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Eight-Hour Ozone High Value Days for 2018
as of June 19

The table below lists the daily maximum eight-hour ozone concentrations measured which meet or exceed 71 parts per billion in 2018 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
2018 Sorted by Maximum Value
LocationRegionCAMSAQSDateTimeValuePOC
Eagle Mountain Lake C75 4 7548_439_0075May 17 201811:00921
Grapevine Fairway C70/A301/X182 4 7048_439_3009May 26 201811:00891
Texas City 34th St. C620 12 62048_167_0056April 24 201811:00881 N
Houston Aldine C8/AF108/X150 12 848_201_0024April 28 201811:00882
Houston Aldine C8/AF108/X150 12 848_201_0024May 7 201810:00882
Wallisville Road C617 12 61748_201_0617May 7 201811:00881 N
Baytown Garth C1017 12 101748_201_1017May 7 201811:00881
Crosby Library C553 12 55348_201_0553April 28 201811:00861 N
Lang C408 12 40848_201_0047April 28 201810:00852
Crosby Library C553 12 55348_201_0553April 25 201809:00851 N
Atascocita C560 12 56048_201_0560May 7 201811:00851 N
Baytown Garth C1017 12 101748_201_1017May 17 201810:00851
Conroe Relocated C78/A321 12 7848_339_0078May 15 201810:00851
Keller C17 4 1748_439_2003May 17 201811:00852
UH Moody Tower C695 12 69548_201_0695May 7 201810:00841 N
Houston East C1/G316 12 148_201_1034May 7 201811:00842
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039May 7 201810:00841
Seabrook Friendship Park C45 12 4548_201_1050April 24 201812:00841
Camp Bullis C58 13 5848_029_0052May 7 201809:00831
Dallas North No.2 C63/C679 4 6348_113_0075May 26 201811:00831
Chamizal C41/AH126 6 4148_141_0044June 4 201811:00831
Galveston 99th St. C1034/A320/X183 12 103448_167_1034April 24 201812:00831
Galveston 99th St. C1034/A320/X183 12 103448_167_1034May 7 201811:00831
Northwest Harris Co. C26/A110/X154 12 2648_201_0029April 28 201811:00832
Lynchburg Ferry C1015/A165 12 101548_201_1015May 7 201811:00831
Ft. Worth Northwest C13/AH302 4 1348_439_1002May 17 201811:00832
El Paso UTEP C12/A125/X151 6 1248_141_0037June 4 201811:00822
Ascarate Park SE C37/A332/A172/X159 6 3748_141_0055June 4 201811:00821
Houston North Wayside C405 12 40548_201_0046April 28 201810:00821
Crosby Library C553 12 55348_201_0553May 7 201811:00821 N
Crosby Library C553 12 55348_201_0553May 15 201810:00821 N
Wallisville Road C617 12 61748_201_0617May 17 201810:00821 N
Houston East C1/G316 12 148_201_1034April 28 201810:00822
Killeen Skylark Field C1047 9 104748_027_1047May 7 201811:00811
Frisco C31/C680 4 3148_085_0005May 7 201812:00811
Frisco C31/C680 4 3148_085_0005May 26 201811:00811
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069April 24 201811:00813
Dallas North No.2 C63/C679 4 6348_113_0075April 28 201812:00811
Dallas North No.2 C63/C679 4 6348_113_0075May 6 201812:00811
Dallas Executive Airport C402 4 40248_113_0087April 24 201811:00811
Channelview C15/AH115 12 1548_201_0026April 28 201812:00813
Channelview C15/AH115 12 1548_201_0026May 7 201810:00813
Wallisville Road C617 12 61748_201_0617May 15 201809:00811 N
Baytown Garth C1017 12 101748_201_1017April 25 201809:00811
Baytown Garth C1017 12 101748_201_1017May 15 201809:00811
Cleburne Airport C77/C682 4 7748_251_0003May 16 201812:00811
Rockwall Heath C69 4 6948_397_0001May 6 201811:00811
