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Areas designated nonattainment in 1991(1) that failed
to meet the 1-hr ozone NAAQS in 2000-2002


Designated Area

Ozone Design
Value(2) (ppm)

  AL Birmingham 0.127
  CA Los Angeles South Coast Air Basin 0.169
  CA Sacramento Metro 0.148
  CA San Francisco Bay Area 0.126
  CA San Joaquin Valley 0.151
  CA Southeast Desert Modified AQMA 0.146
  CA Imperial Co. 0.147
  CT Greater Connecticut 0.146
  CT New York-N. New Jersey-Long Island, NY-NJ-CT


  GA Athens (4)


  GA Atlanta


  GA Macon 0.125
  LA Baton Rouge 0.135
  ME Portland 0.126
  MD Baltimore 0.143
  MD Kent and Queen Anne's Counties 0.128
  MA Boston-Lawrence-Worchester (E. MA), MA-NH 0.130
  MA Springfield (Western MA) 0.132
  NH Manchester 0.123
  NH Portmouth-Dover-Rochester (4)


  NY Poughkeepsie 0.126
  NC Charlotte-Gastonia 0.130
  OH Cleveland-Akron-Lorain


  PA Philadelphia-Wilmington-Trenton, PA-NJ-DE-MD 0.135
  RI Providence (All RI) 0.130
  TN Knoxville (4) 0.116
  TX Dallas-Fort Worth 0.135
  TX Houston-Galveston-Brazoria 0.175
  VA Richmond-Petersburg 0.124
  VA Washington DC-MD-VA 0.131
  WI Chicago-Gary-Lake County


  WI Milwaukee-Racine



1. Designations and classifications for ozone nonattainment areas as published in the Federal Register, 40 CFR Part 81. Unclassified and transitional nonattainment areas are not included in Table in this table.

2. The updated air quality design value is estimated for the 2000-2002 period using all air quality data reported to EPA's Air Quality System (AQS). The computation procedures follow EPA guidance for calculating design values (Laxton Memorandum, June 18, 1990). For sites with three complete years of monitoring data, the air quality design value is the fourth highest daily maximum 1-hour ozone concentration, because the standard allows one exceedance per year on average. It is important to note that the 1990 Clean Air Act Amendments required that nonattainment areas be classified on the basis of the design value at the time the Amendments were passed, generally the 1987-89 period was used.

3. The level of the 1-hour ozone Ambient Air Quality standard is 0.12 parts per million (ppm) daily maximum 1-hour average concentration not to be exceeded more than once per year on average. The average estimated number of exceedances column shows the number of days the 0.12 ppm 1-hour ozone standard was exceeded on average at the site recording the highest updated air quality value. This computation is performed after adjustment for any missing sampling days during the 3-year period, 2000-2002. The values in parentheses are associated with the monitor with highest average estimated number of exceedances within the designated area; sometimes this statistic is associated with a different site than the site recording the highest updated air quality value.

4. These areas have an average expected exceedances for 2000-2002 greater than 1 but a design value that is less than 0.125 ppm. Further review will be required before determining the applicability of the estimated design value due to less than 3 valid years of data.

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