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Four Highest Eight-Hour Ozone Concentrations in 2026
as of September 15

Use this form to retrieve the four highest eight-hour ozone concentration averages from data collected at TCEQ monitoring sites beginning December 14, 2005 through today. Although this is our most current data, it is not considered official until it has been certified by our technical staff. This information is updated hourly. All times shown are in Local Standard Time.

The table below lists the four highest daily maximum eight-hour ozone concentrations measured in 2026 in each community where the TCEQ measures ozone. Concentrations that are rated Moderate or higher are color-highlighted based on the EPA-defined Air Quality Index colors. (See Interpreting the AQI.) The fourth-highest average is in bold black (unless it is highlighted). All ozone measurements are in parts per billion. Times are shown in 24-hour format and correspond to the beginning of the eight hour average.

Use the selection boxes below to customize this report. You may select a different year or a different report format. If you want to cut and paste data from this web page into another application, such as a spreadsheet, select the comma-delimited format. Click on the Generate Report button once you have made your selections.

YearReport Format
Highlight with AQI colors
Area Monitoring Site POC Highest Second Highest Third Highest Fourth Highest
Date Time Value Date Time Value Date Time Value Date Time Value
Dallas-Fort Worth
Ft. Worth Northwest C13/AH302 208/28/202610008408/03/202610007905/14/202611007805/13/2026100078
Keller C17208/28/202610007708/03/202611007705/13/202611007605/14/2026110073
Frisco C31/C680105/13/202611008608/03/202611008405/29/202611008405/14/2026100081
Denton Airport South C56/A163/X157108/03/202612009305/13/202611008805/14/202610008005/12/2026120079
Arlington Municipal Airport C61108/26/202611008908/27/202609008107/22/202609007605/14/2026120075
Dallas North No.2 C63/C679108/26/202610007905/13/202611007908/03/202611007808/17/2026110074
Rockwall Heath C69108/26/202611009208/17/202611007605/14/202611007107/07/2026100066
Grapevine Fairway C70/A301/X182108/03/202611009005/13/202611008208/17/202612007908/26/2026090077
Kaufman C71/A304/X071108/26/202613007905/14/202611007507/21/202611006405/13/2026110064
Granbury C73/C681105/14/202613007808/27/202609007007/22/202612006908/28/2026090066
Eagle Mountain Lake C75 108/21/202612007808/28/202610007608/03/202611007505/14/2026100075
Parker County C76108/21/202613008208/28/202612008107/23/202609007405/14/2026140074
Cleburne Airport C77/C682108/27/202609008007/22/202610007608/02/202611007305/14/2026130072
Dallas Executive Airport C402108/26/202612008705/14/202612007707/21/202611007608/27/2026090073
Greenville C1006/A198108/26/202610008105/14/202611007205/29/202610006905/13/2026100065
Pilot Point C1032105/13/202611008608/03/202611008305/14/202610008308/18/2026110080
Italy105/14/202612007708/27/202609007608/02/202612006808/01/2026110068
Corsicana Airport C1051108/27/202610007308/03/202611006708/01/202611006205/28/2026100062
Tyler-Longview-Marshall
Longview C19/A127/C644205/13/202610007108/27/202611006805/12/202611006708/31/2026090064
Tyler Airport Relocated C82105/13/202611007008/27/202610006303/13/202615006305/12/2026100062
Karnack C85/AFHP303105/14/202611006602/24/202613006608/30/202610006305/13/2026100061
El Paso-Juarez
Ascarate Park SE C37/A332/A172/X159105/12/202611007607/24/202610007206/20/202610006906/04/2026100068
Chamizal C41/AH126 106/20/202609006706/13/202611006708/02/202610006305/08/2026100063
Socorro Hueco C49/F312106/13/202612008105/12/202611007004/08/202610006909/10/2026110067
Skyline Park C72105/12/202611007707/24/202612007408/19/202611007208/03/2026110070