Denton Airport South C56/A163/X157 4 5648_121_0034May 26 201811:00801
UH West Liberty C699 12 69948_291_0699April 25 201809:00801 N
Fair Oaks Ranch C502 13 50248_029_0502May 7 201811:00791 N
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069May 6 201811:00793
Houston North Wayside C405 12 40548_201_0046May 7 201810:00791
Houston Bayland Park C53/A146 12 5348_201_0055April 28 201810:00791
HRM-3 Haden Road C603/A114 12 60348_201_0803May 7 201810:00791 N
Rockwall Heath C69 4 6948_397_0001April 28 201811:00791
Bulverde Elementary C503 13 50348_091_0503May 7 201811:00781 N
Houston Aldine C8/AF108/X150 12 848_201_0024April 25 201810:00782
Houston Bayland Park C53/A146 12 5348_201_0055May 7 201811:00781
Crosby Library C553 12 55348_201_0553May 17 201810:00781 N
Wallisville Road C617 12 61748_201_0617April 25 201809:00781 N
UH Moody Tower C695 12 69548_201_0695April 28 201810:00781 N
HRM-3 Haden Road C603/A114 12 60348_201_0803April 28 201810:00781 N
Camp Bullis C58 13 5848_029_0052April 23 201812:00771
Manvel Croix Park C84 12 8448_039_1004April 24 201811:00771
Skyline Park C72 6 7248_141_0058June 4 201811:00771
Houston Westhollow C410 12 41048_201_0066April 28 201810:00771
Park Place C416 12 41648_201_0416May 7 201811:00771
Atascocita C560 12 56048_201_0560April 25 201810:00771 N
Wallisville Road C617 12 61748_201_0617April 28 201810:00771 N
Baytown Garth C1017 12 101748_201_1017April 28 201811:00771
Houston East C1/G316 12 148_201_1034May 17 201811:00772
Hamshire C64/C654 10 6448_245_0022May 17 201810:00771
SETRPC Port Arthur C628 10 62848_245_0628May 17 201808:00771 N
UH WG Jones Forest C698 12 69848_339_0698May 15 201812:00771 N
SETRPC Mauriceville 42 C642/C311/C665 10 64248_361_1100April 25 201811:00771 N
SETRPC Mauriceville 42 C642/C311/C665 10 64248_361_1100April 28 201811:00771 N
Keller C17 4 1748_439_2003April 24 201812:00772
Arlington Municipal Airport C61 4 6148_439_3011April 24 201812:00771
CAPCOG Lake Georgetown C690 11 69048_491_0690May 7 201810:00771 N
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069April 28 201811:00763
Dallas North No.2 C63/C679 4 6348_113_0075May 7 201811:00761
Galveston 99th St. C1034/A320/X183 12 103448_167_1034April 27 201812:00761
Atascocita C560 12 56048_201_0560May 15 201810:00761 N
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039April 24 201812:00761
SETRPC 40 Sabine Pass C640/C1654 10 64048_245_0101April 25 201811:00761
UH WG Jones Forest C698 12 69848_339_0698June 8 201810:00761 N
Rockwall Heath C69 4 6948_397_0001May 7 201811:00761
Ft. Worth Northwest C13/AH302 4 1348_439_1002April 24 201812:00762
Temple Georgia C1045 9 104548_027_1045May 7 201811:00751
Killeen Skylark Field C1047 9 104748_027_1047April 28 201810:00751
San Antonio Northwest C23 13 2348_029_0032May 7 201810:00752
Frisco C31/C680 4 3148_085_0005April 28 201812:00751
City of Garden Ridge C505 13 50548_091_0505May 7 201810:00751 N
Dallas North No.2 C63/C679 4 6348_113_0075April 24 201811:00751
Dallas Executive Airport C402 4 40248_113_0087April 28 201811:00751
Houston Aldine C8/AF108/X150 12 848_201_0024May 17 201812:00752
Beaumont-Downtown C2/A112/C2002 10 248_245_0009April 28 201811:00752
Conroe Relocated C78/A321 12 7848_339_0078May 9 201811:00751
