Technology Transfer Network / NAAQS
Ozone Implementation
Table 1. Ozone Nonattainment Areas -
Air Quality Update, 1991-93
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
AL Birmingham NA Area Marginal 0.124 0.7 0.125 2.0
AZ Phoenix Moderate 0.147 4.0 (#4) 0.126 2.0
CA Los Angeles South Coast Air Basin Extreme 0.300 104.3 0.250 97.6
CA Monterey Bay Unified NA Area Moderate 0.108 0.4 0.104 0.0
CA Sacramento Metro NA Area Serious 0.150 9.7 0.150 3.6
CA San Diego NA Area Severe 15 0.150 11.8 0.159 4.0
CA San Francisco-Bay NA Area Moderate 0.120 0.7 0.130 2.0
CA San Joaquin Valley NA Area Serious 0.159 18.9 0.159 27.5
CA Santa Barbara-Santa Maria-Lompoc Moderate 0.123 1.0 0.114 0.0
CA Southeast Desert Modified AQMD Severe 17 0.200 59.3 0.180 72.6
CA Ventura Co NA Area Severe 15 0.150 15.9 0.144 9.0
CT Greater Connecticut NA Area Serious 0.158 7.5 0.153 6.0
DC-MD-VA Washington NA Area Serious 0.137 1.4 0.132 3.1
DE Sussex Co NA Area Marginal 0.118 1.0 0.115 0.0
FL Miami-Fort Lauderdale-W. Palm Beach Moderate 0.106 0.0 0.122 1.0
FL Tampa-St. Petersburg-Clearwater Marginal 0.110 0.0 0.100 0.0
GA Atlanta NA Area Serious 0.149 4.2 0.162 4.3
IL-IN Chicago-Gary-Lake County NA Area Severe 17 0.145 4.7 (#5) 0.125 2.4
IL Jersey Co NA Area Marginal 0.112 0.7 0.127 2.0
IN Evansville NA Area Marginal 0.110 0.0 0.110 0.0
IN Indianapolis NA Area Marginal 0.104 0.0 0.104 0.0
IN South Bend-Elkhart NA Area Marginal 0.103 0.0 0.096 0.0
KY Edmonson Co NA Area Marginal 0.091 0.0 0.092 0.0
KY-WV Huntington-Ashland NA Area Moderate 0.122 1.0 0.122 1.0
KY Lexington-Fayette NA Area Marginal 0.100 0.0 0.103 0.0
KY-IN Louisville NA Area Moderate 0.130 2.2 0.140 2.0
KY Owensboro NA Area Marginal 0.104 0.0 0.106 0.0
KY Paducah NA Area Marginal 0.106 0.0 0.112 0.0
LA Baton Rouge NA Area Serious 0.135 1.8 0.127 3.0
LA Lake Charles NA Area Marginal 0.132 1.3 (#6) 0.108 0.0
MA-NH Boston-Lawrence-Worcester NA Area Serious 0.137 3.1 0.155 4.0
MA Springfield (W. Mass) NA Area Serious 0.141 4.6 0.133 6.2
MD Baltimore NA Area Severe 15 0.150 4.8 0.146 6.2
MD Kent County and Queen Anne's County Marginal 0.133 2.8 0.128 2.0
ME Hancock Co and Waldo Co NA Area Marginal 0.112 1.3 (#7) 0.094 0.0
ME Knox Co and Lincoln Co NA Area Moderate 0.134 2.3 0.122 1.2
ME Lewiston - Auburn NA Area Moderate 0.106 0.3 0.096 0.0
ME Portland NA Area Moderate 0.147 11.8 0.125 3.8
MI Detroit-Ann Arbor NA Area Moderate 0.122 1.0 0.122 1.0
MI Grands Rapids NA Area Moderate 0.146 3.4 (#8) 0.094 1.0
MI Muskegon NA Area Moderate 0.141 2.3 0.104 1.0
MO-KS Kansas City NA Area Attainment 0.114 0.3 0.114 1.0
MO-IL St. Louis NA Area Moderate 0.132 1.7 0.126 2.1
NC Charlotte-Gastonia NA Area Moderate 0.119 0.7 0.137 2.1
NC Greensboro-Winston-Salem-High Point Attainment 0.113 0.3 0.121 1.0
NC Raleigh-Durham NA Area Attainment 0.118 0.7 0.128 2.1
NH Manchester NA Area Marginal 0.087 0.0 0.086 0.0
NH Portsmouth-Dover-Rochester, NH Serious 0.143 2.2 0.107 1.1
