Skip to content. | Skip to navigation

Personal tools

Navigation

Eight-Hour Ozone High Value Days for 2015
as of September 3

The table below lists the daily maximum eight-hour ozone concentrations measured which meet or exceed 76 parts per billion in 2015 in each community where the TCEQ measures ozone. This information is updated hourly. Concentrations are color-highlighted based on the EPA-defined Air Quality Index colors. (See Interpreting the AQI.) Times shown are in 24-hour format and are Local Standard Time. Our convention is that the time reflects the beginning of the eight-hour average. All ozone measurements are in parts per billion.

Use the selection boxes below to customize this report. You may select a different year, a different sorting order, or a different report format. Click on the Generate Report button once you have made your selections.

YearSort ByReport Format
Highlight with AQI colors
2015 Sorted by Maximum Value
LocationRegionCAMSAQSDateTimeValuePOC
Houston Aldine C8/AF108/X150 12 848_201_0024June 3 201510:001082
HRM-3 Haden Road C603/A114 12 60348_201_0803June 3 201510:001071 N
UH Moody Tower C695 12 69548_201_0695August 12 201513:001061 N
Houston Aldine C8/AF108/X150 12 848_201_0024August 29 201510:001052
Houston Aldine C8/AF108/X150 12 848_201_0024August 12 201512:001022
UH Moody Tower C695 12 69548_201_0695August 28 201511:001021 N
Houston East C1/G316 12 148_201_1034June 3 201510:001022
Galveston 99th St. C1034/A320/X183 12 103448_167_1034August 12 201510:001011
Houston East C1/G316 12 148_201_1034August 3 201510:001012
Park Place C416 12 41648_201_0416August 12 201512:001001
Park Place C416 12 41648_201_0416August 28 201511:00991
HRM-3 Haden Road C603/A114 12 60348_201_0803August 3 201510:00991 N
Houston Bayland Park C53/A146 12 5348_201_0055August 12 201511:00981
La Porte Sylvan Beach C556 12 55648_201_0556June 3 201511:00981 N
Houston Bayland Park C53/A146 12 5348_201_0055August 28 201512:00971
Clear Creek High School C571 12 57148_167_0571June 2 201509:00961 N
HRM-3 Haden Road C603/A114 12 60348_201_0803August 12 201512:00961 N
Texas City 34th St. C620 12 62048_167_0056June 2 201510:00951 N
Houston Aldine C8/AF108/X150 12 848_201_0024August 13 201510:00952
Lang C408 12 40848_201_0047August 3 201510:00952
UH Moody Tower C695 12 69548_201_0695June 6 201511:00951 N
HRM-3 Haden Road C603/A114 12 60348_201_0803August 13 201510:00951 N
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039August 28 201510:00951
Denton Airport South C56/A163/X157 4 5648_121_0034August 28 201511:00941
Lang C408 12 40848_201_0047August 13 201511:00942
Houston Texas Avenue C411 12 41148_201_0075August 12 201512:00941
HRM-3 Haden Road C603/A114 12 60348_201_0803August 28 201510:00941 N
Grapevine Fairway C70/A301/X182 4 7048_439_3009August 3 201510:00941
Texas City 34th St. C620 12 62048_167_0056August 12 201511:00931 N
Channelview C15/AH115 12 1548_201_0026June 3 201510:00933
UH Moody Tower C695 12 69548_201_0695August 13 201511:00931 N
HRM-3 Haden Road C603/A114 12 60348_201_0803August 29 201509:00931 N
Clinton C403/C304/AH113 12 40348_201_1035August 28 201511:00933
Mustang Bayou C619 12 61948_039_0619August 22 201503:00921 N
Denton Airport South C56/A163/X157 4 5648_121_0034June 5 201511:00921
Galveston 99th St. C1034/A320/X183 12 103448_167_1034June 6 201512:00921
Houston Croquet C409 12 40948_201_0051August 12 201511:00922
Clinton C403/C304/AH113 12 40348_201_1035August 12 201512:00923
Seabrook Friendship Park C45 12 4548_201_1050June 2 201508:00921
Manvel Croix Park C84 12 8448_039_1004August 28 201510:00911
Northwest Harris Co. C26/A110/X154 12 2648_201_0029June 4 201510:00912
Northwest Harris Co. C26/A110/X154 12 2648_201_0029August 29 201511:00912
Lang C408 12 40848_201_0047June 6 201510:00912
Lang C408 12 40848_201_0047August 12 201512:00912
Houston Texas Avenue C411 12 41148_201_0075August 28 201511:00911
Clinton C403/C304/AH113 12 40348_201_1035August 3 201509:00913
SETRPC 40 Sabine Pass C640/C1654 10 64048_245_0101August 12 201510:00911
Houston North Wayside C405 12 40548_201_0046August 3 201510:00901