Ivanhoe C414/F514106/13/202612007108/19/202611006806/20/202610006807/24/2026110065
Ojo De Agua C1021/FG121/FG221107/24/202614007207/09/202610006608/10/202612006508/02/2026110064
Waco
Waco Mazanec C1037105/14/202610007308/01/202611006805/28/202610006805/13/2026100064
Temple Georgia C1045108/27/202612008205/14/202611007608/28/202610007105/13/2026100071
Killeen Skylark Field C1047108/27/202613008205/14/202610008208/28/202610007005/13/2026110070
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 205/14/202610006908/29/202610006605/29/202607006005/03/2026100060
West Orange C9/A141205/14/202611007608/03/202610006605/29/202608006308/30/2026100057
Port Arthur West C28/A128/A228105/14/202609006905/28/202617006305/13/202612006308/29/2026100059
Hamshire C64/C654105/14/202609007308/26/202610007005/03/202610006005/04/2026080056
SETRPC Port Arthur C6281 N08/29/202611007005/14/202609006608/30/202603006505/28/2026160064
SETRPC 40 Sabine Pass C640/C1654105/28/202615008205/14/202609007805/13/202611007708/02/2026110071
SETRPC Mauriceville 42 C642/C311/C6651 N05/14/202610008505/29/202608007305/04/202609007005/03/2026100068
SETRPC 43 Jefferson Co Airport C643105/14/202610006705/13/202612006108/29/202610005805/03/2026100057
Nederland 17th Street C1035105/14/202610006908/29/202610006105/28/202617006005/03/2026090059
Austin
Austin North Hills Drive C3/A322205/13/202611007405/14/202610007208/28/202610007005/28/2026110069
Audubon C38105/14/202610007305/13/202611007305/12/202611006608/03/2026110064
Dripping Springs School C6141 N05/14/202610007705/13/202612007705/12/202612007505/03/2026110074
CAPCOG Lake Georgetown C6901 N05/14/202610007305/13/202611006703/13/202612006708/03/2026090064
Lockhart C16041 N05/14/202610007405/13/202611007105/03/202611007103/13/2026110069
St. Edwards University C16051 N08/28/202610007505/13/202611007205/14/202610007008/02/2026110068
CAPCOG Bastrop CAMS16121 N05/14/202610007007/22/202610006808/28/202610006705/13/2026110065
CAPCOG Elgin C16131 N05/14/202610006808/28/202610006605/13/202611006508/03/2026100062
CAPCOG East Austin C16191 N08/28/202610007605/14/202611007105/28/202611007005/13/2026110070
CAPCOG Round Rock Brushy Creek W C16201 N05/14/202610007308/28/202611007105/13/202610006708/03/2026100065
CAPCOG Taylor Murphy Park C16291 N05/14/202610007105/13/202610006608/28/202609006408/27/2026110061
CAPCOG Lake Kyle Park C16301 N05/13/202610006005/12/202611006004/07/202611006009/14/2026040057
CAPCOG San Marcos Staples Road C16751 N05/13/202610006108/02/202612006008/28/202610005707/22/2026110056
Houston-Galveston-Brazoria
Houston East C1/G316208/29/202610008705/13/202611008405/28/202612007905/14/2026090070
Houston Aldine C8/AF108/X150 208/29/202611009305/29/202610008705/13/202611008605/14/2026100078
Channelview C15/AH115 308/29/202610007705/28/202613007408/17/202610007005/14/2026100070
Northwest Harris Co. C26/A110/X154208/29/202611008005/03/202611007705/13/202610007305/14/2026100072
Hou.DeerPrk2 C35/235/1001/AFH139/FP239105/28/202612009505/13/202611008908/29/202610007707/22/2026100070
Seabrook Friendship Park C45105/28/202612008305/13/202611007607/22/202610006408/29/2026100056
Houston Bayland Park C53/A146 105/13/202611009505/12/202611007407/22/202611006905/14/2026090067
Conroe Relocated C78/A321105/29/202612008705/14/202611008608/03/202611007208/17/2026120071
Manvel Croix Park C84105/13/202610009705/28/202611007905/12/202611007708/02/2026110074
Clinton C403/C304/AH113 305/28/202612008105/13/202611008008/29/202611007207/22/2026110064
Houston North Wayside C405/C1033108/29/202611008908/17/202610007105/29/202610006905/28/2026110068
Houston Monroe C406105/13/202610009305/28/202612008607/22/202611007008/02/2026110069
Lang C408205/13/202611008608/29/202611007105/14/202610006905/29/2026100068
Houston Croquet C409205/13/202611009705/12/202611007505/24/202610007105/14/2026090070
