CHICAGO (CN) - The 7th Circuit upheld the Environmental Protection Agency's decision to classify three Midwestern geographic areas, including Greater Chicago, as having met current ozone standards.
In 2012, the EPA reclassified the Milwaukee-Racine area, Greater Chicago, and the greater St. Louis area in Illinois, as having met the 1997 National Ambient Air Quality Standards for ozone.
The agency found that the average ozone concentration in these areas remained below 0.08 parts per million for the last three years as a direct result of "permanent and enforceable reductions in emissions."
The Sierra Club challenged the decision as "arbitrary and capricious," arguing that the agency did not follow its own guidance in determining that the ozone reduction was due to permanent and enforceable measures.
"EPA should have more closely considered the possible effects of the economic recession, fuel prices, weather, and 'other impermanent conditions' on the reductions in ozone (and ozone precursor) levels; without quantifying the effect of each of these variables, EPA cannot meet the requirements of the statute, Sierra Club says," according to the judgment.
But the 7th Circuit disagreed Tuesday, granting deference to the EPA's decision.
"In light of the evidence, EPA contends that - in its experience, expertise, and professional judgment - it 'reasonably attributed' the reductions to permanent and enforceable measures, which is all that its interpretation of the CAA [Clean Air Act] requires," U.S. Circuit Judge Joel Flaum said, writing for the three-judge panel.
While the EPA's report could have been more sophisticated as the Sierra Club demands, the Act does not demand the agency take such measures before making a reclassification decision.
"At bottom, the CAA required EPA to confirm the necessary ozone reduction and tie it to a 'permanent and enforceable' drop in precursor emissions (VOC and NOx) resulting from 'permanent and enforceable' regulation. EPA did that," Flaum said. "The CAA does not require EPA to prove causation to an absolute certainty."