La Porte Sylvan Beach C556 12 55648_201_0556June 2 201509:00901 N
Manvel Croix Park C84 12 8448_039_1004August 12 201511:00891
Denton Airport South C56/A163/X157 4 5648_121_0034August 17 201511:00891
Houston Aldine C8/AF108/X150 12 848_201_0024August 3 201512:00892
Houston Aldine C8/AF108/X150 12 848_201_0024August 28 201510:00892
Lang C408 12 40848_201_0047June 3 201509:00892
Houston Croquet C409 12 40948_201_0051August 28 201510:00892
Houston Monroe C406 12 40648_201_0062August 12 201512:00891
La Porte Sylvan Beach C556 12 55648_201_0556August 12 201512:00891 N
Baytown Garth C1017 12 101748_201_1017June 3 201511:00891
Camp Bullis C58 13 5848_029_0052August 28 201511:00881
Camp Bullis C58 13 5848_029_0052August 29 201510:00881
Denton Airport South C56/A163/X157 4 5648_121_0034August 3 201511:00881
Houston North Wayside C405 12 40548_201_0046June 3 201510:00881
Houston East C1/G316 12 148_201_1034August 13 201510:00882
Houston East C1/G316 12 148_201_1034August 28 201511:00882
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039August 12 201512:00881
Cleburne Airport C77/C682 4 7748_251_0003August 13 201512:00881
Camp Bullis C58 13 5848_029_0052August 27 201511:00871
Manvel Croix Park C84 12 8448_039_1004August 2 201510:00871
Texas City 34th St. C620 12 62048_167_0056August 28 201510:00871 N
Lang C408 12 40848_201_0047August 28 201510:00872
Park Place C416 12 41648_201_0416June 6 201511:00871
Park Place C416 12 41648_201_0416August 13 201510:00871
UH Moody Tower C695 12 69548_201_0695August 10 201511:00871 N
Lynchburg Ferry C1015/A165 12 101548_201_1015June 3 201510:00871
Seabrook Friendship Park C45 12 4548_201_1050August 3 201509:00871
Grapevine Fairway C70/A301/X182 4 7048_439_3009August 28 201511:00871
Manvel Croix Park C84 12 8448_039_1004August 27 201510:00861
Houston Aldine C8/AF108/X150 12 848_201_0024June 7 201510:00862
Houston Aldine C8/AF108/X150 12 848_201_0024August 17 201511:00862
Channelview C15/AH115 12 1548_201_0026August 3 201510:00863
Lang C408 12 40848_201_0047June 4 201510:00862
Houston Texas Avenue C411 12 41148_201_0075August 13 201510:00861
La Porte Sylvan Beach C556 12 55648_201_0556August 10 201511:00861 N
Granbury C73/C681 4 7348_221_0001August 13 201513:00861
Keller C17 4 1748_439_2003August 28 201511:00862
San Antonio Northwest C23 13 2348_029_0032August 29 201510:00852
Manvel Croix Park C84 12 8448_039_1004June 1 201511:00851
Texas City 34th St. C620 12 62048_167_0056August 11 201511:00851 N
Houston Texas Avenue C411 12 41148_201_0075June 6 201511:00851
Park Place C416 12 41648_201_0416August 10 201510:00851
La Porte Sylvan Beach C556 12 55648_201_0556August 3 201510:00851 N
Bunker Hill Village C562 12 56248_201_0562August 28 201512:00851 N
Houston East C1/G316 12 148_201_1034August 29 201510:00852
Seabrook Friendship Park C45 12 4548_201_1050August 12 201511:00851
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 13 201510:00852
Austin Northwest C3/A322 11 348_453_0014August 28 201510:00852
Mustang Bayou C619 12 61948_039_0619August 12 201511:00841 N
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069July 30 201511:00843
Denton Airport South C56/A163/X157 4 5648_121_0034August 27 201511:00841
Galveston 99th St. C1034/A320/X183 12 103448_167_1034August 28 201510:00841
Houston Aldine C8/AF108/X150 12 848_201_0024April 30 201511:00842
Houston Westhollow C410 12 41048_201_0066August 12 201512:00841
Clear Brook High School C570 12 57048_201_0570June 6 201511:00841 N
Baytown Garth C1017 12 101748_201_1017August 3 201510:00841
Houston East C1/G316 12 148_201_1034June 6 201511:00842
Clinton C403/C304/AH113 12 40348_201_1035June 6 201511:00843
San Antonio Northwest C23 13 2348_029_0032August 27 201511:00832
Frisco C31/C680 4 3148_085_0005August 28 201511:00831
Dallas North No.2 C63/C679 4 6348_113_0075August 3 201509:00831
Pilot Point C1032 4 103248_121_1032August 28 201511:00831
Galveston 99th St. C1034/A320/X183 12 103448_167_1034June 2 201510:00831
Longview C19/A127/C644 5 1948_183_0001June 6 201511:00832
Lang C408 12 40848_201_0047August 29 201510:00832