Houston Westhollow C410/C3003105/13/202611007805/12/202611006707/22/202611006205/24/2026110062
Park Place C416105/13/202610009105/28/202612008308/29/202611006605/14/2026090064
Houston Harvard Street C417105/13/202611009505/28/202611007908/29/202611007605/29/2026100074
Sheldon C5511 N05/14/202609006905/13/202610006805/29/202609006608/17/2026090064
Baytown Wetlands Center C5521 N05/28/202612007205/13/202610007205/14/202608006308/17/2026090059
Crosby Library C5531 N05/29/202609007505/14/202609007405/13/202610006008/25/2026100057
West Houston C5541 N05/13/202610008205/03/202610006905/14/202609006605/12/2026100066
La Porte Sylvan Beach C5561 N05/28/202611008705/13/202610008105/14/202608005908/29/2026090055
Mercer Arboretum C5571 N05/29/202609009305/14/202609008808/17/202610008005/13/2026100079
Tom Bass C5581 N05/13/202609009505/28/202611007905/12/202609006807/22/2026110066
Katy Park C5591 N05/13/202610005702/07/202613005705/03/202610005305/24/2026100051
Atascocita C5601 N04/07/202610005503/29/202609005503/13/202610005302/28/2026100053
Meyer Park C5611 N05/13/202611007505/14/202609007405/03/202610007208/17/2026110067
Bunker Hill Village C5621 N05/13/202610008805/12/202610006605/03/202610006605/14/2026090064
Huffman Wolf Road C5631 N05/14/202609008605/29/202609008208/17/202609006708/03/2026090067
HRM-3 Haden Road C603/A114 1 N08/28/2026180023808/17/202610008705/28/202612008305/13/2026110082
Wallisville Road C617 1 N05/14/202609007405/29/202609007105/28/202613007005/13/2026130067
Texas City 34th St. C620 1 N05/28/2026110012207/22/202611009405/13/202611008805/14/2026080068
Lynchburg Ferry C1015/A165 105/28/202612007505/13/202611007408/29/202611006905/14/2026090066
Lake Jackson C1016 102/07/202612006905/12/202610006605/13/202608006305/03/2026100059
Baytown Garth C1017105/14/202610007805/29/202609007408/17/202610007305/28/2026130072
Galveston 99th St. C1034/A320/X183105/28/2026120010905/13/202611008408/02/202611006405/27/2026030062
Oyster Creek C1607 1 N02/07/202611006805/28/202612006705/13/202609006205/12/2026110062
San Antonio
San Antonio Northwest C23205/13/202612007607/22/202610006708/03/202610006605/12/2026120066
Camp Bullis C58 105/13/202611008105/28/202611007308/03/202611006705/03/2026100066
Calaveras Lake C59108/02/202611007202/26/202612006705/13/202612006505/12/2026110060
Elm Creek Elementary C5011 N05/12/202611007107/23/202610007005/13/202611006505/03/2026110062
Fair Oaks Ranch C5021 N05/28/202611007105/13/202611007108/28/202611006708/03/2026110063
Bulverde Elementary C5031 N05/13/202611007103/13/202610006105/28/202611005805/14/2026100058
New Braunfels Airport C5041 N05/13/202610006608/02/202611006003/13/202610006005/03/2026110059
AACOG City of Garden Ridge C505 1 N05/13/202611007105/28/202611006807/22/202612006408/02/2026110062
Seguin Outdoor Learning Center C5061 N05/13/202611006705/03/202611006404/07/202611006303/13/2026100061
Heritage Middle School C6221 N05/13/202611007008/02/202612006705/12/202611006702/26/2026120067
CPS Pecan Valley C6781 N06/18/2026110010406/19/202601006008/02/202611005405/13/2026110052
Government Canyon C16101 N04/07/202611006508/03/202610006105/13/202611006107/22/2026100060
Corpus Christi-Victoria
Corpus Christi West C4205/13/202610006705/12/202611005605/03/202609005504/06/2026120055
Corpus Christi Tuloso C21105/13/202610007105/12/202612005705/03/202610005602/07/2026110053
Victoria C87105/13/202610007505/03/202610006402/07/202611005905/28/2026110058
Lower Rio Grande Valley
Mission C43/AP143105/13/202611006305/12/202610005802/20/202610005705/03/2026080055
Harlingen Teege C1023105/11/202610005403/17/202612005105/03/202608005003/13/2026100050
Laredo
Laredo College C441 N05/13/202611006405/12/202611006205/03/202609005905/27/2026090058
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.