EPA Retains Current Carbon Monoxide Ambient Air Quality Standards

摘要

In an August 31, 2011 final rule (76 FR 54294-54343), EPA has decided to retain the current national ambient air quality standards (NAAQS) for carbon monoxide (CO). The current CO NAAQS were promulgated on April 30, 1971, and are set at 9 ppm with an eight-hour averaging time, and at 35 ppm with a one-hour averaging time, neither to be exceeded more than once per year. In the final rule, the agency indicates: