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Four Highest Eight-Hour Ozone Concentrations in 2026
as of March 12

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 202/28/202611005901/29/202615005402/17/202612004902/24/2026080048
Keller C17202/28/202611006301/29/202615005202/17/202612005102/27/2026110048
Frisco C31/C680102/28/202611006101/29/202614005802/24/202611005301/28/2026100053
Denton Airport South C56/A163/X157102/28/202611006501/28/202611006001/29/202614005702/27/2026110053
Arlington Municipal Airport C61102/28/202611006101/29/202616005302/24/202611005202/27/2026110051
Dallas North No.2 C63/C679102/28/202611005901/29/202614005502/24/202611005302/27/2026110051
Rockwall Heath C69102/28/202611005402/24/202612005101/29/202616005102/27/2026100049
Grapevine Fairway C70/A301/X182102/28/202610005801/29/202614005402/27/202611005002/24/2026100049
Kaufman C71/A304/X071102/28/202610005802/24/202611005701/29/202615005402/27/2026100053
Granbury C73/C681102/28/202611006002/27/202611005001/29/202613004902/26/2026130047
Eagle Mountain Lake C75 102/28/202611006501/29/202614005701/28/202612005502/17/2026130053
Parker County C76102/28/202611005901/29/202614005202/27/202611005101/28/2026120051
Cleburne Airport C77/C682102/28/202610005702/17/202612005102/27/202610005001/29/2026120050
Dallas Executive Airport C402102/28/202610006102/24/202612005601/29/202615005402/27/2026100051
Greenville C1006/A198101/29/202614005702/24/202612005501/28/202610005302/28/2026100052
Pilot Point C1032102/28/202611006501/28/202611006401/29/202614006002/24/2026110053
Italy102/28/202610006102/27/202610005202/26/202611004803/02/2026100046
Corsicana Airport C1051102/28/202611005902/27/202612005503/01/202614005402/24/2026100054
Tyler-Longview-Marshall
Longview C19/A127/C644201/29/202619005703/01/202611005402/28/202611005402/27/2026110052
Tyler Airport Relocated C82102/24/202611005701/29/202613005602/28/202611005402/17/2026130053
Karnack C85/AFHP303102/24/202613006602/28/202611005502/25/202611005303/01/2026120052
El Paso-Juarez
Ascarate Park SE C37/A332/A172/X159102/20/202612004602/22/202610004502/21/202609004503/08/2026100044
Chamizal C41/AH126 102/21/202608004703/08/202610004502/20/202611004501/30/2026100044
Socorro Hueco C49/F312103/08/202610004602/05/202610004603/12/202609004403/09/2026100044
Skyline Park C72102/05/202610004803/12/202609004703/05/202609004603/10/2026100045
Ivanhoe C414/F514102/26/202610004302/21/202610004302/20/202610004303/06/2026090042
Ojo De Agua C1021/FG121/FG221103/12/202609004703/05/202609004402/21/202612004402/04/2026090044
Waco
Waco Mazanec C1037102/28/202610005902/12/202613005602/24/202611005302/27/2026110052
Temple Georgia C1045102/28/202612005502/27/202610005302/24/202610005302/07/2026110052
Killeen Skylark Field C1047102/28/202612006002/27/202610005502/24/202610005502/16/2026120053
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 202/08/202609005202/24/202610005102/27/202610004903/01/2026100047
West Orange C9/A141202/24/202610005402/08/202610005303/01/202610004902/10/2026100049
Port Arthur West C28/A128/A228102/08/202609005402/27/202610005302/24/202609005302/12/2026130053
Hamshire C64/C654102/24/202610005502/27/202611005402/12/202613005203/01/2026100050
SETRPC Port Arthur C6281 N02/08/202610005301/30/202609005101/29/202610005102/12/2026130050
