Skip to main content

Four Highest Eight-Hour Ozone Concentrations in 2023
as of March 26

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 2023 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 203/05/202310005403/15/202314005103/25/202310004903/04/2023100048
Keller C17203/15/202315005003/05/202311005003/04/202311004702/28/2023110046
Frisco C31/C680103/06/202311005603/04/202312005603/05/202311005403/15/2023160051
Denton Airport South C56/A163/X157103/05/202310005603/06/202311005403/04/202311005303/15/2023110051
Arlington Municipal Airport C61103/05/202311005103/04/202312005103/15/202314004903/25/2023110048
Dallas North No.2 C63/C679103/04/202312005203/05/202310004903/25/202310004803/15/2023160048
Rockwall Heath C69103/04/202311004703/19/202310004503/15/202316004503/05/2023100045
Grapevine Fairway C70/A301/X182103/04/202312005103/05/202309005003/06/202310004803/25/2023100045
Kaufman C71/A304/X071103/05/202311005503/04/202311005402/28/202311005403/26/2023080052
Granbury C73/C681103/15/202313005303/05/202310005103/04/202310005003/25/2023100047
Eagle Mountain Lake C75 103/05/202311005403/04/202310005203/15/202313005102/28/2023110051
Parker County C76103/15/202313005302/27/202315005302/28/202309005103/05/2023100049
Cleburne Airport C77/C682103/15/202313005303/05/202311005203/04/202312005103/25/2023100047
Dallas Hinton St. C401/C60/AH161 303/04/202312005103/05/202310004803/15/202316004603/25/2023110045
Dallas Executive Airport C402103/25/202310004903/26/202308004602/05/202311004301/27/2023100043
Greenville C1006/A198103/25/202310005703/05/202310005603/06/202309005103/04/2023110051
Pilot Point C1032103/06/202312005503/05/202310005403/04/202311005403/15/2023110049
Italy C1044/A323103/04/202311005503/15/202313005302/28/202311005203/05/2023100050
Corsicana Airport C1051102/28/202311005503/26/202308005203/04/202311005203/15/2023140051
Tyler-Longview-Marshall
Longview C19/A127/C644203/05/202311005303/25/202311005202/28/202311005203/26/2023080048
Tyler Airport Relocated C82102/28/202311006803/05/202311005903/26/202308005403/25/2023100053
Karnack C85/AFHP303102/28/202310005703/05/202311005302/13/202310005102/27/2023100048
El Paso-Juarez
Ascarate Park SE C37/A332/A172/X159102/26/202315004602/15/202314004403/23/202315004303/18/2023120043
Chamizal C41/AH126 103/24/202310005202/26/202318005203/23/202315005103/05/2023090051
Socorro Hueco C49/F312103/25/202310004903/24/202309004903/05/202310004902/26/2023150048
Skyline Park C72102/26/202315005902/28/202310005802/27/202310005803/02/2023070057
Ivanhoe C414/F514103/14/202310004503/25/202310004303/05/202309004302/26/2023170043
Ojo De Agua C1021/FG121/FG221102/26/202315004802/27/202311004703/18/202313004603/05/2023090046
Waco
Waco Mazanec C1037103/04/202311006202/28/202311005903/15/202312005503/05/2023100054
Temple Georgia C1045103/04/202311006402/27/202310006202/28/202311005803/15/2023110053
Killeen Skylark Field C1047102/27/202310006803/04/202311005902/28/202310005803/05/2023100055
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 203/25/202311005503/05/202310005203/04/202311005103/15/2023110047
West Orange C9/A141203/25/202311005403/05/202311005403/15/202311005101/06/2023110051
Port Arthur West C28/A128/A228103/25/202311005703/05/202311004801/06/202310004703/04/2023110046
Hamshire C64/C654103/25/202311005403/05/202311005403/04/202310005201/06/2023100051
