Yesterday, EPA finally proposed a revised ambient air quality standard for ozone – except that the agency is still hedging its bets. The Clean Air Science Advisory Committee had previously supported a revised ozone NAAQS of 0.060 to 0.070 ppm. EPA has narrowed the range slightly, proposing a revised NAAQS of from 0.065 to 0.070 ppm, but still has not yet picked a number.
EPA’s waffling is particularly annoying because it is of course taking comment on alternatives both below and above the 0.065 to 0.070 ppm range that it is proposing. First, with regard to levels below 0.065, EPA stated that:
Recognizing that the CASAC recommended a range of levels from 0.060 ppm to 0.070 ppm, and that levels as low as 0.060 ppm could potentially be supported, the Administrator solicits comment on alternative standard levels below 0.065 ppm, and as low as 0.060 ppm. However, the Administrator notes that setting a standard below 0.065 ppm, down to 0.060 ppm, would inappropriately place very little weight on the uncertainties in the health effects evidence and exposure/risk information.
This actually should give some comfort to opponents of a lower standard. As we noted previously, CASAC concluded that there are:
clinically significant lung function decrements and airway inflammation, after exposures to 60 ppb ozone in healthy adults with moderate exertion.
We have blogged extensively about the role of CASAC in judicial review of EPA decisions. The current situation appears to be that, if EPA relies on CASAC, it will be affirmed – meaning that a standard of 0.060 ppm would probably survive judicial review – but that courts have given EPA some leeway to depart from CASAC recommendations. EPA’s statement about the uncertainties in data at levels below 0.065 ppm appears to be setting the stage for EPA justifying a standard greater than 0.060 ppm.
EPA is also taking comment on keeping the current ozone NAAQS of 0.075 ppm. I think that the likelihood of EPA keeping that standard is approximately zero – and the likelihood that a decision to do so would survive judicial review is not much greater than zero.
We’re going to end up in the 0.065 to 0.070 ppm range and EPA just seems to want to keep us guessing on the actual number for a little while longer.
By the way, get those permit applications in asap, because EPA will be grandfathering projects that have filed completed applications prior to the effective date of the new standard.