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Eight-Hour Ozone High Value Days for 2016
as of September 25

The table below lists the daily maximum eight-hour ozone concentrations measured which meet or exceed 71 parts per billion in 2016 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
2016 Sorted by Maximum Value
LocationRegionCAMSAQSDateTimeValuePOC
Ft. Worth Northwest C13/AH302 4 1348_439_1002June 7 201612:00952
Arlington Municipal Airport C61 4 6148_439_3011June 7 201611:00951
Houston Aldine C8/AF108/X150 12 848_201_0024August 3 201611:00892
West Houston C554 12 55448_201_0554May 6 201611:00891 N
Parker County C76 4 7648_367_0081June 7 201615:00881
Bunker Hill Village C562 12 56248_201_0562May 6 201611:00861 N
West Houston C554 12 55448_201_0554July 21 201609:00851 N
Cleburne Airport C77/C682 4 7748_251_0003June 7 201611:00851
Keller C17 4 1748_439_2003June 7 201612:00852
Chamizal C41/AH126 6 4148_141_0044June 23 201610:00841
Galveston 99th St. C1034/A320/X183 12 103448_167_1034April 23 201610:00841
Houston Bayland Park C53/A146 12 5348_201_0055May 6 201610:00841
Houston Westhollow C410 12 41048_201_0066May 6 201610:00841
HRM-3 Haden Road C603/A114 12 60348_201_0803September 19 201609:00841 N
Denton Airport South C56/A163/X157 4 5648_121_0034June 8 201610:00831
Pilot Point C1032 4 103248_121_1032June 30 201611:00831
Houston Aldine C8/AF108/X150 12 848_201_0024July 22 201611:00832
Houston Bayland Park C53/A146 12 5348_201_0055April 15 201611:00831
Grapevine Fairway C70/A301/X182 4 7048_439_3009June 7 201611:00831
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069June 7 201611:00823
Galveston 99th St. C1034/A320/X183 12 103448_167_1034May 4 201612:00821
Dallas Executive Airport C402 4 40248_113_0087June 7 201611:00811
Denton Airport South C56/A163/X157 4 5648_121_0034September 21 201611:00811
Chamizal C41/AH126 6 4148_141_0044August 8 201610:00811
UH WG Jones Forest C698 12 69848_339_0698May 7 201610:00811 N
Ascarate Park SE C37/A332/A172/X159 6 3748_141_0055June 23 201610:00801
Lang C408 12 40848_201_0047April 23 201611:00802
Granbury C73/C681 4 7348_221_0001June 7 201611:00801
Cleburne Airport C77/C682 4 7748_251_0003June 6 201611:00801
Conroe Relocated C78/A321 12 7848_339_0078May 7 201611:00801
Denton Airport South C56/A163/X157 4 5648_121_0034July 1 201610:00791
Northwest Harris Co. C26/A110/X154 12 2648_201_0029July 21 201612:00792
Houston Westhollow C410 12 41048_201_0066April 15 201611:00791
Houston Westhollow C410 12 41048_201_0066April 23 201610:00791
Mercer Arboretum C557 12 55748_201_0557July 22 201611:00791 N
Katy Park C559 12 55948_201_0559May 6 201612:00791 N
Pilot Point C1032 4 103248_121_1032June 8 201610:00781
El Paso UTEP C12/A125/X151 6 1248_141_0037June 23 201610:00782
El Paso UTEP C12/A125/X151 6 1248_141_0037August 8 201610:00782
U of H-Sugarland C696 12 69648_157_0696September 3 201610:00781 N
Northwest Harris Co. C26/A110/X154 12 2648_201_0029April 23 201611:00782
Lang C408 12 40848_201_0047May 6 201611:00782
Houston Bayland Park C53/A146 12 5348_201_0055April 23 201610:00781
Houston Bayland Park C53/A146 12 5348_201_0055May 13 201610:00781
Houston Westhollow C410 12 41048_201_0066June 8 201610:00781
Cleburne Airport C77/C682 4 7748_251_0003August 31 201611:00781
UH WG Jones Forest C698 12 69848_339_0698July 22 201612:00781 N
Skyline Park C72 6 7248_141_0058June 23 201610:00771
U of H-Sugarland C696 12 69648_157_0696September 21 201610:00771 N
UH WG Jones Forest C698 12 69848_339_0698April 27 201612:00771 N
Grapevine Fairway C70/A301/X182 4 7048_439_3009June 20 201611:00771
Frisco C31/C680 4 3148_085_0005June 30 201610:00761
Frisco C31/C680 4 3148_085_0005July 1 201609:00761
Denton Airport South C56/A163/X157 4 5648_121_0034June 30 201611:00761