SETRPC Port Arthur C6281 N03/05/202312005503/15/202311005103/04/202310005101/06/2023110051
SETRPC 40 Sabine Pass C640/C1654103/25/202310005503/05/202311005303/20/202315005003/15/2023110048
SETRPC Mauriceville 42 C642/C311/C6651 N03/05/202310005801/06/202311005603/15/202312005303/04/2023110052
SETRPC 43 Jefferson Co Airport C643103/25/202311005903/04/202311005203/05/202311004903/20/2023120045
Nederland 17th Street C1035103/25/202311006303/04/202311005603/05/202311005301/06/2023110049
Austin
Austin North Hills Drive C3/A322203/04/202311007202/27/202310006703/05/202310005803/03/2023100053
Audubon C38103/04/202311006202/27/202310006102/28/202311005403/05/2023100051
Dripping Springs School C6141 N03/04/202312006203/05/202311004903/25/202310004603/03/2023100045
CAPCOG Lake Georgetown C6901 N02/27/202313006403/04/202311005703/05/202310005102/28/2023100050
Lockhart C16041 N03/04/202310005903/19/202311004903/05/202311004903/25/2023100048
St. Edwards University C16051 N03/04/202311005402/27/202310004903/25/202310004603/19/2023100045
CAPCOG Bastrop CAMS16121 N02/27/202310005803/04/202311005603/25/202310004803/05/2023110048
CAPCOG Elgin C16131 N02/27/202310006203/04/202311005703/25/202311005403/05/2023110049
CAPCOG East Austin C16191 N03/04/202311006602/27/202311006203/25/202311005703/05/2023110055
CAPCOG Round Rock Brushy Creek W C16201 N03/13/202307006803/04/202312006302/27/202310006103/05/2023110053
CAPCOG San Marcos Staples Road C16751 N03/04/202310006103/05/202311005203/25/202310005103/03/2023100051
Houston-Galveston-Brazoria
Houston East C1/G316203/04/202311006703/25/202311006503/05/202310006003/15/2023110051
Houston Aldine C8/AF108/X150 203/04/202311006403/25/202311005503/05/202310005502/27/2023110052
Channelview C15/AH115 303/25/202310006003/04/202310005803/05/202311005403/19/2023110046
Northwest Harris Co. C26/A110/X154203/05/202311007003/04/202312006302/27/202310006103/25/2023100055
Hou.DeerPrk2 C35/235/1001/AFH139FP239103/25/202312006803/05/202311005603/04/202311005602/12/2023110052
Seabrook Friendship Park C45103/25/202311005703/20/202311004603/14/202312004603/03/2023100045
Houston Bayland Park C53/A146 103/25/202311006503/04/202311006503/05/202311005902/27/2023120055
Conroe Relocated C78/A321102/27/202310006403/05/202311006203/04/202311006003/15/2023110057
Manvel Croix Park C84103/25/202311006303/04/202311005903/05/202310005403/15/2023110049
Clinton C403/C304/AH113 303/25/202312006703/04/202311006203/05/202311005903/15/2023110049
Houston North Wayside C405/C1033103/04/202310006203/25/202311005503/05/202310005303/15/2023110042
Houston Monroe C406103/25/202312005803/04/202310005103/05/202310004903/15/2023110045
Lang C408203/04/202311006503/05/202310006103/25/202310005802/27/2023110057
Houston Croquet C409203/25/202312005903/04/202311005903/05/202311005403/15/2023110050
Houston Westhollow C410/C3003103/04/202311005503/25/202310004903/05/202311004902/27/2023100046
Park Place C416103/04/202311006003/05/202310005703/15/202311005002/12/2023120048
Houston Harvard Street C417103/04/202311006803/25/202312006403/05/202311006303/15/2023110052
Sheldon C5511 N03/04/202310006103/25/202310005502/27/202313005403/05/2023110051
Baytown Wetlands Center C5521 N03/25/202310005503/05/202311004803/04/202311004803/20/2023130044
Crosby Library C5531 N03/04/202311005902/27/202312005403/25/202310005303/05/2023110052
West Houston C5541 N03/04/202312006703/05/202311006102/27/202311005803/25/2023090053
