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Eight-Hour Ozone High Value Days for 2019
as of June 18

The table below lists the daily maximum eight-hour ozone concentrations measured which meet or exceed 71 parts per billion in 2019 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.

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YearSort ByReport Format
Highlight with AQI colors
2019 Sorted by Maximum Value
LocationRegionCAMSAQSDateTimeValuePOC
UH Moody Tower C695 12 69548_201_0695June 9 201909:00931 N
Clinton C403/C304/AH113 12 40348_201_1035June 9 201909:00923
Houston Bayland Park C53/A146 12 5348_201_0055June 12 201911:00911
Tom Bass C558 12 55848_201_0558June 12 201912:00911 N
Manvel Croix Park C84 12 8448_039_1004June 12 201911:00901
Lang C408 12 40848_201_0047June 9 201909:00882
Park Place C416 12 41648_201_0416June 9 201909:00881
Houston East C1/G316 12 148_201_1034June 9 201909:00882
HRM-3 Haden Road C603/A114 12 60348_201_0803June 9 201909:00861 N
SETRPC 40 Sabine Pass C640/C1654 10 64048_245_0101June 12 201911:00851
Houston Croquet C409 12 40948_201_0051June 12 201911:00842
Texas City 34th St. C620 12 62048_167_0056June 12 201913:00831 N
Houston Croquet C409 12 40948_201_0051June 11 201909:00832
Houston Bayland Park C53/A146 12 5348_201_0055June 9 201909:00831
UH Moody Tower C695 12 69548_201_0695June 12 201911:00831 N
Conroe Relocated C78/A321 12 7848_339_0078June 14 201910:00831
UH WG Jones Forest C698 12 69848_339_0698June 14 201910:00831 N
Park Place C416 12 41648_201_0416June 12 201911:00821
Galveston 99th St. C1034/A320/X183 12 103448_167_1034June 8 201915:00811
Galveston 99th St. C1034/A320/X183 12 103448_167_1034June 13 201917:00811
Houston Aldine C8/AF108/X150 12 848_201_0024June 1 201911:00812
Houston Aldine C8/AF108/X150 12 848_201_0024June 17 201912:00812
Houston Monroe C406 12 40648_201_0062June 12 201911:00811
Manvel Croix Park C84 12 8448_039_1004June 11 201910:00801
Pilot Point C1032 4 103248_121_1032May 14 201911:00801
Houston Bayland Park C53/A146 12 5348_201_0055May 13 201911:00801
Houston Bayland Park C53/A146 12 5348_201_0055June 13 201911:00801
Tom Bass C558 12 55848_201_0558June 13 201910:00801 N
Tyler Airport Relocated C82 5 8248_423_0007April 9 201911:00801
Manvel Croix Park C84 12 8448_039_1004June 13 201910:00791
Galveston 99th St. C1034/A320/X183 12 103448_167_1034March 22 201913:00791
Tom Bass C558 12 55848_201_0558June 11 201910:00791 N
SETRPC Port Arthur C628 10 62848_245_0628June 12 201911:00791 N
San Antonio Northwest C23 13 2348_029_0032June 13 201911:00782
Frisco C31/C680 4 3148_085_0005May 31 201913:00781
Houston Bayland Park C53/A146 12 5348_201_0055June 11 201910:00781
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039June 12 201910:00781
Conroe Relocated C78/A321 12 7848_339_0078March 22 201911:00781
Texas City 34th St. C620 12 62048_167_0056June 13 201919:00771 N
Northwest Harris Co. C26/A110/X154 12 2648_201_0029March 27 201911:00772
Houston Westhollow C410 12 41048_201_0066May 13 201911:00771
UH Moody Tower C695 12 69548_201_0695March 20 201911:00771 N
UH Moody Tower C695 12 69548_201_0695June 17 201914:00771 N
Lynchburg Ferry C1015/A165 12 101548_201_1015June 17 201913:00771
Clinton C403/C304/AH113 12 40348_201_1035March 20 201910:00773
UH WG Jones Forest C698 12 69848_339_0698March 22 201911:00771 N
San Antonio Northwest C23 13 2348_029_0032June 8 201911:00762
Frisco C31/C680 4 3148_085_0005June 18 201911:00761
Channelview C15/AH115 12 1548_201_0026June 17 201913:00763
Northwest Harris Co. C26/A110/X154 12 2648_201_0029May 15 201911:00762
Houston Bayland Park C53/A146 12 5348_201_0055April 26 201912:00761
Houston Westhollow C410 12 41048_201_0066June 9 201909:00761
Wallisville Road C617 12 61748_201_0617June 17 201913:00761 N
Baytown Garth C1017 12 101748_201_1017June 17 201913:00761
Houston East C1/G316 12 148_201_1034June 17 201913:00762
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039April 9 201912:00761
Cleburne Airport C77/C682 4 7748_251_0003June 14 201911:00761
Arlington Municipal Airport C61 4 6148_439_3011June 17 201913:00761
Manvel Croix Park C84 12 8448_039_1004April 26 201911:00751
Frisco C31/C680 4 3148_085_0005May 14 201911:00751
Lang C408 12 40848_201_0047June 17 201913:00752
Houston Croquet C409 12 40948_201_0051June 13 201910:00752
