Tighter ozone standard sought

EPA staff members are recommending that the agency lower the current national ambient air quality standard for ozone, the main component of smog. That standard is now 0.08 parts per million, averaged over eight hours. A final staff recommendation unveiled on Jan. 30 reports that current scientific data show significant adverse health effects can occur from exposure to ozone "even in areas with ozone levels below the current standard," EPA says. The recommendation says the agency should ratchet down the standard somewhere below 0.080 ppm, to as low as 0.060 ppm. It also advises that, because of improvements in ozone measurements, the agency now specify the standard to three decimal places. Last October, EPA's Clean Air Scientific Advisory Committee recommended that the agency set the new standard between 0.060 and 0.070 ppm (C&EN, Oct. 30, 2006, page 34). The agency is under court order to propose by June 20 whether it will keep or change the current ozone air quality standard and to make a final decision by March 12, 2008.