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Four Highest Eight-Hour Ozone Concentrations in 2023
as of September 29

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 208/31/202311009208/25/202310009209/02/202311008608/16/2023120084
Keller C17208/31/202311009408/25/202310009009/01/202311008106/07/2023120080
Frisco C31/C680108/18/202311008708/17/202310008709/06/202312008208/31/2023100082
Denton Airport South C56/A163/X157108/01/202310008807/24/202311008605/22/202311008006/09/2023120078
Arlington Municipal Airport C61108/16/202311008408/25/202309008206/07/202310007608/31/2023110074
Dallas North No.2 C63/C679109/06/202312008408/31/202311008308/26/202310008308/25/2023100080
Rockwall Heath C69109/08/202311007006/08/202310006909/07/202311006808/26/2023100067
Grapevine Fairway C70/A301/X182108/31/202311009408/25/202310009008/01/202309008708/24/2023100084
Kaufman C71/A304/X071109/19/202311008006/07/202310007309/03/202310007109/02/2023110071
Granbury C73/C681108/31/202310008309/09/202315007909/01/202311007908/21/2023100079
Eagle Mountain Lake C75 108/31/202312008909/01/202311008509/27/202312008108/25/2023120081
Parker County C76108/21/202310008209/02/202311007909/01/202313007808/25/2023130078
Cleburne Airport C77/C682108/31/202310007808/16/202313007809/02/202311007609/01/2023110075
Dallas Hinton St. C401/C60/AH161 306/07/202311009408/25/202310008208/26/202311008108/31/2023110079
Dallas Executive Airport C402106/07/202311009108/16/202311008108/31/202311007908/25/2023100079
Greenville C1006/A198106/08/202310007609/19/202310007409/08/202311007009/07/2023110069
Pilot Point C1032108/17/202310009608/31/202310008808/18/202311008809/18/2023110081
Italy C1044/A323109/19/202310007409/12/202311007109/01/202310007008/31/2023110070
Corsicana Airport C1051108/25/202310006909/02/202311006809/12/202311006409/03/2023110064
Tyler-Longview-Marshall
Longview C19/A127/C644209/02/202311008608/17/202311007805/23/202310006808/25/2023100067
Tyler Airport Relocated C82105/27/202310007608/21/202311007508/17/202312007206/06/2023100071
Karnack C85/AFHP303109/19/202310006906/09/202310006709/21/202311006508/25/2023090065
El Paso-Juarez
Ascarate Park SE C37/A332/A172/X159108/04/202311007708/03/202311007308/02/202310006908/01/2023110069
Chamizal C41/AH126 108/04/202311007707/04/202311007008/03/202310006908/01/2023110068
Socorro Hueco C49/F312108/03/202309007805/12/202310007308/04/202310007207/19/2023110066
Skyline Park C72108/31/202310007408/04/202310006908/03/202311006908/02/2023080068
Ivanhoe C414/F514108/03/202311007708/04/202310006807/05/202311006708/02/2023090064
Ojo De Agua C1021/FG121/FG221108/04/202312007808/31/202310007508/03/202311007407/04/2023110074
Waco
Waco Mazanec C1037108/30/202310007909/12/202311007709/02/202310007709/19/2023100076
Temple Georgia C1045109/19/202310007909/02/202310007709/01/202311007708/31/2023100076
Killeen Skylark Field C1047109/01/202311008009/19/202308007708/31/202311007709/02/2023110076
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 209/02/202309007107/24/202309007108/17/202309006805/19/2023080068
West Orange C9/A141205/19/202309007106/09/202312006908/17/202310006809/12/2023110065
Port Arthur West C28/A128/A228105/01/202311006705/26/202310006409/01/202309006306/09/2023110063
Hamshire C64/C654109/01/202310006909/18/202309006708/31/202311006708/17/2023090067
SETRPC Port Arthur C6281 N06/09/202310008205/26/202310007305/22/202311007305/23/2023080071
