The U.S. Environmental Protection Agency (EPA) is proposing to strengthen the nation’s sulfur dioxide (SO2) air quality standard. The EPA is taking comment on a proposal to establish a new national one-hour SO2 standard of between 50 and 100 parts per billion (ppb). According to the EPA, 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, the EPA is proposing to revoke the current 24-hour and annual SO2 health standards.
The EPA is also 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 would also 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. The EPA will address the secondary standard (designed to protect the public welfare, including the environment) as part of a separate proposal in 2011.
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 January 5, 2010, in Atlanta. The EPA must issue final standards by June 2, 2010.
For more information about the proposal, visit www.epa.gov/air/sulfurdioxide