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Following 8-Hour Ozone
Standard Activities

On March 10, 2009, the US EPA requested that the Court vacate the existing briefing schedule and hold the consolidated cases in abeyance. EPA requested the extension to allow time for appropriate EPA officials that are appointed by the new Administration to review the Ozone NAAQS Rule to determine whether the standards established in the Ozone NAAQS Rule should be maintained, modified, or otherwise reconsidered. EPA further requested that it be directed to notify the Court and the Parties within 180 days of the Court's order vacating the briefing schedule of the actions the Agency has taken or intends to take, if any, with regard to the Ozone NAAQS Rule, and the anticipated time frame for any such actions. On September 16, 2009, the EPA announced it would reconsider the 2008 national ambient air quality standards (NAAQS) for ground-level ozone for both human health and environmental effects. The Agency planned to propose any needed revisions to the ozone standards by December 2009 and issue a final decision by August 2010. However, on August 20, the Agency announced that it would delay its announcement to on or around the end of October. In early November, the EPA announced that it would reach a final decision on the ozone standards by December 31, 2010. On December 8, the EPA announced that it would delay its final decision on the ozone standards until July 2011. EPA announced on July 26 that it would not make a decision on the ozone standards by its previously announced deadline of July 29. On September 2, 2011, President Obama requested that the EPA withdraw its proposed revisions to the ozone standards.

On September 22, 2011, the EPA announced the schedule for implementing the 0.075 ppm 8-hour ozone NAAQS. EPA faces possibilities for litigation and the timing proposed may be impacted by the litigation.

Some background information on the 0.075 ppm standard. On January 7, 2010, the EPA announced on its web site its proposal to strengthen the national ambient air quality standards for ground-level ozone. The EPA's proposal decreases the 8-hour “primary” ozone standard level, designed to protect public health, to a level within the range of 0.060-0.070 parts per million (ppm). EPA is also proposing to establish a distinct cumulative, seasonal “secondary” standard, referred to as the W126 index, which is designed to protect sensitive vegetation and ecosystems, including forests, parks, wildlife refuges, and wilderness areas. EPA is proposing to set the level of the W126 secondary standard within the range of 7-15 ppm-hours. On August 20, the Agency announced that it will delay its announcement to on or around the end of October. The proposed revisions result from a reconsideration of the identical primary and secondary ozone standards set at 0.075 ppm in March 2008. In May 27, 2008, health and environmental organizations filed a lawsuit arguing that the EPA failed to protect public health and the environment when it issued in March 2008 new ozone standards. The suit was filed in the U.S. Court of Appeals for the District of Columbia Circuit by Earthjustice on behalf of a number of environmental and conservation groups and the American Lung Association. Other health and environmental organizations involved in the lawsuit are the Natural Resources Defense Council, Environmental Defense Fund, National Parks and Conservation Association, and the Appalachian Mountain Club. Eleven states filed a parallel suit against the EPA in an effort to overturn EPA's decision on the ozone standards. The states were Connecticut, California, Delaware, Illinois, Massachusetts, Maryland, Maine, New Hampshire, New Jersey, New York, and Rhode Island. Other plaintiffs were the District of Columbia, the city of New York and Pennsylvania's department of environmental protection. Besides questioning EPA's decision to change the health ozone standard from 0.084 ppm to 0.075 ppm, the suit challenges EPA's decision on ignoring CASAC's recommendation to establish the cumulative seasonal W126 standard to protect the environment, especially plants. EPA and White House officials had acknowledged previously that the seasonal W126 standard had been opposed by the White House Office of Management and Budget, which oversees government regulation. Memos in the public record indicate that the issue was settled after President Bush intervened directly on behalf of the White House staff.

Historically, it is important to understand some of the background to the original 8-hour 0.08 ppm ozone standard. On March 26, 2002, the U.S. Court of Appeals for the District of Columbia decided on the Petitioners' specific challenges to the original 8-hour ozone air quality standards that remained unresolved. The Court rejected the argument that the language and reasoning of their earlier decision determined the outcome of these remaining claims. Finding the challenged air quality standards neither arbitrary nor capricious, the Court of Appeals denied the petitions for review except to the extent the Supreme Court's and their earlier decisions require further action by EPA. For more information on the earlier court decision, please go to our summary.

