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Eight-Hour Ozone High Value Days for 2020
as of October 31

The table below lists the daily maximum eight-hour ozone concentrations measured which meet or exceed 71 parts per billion in 2020 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
2020 Sorted by Maximum Value
LocationRegionCAMSAQSDateTimeValuePOC
Socorro Hueco C49/F312 6 4948_141_0057August 21 202011:001021
Manvel Croix Park C84 12 8448_039_1004August 18 202010:00981
Oyster Creek C1607 12 160748_039_1607August 19 202010:00931 N
UH Smith Point C1606 12 160648_071_1606August 3 202010:00891 N
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 4 202012:00892
Texas City 34th St. C620 12 62048_167_0056May 18 202010:00881 N
Grapevine Fairway C70/A301/X182 4 7048_439_3009August 17 202013:00881
Frisco C31/C680 4 3148_085_0005August 17 202012:00871
Tom Bass C558 12 55848_201_0558August 18 202010:00871 N
Houston East C1/G316 12 148_201_1034May 18 202010:00862
Grapevine Fairway C70/A301/X182 4 7048_439_3009May 19 202010:00861
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037August 8 202011:00852
Baytown Wetlands Center C552 12 55248_201_0552May 18 202010:00851 N
Northwest Harris Co. C26/A110/X154 12 2648_201_0029June 16 202010:00842
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037July 25 202011:00832
Ft. Worth Northwest C13/AH302 4 1348_439_1002May 19 202011:00832
Ivanhoe C414/F514 6 41448_141_0029August 21 202011:00821
Houston Croquet C409 12 40948_201_0051October 13 202011:00822
Houston Bayland Park C53/A146 12 5348_201_0055August 18 202010:00821
Camp Bullis C58 13 5848_029_0052April 30 202011:00811
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037August 1 202010:00812
Channelview C15/AH115 12 1548_201_0026May 18 202010:00813
Houston Croquet C409 12 40948_201_0051August 18 202011:00812
Houston Bayland Park C53/A146 12 5348_201_0055October 5 202011:00811
Wallisville Road C617 12 61748_201_0617May 18 202011:00811 N
Baytown Garth C1017 12 101748_201_1017May 18 202011:00811
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039May 18 202010:00811
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039August 18 202010:00811
UH WG Jones Forest C698 12 69848_339_0698August 7 202011:00811 N
Manvel Croix Park C84 12 8448_039_1004October 4 202010:00801
Dallas North No.2 C63/C679 4 6348_113_0075August 17 202012:00801
Texas City 34th St. C620 12 62048_167_0056June 13 202010:00801 N
Galveston 99th St. C1034/A320/X183 12 103448_167_1034August 19 202015:00801
Houston Monroe C406 12 40648_201_0062August 18 202011:00801
Park Place C416 12 41648_201_0416August 18 202011:00801
Meyer Park C561 12 56148_201_0561June 16 202011:00801 N
UH Moody Tower C695 12 69548_201_0695August 18 202010:00801 N
Rockwall Heath C69 4 6948_397_0001August 17 202013:00801
Oyster Creek C1607 12 160748_039_1607August 18 202012:00791 N
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037July 7 202010:00792
Skyline Park C72 6 7248_141_0058August 21 202010:00791
La Porte Sylvan Beach C556 12 55648_201_0556May 18 202010:00791 N
UH Moody Tower C695 12 69548_201_0695October 5 202011:00791 N
HRM-3 Haden Road C603/A114 12 60348_201_0803May 18 202010:00791 N
Conroe Relocated C78/A321 12 7848_339_0078June 17 202011:00791
Eagle Mountain Lake C75 4 7548_439_0075August 21 202011:00791
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 21 202012:00792
Pilot Point C1032 4 103248_121_1032May 18 202012:00781
Texas City 34th St. C620 12 62048_167_0056August 18 202010:00781 N
UH Launch Trailer C1611 12 161148_201_1611October 5 202011:00781 N
CAPCOG San Marcos Staples Road C1675 11 167548_209_1675August 18 202011:00781 N
UH WG Jones Forest C698 12 69848_339_0698June 16 202011:00781 N
Eagle Mountain Lake C75 4 7548_439_0075August 4 202011:00781
Camp Bullis C58 13 5848_029_0052October 6 202010:00771
Denton Airport South C56/A163/X157 4 5648_121_0034August 17 202011:00771
Pilot Point C1032 4 103248_121_1032August 17 202011:00771
Ascarate Park SE C37/A332/A172/X159 6 3748_141_0055August 21 202011:00771
Park Place C416 12 41648_201_0416October 13 202010:00771
Tom Bass C558 12 55848_201_0558October 4 202010:00771 N
Meyer Park C561 12 56148_201_0561October 3 202011:00771 N
UH Moody Tower C695 12 69548_201_0695May 18 202010:00771 N
Conroe Relocated C78/A321 12 7848_339_0078August 6 202011:00771
Conroe Relocated C78/A321 12 7848_339_0078August 7 202011:00771