NJ Atlantic City NA Area Moderate 0.122 1.0 0.115 0.0
NV Reno Marginal 0.089 0.0 0.089 0.0
NY Albany-Schenectady-Troy NA Area Marginal 0.104 0.0 0.106 0.0
NY Buffalo-Niagara Falls NA Area Marginal 0.106 0.0 0.090 0.0
NY Essex Co NA Area Marginal 0.116 0.0 0.100 0.0
NY Jefferson Co NA Area Marginal 0.110 0.0 0.092 0.0
NY-NJ-CT New York-N. New Jersey-Long Island Severe 17 0.158 6.1 0.165 6.0
NY Poughkeepsie NA Area Marginal 0.126 1.4 0.139 2.0
OH Canton NA Area Marginal 0.109 0.3 0.109 0.0
OH-KY Cincinnati-Hamilton NA Area Moderate 0.125 1.3 0.121 1.0
OH Cleveland-Akron-Lorain NA Area Moderate 0.125 1.7 (#9) 0.117 0.0
OH Columbus NA Area Marginal 0.118 0.3 0.105 0.0
OH Dayton-Springfield NA Area Moderate 0.112 0.0 0.120 1.0
OH Toledo NA Area Moderate 0.120 0.3 0.121 1.0
OH-PA Youngstown-Warren-Sharon NA Area Marginal 0.113 0.3 0.120 1.0
OR Portland-Vancouver AQMA NA Area Marginal 0.108 0.7 0.103 0.0
PA-NJ Allentown-Bethlehem-Easton NA Area Marginal 0.115 0.0 0.110 0.0
PA Altoona NA Area Marginal 0.105 0.0 0.100 0.0
PA Erie NA Area Marginal 0.110 0.0 0.107 0.0
PA Harrisburg-Lebanon-Carlisle NA Marginal 0.111 0.0 0.118 0.0
PA Johnstown NA Area Marginal 0.107 0.0 0.099 0.0
PA Lancaster NA Area Marginal 0.118 0.3 0.118 1.0
PA-NJ-DE-MD Philadelphia-Wilmington-Trenton Severe 15 0.156 10.3 0.147 5.2
PA Pittsburgh-Beaver Valley NA Area Moderate 0.119 0.7 0.124 0.0
PA Reading NA Area Moderate 0.118 0.3 0.110 0.0
PA Scranton-Wilkes-Barre NA Area Marginal 0.117 0.4 0.112 0.0
PA York NA Area Marginal 0.113 0.0 0.112 0.0
RI Providence (all of RI) NA Area Serious 0.152 4.0 0.117 1.4
SC Cherokee Co NA Area Attainment 0.105 0.3 0.108 0.0
TN Knoxville NA Area Attainment 0.118 0.0 0.120 0.0
TN Memphis NA Area Marginal 0.115 0.3 0.119 1.0
TN Nashville NA Area Moderate 0.124 1.1 0.126 2.1
TX Beaumont-Port Arthur NA Area Serious 0.130 2.7 0.122 0.0
TX Dallas-Fort Worth NA Area Moderate 0.141 2.0 0.140 2.3
TX El Paso NA Area Serious 0.136 3.7 0.135 4.1
TX Houston-Galveston-Brazoria NA Severe 17 0.200 6.3 0.197 10.4
UT Salt Lake City-Ogden NA Area Moderate 0.106 0.0 0.104 0.0
VA Norfolk-Virginia Beach-Newport News Marginal 0.131 1.7 0.131 3.0
VA Richmond-Petersburg NA Area Moderate 0.128 1.4 0.132 3.1
VA Smyth County NA Area Marginal ND ND (#10) ND ND
WA Seattle - Tacoma NA Area Marginal 0.105 0.0 0.100 0.0
WI Door Co NA Area Marginal 0.125 1.6 0.098 0.0
WI Kewaunee Co NA Area Moderate 0.107 0.8 0.095 0.0
WI Manitowoc Co NA Area Moderate 0.132 2.0 0.095 0.0
WI Milwaukee-Racine NA Area Severe 17 0.148 3.9 0.125 2.4
WI Sheboygan NA Area Moderate 0.139 2.6 (#11) 0.095 0.0
WI Walworth Co NA Area Marginal 0.120 0.3 0.093 0.0
WV Charleston NA Area Attainment 0.106 0.3 0.075 0.0
WV Greenbrier NA Area Marginal 0.101 0.4 0.090 0.0
WV Parkersburg NA Area Attainment 0.118 0.0 0.104 0.0
91 Nonattainment Areas
