On June 3rd, EPA announced a final rule that will tighten the National Ambient Air Quality Standards (NAAQS) for sulfur dioxide (SO2) under the Clean Air Act, abandoning the currently applicable 24-hour and annual standards in favor of a 1-hour standard. The NAAQS also establish a new monitoring network for areas where SO2 emissions coincide with high population densities. The new regulations are aimed at preventing short-term exposure to SO2 and are specifically meant to curb the negative health effects associated with SO2 emissions including asthma, emphysema and other respiratory conditions.
EPA is required by statute to revise the NAAQSs for SO2 under Clean Air Act Sections 108 and 109. This revision is the result of a challenge[1] by the American Lung Association to EPA’s 1996 findings that the anticipated health benefits from revising the NAAQS for sulfur oxides to include short-term and peak concentration limits were not compelling.[2] As a result of the American Lung Association’s challenge, the EPA was directed to further explain its position that 5-minute and peak limits were unjustified. The resulting rule relies on the science of respiratory morbidity following short-term exposure to SO2, finding that a limit of 75 ppb 1-hour standard provides the requisite protection of public health. EPA will consider secondary standards, aimed at protecting public welfare (including the environment) in 2012.
The final rule will take effect sixty days after publication in the Federal Register and is available here.
Maggie Macdonald is a summer associate at Sive, Paget & Riesel, P.C.
[1] American Lung Ass’n v. EPA, 134 F. 3d 388 (D.C. Cir. 1998).
[2] 61 Fed. Reg. 25,572 at 25,575.