Conroe Relocated C78/A321 12 7848_339_0078May 14 201811:00751
UH WG Jones Forest C698 12 69848_339_0698April 28 201812:00751 N
West Orange C9/A141 10 948_361_1001April 25 201810:00752
Parker County C76 4 7648_367_0081May 17 201811:00751
Keller C17 4 1748_439_2003April 28 201811:00752
Pilot Point C1032 4 103248_121_1032May 29 201811:00741
Ivanhoe C414 6 41448_141_0029June 4 201811:00741
Texas City 34th St. C620 12 62048_167_0056May 7 201810:00741 N
UH Moody Tower C695 12 69548_201_0695April 25 201810:00741 N
UH WG Jones Forest C698 12 69848_339_0698May 8 201811:00741 N
Eagle Mountain Lake C75 4 7548_439_0075April 24 201811:00741
Grapevine Fairway C70/A301/X182 4 7048_439_3009April 24 201811:00741
Grapevine Fairway C70/A301/X182 4 7048_439_3009May 7 201811:00741
Arlington Municipal Airport C61 4 6148_439_3011May 26 201810:00741
San Antonio Northwest C23 13 2348_029_0032April 23 201812:00732
Camp Bullis C58 13 5848_029_0052April 24 201809:00731
Heritage Middle School C622 13 62248_029_0622May 6 201811:00731 N
City of Garden Ridge C505 13 50548_091_0505May 16 201811:00731 N
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069May 26 201811:00733
Dallas Executive Airport C402 4 40248_113_0087May 6 201811:00731
Midlothian OFW C52/A137 4 5248_139_0016April 24 201812:00731
Channelview C15/AH115 12 1548_201_0026May 15 201810:00733
Lang C408 12 40848_201_0047May 7 201811:00732
Houston Bayland Park C53/A146 12 5348_201_0055April 25 201810:00731
Park Place C416 12 41648_201_0416April 28 201810:00731
Houston East C1/G316 12 148_201_1034April 25 201810:00732
Clinton C403/C304/AH113 12 40348_201_1035April 28 201810:00733
Clinton C403/C304/AH113 12 40348_201_1035May 7 201811:00733
Greenville C1006/A198 4 100648_231_1006May 7 201810:00731
SETRPC 43 Jefferson Co Airport C643 10 64348_245_0102April 28 201811:00731
Nederland High School C1035 10 103548_245_1035April 28 201812:00731
Conroe Relocated C78/A321 12 7848_339_0078May 10 201810:00731
Conroe Relocated C78/A321 12 7848_339_0078June 8 201811:00731
UH WG Jones Forest C698 12 69848_339_0698May 9 201810:00731 N
West Orange C9/A141 10 948_361_1001May 8 201810:00732
West Orange C9/A141 10 948_361_1001May 16 201811:00732
Tyler Airport Relocated C82 5 8248_423_0007April 28 201810:00731
Keller C17 4 1748_439_2003May 26 201811:00732
Grapevine Fairway C70/A301/X182 4 7048_439_3009April 28 201812:00731
Grapevine Fairway C70/A301/X182 4 7048_439_3009May 17 201811:00731
CAPCOG Lake Georgetown C690 11 69048_491_0690April 28 201810:00731 N
Camp Bullis C58 13 5848_029_0052April 28 201810:00721
Fair Oaks Ranch C502 13 50248_029_0502April 28 201810:00721 N
Dallas Executive Airport C402 4 40248_113_0087May 7 201811:00721
Denton Airport South C56/A163/X157 4 5648_121_0034May 29 201810:00721
Pilot Point C1032 4 103248_121_1032May 7 201811:00721
Italy C1044/A323 4 104448_139_1044May 16 201812:00721
Galveston 99th St. C1034/A320/X183 12 103448_167_1034April 28 201811:00721
Houston Aldine C8/AF108/X150 12 848_201_0024April 29 201810:00722
Houston Aldine C8/AF108/X150 12 848_201_0024June 8 201809:00722
Channelview C15/AH115 12 1548_201_0026May 17 201810:00723
Northwest Harris Co. C26/A110/X154 12 2648_201_0029April 29 201810:00722
Lang C408 12 40848_201_0047April 25 201809:00722