Eagle Mountain Lake C75 4 7548_439_0075June 12 202011:00771
Grapevine Fairway C70/A301/X182 4 7048_439_3009August 16 202011:00771
Grapevine Fairway C70/A301/X182 4 7048_439_3009August 21 202010:00771
Galveston 99th St. C1034/A320/X183 12 103448_167_1034May 18 202010:00761
Northwest Harris Co. C26/A110/X154 12 2648_201_0029October 3 202011:00762
Lynchburg Ferry C1015/A165 12 101548_201_1015May 18 202010:00761
Baytown Garth C1017 12 101748_201_1017August 4 202010:00761
UH WG Jones Forest C698 12 69848_339_0698August 6 202011:00761 N
Eagle Mountain Lake C75 4 7548_439_0075August 22 202011:00761
Camp Bullis C58 13 5848_029_0052October 13 202011:00751
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069May 19 202011:00753
Denton Airport South C56/A163/X157 4 5648_121_0034May 18 202011:00751
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037May 9 202011:00752
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037June 25 202010:00752
Texas City 34th St. C620 12 62048_167_0056April 23 202010:00751 N
Houston Aldine C8/AF108/X150 12 848_201_0024June 16 202010:00752
Seabrook Friendship Park C45 12 4548_201_1050May 18 202010:00751
UH Launch Trailer C1611 12 161148_201_1611May 18 202010:00751 N
UH Launch Trailer C1611 12 161148_201_1611August 18 202010:00751 N
UH Launch Trailer C1611 12 161148_201_1611August 21 202011:00751 N
Conroe Relocated C78/A321 12 7848_339_0078May 1 202010:00751
UH WG Jones Forest C698 12 69848_339_0698June 17 202011:00751 N
Parker County C76 4 7648_367_0081August 5 202012:00751
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 20 202011:00752
Camp Bullis C58 13 5848_029_0052October 7 202010:00741
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037May 6 202010:00742
Socorro Hueco C49/F312 6 4948_141_0057August 1 202008:00741
Socorro Hueco C49/F312 6 4948_141_0057August 4 202011:00741
Socorro Hueco C49/F312 6 4948_141_0057August 14 202011:00741
Skyline Park C72 6 7248_141_0058August 4 202011:00741
Texas City 34th St. C620 12 62048_167_0056October 1 202010:00741 N
Houston Aldine C8/AF108/X150 12 848_201_0024May 18 202011:00742
Northwest Harris Co. C26/A110/X154 12 2648_201_0029May 11 202011:00742
Houston Westhollow C410 12 41048_201_0066August 18 202010:00741
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039August 21 202009:00741
Seabrook Friendship Park C45 12 4548_201_1050August 3 202011:00741
Eagle Mountain Lake C75 4 7548_439_0075May 19 202010:00741
Eagle Mountain Lake C75 4 7548_439_0075August 17 202012:00741
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 5 202011:00742
Keller C17 4 1748_439_2003May 19 202011:00742
Calaveras Lake C59 13 5948_029_0059August 19 202010:00731
Lake Jackson C1016 12 101648_039_1016August 18 202009:00731
Lake Jackson C1016 12 101648_039_1016August 19 202010:00731
Oyster Creek C1607 12 160748_039_1607June 10 202010:00731 N
Frisco C31/C680 4 3148_085_0005May 18 202011:00731
Dallas Executive Airport C402 4 40248_113_0087August 4 202012:00731
Ivanhoe C414/F514 6 41448_141_0029August 19 202009:00731
Chamizal C41/AH126 6 4148_141_0044July 7 202010:00731
Chamizal C41/AH126 6 4148_141_0044August 1 202008:00731
Chamizal C41/AH126 6 4148_141_0044August 8 202010:00731
Socorro Hueco C49/F312 6 4948_141_0057May 9 202011:00731
Socorro Hueco C49/F312 6 4948_141_0057August 22 202010:00731
Skyline Park C72 6 7248_141_0058August 8 202011:00731
Lang C408 12 40848_201_0047June 2 202010:00732
Lang C408 12 40848_201_0047June 16 202009:00732
Houston Bayland Park C53/A146 12 5348_201_0055August 17 202011:00731
Houston Bayland Park C53/A146 12 5348_201_0055August 20 202011:00731
Houston East C1/G316 12 148_201_1034August 21 202009:00732
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039October 4 202010:00731
Conroe Relocated C78/A321 12 7848_339_0078October 14 202012:00731
Eagle Mountain Lake C75 4 7548_439_0075May 30 202011:00731
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 22 202010:00732
Keller C17 4 1748_439_2003August 21 202011:00732
Grapevine Fairway C70/A301/X182 4 7048_439_3009June 12 202010:00731
CAPCOG East Austin C1619 11 161948_453_1619August 18 202010:00731 N
Camp Bullis C58 13 5848_029_0052April 20 202011:00721
Camp Bullis C58 13 5848_029_0052October 1 202010:00721
Dallas North No.2 C63/C679 4 6348_113_0075May 19 202010:00721
Denton Airport South C56/A163/X157 4 5648_121_0034June 1 202011:00721
Pilot Point C1032 4 103248_121_1032August 28 202010:00721