Houston Monroe C406 12 40648_201_0062August 28 201511:00831
Clear Lake High School C572 12 57248_201_0572June 2 201509:00831 N
Clinton C403/C304/AH113 12 40348_201_1035August 13 201510:00833
Seabrook Friendship Park C45 12 4548_201_1050June 3 201509:00831
UH WG Jones Forest C698 12 69848_339_0698June 7 201512:00831 N
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 3 201510:00832
Austin Northwest C3/A322 11 348_453_0014August 29 201510:00832
CAPCOG Lake Georgetown C690 11 69048_491_0690August 28 201512:00831 N
Frisco C31/C680 4 3148_085_0005August 3 201510:00821
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069August 10 201512:00823
Dallas North No.2 C63/C679 4 6348_113_0075August 28 201511:00821
Denton Airport South C56/A163/X157 4 5648_121_0034June 4 201510:00821
Pilot Point C1032 4 103248_121_1032August 29 201510:00821
Channelview C15/AH115 12 1548_201_0026April 30 201510:00823
Northwest Harris Co. C26/A110/X154 12 2648_201_0029August 3 201511:00822
Sheldon C551 12 55148_201_0551June 3 201510:00821 N
La Porte Sylvan Beach C556 12 55648_201_0556August 11 201511:00821 N
Clear Brook High School C570 12 57048_201_0570June 2 201511:00821 N
HRM-3 Haden Road C603/A114 12 60348_201_0803June 6 201510:00821 N
HRM-3 Haden Road C603/A114 12 60348_201_0803August 10 201511:00821 N
Baytown Garth C1017 12 101748_201_1017April 30 201510:00821
Clinton C403/C304/AH113 12 40348_201_1035August 10 201510:00823
Port Arthur West C28/A128/A228 10 2848_245_0011August 3 201509:00821
Rockwall Heath C69 4 6948_397_0001April 30 201511:00821
Austin Northwest C3/A322 11 348_453_0014August 27 201511:00822
Audubon C38 11 3848_453_0020August 28 201511:00821
San Antonio Northwest C23 13 2348_029_0032August 28 201511:00812
Fair Oaks Ranch C502 13 50248_029_0502August 28 201511:00811 N
Fair Oaks Ranch C502 13 50248_029_0502August 29 201510:00811 N
Bulverde Elementary C503 13 50348_091_0503August 28 201512:00811 N
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069August 3 201510:00813
Midlothian OFW C52/A137 4 5248_139_0016August 11 201510:00811
El Paso UTEP C12/A125/X151 6 1248_141_0037June 17 201510:00812
Channelview C15/AH115 12 1548_201_0026August 13 201510:00813
Houston Westhollow C410 12 41048_201_0066August 28 201511:00811
La Porte Sylvan Beach C556 12 55648_201_0556August 28 201509:00811 N
Tom Bass C558 12 55848_201_0558August 12 201512:00811 N
Meyer Park C561 12 56148_201_0561June 3 201511:00811 N
UH Moody Tower C695 12 69548_201_0695May 1 201511:00811 N
HRM-3 Haden Road C603/A114 12 60348_201_0803April 30 201510:00811 N
Lynchburg Ferry C1015/A165 12 101548_201_1015August 3 201510:00811
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039June 3 201510:00811
Seabrook Friendship Park C45 12 4548_201_1050August 28 201511:00811
UH WG Jones Forest C698 12 69848_339_0698May 2 201511:00811 N
Eagle Mountain Lake C75 4 7548_439_0075August 26 201512:00811
Eagle Mountain Lake C75 4 7548_439_0075August 27 201511:00811
Keller C17 4 1748_439_2003August 3 201510:00812
Grapevine Fairway C70/A301/X182 4 7048_439_3009August 17 201511:00811
Audubon C38 11 3848_453_0020August 27 201511:00811
Temple Georgia C1045 9 104548_027_1045August 28 201511:00801
Camp Bullis C58 13 5848_029_0052August 3 201510:00801
Bulverde Elementary C503 13 50348_091_0503August 29 201512:00801 N
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069August 28 201511:00803
Galveston 99th St. C1034/A320/X183 12 103448_167_1034May 1 201511:00801
Houston Aldine C8/AF108/X150 12 848_201_0024August 30 201511:00802
Houston Bayland Park C53/A146 12 5348_201_0055August 13 201510:00801
Meyer Park C561 12 56148_201_0561August 29 201511:00801 N
Bunker Hill Village C562 12 56248_201_0562August 12 201511:00801 N
Houston East C1/G316 12 148_201_1034August 10 201511:00802
SETRPC Port Arthur C628 10 62848_245_0628August 12 201510:00801 N
Conroe Relocated C78/A321 12 7848_339_0078May 2 201511:00801
Parker County C76 4 7648_367_0081July 31 201509:00801
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 27 201510:00802
Keller C17 4 1748_439_2003August 27 201511:00802
Audubon C38 11 3848_453_0020August 29 201511:00801
