EPA Finally Proposes a Revised Ozone Standard, Sort Of

Yesterday, EPA finally proposed a revised ambient air quality standard for ozone – Ozone_Molecule_Formulaexcept 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.

3 thoughts on “EPA Finally Proposes a Revised Ozone Standard, Sort Of

  1. John: Like most issues related to the CAA, it’s complicated. I’m not sure I have much to say other than different sections are applied differently. I think that the logic is that NAAQS aren’t seen as standards that apply to individual facilities; compliance is achieved by the states through the promulgation of SIPs that, EPA agrees, are sufficient to attain the standard. Thus, although individual facilities must demonstrate that their emissions won’t cause or contribute to a NAAQS exceedance, it is acceptable, so long as EPA so provides by rule, rather than on a case-by-case basis, to make that demonstration at the time the permit application is submitted, utilizing the NAAQS in effect at that time.

    • All excellent observations. I think you wrote on Avenal in the past.. 9th rejected EPA grandfathering at least as it applies to psd permits (the rare exception that requires individual sources to make a naaqs demonstration) http://cdn.ca9.uscourts.gov/datastore/opinions/2014/08/12/11-73342.pdf

      One point that might be interesting is that even in areas that might be in attainment after the new standard, I think there will be more emphasis on ozone modeling in support of individual psd permits. In the past states didn’t normally require ozone naaqs modeling but now might require some cause or contribute demonstration because every area will be borderline attainment.

      Great blog and happy thanksgiving.

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