UH Moody Tower C695 12 69548_201_0695April 9 201911:00751 N
UH Moody Tower C695 12 69548_201_0695June 13 201910:00751 N
HRM-3 Haden Road C603/A114 12 60348_201_0803June 17 201913:00751 N
SETRPC 43 Jefferson Co Airport C643 10 64348_245_0102June 12 201910:00751
Conroe Relocated C78/A321 12 7848_339_0078April 21 201910:00751
Dallas Executive Airport C402 4 40248_113_0087June 17 201912:00741
Texas City 34th St. C620 12 62048_167_0056June 9 201910:00741 N
Longview C19/A127/C644 5 1948_183_0001April 9 201911:00742
Houston Aldine C8/AF108/X150 12 848_201_0024April 9 201911:00742
Houston North Wayside C405 12 40548_201_0046June 9 201909:00741
Lang C408 12 40848_201_0047June 12 201910:00742
Tom Bass C558 12 55848_201_0558April 26 201911:00741 N
Katy Park C559 12 55948_201_0559May 14 201910:00741 N
Wallisville Road C617 12 61748_201_0617April 9 201911:00741 N
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039June 9 201909:00741
SETRPC 43 Jefferson Co Airport C643 10 64348_245_0102March 22 201911:00741
Conroe Relocated C78/A321 12 7848_339_0078April 27 201910:00741
Oyster Creek C1607 12 160748_039_1607March 22 201910:00731 N
Dallas North No.2 C63/C679 4 6348_113_0075May 31 201913:00731
Pilot Point C1032 4 103248_121_1032May 16 201910:00731
Texas City 34th St. C620 12 62048_167_0056June 8 201910:00731 N
Galveston 99th St. C1034/A320/X183 12 103448_167_1034June 9 201911:00731
Galveston 99th St. C1034/A320/X183 12 103448_167_1034June 12 201912:00731
Houston Aldine C8/AF108/X150 12 848_201_0024March 27 201910:00732
Channelview C15/AH115 12 1548_201_0026April 9 201911:00733
Tom Bass C558 12 55848_201_0558June 9 201912:00731 N
Baytown Garth C1017 12 101748_201_1017April 9 201911:00731
Clinton C403/C304/AH113 12 40348_201_1035June 12 201910:00733
Hou.DeerPrk2 C35/235/1001/AFH139FP239 12 3548_201_1039March 20 201912:00731
Cleburne Airport C77/C682 4 7748_251_0003May 19 201911:00731
Cleburne Airport C77/C682 4 7748_251_0003June 13 201911:00731
Killeen Skylark Field C1047 9 104748_027_1047April 9 201911:00721
Government Canyon C1610 13 161048_029_1610June 8 201911:00721 N
Danciger C618 12 61848_039_0618June 13 201910:00721 N
Pilot Point C1032 4 103248_121_1032May 15 201910:00721
Texas City 34th St. C620 12 62048_167_0056April 9 201910:00721 N
Texas City 34th St. C620 12 62048_167_0056June 11 201910:00721 N
Galveston 99th St. C1034/A320/X183 12 103448_167_1034June 11 201911:00721
Houston Aldine C8/AF108/X150 12 848_201_0024June 3 201911:00722
Houston Aldine C8/AF108/X150 12 848_201_0024June 9 201908:00722
Northwest Harris Co. C26/A110/X154 12 2648_201_0029March 22 201910:00722
Park Place C416 12 41648_201_0416April 9 201911:00721
Park Place C416 12 41648_201_0416June 13 201910:00721
UH Moody Tower C695 12 69548_201_0695April 26 201912:00721 N
UH Moody Tower C695 12 69548_201_0695May 13 201910:00721 N
HRM-3 Haden Road C603/A114 12 60348_201_0803March 20 201910:00721 N
SETRPC 40 Sabine Pass C640/C1654 10 64048_245_0101June 13 201911:00721
Cleburne Airport C77/C682 4 7748_251_0003June 8 201912:00721
Conroe Relocated C78/A321 12 7848_339_0078April 15 201911:00721
UH WG Jones Forest C698 12 69848_339_0698April 27 201910:00721 N
Killeen Skylark Field C1047 9 104748_027_1047June 14 201909:00711
Government Canyon C1610 13 161048_029_1610June 13 201911:00711 N
Manvel Croix Park C84 12 8448_039_1004March 20 201911:00711
Oyster Creek C1607 12 160748_039_1607April 26 201911:00711 N
Frisco C31/C680 4 3148_085_0005May 15 201910:00711
Pilot Point C1032 4 103248_121_1032June 18 201911:00711
Texas City 34th St. C620 12 62048_167_0056March 21 201911:00711 N
Houston Aldine C8/AF108/X150 12 848_201_0024March 22 201910:00712
Houston Aldine C8/AF108/X150 12 848_201_0024June 14 201909:00712
Channelview C15/AH115 12 1548_201_0026June 1 201912:00713
Houston Monroe C406 12 40648_201_0062June 13 201910:00711
Houston Westhollow C410 12 41048_201_0066June 11 201910:00711
Katy Park C559 12 55948_201_0559June 9 201909:00711 N
HRM-3 Haden Road C603/A114 12 60348_201_0803April 9 201911:00711 N
Port Arthur West C28/A128/A228 10 2848_245_0011June 12 201911:00711
UH WG Jones Forest C698 12 69848_339_0698April 9 201911:00711 N
UH WG Jones Forest C698 12 69848_339_0698June 3 201911:00711 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.