San Antonio Northwest C23 13 2348_029_0032August 13 201512:00792
Camp Bullis C58 13 5848_029_0052May 1 201511:00791
Manvel Croix Park C84 12 8448_039_1004May 1 201510:00791
Manvel Croix Park C84 12 8448_039_1004June 2 201510:00791
Bulverde Elementary C503 13 50348_091_0503August 27 201512:00791 N
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069August 24 201511:00793
Dallas North No.2 C63/C679 4 6348_113_0075April 30 201511:00791
Dallas North No.2 C63/C679 4 6348_113_0075August 24 201510:00791
Pilot Point C1032 4 103248_121_1032June 6 201511:00791
Pilot Point C1032 4 103248_121_1032August 17 201510:00791
U of H-Sugarland C696 12 69648_157_0696August 26 201511:00791 N
Texas City 34th St. C620 12 62048_167_0056June 3 201510:00791 N
Texas City 34th St. C620 12 62048_167_0056June 6 201510:00791 N
Clear Creek High School C571 12 57148_167_0571May 1 201511:00791 N
UH Coastal Center C697 12 69748_167_0697August 12 201510:00791 N
Houston Aldine C8/AF108/X150 12 848_201_0024May 1 201510:00792
Channelview C15/AH115 12 1548_201_0026August 29 201509:00793
Houston North Wayside C405 12 40548_201_0046August 29 201510:00791
Houston Croquet C409 12 40948_201_0051June 2 201510:00792
Houston Bayland Park C53/A146 12 5348_201_0055May 1 201511:00791
Houston Bayland Park C53/A146 12 5348_201_0055June 6 201510:00791
Houston Westhollow C410 12 41048_201_0066August 13 201511:00791
Houston Texas Avenue C411 12 41148_201_0075August 10 201511:00791
Sheldon C551 12 55148_201_0551August 3 201510:00791 N
West Houston C554 12 55448_201_0554August 13 201511:00791 N
Mercer Arboretum C557 12 55748_201_0557June 3 201511:00791 N
Meyer Park C561 12 56148_201_0561June 4 201511:00791 N
Clear Brook High School C570 12 57048_201_0570June 1 201511:00791 N
UH Moody Tower C695 12 69548_201_0695August 24 201514:00791 N
Lynchburg Ferry C1015/A165 12 101548_201_1015April 30 201510:00791
Lynchburg Ferry C1015/A165 12 101548_201_1015August 13 201510:00791
Houston East C1/G316 12 148_201_1034June 4 201509:00792
Dripping Springs School C614 11 61448_209_0614August 28 201511:00791 N
Parker County C76 4 7648_367_0081May 1 201510:00791
Eagle Mountain Lake C75 4 7548_439_0075August 28 201511:00791
Ft. Worth Northwest C13/AH302 4 1348_439_1002July 31 201509:00792
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 26 201511:00792
Grapevine Fairway C70/A301/X182 4 7048_439_3009June 5 201510:00791
Grapevine Fairway C70/A301/X182 4 7048_439_3009August 24 201512:00791
Grapevine Fairway C70/A301/X182 4 7048_439_3009August 27 201511:00791
CAPCOG Lake Georgetown C690 11 69048_491_0690August 27 201510:00791 N
San Antonio Northwest C23 13 2348_029_0032August 15 201512:00782
Frisco C31/C680 4 3148_085_0005August 27 201511:00781
Dallas North No.2 C63/C679 4 6348_113_0075August 10 201513:00781
Denton Airport South C56/A163/X157 4 5648_121_0034June 6 201511:00781
Pilot Point C1032 4 103248_121_1032May 2 201510:00781
Pilot Point C1032 4 103248_121_1032June 4 201509:00781
Pilot Point C1032 4 103248_121_1032August 4 201511:00781
Pilot Point C1032 4 103248_121_1032August 27 201510:00781
Galveston 99th St. C1034/A320/X183 12 103448_167_1034August 2 201512:00781
Houston Aldine C8/AF108/X150 12 848_201_0024May 2 201510:00782
Northwest Harris Co. C26/A110/X154 12 2648_201_0029June 3 201511:00782
Houston North Wayside C405 12 40548_201_0046August 12 201512:00781
Houston North Wayside C405 12 40548_201_0046August 13 201510:00781
Houston Croquet C409 12 40948_201_0051May 1 201511:00782
Houston Bayland Park C53/A146 12 5348_201_0055June 2 201511:00781
West Houston C554 12 55448_201_0554June 6 201511:00781 N
La Porte Sylvan Beach C556 12 55648_201_0556June 6 201511:00781 N
Wallisville Road C617 12 61748_201_0617June 3 201510:00781 N
HRM-3 Haden Road C603/A114 12 60348_201_0803May 1 201511:00781 N
Houston East C1/G316 12 148_201_1034April 30 201510:00782
Houston East C1/G316 12 148_201_1034May 1 201511:00782
UH WG Jones Forest C698 12 69848_339_0698August 29 201512:00781 N
Eagle Mountain Lake C75 4 7548_439_0075June 5 201510:00781
Eagle Mountain Lake C75 4 7548_439_0075August 3 201511:00781