SETRPC 40 Sabine Pass C640/C1654105/23/202310007505/22/202311007409/09/202311006806/09/2023110068
SETRPC Mauriceville 42 C642/C311/C6651 N07/24/202310006606/01/202310006605/04/202309006405/02/2023090064
SETRPC 43 Jefferson Co Airport C643105/01/202311007208/01/202310006709/11/202309006608/16/2023100065
Nederland 17th Street C1035105/01/202310007708/01/202310007209/02/202308007008/16/2023100070
Austin
Austin North Hills Drive C3/A322209/02/202310007609/01/202311007608/28/202313007509/19/2023100074
Audubon C38109/02/202310007609/01/202311007508/16/202311007309/19/2023100070
Dripping Springs School C6141 N08/31/202311008109/02/202311008009/01/202311007908/28/2023150078
CAPCOG Lake Georgetown C6901 N09/19/202310008009/01/202311007609/02/202310007509/18/2023110074
Lockhart C16041 N05/17/202310007309/18/202310007108/28/202313007109/19/2023100070
St. Edwards University C16051 N09/18/202311007609/19/202309007208/28/202313007109/02/2023100067
CAPCOG Bastrop CAMS16121 N09/19/202310006909/18/202310006909/12/202310006909/01/2023110069
CAPCOG Elgin C16131 N08/28/202312007009/01/202311006808/31/202310006808/30/2023130068
CAPCOG East Austin C16191 N08/28/202312008408/25/202311007908/16/202311007808/30/2023110075
CAPCOG Round Rock Brushy Creek W C16201 N08/28/202312007409/01/202310007309/02/202310007209/19/2023080071
CAPCOG Taylor Murphy Park C16291 N08/28/202312007709/19/202310007009/02/202310007009/01/2023110070
CAPCOG Lake Kyle Park C16301 N09/18/202310007409/19/202310007208/28/202311007208/31/2023110071
CAPCOG San Marcos Staples Road C16751 N09/19/202310007309/18/202310007308/31/202311007009/01/2023110069
Houston-Galveston-Brazoria
Houston East C1/G316205/18/2023100011009/11/202311009105/01/202311009109/12/2023100090
Houston Aldine C8/AF108/X150 206/09/202310008105/18/202311007909/12/202311007808/01/2023100078
Channelview C15/AH115 306/09/202310009109/12/202311008905/18/202311008708/01/2023100085
Northwest Harris Co. C26/A110/X154209/19/202310008906/02/202309008205/31/202310008208/25/2023100079
Hou.DeerPrk2 C35/235/1001/AFH139FP239109/11/202310009505/18/202311009306/07/202310008909/01/2023100083
Seabrook Friendship Park C45105/23/202310007508/28/202311007408/15/202310007405/22/2023120073
Houston Bayland Park C53/A146 109/18/202311009709/11/202311009705/18/202311009709/01/2023100087
Conroe Relocated C78/A321106/02/202311007705/19/202312007708/18/202312007406/22/2023110072
Manvel Croix Park C84109/01/202310008809/11/202310008508/31/202310008408/16/2023100082
Clinton C403/C304/AH113 305/18/2023110010809/11/202311008805/01/202311008609/12/2023100082
Houston North Wayside C405/C1033105/18/202311008406/09/202310008109/12/202311007506/02/2023100074
Houston Monroe C406109/11/202309008305/18/202310008106/07/202310007908/16/2023100078
Lang C408205/18/202312009609/12/202310008509/11/202311008305/01/2023110083
Houston Croquet C409209/18/202311009209/11/202310008505/18/202311008209/01/2023100080
Houston Westhollow C410/C3003109/18/202311008609/09/202311008209/11/202311008109/01/2023100077
Park Place C416105/18/2023110010109/11/202311009209/18/202310008805/27/2023100085
Houston Harvard Street C417105/18/2023110010809/11/202311008609/12/202310008409/02/2023100078
Sheldon C5511 N09/12/202310008308/01/202310007706/09/202310007709/11/2023100071
Baytown Wetlands Center C5521 N05/18/202311008909/12/202309008109/11/202310007408/01/2023090072