SOURCE: EPA's air quality data system, the Aerometric Information Retrieval System (AIRS), with supplemental data from EPA Regional Offices.
NOTES:
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 this listing.
2. The updated air quality value is estimated for the 1991-93 period using EPA guidance for calculating design values (Laxton Memorandum, June 18, 1990). Generally, the fourth highest monitored value with 3 complete years of data is selected as the updated air quality value because the standard allows one exceedance for each year. It is important to note that the 1990 Clean Air Act Amendments required that O3 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 National Ambient Air Quality standard for ozone is 0.12 parts per million (ppm) daily maximum 1-hour average 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 standard was exceeded on average at the site recording the highest updated air quality value. This is done after adjustment for incomplete, or missing days, during the 3-year period, 1991-93. The last two columns contain data from the site recording the highest second daily maximum 1-hour concentration in 1993. The last column shows the estimated exceedances for 1993 at the site recording the highest second maximum 1-hour concentration listed in the previous column.
4. Special purpose monitoring (SPM) operating during the ozone monitoring season.
5. The nonattainment/updated air quality value site for the Chicago NA Area is in Kenosha County, WI.
6. The Regional Office is reviewing the status of the area based on data through 1994.
7. Incomplete data reported in 1991.
8. Calculation of the updated air quality value and estimated exceedances adjusted to account for start-up of a LMOS Study site with data only in 1991.
9. Data from a monitoring site located at the water treatment plant not used due to localized interference.
10. The site was located atop Whitetop Mountain, VA as part of the Mountain Cloud Study. Site elevation is 5520 feet. No data reported after 1988. This is a rural transport area. The nonattainment area is that portion of Whitetop Mountain above 4500 feet elevation.
11. Calculation of estimated exceedances adjusted for Wisconsin ozone season not yet reflected in AIRS.
Table 2. Additional Areas With Average Estimated Exceedances Greater than 1.0 for 1991-93
1993 1993
Clean Air Act 1991-93 Updated A.Q. Value 2nd Daily Est.
STATE AREA NAME CLASSIFICATION A.Q. Value Avg. Est. Exc. Max 1-hr Exc.
CA Mono County, CA Unclassifiable 0.130 1.5 (#1) 0.090 0.0
CA Imperial County, CA Transitional 0.150 12.2 (#2) 0.150 14.7
NM Dona Ana County, NM Unclassifiable 0.131 2.9 (#3) 0.106 0.0
OH Washington County, OH Attainment 0.137 1.4 (#4) 0.124 1.1
Notes:
(1) Exceedances are under review by the APCD.
(2) A new monitoring site which started in October 1991.
(3) The EPA Regional Office will be reviewing the monitoring data through calendar year 1994 to assess the air quality status of this area.