Ft. Worth Northwest C13/AH302 4 1348_439_1002July 30 201512:00782
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 14 201511:00782
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 28 201511:00782
CAPCOG Lake Georgetown C690 11 69048_491_0690August 29 201511:00781 N
San Antonio Northwest C23 13 2348_029_0032May 2 201510:00772
Heritage Middle School C622 13 62248_029_0622August 13 201511:00771 N
Frisco C31/C680 4 3148_085_0005May 2 201510:00771
Denton Airport South C56/A163/X157 4 5648_121_0034May 1 201511:00771
Denton Airport South C56/A163/X157 4 5648_121_0034August 1 201510:00771
Denton Airport South C56/A163/X157 4 5648_121_0034August 31 201510:00771
El Paso UTEP C12/A125/X151 6 1248_141_0037June 21 201511:00772
Texas City 34th St. C620 12 62048_167_0056May 1 201510:00771 N
Texas City 34th St. C620 12 62048_167_0056August 3 201508:00771 N
Clear Creek High School C571 12 57148_167_0571June 3 201511:00771 N
Houston Monroe C406 12 40648_201_0062June 6 201510:00771
Park Place C416 12 41648_201_0416May 1 201511:00771
Park Place C416 12 41648_201_0416August 24 201512:00771
Sheldon C551 12 55148_201_0551August 29 201509:00771 N
Clear Brook High School C570 12 57048_201_0570May 1 201511:00771 N
UH Moody Tower C695 12 69548_201_0695June 2 201511:00771 N
Baytown Garth C1017 12 101748_201_1017August 30 201510:00771
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039May 1 201511:00771
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039August 13 201510:00771
Nederland High School C1035 10 103548_245_1035August 2 201510:00771
Nederland High School C1035 10 103548_245_1035August 3 201509:00771
Parker County C76 4 7648_367_0081August 13 201514:00771
Rockwall Heath C69 4 6948_397_0001August 10 201511:00771
Eagle Mountain Lake C75 4 7548_439_0075May 1 201510:00771
CAPCOG Hutto College Street C6602 11 660248_491_6602August 28 201510:00771 N
Temple Georgia C1045 9 104548_027_1045August 29 201511:00761
San Antonio Northwest C23 13 2348_029_0032August 3 201510:00762
Fair Oaks Ranch C502 13 50248_029_0502May 1 201511:00761 N
City of Garden Ridge C505 13 50548_091_0505April 30 201511:00761 N
Dallas North No.2 C63/C679 4 6348_113_0075June 28 201512:00761
Skyline Park C72 6 7248_141_0058July 1 201512:00761
Galveston 99th St. C1034/A320/X183 12 103448_167_1034July 31 201516:00761
Lang C408 12 40848_201_0047May 1 201511:00762
Houston Croquet C409 12 40948_201_0051August 2 201510:00762
Houston Croquet C409 12 40948_201_0051August 26 201511:00762
Houston Texas Avenue C411 12 41148_201_0075August 3 201509:00761
West Houston C554 12 55448_201_0554August 28 201511:00761 N
Tom Bass C558 12 55848_201_0558August 28 201511:00761 N
UH Moody Tower C695 12 69548_201_0695April 30 201511:00761 N
UH Moody Tower C695 12 69548_201_0695June 3 201509:00761 N
UH Moody Tower C695 12 69548_201_0695June 4 201510:00761 N
UH Moody Tower C695 12 69548_201_0695August 3 201509:00761 N
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039August 3 201510:00761
Dripping Springs School C614 11 61448_209_0614August 29 201510:00761 N
CAPCOG San Marcos Staples Road C1675 11 167548_209_1675August 13 201511:00761 N
Granbury C73/C681 4 7348_221_0001July 31 201511:00761
Port Arthur West C28/A128/A228 10 2848_245_0011August 2 201509:00761
SETRPC Port Arthur C628 10 62848_245_0628August 13 201510:00761 N
Parker County C76 4 7648_367_0081August 14 201511:00761
Parker County C76 4 7648_367_0081August 15 201511:00761
Parker County C76 4 7648_367_0081August 26 201512:00761
Parker County C76 4 7648_367_0081August 27 201511:00761
Keller C17 4 1748_439_2003May 1 201511:00762
Keller C17 4 1748_439_2003June 5 201510:00762
Grapevine Fairway C70/A301/X182 4 7048_439_3009May 1 201511:00761
Arlington Municipal Airport C61 4 6148_439_3011July 30 201512:00761
Gorzycki Middle School C1603 11 160348_453_1603August 28 201511:00761 N
POC (Parameter Occurrence Code): a code used to correctly separate data from multiple instruments at one site.
 N - Data from this instrument does not meet EPA quality assurance criteria and cannot be used for regulatory purposes.

