EPA Fights Attacks On Background Ozone, Permit Waiver In NAAQS Suit

摘要

EPA is defending its decision to tighten its ozone standard to 70 parts per billion (ppb) in part by rejecting claims from several states and industry groups that the rule is unlawful because natural "background" ozone will make it impossible to meet the limit, and defending a waiver for some existing air permits from having to meet the standard. In a July 29 brief in Murray Energy Corp. v. EPA, filed in the U.S. Court of Appeals for the District of Columbia Circuit, EPA says that it rationally reviewed the science on ozone's impacts on human health and welfare in its Oct. 1 decision to tighten its primary, health-based ozone national ambient air quality standard (NAAQS) down from the prior 2008 limit of 75 ppb.