(4) Adjacent to the Parkersburg, WV NA area.
Region I
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
CT Greater Connecticut NA Area Serious 0.158 7.5 0.153 6.0
MA-NH Boston-Lawrence-Worcester NA Area Serious 0.137 3.1 0.155 4.0
MA Springfield (W. Mass) NA Area Serious 0.141 4.6 0.133 6.2
ME Hancock Co and Waldo Co NA Area Marginal 0.112 1.3 (#7) 0.094 0.0
ME Knox Co and Lincoln Co NA Area Moderate 0.134 2.3 0.122 1.2
ME Lewiston - Auburn NA Area Moderate 0.106 0.3 0.096 0.0
ME Portland NA Area Moderate 0.147 11.8 0.125 3.8
NH Manchester NA Area Marginal 0.087 0.0 0.086 0.0
NH Portsmouth-Dover-Rochester, NH Serious 0.143 2.2 0.107 1.1
NY-NJ-CT New York-N. New Jersey-Long Island Severe 17 0.158 6.1 0.165 6.0
RI Providence (all of RI) NA Area Serious 0.152 4.0 0.117 1.4
Region II
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
NJ Atlantic City NA Area Moderate 0.122 1.0 0.115 0.0
NY Albany-Schenectady-Troy NA Area Marginal 0.104 0.0 0.106 0.0
NY Buffalo-Niagara Falls NA Area Marginal 0.106 0.0 0.090 0.0
NY Essex Co NA Area Marginal 0.116 0.0 0.100 0.0
NY Jefferson Co NA Area Marginal 0.110 0.0 0.092 0.0
NY-NJ-CT New York-N. New Jersey-Long Island Severe 17 0.158 6.1 0.165 6.0
NY Poughkeepsie NA Area Marginal 0.126 1.4 0.139 2.0
PA-NJ Allentown-Bethlehem-Easton NA Area Marginal 0.115 0.0 0.110 0.0
PA-NJ-DE-MD Philadelphia-Wilmington-Trenton Severe 15 0.156 10.3 0.147 5.2
Region III
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
DC-MD-VA Washington NA Area Serious 0.137 1.4 0.132 3.1
DE Sussex Co NA Area Marginal 0.118 1.0 0.115 0.0
MD Baltimore NA Area Severe 15 0.150 4.8 0.146 6.2
MD Kent County and Queen Anne's County Marginal 0.133 2.8 0.128 2.0
OH-PA Youngstown-Warren-Sharon NA Area Marginal 0.113 0.3 0.120 1.0
PA-NJ Allentown-Bethlehem-Easton NA Area Marginal 0.115 0.0 0.110 0.0
PA Altoona NA Area Marginal 0.105 0.0 0.100 0.0
PA Erie NA Area Marginal 0.110 0.0 0.107 0.0
PA Harrisburg-Lebanon-Carlisle NA Marginal 0.111 0.0 0.118 0.0
PA Johnstown NA Area Marginal 0.107 0.0 0.099 0.0
PA Lancaster NA Area Marginal 0.118 0.3 0.118 1.0
PA-NJ-DE-MD Philadelphia-Wilmington-Trenton Severe 15 0.156 10.3 0.147 5.2
PA Pittsburgh-Beaver Valley NA Area Moderate 0.119 0.7 0.124 0.0
PA Reading NA Area Moderate 0.118 0.3 0.110 0.0
PA Scranton-Wilkes-Barre NA Area Marginal 0.117 0.4 0.112 0.0
PA York NA Area Marginal 0.113 0.0 0.112 0.0
WV Charleston NA Area Moderate 0.106 0.3 0.075 0.0
WV Greenbrier NA Area Marginal 0.101 0.4 0.090 0.0
WV Parkersburg NA Area Moderate 0.118 0.0 0.104 0.0
VA Norfolk-Virginia Beach-Newport News Marginal 0.131 1.7 0.131 3.0
VA Richmond-Petersburg NA Area Moderate 0.128 1.4 0.132 3.1
VA Smyth County NA Area Marginal ND ND (#10) ND ND
Region IV
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
AL Birmingham NA Area Marginal 0.124 0.7 0.125 2.0
FL Miami-Fort Lauderdale-W. Palm Beach Moderate 0.106 0.0 0.122 1.0
FL Tampa-St. Petersburg-Clearwater Marginal 0.110 0.0 0.100 0.0
GA Atlanta NA Area Serious 0.149 4.2 0.162 4.3
