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EPA Reinstated the 1-Hour Ground-Level Ozone (Smog) Standard

July 5, 2000

On July 5, 2000, EPA reinstated the 1-hour standard for ozone in nearly 3000 counties, where the standard had been revoked since 1998. Following promulgation of the 8-hour ozone standard, on June 15, 2005, the 1-hour ozone standard was revoked for all areas except the 8-hour ozone nonattainment Early Action Compact Areas (EAC) areas. The information about the July 5, 2000 action is provided here for historical purposes and does not refer to any actions that may take place by the EPA in association with the December 22, 2006 decision by the Federal Appeals Court in regard to the 1-hour ozone standard.

On July 5, 2000, EPA reinstated the 1-hour standard for ozone in nearly 3,000 counties where the standard was previously revoked. The reinstatement returned all affected counties to the ozone designations (attainment, nonattainment or unclassifiable) that were in place when the standard was revoked. In addition, area classifications (severe, serious, etc.) at the time of revocation were restored. For most of the affected areas, the reinstatement was effective 90 days after the final rule was published in the Federal Register. However, 45 areas with clean air that had previously been designated as nonattainment did get 180 days to submit redesignation requests. All affected areas were required to continue monitoring for ozone; some would need to take action to prevent or eliminate ozone violations. Those requirements included implementation of maintenance plans, transportation and general conformity and new source review requirements.


The July 5, 2000 announcement indicated that most of the affected counties have never had an ozone problem and continued to meet the 1-hour ozone standard. Reinstatement of the 1-hour ozone standard will not trigger any new requirements for those areas. Based on 1996-98 data, fifty-three areas comprising 114 counties (both nonattainment and attainment) will be required to take some action to further reduce ozone pollution or to prevent future ozone increases. Attainment and nonattainment are legal designations; they do not indicate whether an area's air currently is clean or dirty. (See attached for a list of the areas.) Seven of the 53 areas affected by the final reinstatement will need to implement contingency measures in their existing maintenance plans, because the areas violated the 1-hour standard based on 1996-1998 data.

A maintenance plan is required for areas that once were designated as nonattainment but were reclassified as attainment after monitors showed clean air for at least three years, and the areas met other criteria. The plans are intended to ensure that an area will continue to comply with ozone standards. Contingency measures are corrective steps invoked when a maintenance area records a new violation of the standard.

Forty-five of the 53 areas that will return to nonattainment status have had "clean air" during the revocation period. To have the nonattainment designation removed, those areas will need to submit a request that EPA redesignate them as attainment areas, and they must meet certain criteria.

EPA has extended the effective date of the's action for those 45 areas, to allow them time to make the redesignation requests. For those areas, reinstatement will apply 180 days after this final rule is published in the Federal Register.

Areas that are not redesignated to attainment will have to meet conformity and new source review requirements when this final rule takes effect. Areas that are redesignated will have to meet conformity and prevention of significant deterioration requirements, in addition to other requirements of their maintenance plans.

Conformity refers to requirements under the Clean Air Act that federally funded transportation projects not aggravate air quality problems.

In nonattainment areas, new source review requirements apply to new and modified industrial facilities to prevent air quality from declining. New Source Review requires newly built or modified facilities 1) to install state-of-the-art emission controls and 2) to purchase "emission reduction offsets" from existing sources to compensate for the new pollution.

Prevention of significant deterioration refers to requirements for areas with clean air to assure that new and modified sources do not cause significant air quality degradation.

One of the 53 areas formerly designated as nonattainment (Sussex County, Del.) had a violation of the 1-hour ozone standard, based on air quality data from 1996-1998 and will remain subject to conformity and new source review as well as other necessary Clean Air Act requirements for such nonattainment areas.

Four additional counties have always been designated attainment, but data show they violated the 1-hour standard between 1996 and 1998. These counties (Berrien Co., Mich; Hamilton Co., Ind.; Hamilton Co., Tenn.; and Rowan Co., N.C.) will not have to take any immediate action upon reinstatement of the 1-hour standard. However, if EPA later decides to designate them as nonattainment, they would be subject to conformity, new source review and other nonattainment area planning requirements.

Fifty-Three Areas That Will Have to Take Action as a Result of Reinstatement of 1-Hour Ozone Standard

Seven Areas Designated Attainment (With Maintenance Plans) With Violations Since Revocation Includes 7 areas (24 counties) violating the 1-hour standard based on 1996-1998 data.

Charlotte-Gastonia, NC (2 counties)
Huntington-Ashland, WV-KY (4 counties)
Knoxville, TN (1 county)
Nashville, TN (5 counties)
Portland-Vancouver AQMA, OR-WA (4 counties)
Richmond, VA (7 counties)
Sheboygan, WI (1 county)

45 Areas Designated Nonattainment With No Violations Since Revocation Includes 45 areas (96 counties) that did not violate the 1-hour standard based on 1996-98 data. (These areas may apply for redesignation to attainment.)

Boston-Lawrence-Worcester (E. MA), MA-NH (12 counties)
Portsmouth-Dover-Rochester, NH (1 county)
Providence (All RI), RI (5 counties)

Atlantic City, NJ (2 counties)
Knox & Lincoln Cos., ME (2 counties)
Lewiston-Auburn, ME (2 counties)
Muskegon, MI (1 county)
Portland, ME (3 counties)
Poughkeepsie, NY (3 counties)

Albany-Schenectady-Troy, NY (6 counties)
Allentown-Bethlehem-Easton, PA-NJ (4 counties)
Altoona, PA (1 county)
Buffalo-Niagara Falls, NY (2 counties)
Door Co., WI
Erie, PA (1 county)
Essex Co., NY
Harrisburg-Lebanon-Carlisle, PA (4 counties)
Jefferson Co., NY
Johnstown, PA (2 counties)
Manchester, NH (1 county)
Reno, NV (1 county)
Scranton-Wilkes-Barre, PA (5 counties)
Smyth Co., VA (White Top Mtn)
York, PA (2 counties)
Youngstown-Warren-Sharon, OH-PA (3 counties)

SECTION 185A AREAS (Section 185A areas, previously called transitional areas, had three complete years of clean data from 1987-89)

Chico, CA (1 county)
Denver-Boulder, CO (6 counties)
Flint, MI (1 county)
Yuba City, CA (2 counties)

INCOMPLETE DATA CLASSIFICATION (Incomplete data areas had no data or less than 3 complete years of data at time of classification)

Allegan Co., MI
Cheshire Co., NH
Crawford Co., PA
Franklin Co., PA
Greene Co, PA
Juniata Co., PA
Lawrence Co., PA
Northumberland Co., PA
Pike Co., PA
Saginaw-Bay City-Midland, MI (3 counties)
Salem, OR (2 counties)
Schuylkill Co., PA
Snyder Co., PA
Susquehanna Co., PA
Warren Co., PA
Wayne Co., PA

Areas Designated Nonattainment With Violations Since Revocation Includes
only 1 county violating the 1-hour standard based on 1996-98 data.

Sussex Co., DE

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