CASAC Weighs in on the Ozone NAAQS: Might the Clean Air Act Require a Standard Below Background?

The Daily Environment Report last week provided an update on the current status of EPA’s development of a new National Ambient Air Quality Standard for ozone. The current 8-hour standard of 75 ppb is going to be revised downward; EPA currently plans to issue a final rule by September 2014.

Last month, the Clean Air Science Advisory Committee weighed in on EPA’s draft policy assessment for the ozone NAAQS. CASAC found that

the PA provides a strong rationale for consideration of ozone standards (8 hour averages) of 60 ppb and 70 ppb. The PA also provides adequate justification for considering concentrations below 60 ppb, in the 50 to 60 ppb range.

Unfortunately, a standard at or near 50 ppb could be below natural background.  According to Daily Environment Report, even Bill Becker, executive director of the National Association of Clean Air Agencies, acknowledges this and predicts that the standard will not be set at 50 ppb.  The problem is that § 109 of the CAA provides that NAAQS shall be set at a level which, “allowing an adequate margin of safety, are requisite to protect the public health.” The is no discussion of background and no provision to allow for consideration of the economics of attaining such a standard.

I was just about to publish this post, I saw in this morning’s Daily Environmental Report that CASAC appears to have backed off of its support for a standard between 50 ppb and 60 ppb.  Apparently, during a conference call yesterday, CASAC agreed to revise the language to state that

If EPA considers levels below 60 ppb, adequate justification should be provided.

While this may make it easier for EPA to set the new NAAQS at 60 ppb or above, it doesn’t eliminate the difficulty.  In the old world, when environmental policy was bipartisan, one could imagine some kind of compromise on this issue. Now, where one party sees all EPA regulations as “job-killers”, judicial decisions forcing EPA to ensure that NAAQS comply with the stringent CAA language are one of the critical hooks that environmentalists have to maintain a tough emissions regime under the CAA.

I don’t really see a way out of this conundrum in the short-term, but I do expect EPA to promulgate a revised ozone NAAQS between 60 ppb and 70 ppb. I further expect any standard below 70 ppb and at or above 60 ppb to withstand judicial review. The interesting cases would be if EPA were to promulgate a standard either at 70 ppb, which would be challenged by clean air NGOs, or below 60 ppb, which could squarely raise the background issue.

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