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Health-based limit for ozone affirmed by US court

Court also jettisons provision supported by chemical industry

by Cheryl Hogue
August 27, 2019 | A version of this story appeared in Volume 97, Issue 34

Photo shows a view of the Los Angeles skyline surrounded by smog.
Credit: Shutterstock
Los Angeles has battled smog⁠—a mixture of ground-level ozone and other air pollutants⁠—for decades.

Rejecting industry arguments, a federal court in late August upheld a limit for smog pollution set by the Obama administration to protect health.

At issue was a 2015 Clean Air Act regulation that tightened the allowable limit of ground-level ozone, a major component of smog, to 70 parts per billion. The previous limit was 75 ppb, set in 2008. The 2015 rule was among those listed as “Top Regulations of Concern” that industry, including several chemical companies, asked the Trump administration to ax.

The US chemical sector’s main lobbying association, the American Chemistry Council, was one of many business groups that opposed the 2015 standard.

In addition to affirming the lower limit for ozone, the US Court of Appeals for the District of Columbia Circuit also struck down a provision of the rule that ACC backed. That part would have allowed some facilities that had pending applications for Clean Air Act permits to comply with the 75 ppb standard rather than the stricter one.

“ACC strongly supported EPA’s proposal to grandfather [Clean Air Act] permit applications already in progress” when the new standard took effect, the organization says in a statement. Applicants would have already planned to meet the 75 ppb limit, ACC says.

The court found the Clean Air Act forbids construction of a facility that will cause or contribute to pollution that exceeds any existing clean air standard.



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