Court Vacates Portions of EPA’s Ozone Rule

on January 02, 2015 at 2:00 PM


A federal appeals court has rejected portions of revisions to EPA’s 2008 ozone rule that would delay compliance deadlines and revoke transportation conformity requirements.

On December 23, 2014, the U.S. Court of Appeals for the District of Columbia Circuit vacated portions of the Environmental Protection Agency’s (EPA) 2008 National Ambient Air Quality Standards for ground-level ozone.  The court agreed with the Natural Resources Defense Council’s (NRDC) challenges to the 2008 NAAQS implementation rule’s schedule of attainment deadlines and revocation of the 1997 NAAQS for transportation conformity purposes.  It held that EPA’s decision to extend the compliance deadline and revoke transportation conformity requirements exceeds its authority under the Clean Air Act (CAA).

The EPA’s 2008 ozone rule – which aims to reduce ozone levels to 75 parts per billion (ppb) across the country — extended the compliance deadline for certain areas – allowing approximately one-third increase in time compared to the previous revision.  It also revoked the transportation conformity requirements for areas that had yet to attain standards or had recently reached attainment status and remained under obligations to prevent reversion to nonattainment status.  Transportation conformity requirements obligate affected regions to assure that any proposed transportation infrastructure project – that would significantly increase emissions – align with the maximum emissions levels established in EPA-approved plans to meet air quality standards.

The CAA requires EPA to set:

  • primary ozone standards to protect public health;
  • secondary ozone standards to protect public welfare;
  • designate air quality regions as “attainment” if pollutant levels fall below the allowed level;
  • designate “nonattainment” if pollutant level is above the allowed level;
  • and designate “unclassifiable” if there is insufficient information.


The EPA can redesignate an attainment area to nonattainment when the pollutant concentration rises.  To redesignate from nonattainment to attainment, the CAA requires EPA to determine if the air quality improvement is due to permanent and enforceable emissions reductions and approve a maintenance plan to ensure that the area remains in compliance with the standard.  Both maintenance and nonattainment areas must adhere to transportation conformity requirements, which condition federal funding and approval of proposed transportation projects on their compliance with applicable state implementation plans.

With regard to the attainment deadlines, the court observed that statutory indications prevent allowing EPA’s extension of compliance deadlines for revised standards.  Congress prescribed initial attainment deadlines under the 1990 CAA amendments based on a trigger designation date – November 15, 1990 – on which initial designations and classifications took effect.  It also required measuring attainment deadlines based on a trigger date equaling the redesignation date.  The CAA mandates using the same attainment periods with a trigger date of designation or redesignation.  As designations and classifications for the 2008 NAAQS became effective on July 20, 2012 (trigger date), the attainment deadline would fall on July 20, 2015; however, EPA deferred the trigger date to December 31, 2012 and set the attainment deadline as December 31, 2015.

Regarding transportation conformity requirements, the court held that the CAA does not authorize EPA to limit the applicability of conformity requirements by exempting some nonattainment areas, even for a limited period of time.  Areas that have attained the 2008 standard – indicating improvement in air quality – would be in maintenance or nonattainment status for purposes of the still-operative 1997 standard.  For areas in maintenance status – that would have attained the 1997 status – Congress determined that they must continue to satisfy maintenance obligations (maintenance requirements remain in effect for twenty years). EPAozoneBCA While EPA may revise NAAQS to relax the standards, the CAA contains an anti-backsliding provision requiring EPA to promulgate requirements that provide for controls which are not less stringent than those applicable to areas designated nonattainment before the relaxation.  NRDC contended that the partial revocation exceeds EPA’s statutory authority and violates the anti-backsliding provision.  The court agreed that EPA lacks the authority to revoke conformity requirements and hence, did not address applicability of the anti-backsliding provision.

EPA proposed in November 2014 to strengthen the 2008 standard from 75 ppb to between 65 and 70 ppb for 2025. The agency will hold three public hearings in early 2015. Comments on the proposed rule are due by Mar 17, 2015.

Originally published by EnerKnol.

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