On April 15, 2004, the EPA designated 474 counties as nonattainment for the original 0.08 ppm 8-hour ozone standard. A map is available to review the current violating counties. For additional information concerning EPA's implemenation for the 0.08 ppm 8-hour standard, please go to the Agency's web page.

The phase 1 final rule sets forth the classification scheme for nonattainment areas and requirements for States continued obligations with respect to existing 1-hour ozone requirements. In the final rule, EPA will separate areas based generally on their 1-hour ozone design value. A design value is an air quality measurement used to determine an area's air quality status in reference to a national standard. (attainment or nonattainment). This final rule separates 8-hour ozone nonattainment areas into two categories:

  • Areas whose 1-hour ozone design value is less than 0.121 parts per million fall under the more general requirements (attainment deadlines 5-10 years after designation). These areas may be referred to as "Basic Nonattainment Areas" in public communication materials.
  • Areas whose 1-hour design value is greater than or equal to 0.121 ppm under the more specific requirements (attainment dates 2007 - 2021). These areas would be further classified as "marginal", "moderate", "serious", "severe", or "extreme" based on the severity of their 8-hour ozone problem.

EPA will revoke the 1-hour standard one year after the effective date of designating attainment and nonattainment areas for the 8-hour standard. To avoid "backsliding," or losing clean air progress towards attaining the 1-hour ozone standard, this rule will require the very specific control measures for the 1-hour standard and included in a state's implementation plan to stay in place until an area attains the 8-hour standard. The discretionary emissions reductions in a state's implementation plan would also remain but could be revised or dropped based on modeling demonstrating that it would be appropriate. Phase 2 of the final 8-hour ozone implementation rule will address, among other things, reasonably available control measures, reasonably available control technology, attainment demonstrations and modeling requirements, and will be issued in the next several months.

In the June 1998 issue of Environmental Science & Technology (32(11):276A-282A), an article about the "piston" effect discusses why the 8-hour ozone standard may be difficult to attain. The EPA has confirmed that its emission reduction modeling results are showing inconsistencies. In addition, a paper has just been published in the prestigious journal, Atmospheric Environment, that discusses the difficulty in applying enough emission reductions to attain the new ozone standard. Clearly, the "piston" effect appears to be interfering with attaining the 8-hour ozone standard. With continuing research on the "piston" effect and its ramifications, it may become apparent to the EPA and Congress that action may have to be taken prior to the planned attainment deadline years to modify the form of the 8-hour ozone standard. Alternative forms that will protect the public's health, at the same level as the 8-hour standard, are available. For more information on the "piston" effect, please see the Table of Contents web page.

On July 5, 2000, EPA reinstated the 1-hour standard for ozone in nearly 3000 counties, where the standard had been revoked since 1998. The reinstatement of the 1-hour standard affected some areas that had been designated as "attainment" for EPA's 1-hour ozone standard and some that formerly were designated as "nonattainment," but where monitors showed clean air for 3 consecutive years. According to the Agency, the reinstatement created a safety net for nearly 3,000 counties across the country, while EPA was waiting for the U.S. Supreme Court decision on its 8-hour standard.

On July 22, 1999, the U.S. EPA issued a response to an article written in the Winter/Spring NARSTO News. The article summarizes items from a critical review paper by Parrish and Fehsenfeld, which expressed concerns about the integrity of ambient ozone measurements, using the EPA-approved UV absorption monitoring method. The potential measurement errors cited were calibration uncertainties, ambient interferences, and anomalous operating conditions. The EPA agreed that there was a need for additional field intercomparisons of the UV technique with other ozone measurement techniques, particularly during conditions typical of ozone exceedances, to better define the scope and impact of any potential UV ozone measurement uncertainties.

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