KY Edmonson Co NA Area Marginal 0.091 0.0 0.092 0.0
KY-WV Huntington-Ashland NA Area Moderate 0.122 1.0 0.122 1.0
KY Lexington-Fayette NA Area Marginal 0.100 0.0 0.103 0.0
KY-IN Louisville NA Area Moderate 0.130 2.2 0.140 2.0
KY Owensboro NA Area Marginal 0.104 0.0 0.106 0.0
KY Paducah NA Area Marginal 0.106 0.0 0.112 0.0
NC Charlotte-Gastonia NA Area Moderate 0.119 0.7 0.137 2.1
NC Greensboro-Winston-Salem-High Point Attainment 0.113 0.3 0.121 1.0
NC Raleigh-Durham NA Area Attainment 0.118 0.7 0.128 2.1
OH-KY Cincinnati-Hamilton NA Area Moderate 0.125 1.3 0.121 1.0
SC Cherokee Co NA Area Attainment 0.105 0.3 0.108 0.0
TN Knoxville NA Area Attainment 0.118 0.0 0.120 0.0
TN Memphis NA Area Marginal 0.115 0.3 0.119 1.0
TN Nashville NA Area Moderate 0.124 1.1 0.126 2.1
Region V
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
IL-IN Chicago-Gary-Lake County NA Area Severe 17 0.145 4.7 (#5) 0.125 2.4
IL Jersey Co NA Area Marginal 0.112 0.7 0.127 2.0
IN Evansville NA Area Marginal 0.110 0.0 0.110 0.0
IN Indianapolis NA Area Marginal 0.104 0.0 0.104 0.0
IN South Bend-Elkhart NA Area Marginal 0.103 0.0 0.096 0.0
MI Detroit-Ann Arbor NA Area Moderate 0.122 1.0 0.122 1.0
MI Grands Rapids NA Area Moderate 0.146 3.4 (#8) 0.094 1.0
MI Muskegon NA Area Moderate 0.141 2.3 0.104 1.0
OH Canton NA Area Marginal 0.109 0.3 0.109 0.0
OH-KY Cincinnati-Hamilton NA Area Moderate 0.125 1.3 0.121 1.0
OH Cleveland-Akron-Lorain NA Area Moderate 0.125 1.7 (#9) 0.117 0.0
OH Columbus NA Area Marginal 0.118 0.3 0.105 0.0
OH Dayton-Springfield NA Area Moderate 0.112 0.0 0.120 1.0
OH Toledo NA Area Moderate 0.120 0.3 0.121 1.0
OH-PA Youngstown-Warren-Sharon NA Area Marginal 0.113 0.3 0.120 1.0
WI Door Co NA Area Marginal 0.125 1.6 0.098 0.0
WI Kewaunee Co NA Area Moderate 0.107 0.8 0.095 0.0
WI Manitowoc Co NA Area Moderate 0.132 2.0 0.095 0.0
WI Milwaukee-Racine NA Area Severe 17 0.148 3.9 0.125 2.4
WI Sheboygan NA Area Moderate 0.139 2.6 (#11) 0.095 0.0
WI Walworth Co NA Area Marginal 0.120 0.3 0.093 0.0
Region VI
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
LA Baton Rouge NA Area Serious 0.135 1.8 0.127 3.0
LA Lake Charles NA Area Marginal 0.132 1.3 (#6) 0.108 0.0
TX Beaumont-Port Arthur NA Area Serious 0.130 2.7 0.122 0.0
TX Dallas-Fort Worth NA Area Moderate 0.141 2.0 0.140 2.3
TX El Paso NA Area Serious 0.136 3.7 0.135 4.1
TX Houston-Galveston-Brazoria NA Severe 17 0.200 6.3 0.197 10.4
Region VII
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
MO-KS Kansas City NA Area Attainment 0.114 0.3 0.114 1.0
MO-IL St. Louis NA Area Moderate 0.132 1.7 0.126 2.1
Region VIII
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
UT Salt Lake City-Ogden NA Area Moderate 0.106 0.0 0.104 0.0
Region IX
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
AZ Phoenix Moderate 0.147 4.0 (#4) 0.126 2.0
CA Los Angeles South Coast Air Basin Extreme 0.300 104.3 0.250 97.6
CA Monterey Bay Unified NA Area Moderate 0.108 0.4 0.104 0.0
CA Sacramento Metro NA Area Serious 0.150 9.7 0.150 3.6
