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Eight-Hour Ozone High Value Days for 2017
as of May 24

The table below lists the daily maximum eight-hour ozone concentrations measured which meet or exceed 71 parts per billion in 2017 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
2017 Sorted by Maximum Value
LocationRegionCAMSAQSDateTimeValuePOC
Crosby Library C553 12 55348_201_0553May 6 201711:00841 N
Baytown Garth C1017 12 101748_201_1017May 6 201710:00841
Crosby Library C553 12 55348_201_0553April 24 201710:00831 N
UH WG Jones Forest C698 12 69848_339_0698May 7 201710:00831 N
Wallisville Road C617 12 61748_201_0617May 6 201710:00821 N
UH Moody Tower C695 12 69548_201_0695May 6 201711:00811 N
HRM-3 Haden Road C603/A114 12 60348_201_0803May 6 201710:00811 N
Houston East C1/G316 12 148_201_1034May 6 201710:00812
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039May 6 201710:00811
Conroe Relocated C78/A321 12 7848_339_0078April 7 201711:00811
Manvel Croix Park C84 12 8448_039_1004May 6 201711:00801
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069May 6 201711:00803
Dallas North No.2 C63/C679 4 6348_113_0075May 6 201711:00801
Conroe Relocated C78/A321 12 7848_339_0078April 24 201712:00801
UH WG Jones Forest C698 12 69848_339_0698April 24 201711:00801 N
Conroe Relocated C78/A321 12 7848_339_0078May 15 201710:00791
UH WG Jones Forest C698 12 69848_339_0698April 7 201712:00791 N
Channelview C15/AH115 12 1548_201_0026May 6 201712:00783
Baytown Garth C1017 12 101748_201_1017April 7 201711:00781
Clinton C403/C304/AH113 12 40348_201_1035May 6 201711:00783
UH West Liberty C699 12 69948_291_0699April 7 201711:00781 N
Elm Creek Elementary C501 13 50148_029_0501May 13 201712:00771 N
Manvel Croix Park C84 12 8448_039_1004May 23 201711:00771
Conroe Relocated C78/A321 12 7848_339_0078May 7 201710:00771
UH WG Jones Forest C698 12 69848_339_0698May 15 201711:00771 N
Galveston 99th St. C1034/A320/X183 12 103448_167_1034May 12 201711:00761
Houston Aldine C8/AF108/X150 12 848_201_0024May 6 201711:00762
Houston Aldine C8/AF108/X150 12 848_201_0024May 14 201710:00762
Houston North Wayside C405 12 40548_201_0046May 6 201711:00761
UH WG Jones Forest C698 12 69848_339_0698May 2 201710:00761 N
Temple Georgia C1045 9 104548_027_1045May 6 201710:00751
Wallisville Road C617 12 61748_201_0617April 7 201710:00751 N
Baytown Garth C1017 12 101748_201_1017April 24 201710:00751
UH West Liberty C699 12 69948_291_0699April 24 201711:00751 N
Keller C17 4 1748_439_2003May 6 201712:00752
San Antonio Northwest C23 13 2348_029_0032May 7 201710:00742
U of H-Sugarland C696 12 69648_157_0696May 6 201711:00741 N
Galveston 99th St. C1034/A320/X183 12 103448_167_1034May 6 201713:00741
Northwest Harris Co. C26/A110/X154 12 2648_201_0029May 14 201711:00742
Houston Croquet C409 12 40948_201_0051May 6 201711:00742
Houston Bayland Park C53/A146 12 5348_201_0055May 6 201711:00741
Clear Brook High School C570 12 57048_201_0570May 6 201711:00741 N
Wallisville Road C617 12 61748_201_0617April 24 201710:00741 N
Waco Mazanec C1037 9 103748_309_1037May 6 201710:00741
Ft. Worth Northwest C13/AH302 4 1348_439_1002May 13 201712:00742
Frisco C31/C680 4 3148_085_0005May 6 201712:00731
Denton Airport South C56/A163/X157 4 5648_121_0034May 7 201710:00731
Texas City 34th St. C620 12 62048_167_0056May 6 201711:00731 N
Galveston 99th St. C1034/A320/X183 12 103448_167_1034May 7 201703:00731
Park Place C416 12 41648_201_0416May 6 201710:00731
Seabrook Friendship Park C45 12 4548_201_1050May 6 201711:00731
Beaumont-Downtown C2/A112/C2002 10 248_245_0009May 14 201710:00732
Cleburne Airport C77/C682 4 7748_251_0003May 13 201711:00731
Conroe Relocated C78/A321 12 7848_339_0078May 2 201710:00731
CAPCOG Lake Georgetown C690 11 69048_491_0690May 6 201711:00731 N
Temple Georgia C1045 9 104548_027_1045May 7 201711:00721
Camp Bullis C58 13 5848_029_0052May 7 201711:00721
Chamizal C41/AH126 6 4148_141_0044May 20 201712:00721
Texas City 34th St. C620 12 62048_167_0056May 12 201710:00721 N
Galveston 99th St. C1034/A320/X183 12 103448_167_1034April 7 201710:00721
Rockwall Heath C69 4 6948_397_0001May 6 201711:00721
Ft. Worth Northwest C13/AH302 4 1348_439_1002May 6 201711:00722
Killeen Skylark Field C1047 9 104748_027_1047April 7 201711:00711
Denton Airport South C56/A163/X157 4 5648_121_0034May 6 201710:00711
Houston Aldine C8/AF108/X150 12 848_201_0024May 7 201709:00712
Northwest Harris Co. C26/A110/X154 12 2648_201_0029May 7 201711:00712
Houston North Wayside C405 12 40548_201_0046May 14 201710:00711
Houston Westhollow C410 12 41048_201_0066May 6 201711:00711
HRM-3 Haden Road C603/A114 12 60348_201_0803April 7 201710:00711 N
Arlington Municipal Airport C61 4 6148_439_3011May 13 201711:00711
Austin Northwest C3/A322 11 348_453_0014May 6 201710:00712
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

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.