Interpreting the AQI

Air Quality Index

Each NAAQS pollutant has a separate AQI scale, with an AQI rating of 100 corresponding to the concentration of the Federal Standard for that pollutant. Additional information about the AQI and how it can be used is available from the EPA's AirNow web site.

Place your mouse pointer over the scale displayed above to view information about the Air Quality Index, and each of the rating levels.

The actual index calculation is different for each parameter measured and is specified by the EPA. The following table shows the various breakpoints used in calculating the AQI.

AQI Breakpoint Definitions
AQI Range 1hr Ozone
in ppm
8hr Ozone
in ppm
0 - 50 Not Defined 0 - 0.059
51 - 100 Not Defined 0.06 - 0.075
101 - 150 0.125 - 0.164 0.076 - 0.095
151 - 200 0.165 - 0.204 0.096 - 0.115
201 - 300 0.205 - 0.404 0.116 - 0.374
301 - 400 0.405 - 0.504 Not Defined
401 - 500 0.505 - 0.604 Not Defined
500+ Not Defined Not Defined

PLEASE NOTE:  This data has not been verified by the TCEQ and may change. This is the most current data, but it is not official until it has been certified by our technical staff. Data is collected from TCEQ ambient monitoring sites and may include data collected by other outside agencies. This data is updated hourly. All times shown are in local standard time unless otherwise indicated.

Following EPA reporting guidelines, negative values may be displayed in our hourly criteria air quality data beginning 1/1/2013, down to the negative of the EPA listed Method Detection Limit (MDL) for the particular instrument that made the measurements. The reported concentrations can be negative due to zero drift in the electronic instrument output, data logger channel, or calibration adjustments to the data. Prior to 1/1/2013, slightly negative values were automatically set to zero.