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037August 19 202010:00722
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037August 22 202011:00722
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037August 29 202010:00722
Chamizal C41/AH126 6 4148_141_0044May 9 202011:00721
Houston Bayland Park C53/A146 12 5348_201_0055April 20 202012:00721
Park Place C416 12 41648_201_0416October 5 202011:00721
Huffman Wolf Road C563 12 56348_201_0563June 17 202009:00721 N
Lynchburg Ferry C1015/A165 12 101548_201_1015August 21 202009:00721
Houston East C1/G316 12 148_201_1034October 5 202011:00722
Clinton C403/C304/AH113 12 40348_201_1035August 18 202010:00723
Dripping Springs School C614 11 61448_209_0614May 18 202011:00721 N
Beaumont-Downtown C2/A112/C2002 10 248_245_0009June 2 202010:00722
Cleburne Airport C77/C682 4 7748_251_0003May 29 202011:00721
Conroe Relocated C78/A321 12 7848_339_0078April 24 202011:00721
SETRPC Mauriceville 42 C642/C311/C665 10 64248_361_1100October 14 202011:00721 N
Eagle Mountain Lake C75 4 7548_439_0075August 5 202012:00721
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 24 202010:00722
Grapevine Fairway C70/A301/X182 4 7048_439_3009June 1 202011:00721
San Antonio Northwest C23 13 2348_029_0032August 20 202009:00712
San Antonio Northwest C23 13 2348_029_0032October 7 202010:00712
Camp Bullis C58 13 5848_029_0052August 19 202010:00711
Oyster Creek C1607 12 160748_039_1607October 6 202010:00711 N
Frisco C31/C680 4 3148_085_0005October 6 202011:00711
Dallas North No.2 C63/C679 4 6348_113_0075May 18 202012:00711
Dallas Executive Airport C402 4 40248_113_0087June 8 202011:00711
Denton Airport South C56/A163/X157 4 5648_121_0034June 13 202011:00711
Denton Airport South C56/A163/X157 4 5648_121_0034October 8 202011:00711
Pilot Point C1032 4 103248_121_1032October 6 202011:00711
Ivanhoe C414/F514 6 41448_141_0029August 4 202011:00711
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037August 27 202010:00712
Chamizal C41/AH126 6 4148_141_0044July 25 202011:00711
Ascarate Park SE C37/A332/A172/X159 6 3748_141_0055August 14 202011:00711
Socorro Hueco C49/F312 6 4948_141_0057July 14 202010:00711
Socorro Hueco C49/F312 6 4948_141_0057August 18 202010:00711
Skyline Park C72 6 7248_141_0058August 19 202010:00711
Texas City 34th St. C620 12 62048_167_0056August 2 202009:00711 N
Texas City 34th St. C620 12 62048_167_0056August 19 202009:00711 N
Northwest Harris Co. C26/A110/X154 12 2648_201_0029June 2 202012:00712
Houston Westhollow C410 12 41048_201_0066April 20 202012:00711
Mercer Arboretum C557 12 55748_201_0557June 16 202010:00711 N
Tom Bass C558 12 55848_201_0558August 20 202011:00711 N
Huffman Wolf Road C563 12 56348_201_0563May 18 202012:00711 N
Wallisville Road C617 12 61748_201_0617August 21 202009:00711 N
UH Moody Tower C695 12 69548_201_0695August 21 202009:00711 N
HRM-3 Haden Road C603/A114 12 60348_201_0803August 21 202009:00711 N
Baytown Garth C1017 12 101748_201_1017August 21 202009:00711
Clinton C403/C304/AH113 12 40348_201_1035May 18 202010:00713
Clinton C403/C304/AH113 12 40348_201_1035August 21 202009:00713
Clinton C403/C304/AH113 12 40348_201_1035October 5 202011:00713
Cleburne Airport C77/C682 4 7748_251_0003June 11 202013:00711
UH WG Jones Forest C698 12 69848_339_0698May 1 202010:00711 N
West Orange C9/A141 10 948_361_1001June 2 202009:00712
Eagle Mountain Lake C75 4 7548_439_0075August 20 202011:00711
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 17 202012:00712
Keller C17 4 1748_439_2003June 12 202011:00712
Keller C17 4 1748_439_2003August 17 202012:00712
Grapevine Fairway C70/A301/X182 4 7048_439_3009June 13 202011:00711
Arlington Municipal Airport C61 4 6148_439_3011August 3 202012:00711
Arlington Municipal Airport C61 4 6148_439_3011August 4 202012:00711
Arlington Municipal Airport C61 4 6148_439_3011August 17 202012:00711
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 - 0.054
51 - 100 Not Defined 0.055 - 0.070
101 - 150 0.125 - 0.164 0.071 - 0.085
151 - 200 0.165 - 0.204 0.086 - 0.105
201 - 300 0.205 - 0.404 0.106 - 0.200
301 - 400 0.405 - 0.504 Not Defined
401 - 500 Not Defined Not Defined
500+ Not Defined Not Defined
  • The AQI for ozone is based on either the peak eight-hour running average since midnight OR the peak one-hour measurement since midnight.

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, 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.