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Eight-Hour Ozone High Value Days for 2020
as of August 14

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
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
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
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
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
UH WG Jones Forest C698 12 69848_339_0698August 7 202011:00811 N
Texas City 34th St. C620 12 62048_167_0056June 13 202010:00801 N
Meyer Park C561 12 56148_201_0561June 16 202011:00801 N
El Paso UTEP C12/A125/X151/G125 6 1248_141_0037July 7 202010:00792
La Porte Sylvan Beach C556 12 55648_201_0556May 18 202010:00791 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
Pilot Point C1032 4 103248_121_1032May 18 202012:00781
UH WG Jones Forest C698 12 69848_339_0698June 16 202011:00781 N
Eagle Mountain Lake C75 4 7548_439_0075August 4 202011:00781
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
Galveston 99th St. C1034/A320/X183 12 103448_167_1034May 18 202010:00761
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
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
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
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
Skyline Park C72 6 7248_141_0058August 4 202011:00741
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
Seabrook Friendship Park C45 12 4548_201_1050August 3 202011:00741
Eagle Mountain Lake C75 4 7548_439_0075May 19 202010:00741
Ft. Worth Northwest C13/AH302 4 1348_439_1002August 5 202011:00742
Keller C17 4 1748_439_2003May 19 202011:00742
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
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
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
Wallisville Road C617 12 61748_201_0617July 4 202011:00731 N
Eagle Mountain Lake C75 4 7548_439_0075May 30 202011:00731
Grapevine Fairway C70/A301/X182 4 7048_439_3009June 12 202010:00731
Camp Bullis C58 13 5848_029_0052April 20 202011:00721
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
Chamizal C41/AH126 6 4148_141_0044May 9 202011:00721
Houston Bayland Park C53/A146 12 5348_201_0055April 20 202012:00721
Huffman Wolf Road C563 12 56348_201_0563June 17 202009:00721 N
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
Eagle Mountain Lake C75 4 7548_439_0075August 5 202012:00721
Grapevine Fairway C70/A301/X182 4 7048_439_3009June 1 202011:00721
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
Ivanhoe C414/F514 6 41448_141_0029August 4 202011:00711
Chamizal C41/AH126 6 4148_141_0044July 25 202011:00711
Socorro Hueco C49/F312 6 4948_141_0057July 14 202010:00711
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
Huffman Wolf Road C563 12 56348_201_0563May 18 202012:00711 N
Clinton C403/C304/AH113 12 40348_201_1035May 18 202010:00713
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
Keller C17 4 1748_439_2003June 12 202011:00712
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
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.