Upon promulgation of the new eight-hour ozone standard in 1997, the US Environmental Protection Agency (EPA) began to revoke the older one-hour standard for ozone in areas that were not currently violating the older standard. EPA intended to retire the one-hour standard in favor of the more protective eight-hour standard in order to ensure protective coverage for ozone throughout the country.
In 1998, the American Trucking Association, the US Chamber of Commerce and other state and business groups challenged the new eight-hour standard in court on the basis of how the threshold was determined. The courts remanded the eight-hour standard back to EPA, but did not vacate it, meaning that the eight-hour standard technically continued to exist, but was unenforceable until the technical justification for it was clarified. EPA appealed the ruling. In early 2001, the US Supreme Court reversed the lower court rulings and upheld EPA’s authority to set and implement revised national ambient air quality standards. The Court instructed EPA to develop an implementation plan (including a timetable) consistent with the Court’s decision. (EPA web site on background and court cases on the revised standard)
While the case was pending before the Supreme Court, the ozone standard remained in effect and EPA started the process of transitioning from the one-hour standard to the eight-hour standard. EPA is required by law to designate nonattainment areas within 2 years of promulgation. Although the designation process was started and EPA required states to submit proposed nonattainment area designations in 2000, this process has been slowed pending resolution of the litigation and EPA’s response to the 2001 Supreme Court ruling. In a settlement with nine environmental groups, EPA has agreed to an April 15, 2004 deadline for designating attainment and nonattainment areas for the eight-hour ozone standard. According to EPA’s schedule, states are required to propose eight-hour ozone nonattainment areas by April 15, 2003 and subsequently file state implementation plans (SIPs) with control requirements three years after area designations. Attainment dates for eight-hour ozone could begin as early as 2007 for the least severe nonattainment areas.
One-Hour Ozone Standard
In June of 1998, DES filed its one-hour ozone attainment demonstration with EPA. In September of 1998 New Hampshire began monitoring attainment of the one-hour standard statewide, making the state eligible for redesignation to attainment or revocation of the one-hour standard, a move at the time designed to transition the state to the new eight-hour ozone standard.
The one-hour ozone standard was revoked throughout New Hampshire in May 1999. Pending litigation against the eight-hour standard, this inadvertently left New Hampshire and many other states without any enforceable ozone standard. In an attempt to better protect these areas, EPA reinstated the old one-hour ozone standard nationwide in 2000. This action returned portions of Hillsborough, Rockingham, and Stafford counties to "Serious" nonattainment, and Cheshire County and the Manchester region to "Unclassified" and "Marginal" nonattainment, respectfully (map of one-hour ozone nonattainment areas). All of these areas currently meet the one-hour NAAQS. EPA plans to eventually revoke the one-hour standard again in conjunction with designation of areas for the eight-hour standard.
Chronology for Establishing 8-Hour Ozone Nonattainment Areas
- Following the adoption of the eight-hour ozone NAAQS in July 1997, EPA asked states to track monitored eight-hour ozone values to determine which areas exceed the new standard.
- In 1998, eight-hour ozone standard is challenged by the American Trucking Association (and others) for among other things failing to consider the benefits of the pollutant ozone.
- On August 18, 1999, New Hampshire begins submiting eight-hour ozone values to EPA Aerometric Information Retrieval System (AIRS) data base.
- In a March 28, 2000 memo, EPA requested that states submit final recommendations for nonattainment area boundaries based on 1997-99 monitoring data. Governor Shaheen submitted New Hampshire’s proposed eight-hour ozone nonattainment area designations to EPA on July 24, 2000.
- February, 2001 – US Supreme Court upholds the constitutionality of the Clean Air Act as EPA had interpreted it in setting the new eight-hour ozone standard.
- March, 2002 – DC Circuit Court upholds the revised standards and rejects all remaining challenges to EPA’s 1997 NAAQS for ozone (and for fine particulate matter).
- December, 2002 – EPA issues final response to the DC Circuit’s remand to consider the potential beneficial effects of ozone. EPA reaffirms the eight-hour ozone standard.
- March through April 2002 – EPA holds public meetings for implementation options.
- 2002-2003 – EPA plans to work with states and other interested parties to develop rule on implementation of eight-hour ozone NAAQS, including area designation issues and ozone attainment requirements.
- Early 2003 – EPA publishes proposed rule for implementation.
- April 2003 – States provide designation recommendations.
- Late 2003 – EPA publishes final imlementation rule.
- April 2004 – EPA finalizes nonattainment area designations.
- April 2004-May 2007 – Nonattainment area State Implementation Plans (SIPs) submitted to EPA.
- 2010 – Likely attainment date for all New Hampshire nonattainment areas.
US EPA’s web site: Ozone Eight-Hour Implementation Approach