17 November 2009-- The Environmental Protection Agency (EPA) is proposing to establish a new national one-hour sulfur dioxide (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 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.
Want more news? Subscribe to the FREE E-newsletter!
Related article
EPA proposes hourly for nitrogen dioxide