CA San Diego NA Area Severe 15 0.150 11.8 0.160 4.0
CA San Francisco-Bay NA Area Moderate 0.120 0.7 0.130 2.0
CA San Joaquin Valley NA Area Serious 0.160 18.9 0.160 27.5
CA Santa Barbara-Santa Maria-Lompoc Moderate 0.123 1.0 0.114 0.0
CA Southeast Desert Modified AQMD Severe 17 0.200 59.3 0.180 72.6
CA Ventura Co NA Area Severe 15 0.150 15.9 0.144 9.0
NV Reno Marginal 0.089 0.0 0.089 0.0
Region X
Table 1. Ozone Nonattainment Areas - Air Quality Update, 1991-93
1991-93 Update 1993 1993
Clean Air Act A.Q. Average 2nd Daily Estimated
State Nonattainment Area Name Classification Value Est. Exc. Max 1-hr Exceedances
OR Portland-Vancouver AQMA NA Area Marginal 0.108 0.7 0.103 0.0
WA Seattle - Tacoma NA Area Marginal 0.105 0.0 0.100 0.0
SOURCE: EPA's air quality data system, the Aerometric Information Retrieval System (AIRS), with supplemental data from EPA Regional Offices.
NOTES:
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 this listing.
2. The updated air quality value is estimated for the 1991-93 period using EPA guidance for calculating design values (Laxton Memorandum, June 18, 1990). Generally, the fourth highest monitored value with 3 complete years of data is selected as the updated air quality value because the standard allows one exceedance for each year. It is important to note that the 1990 Clean Air Act Amendments required that O3 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 National Ambient Air Quality standard for ozone is 0.12 parts per million (ppm) daily maximum 1-hour average 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 standard was exceeded on average at the site recording the highest updated air quality value. This is done after adjustment for incomplete, or missing days, during the 3-year period, 1991-93. The last two columns contain data from the site recording the highest second daily maximum 1-hour concentration in 1993. The last column shows the estimated exceedances for 1993 at the site recording the highest second maximum 1-hour concentration listed in the previous column.
4. Special purpose monitoring (SPM) operating during the ozone monitoring season.
5. The nonattainment/updated air quality value site for the Chicago NA Area is in Kenosha County, WI.
6. The Regional Office is reviewing the status of the area based on data through 1994.
7. Incomplete data reported in 1991.
8. Calculation of the updated air quality value and estimated exceedances adjusted to account for start-up of a LMOS Study site with data only in 1991.
9. Data from a monitoring site located at the water treatment plant not used due to localized interference.
10. The site was located atop Whitetop Mountain, VA as part of the Mountain Cloud Study. Site elevation is 5520 feet. No data reported after 1988. This is a rural transport area. The nonattainment area is that portion of Whitetop Mountain above 4500 feet elevation.
11. Calculation of estimated exceedances adjusted for Wisconsin ozone season not yet reflected in AIRS.