SETRPC 40 Sabine Pass C640/C1654102/27/202611006402/24/202610006102/10/202609005802/08/2026100057
SETRPC Mauriceville 42 C642/C311/C6651 N02/08/202610005901/29/202610005201/19/202611005202/10/2026100051
SETRPC 43 Jefferson Co Airport C643102/24/202610005202/08/202609005202/27/202611005002/12/2026130048
Nederland 17th Street C1035102/08/202610005402/27/202610005102/12/202613005101/30/2026090049
Austin
Austin North Hills Drive C3/A322202/28/202611005402/27/202610005402/26/202612005202/25/2026120052
Audubon C38102/28/202611005702/27/202610005602/26/202611005302/07/2026120052
Dripping Springs School C6141 N02/28/202611005302/27/202611005303/12/202609004403/11/2026110043
CAPCOG Lake Georgetown C6901 N02/28/202612005602/27/202610005302/24/202611005102/26/2026110049
Lockhart C16041 N02/28/202611004702/27/202611004702/26/202612004603/12/2026090043
St. Edwards University C16051 N02/28/202611005202/26/202612004702/22/202612004503/12/2026090044
CAPCOG Bastrop CAMS16121 N02/28/202612004902/27/202610004602/26/202612004503/01/2026140041
CAPCOG Elgin C16131 N02/28/202612004902/27/202610004802/26/202612004303/12/2026090042
CAPCOG East Austin C16191 N02/28/202611005903/02/202611004903/01/202611004603/03/2026100038
CAPCOG Round Rock Brushy Creek W C16201 N02/28/202612005102/27/202610004802/24/202611004602/25/2026110045
CAPCOG Lake Kyle Park C16301 N02/28/202611004601/19/202611004003/12/202609003903/02/2026120037
CAPCOG San Marcos Staples Road C16751 N02/28/202611005002/27/202611004803/11/202611004203/12/2026090040
Houston-Galveston-Brazoria
Houston East C1/G316202/24/202610005103/01/202610005002/28/202611004802/12/2026120048
Houston Aldine C8/AF108/X150 202/28/202611005602/12/202612005603/01/202610005502/24/2026100054
Channelview C15/AH115 302/21/202614005102/27/202611004902/22/202609004903/01/2026100048
Northwest Harris Co. C26/A110/X154202/07/202611006102/28/202611005602/24/202610005403/01/2026100053
Hou.DeerPrk2 C35/235/1001/AFH139/FP239102/12/202611006102/27/202610005802/24/202609005502/07/2026110055
Seabrook Friendship Park C45102/24/202609005202/12/202610005202/07/202611004702/27/2026120045
Houston Bayland Park C53/A146 102/07/202612005702/12/202612005502/27/202611005402/24/2026090051
Conroe Relocated C78/A321102/28/202610006703/01/202611005502/07/202612005502/24/2026110053
Manvel Croix Park C84102/27/202611005902/07/202612005602/12/202611005403/01/2026100053
Clinton C403/C304/AH113 303/01/202610004602/27/202611004602/24/202610004302/12/2026110043
Houston North Wayside C405/C1033103/01/202609004802/07/202611004702/28/202611004602/12/2026110045
Houston Monroe C406102/12/202611005102/07/202611005102/24/202610005002/27/2026100046
Lang C408202/07/202611005502/12/202612005202/28/202611005102/24/2026100051
Houston Croquet C409202/07/202611005802/27/202611005602/12/202611005603/01/2026100052
Houston Westhollow C410/C3003102/07/202612006102/27/202611005502/12/202611005502/24/2026100052
Park Place C416102/12/202612005102/07/202611005002/24/202610004903/01/2026090048
Houston Harvard Street C417102/12/202612005502/07/202612005502/24/202610005203/01/2026100051
Sheldon C5511 N01/30/202601004301/17/202612004101/01/202611004101/16/2026220040
Baytown Wetlands Center C5521 N01/19/202612004701/20/202610004401/01/202609004301/17/2026100042
