The Supreme Court declined to review January 22 a U.S. Court of Appeals for the District of Columbia Circuit decision upholding the Environmental Protection Agency’s SO2 air quality standard. ASARCO LLC had petitioned the court October 18 to take up the case, arguing that the standard is more stringent than necessary to protect the public health; the agency set the hourly national ambient air quality standard for SO2 at 75 ppb in June 2010. The court denied the petition without comment.