A federal court today sided with the Sierra Club in a challenge to a U.S. EPA program that exempts some new facilities from air monitoring and emissions requirements. A three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit ruled unanimously that EPA exceeded its statutory authority when it set up a significant impact level (SIL) and significant monitoring concentration (SMC) for fine particle pollution from new facilities. The programs allow new facilities to obtain an exemption from Clean Air Act soot standards if they show their emissions will have only a minimal impact on air quality in the area.

The Supreme Court opted against hearing a challenge today to U.S. EPA's most recent air regulation aimed at protecting human health from short-term spikes in sulfur dioxide emissions. In July, the U.S. Court of Appeals for the District of Columbia Circuit held that EPA didn't act unlawfully in setting a new SO2 standard of 75 parts per billion averaged over an hour. The court didn't rule on another part of the challenge on how the rule will be implemented because EPA hasn't finalized its plans.