Ascarate Park SE C37/A332/A172/X159 6 3748_141_0055August 8 201610:00761
UH WG Jones Forest C698 12 69848_339_0698August 4 201611:00761 N
Grapevine Fairway C70/A301/X182 4 7048_439_3009June 30 201610:00761
Denton Airport South C56/A163/X157 4 5648_121_0034June 9 201609:00751
Pilot Point C1032 4 103248_121_1032June 9 201610:00751
Pilot Point C1032 4 103248_121_1032July 1 201610:00751
Galveston 99th St. C1034/A320/X183 12 103448_167_1034June 8 201612:00751
Houston Aldine C8/AF108/X150 12 848_201_0024April 27 201611:00752
Houston Texas Avenue C411 12 41148_201_0075May 6 201610:00751
Conroe Relocated C78/A321 12 7848_339_0078April 5 201611:00751
Conroe Relocated C78/A321 12 7848_339_0078April 27 201611:00751
Grapevine Fairway C70/A301/X182 4 7048_439_3009September 21 201611:00751
Galveston 99th St. C1034/A320/X183 12 103448_167_1034April 7 201611:00741
Houston Aldine C8/AF108/X150 12 848_201_0024April 23 201611:00742
Lang C408 12 40848_201_0047July 21 201610:00742
Houston Croquet C409 12 40948_201_0051September 21 201610:00742
UH Moody Tower C695 12 69548_201_0695May 6 201610:00741 N
SETRPC 40 Sabine Pass C640/C1654 10 64048_245_0101April 4 201611:00741
UH WG Jones Forest C698 12 69848_339_0698March 26 201612:00741 N
UH WG Jones Forest C698 12 69848_339_0698April 5 201611:00741 N
San Antonio Northwest C23 13 2348_029_0032May 5 201611:00732
Frisco C31/C680 4 3148_085_0005August 5 201611:00731
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069September 11 201612:00733
Denton Airport South C56/A163/X157 4 5648_121_0034June 10 201610:00731
Pilot Point C1032 4 103248_121_1032September 22 201610:00731
Houston Aldine C8/AF108/X150 12 848_201_0024April 3 201611:00732
Houston Westhollow C410 12 41048_201_0066May 13 201610:00731
SETRPC 40 Sabine Pass C640/C1654 10 64048_245_0101April 7 201612:00731
UH WG Jones Forest C698 12 69848_339_0698August 3 201613:00731 N
Ft. Worth Northwest C13/AH302 4 1348_439_1002July 26 201610:00732
Denton Airport South C56/A163/X157 4 5648_121_0034June 20 201612:00721
Denton Airport South C56/A163/X157 4 5648_121_0034September 22 201610:00721
El Paso UTEP C12/A125/X151 6 1248_141_0037June 6 201611:00722
Ascarate Park SE C37/A332/A172/X159 6 3748_141_0055July 16 201610:00721
Houston Aldine C8/AF108/X150 12 848_201_0024July 21 201610:00722
Houston Croquet C409 12 40948_201_0051June 8 201610:00722
Houston Bayland Park C53/A146 12 5348_201_0055September 21 201609:00721
Sheldon C551 12 55148_201_0551April 3 201610:00721 N
Holly Road C660 14 66048_355_0660September 2 201611:00721 N
Eagle Mountain Lake C75 4 7548_439_0075June 7 201612:00721
Keller C17 4 1748_439_2003June 29 201611:00722
Keller C17 4 1748_439_2003July 26 201610:00722
Grapevine Fairway C70/A301/X182 4 7048_439_3009September 20 201610:00721
San Antonio Northwest C23 13 2348_029_0032May 6 201610:00712
Dallas Hinton St. C401/C60/AH161 4 40148_113_0069June 20 201611:00713
Pilot Point C1032 4 103248_121_1032August 5 201612:00711
El Paso UTEP C12/A125/X151 6 1248_141_0037July 16 201611:00712
Galveston 99th St. C1034/A320/X183 12 103448_167_1034April 14 201611:00711
Galveston 99th St. C1034/A320/X183 12 103448_167_1034May 7 201617:00711
Houston Aldine C8/AF108/X150 12 848_201_0024May 7 201609:00712
Crosby Library C553 12 55348_201_0553April 3 201613:00711 N
West Houston C554 12 55448_201_0554June 8 201610:00711 N
Bunker Hill Village C562 12 56248_201_0562April 23 201611:00711 N
Houston East C1/G316 12 148_201_1034May 6 201611:00712
Conroe Relocated C78/A321 12 7848_339_0078August 4 201611:00711
Tyler Airport Relocated C82 5 8248_423_0007June 30 201611:00711
Grapevine Fairway C70/A301/X182 4 7048_439_3009July 1 201610:00711
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

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.