La Porte Sylvan Beach C5561 N03/05/202313005203/15/202310004803/20/202311004703/14/2023110045
Mercer Arboretum C5571 N03/04/202311006703/05/202311006202/27/202311005903/25/2023100054
Tom Bass C5581 N03/25/202311006403/04/202311005903/05/202311005503/15/2023100050
Katy Park C5591 N03/04/202312006003/05/202311005502/27/202311005403/15/2023100049
Atascocita C5601 N03/04/202311006202/27/202312004903/25/202310004703/15/2023100045
Meyer Park C5611 N03/05/202311006703/04/202311006702/27/202311006203/15/2023100053
Bunker Hill Village C5621 N03/04/202312006203/05/202311005702/27/202311005102/13/2023110042
Huffman Wolf Road C5631 N03/04/202311005702/27/202312005603/05/202311005303/15/2023100049
HRM-3 Haden Road C603/A114 1 N02/12/202312004902/27/202311004402/13/202310004402/18/2023100042
Wallisville Road C617 1 N02/12/202311005402/13/202311004701/05/202311004701/06/2023100046
Texas City 34th St. C620 1 N03/05/202312006403/04/202311006303/15/202311005903/03/2023100056
UH Moody Tower C6951 N03/25/202313006803/04/202311006003/05/202311005702/27/2023130055
UH WG Jones Forest C6981 N02/27/202313007203/04/202312006703/05/202311006503/15/2023110058
Lynchburg Ferry C1015/A165 103/05/202312005403/25/202311005203/04/202311005003/15/2023100047
Lake Jackson C1016 103/25/202311006603/05/202310006103/04/202311006002/12/2023110053
Baytown Garth C1017103/25/202311006403/05/202311006403/04/202310006002/12/2023120060
Galveston 99th St. C1034/A320/X183103/25/202314006403/05/202316006202/12/202314005703/04/2023110056
Oyster Creek C1607 1 N03/05/202310005803/04/202310005702/12/202312005503/15/2023140051
Liberty Sam Houston Library C16261 N03/05/202310005602/27/202311005403/04/202311005302/13/2023100052
San Antonio
San Antonio Northwest C23203/04/202311006103/05/202310005802/27/202308005403/25/2023110051
Camp Bullis C58 103/04/202310006303/05/202310006002/27/202309005603/25/2023110051
Calaveras Lake C59102/27/202310006503/04/202310006403/03/202311006303/05/2023110056
Elm Creek Elementary C5011 N03/04/202310005702/27/202309005403/25/202311005303/05/2023100051
Fair Oaks Ranch C5021 N03/04/202311005403/05/202309005002/27/202309004802/28/2023120044
Bulverde Elementary C5031 N03/04/202311005203/05/202310004502/27/202309004503/25/2023110041
New Braunfels Airport C5041 N03/04/202310006002/27/202310005703/05/202310005103/03/2023090050
AACOG City of Garden Ridge C505 1 N03/04/202311005902/27/202309005303/05/202311004903/25/2023110047
Seguin Outdoor Learning Center C5061 N03/04/202311005502/27/202311005203/05/202311004703/25/2023120046
Heritage Middle School C6221 N02/27/202311006003/04/202310005703/03/202311005603/25/2023110052
CPS Pecan Valley C6781 N03/04/202310004302/27/202311004203/03/202311003803/05/2023110037
Government Canyon C16101 N03/04/202310005602/27/202307005103/05/202310004803/03/2023100045
Corpus Christi-Victoria
Corpus Christi West C4203/25/202315006403/03/202311005703/04/202311005603/05/2023090052
Corpus Christi Tuloso C21103/25/202315006203/04/202310005803/03/202310005803/05/2023090052
Victoria C87103/04/202311005603/03/202312005203/05/202310005103/25/2023100049
Lower Rio Grande Valley
Harlingen Teege C1023103/04/202310005603/05/202308005303/25/202313005103/03/2023100051
Laredo
Laredo College C441 N03/04/202311005803/25/202311005703/05/202309005402/23/2023110052
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.