Opinion ID: 1033609
Heading Depth: 2
Heading Rank: 2

Heading: NAAQS Regulating Sulfur Dioxide

Text: Emissions Sulfur dioxide, or SO2, is a ―highly reactive colorless gas‖ that derives mainly from fossil fuel combustion. Am. 8 Lung Ass‘n v. EPA, 134 F.3d 388, 389 (D.C. Cir. 1998). It smells like rotten eggs and causes acid rain at elevated concentrations in the air. Id. The presence of sulfur dioxide in the air creates adverse health effects, especially for people with asthma. Id. On June 22, 2010, the EPA revised the NAAQS that had previously regulated sulfur dioxide emissions to enact stricter standards and ensure the continued protection of public health with an ―adequate margin of safety.‖ Primary National Ambient Air Quality Standard for Sulfur Dioxide, 75 Fed. Reg. 35,520, 35,521 (June 22, 2010) (to be codified at 40 C.F.R. pts. 50, 53, 58) (―1-hour SO2 NAAQS‖). Specifically, the EPA replaced the 24-hour and the annual standards that had been in place with a new shortterm, more stringent standard that sets the level of sulfur dioxide emissions at 75 ppb (parts per billion) per the hour. Id. 1-hour SO2 NAAQS became effective on August 23, 2010. As part of the implementation process of the 1-hour SO2 NAAQS, states are required to submit their SIPs by June 2013 and to achieve attainment, implementation, maintenance, and enforcement of the NAAQS by August 2017. Id. at 35,577.