Park Place C416 12 41648_201_0416April 24 201812:00721
Crosby Library C553 12 55348_201_0553May 8 201811:00721 N
Crosby Library C553 12 55348_201_0553May 16 201811:00721 N
Atascocita C560 12 56048_201_0560May 17 201811:00721 N
UH Moody Tower C695 12 69548_201_0695April 24 201811:00721 N
Hamshire C64/C654 10 6448_245_0022April 25 201809:00721
SETRPC 43 Jefferson Co Airport C643 10 64348_245_0102May 15 201809:00721
SETRPC Port Arthur C628 10 62848_245_0628May 15 201809:00721 N
UH West Liberty C699 12 69948_291_0699May 15 201810:00721 N
Conroe Relocated C78/A321 12 7848_339_0078May 29 201811:00721
Corsicana Airport C1051 4 105148_349_1051April 28 201810:00721
West Orange C9/A141 10 948_361_1001April 28 201810:00722
SETRPC Mauriceville 42 C642/C311/C665 10 64248_361_1100May 8 201811:00721 N
SETRPC Mauriceville 42 C642/C311/C665 10 64248_361_1100May 16 201812:00721 N
Parker County C76 4 7648_367_0081April 24 201812:00721
Ft. Worth Northwest C13/AH302 4 1348_439_1002May 26 201811:00722
Austin Northwest C3/A322 11 348_453_0014May 7 201810:00722
Temple Georgia C1045 9 104548_027_1045April 28 201809:00711
Killeen Skylark Field C1047 9 104748_027_1047May 8 201811:00711
CPS Pecan Valley C678 13 67848_029_0055May 6 201810:00711 N
Calaveras Lake C59 13 5948_029_0059May 6 201811:00711
Calaveras Lake C59 13 5948_029_0059May 7 201811:00711
Frisco C31/C680 4 3148_085_0005April 24 201811:00711
Frisco C31/C680 4 3148_085_0005May 8 201811:00711
Frisco C31/C680 4 3148_085_0005May 29 201810:00711
City of Garden Ridge C505 13 50548_091_0505April 23 201812:00711 N
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069May 7 201811:00713
Denton Airport South C56/A163/X157 4 5648_121_0034April 28 201811:00711
Denton Airport South C56/A163/X157 4 5648_121_0034June 5 201810:00711
Pilot Point C1032 4 103248_121_1032May 8 201811:00711
Pilot Point C1032 4 103248_121_1032May 18 201810:00711
Italy C1044/A323 4 104448_139_1044May 7 201810:00711
Skyline Park C72 6 7248_141_0058May 22 201810:00711
Texas City 34th St. C620 12 62048_167_0056April 27 201812:00711 N
Galveston 99th St. C1034/A320/X183 12 103448_167_1034April 26 201812:00711
Channelview C15/AH115 12 1548_201_0026April 25 201809:00713
Wallisville Road C617 12 61748_201_0617May 8 201810:00711 N
Lynchburg Ferry C1015/A165 12 101548_201_1015April 28 201811:00711
Baytown Garth C1017 12 101748_201_1017May 8 201810:00711
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039April 28 201810:00711
Dripping Springs School C614 11 61448_209_0614May 7 201811:00711 N
Beaumont-Downtown C2/A112/C2002 10 248_245_0009April 25 201810:00712
SETRPC 40 Sabine Pass C640/C1654 10 64048_245_0101April 28 201811:00711
SETRPC 43 Jefferson Co Airport C643 10 64348_245_0102April 25 201810:00711
Cleburne Airport C77/C682 4 7748_251_0003April 24 201811:00711
UH West Liberty C699 12 69948_291_0699April 28 201811:00711 N
Conroe Relocated C78/A321 12 7848_339_0078May 8 201811:00711
Rockwall Heath C69 4 6948_397_0001April 24 201811:00711
Gorzycki Middle School C1603 11 160348_453_1603May 7 201811:00711 N
CAPCOG Hutto College Street C6602 11 660248_491_6602May 7 201810:00711 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 - 0.054
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.