standards, stepping up monitoring and reporting in communities most in need, and providing the American people with protections they rightly deserve.”
EPA is taking comment on a proposal to establish a new national one-hour SO2 standard, between 50 and 100 parts per billion (ppb). This standard is designed to protect against short-term exposures ranging from five minutes to 24 hours. Because the revised standards would be more protective, EPA is proposing to revoke the current 24-hour and annual SO2 health standards.
EPA also is proposing changes to monitoring and reporting requirements for SO2. Monitors would be placed in areas with high SO2 emission levels as well as in urban areas. The proposal also would change the Air Quality Index to reflect the revised SO2 standards. This change would improve states’ ability to alert the public when short-term SO2 levels may affect their health.
The proposal addresses only the SO2 primary standards, which are designed to protect public health. EPA will address the secondary standard – designed to protect the public welfare, including the environment – as part of a separate proposal in 2011.
EPA first set National Ambient Air Quality Standards for SO2 in 1971, establishing both a primary standard to protect health and a secondary standard to protect the public welfare. Annual average SO2 concentrations have decreased by more than 71 percent since 1980.
The public comment period will be open for 60 days after the proposal is published in the Federal Register. The agency will hold a public hearing on Jan. 5, 2010 in Atlanta. EPA must issue final standards by June 2, 2010.