Environmental and public health groups are asking a federal court to force EPA to complete its review of the national air quality standard for ozone as required by the Clean Air Act. The statute requires the agency to review and consider revising the standard every five years. EPA last revised the ozone standard in March 2008 and missed its March 2013 deadline for completing the next review. In a Jan. 21 filing, the Sierra Club, American Lung Association, and other groups asked the U.S. District Court for the Northern District of California to require EPA to finish examining the current science and by October 2015 set a new limit on the amount of ozone allowable in the air. The current standard is 75 ppb. A tighter limit could lead to new emissions controls on industrial facilities and other sources of pollutants that contribute to ozone formation, such as nitrogen oxides and volatile organic compounds.