Crosby Library C5531 N02/07/202611004701/30/202602004601/29/202610004602/12/2026130045
West Houston C5541 N02/07/202612006303/01/202611005302/24/202610005302/12/2026120053
La Porte Sylvan Beach C5561 N02/24/202610005102/12/202613004902/07/202613004803/01/2026110044
Mercer Arboretum C5571 N03/12/202609004303/11/202621003203/05/202609003203/10/2026090027
Tom Bass C5581 N02/07/202612006002/27/202612005902/24/202610005702/12/2026120057
Katy Park C5591 N02/07/202613005701/29/202610004201/01/202610004102/06/2026100040
Atascocita C5601 N02/28/202610005302/07/202613004903/01/202610004702/12/2026120043
Meyer Park C5611 N02/28/202611005703/01/202610005502/07/202611005402/24/2026100052
Bunker Hill Village C5621 N02/07/202612005802/27/202611005302/24/202610005202/12/2026120052
Huffman Wolf Road C5631 N02/28/202610005902/24/202610005702/27/202611005001/29/2026110050
HRM-3 Haden Road C603/A114 1 N02/12/202612005102/07/202611005101/29/202609004702/08/2026110046
Wallisville Road C617 1 N02/12/202611005802/07/202611005201/29/202610005002/08/2026110049
Texas City 34th St. C620 1 N02/07/202611005602/12/202612005301/19/202610005302/06/2026100051
Lynchburg Ferry C1015/A165 102/24/202609005703/01/202610004802/12/202612004802/10/2026100046
Lake Jackson C1016 102/07/202612006902/06/202611005402/24/202609005202/21/2026130050
Baytown Garth C1017102/12/202611005802/28/202610005302/24/202610005303/01/2026100050
Galveston 99th St. C1034/A320/X183102/24/202609005502/07/202611005503/01/202610005402/06/2026130053
Oyster Creek C1607 1 N02/07/202611006802/24/202609005502/06/202612005402/12/2026100053
San Antonio
San Antonio Northwest C23202/07/202611005802/26/202613005702/27/202610005302/16/2026110050
Camp Bullis C58 102/07/202610005802/26/202613005602/27/202610005502/28/2026100051
Calaveras Lake C59102/26/202612006702/07/202611005402/27/202611004902/06/2026100049
Elm Creek Elementary C5011 N02/26/202613005702/27/202611005103/12/202609004802/24/2026100047
Fair Oaks Ranch C5021 N02/27/202611004702/28/202610004603/12/202609004302/16/2026120042
Bulverde Elementary C5031 N02/26/202612005802/27/202610005602/28/202610005402/24/2026100053
New Braunfels Airport C5041 N02/26/202612005902/28/202610005502/27/202610005302/24/2026110051
AACOG City of Garden Ridge C505 1 N02/26/202613006202/27/202611005602/28/202611005302/25/2026110052
Seguin Outdoor Learning Center C5061 N02/26/202612005802/28/202611005602/27/202611005502/24/2026100052
Heritage Middle School C6221 N02/26/202612006702/07/202611006002/06/202611005302/27/2026110049
CPS Pecan Valley C6781 N02/26/202615004602/27/202611004203/12/202609004102/28/2026100038
Corpus Christi-Victoria
Corpus Christi West C4203/11/202612005202/07/202611005202/23/202611005002/21/2026130049
Corpus Christi Tuloso C21102/07/202611005303/11/202611005102/21/202613005101/30/2026090049
Victoria C87102/07/202611005902/06/202613005802/27/202613005503/11/2026130054
Lower Rio Grande Valley
Mission C43/AP143102/20/202610005702/19/202611005402/06/202611005402/26/2026100052
Harlingen Teege C1023103/11/202611004902/07/202611004901/30/202610004802/16/2026100047
Laredo
Laredo College C441 N02/16/202611005502/25/202610005301/06/202611005302/20/2026110052
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.