Crosby Library C5531 N09/12/202310008506/09/202310007608/01/202310007306/03/2023090070
West Houston C5541 N09/18/202310008909/19/202310008609/09/202310008509/11/2023100084
La Porte Sylvan Beach C5561 N06/07/202310007506/04/202309007209/12/202309006909/11/2023100069
Mercer Arboretum C5571 N06/09/202310008309/12/202310008208/18/202310007908/02/2023100078
Tom Bass C5581 N09/11/202310008909/18/202310008609/01/202309008505/23/2023090085
Katy Park C5591 N09/09/202310008409/18/202310008305/27/202309007609/01/2023090075
Atascocita C5601 N09/12/202310007608/01/202310007107/31/202310007108/02/2023090070
Meyer Park C5611 N08/02/202310008906/02/202310008309/19/202309008109/11/2023100077
Bunker Hill Village C5621 N05/18/202310009305/27/202309008109/01/202309007705/23/2023090076
Huffman Wolf Road C5631 N06/03/202309007405/19/202309007406/09/202310007209/12/2023090071
HRM-3 Haden Road C603/A114 1 N05/18/2023110010509/12/202310009205/01/202311009009/11/2023110086
Wallisville Road C617 1 N09/12/202311009706/09/202310009108/01/202311009009/11/2023110078
Texas City 34th St. C620 1 N05/23/202310009806/04/202310009008/28/202311008906/07/2023090083
UH Moody Tower C6951 N05/18/2023110010809/11/202311009006/07/202310008009/18/2023100079
UH WG Jones Forest C6981 N06/02/202310008308/02/202311008006/01/202311008008/18/2023110079
Lynchburg Ferry C1015/A165 105/18/202311009909/12/202310008806/09/202311008808/01/2023110082
Lake Jackson C1016 108/28/202310008008/31/202310007505/24/202310007408/30/2023100073
Baytown Garth C1017106/09/2023100010408/01/2023110010005/18/202312008408/18/2023100083
Galveston 99th St. C1034/A320/X183108/28/202313008909/26/202310008609/17/202313008308/31/2023100081
UH Smith Point C16061 N05/18/202312007808/31/202311007605/03/202313007505/26/2023100074
Oyster Creek C1607 1 N08/28/202311008209/17/202311007808/31/202311007808/30/2023100074
UH Launch Trailer C16111 N05/18/2023110011409/11/202311009305/01/202311008306/07/2023100082
Liberty Sam Houston Library C16261 N05/19/202310008508/17/202309006905/03/202314006509/12/2023110063
San Antonio
San Antonio Northwest C23209/01/202310007808/31/202311007809/18/202311007409/11/2023100074
Camp Bullis C58 109/01/202310008108/31/202311007709/02/202311007606/21/2023100076
Calaveras Lake C59108/31/202310007708/29/202311007709/01/202311007309/02/2023110071
Elm Creek Elementary C5011 N08/31/202311007809/01/202311007209/02/202311007108/29/2023100068
Fair Oaks Ranch C5021 N06/21/202310007509/11/202310007109/19/202310006709/18/2023110066
Bulverde Elementary C5031 N09/01/202310008008/31/202311007609/19/202310007409/18/2023100074
New Braunfels Airport C5041 N09/27/202310006003/04/202310006009/01/202311005902/27/2023100057
AACOG City of Garden Ridge C505 1 N09/27/202311007709/01/202311007608/31/202311007609/02/2023100074
Seguin Outdoor Learning Center C5061 N09/19/202310007108/31/202311006309/01/202311006209/27/2023100061
Heritage Middle School C6221 N08/31/202310008208/29/202310008209/01/202311007809/02/2023110075
CPS Pecan Valley C6781 N09/18/202310006508/31/202311006509/01/202311006409/02/2023100062
Government Canyon C16101 N08/31/202310006609/27/202310006309/01/202310006309/28/2023100062
Corpus Christi-Victoria
Corpus Christi West C4208/29/202310006905/25/202309006808/28/202313006403/25/2023150064
Corpus Christi Tuloso C21108/29/202309007105/25/202310007105/24/202310006608/30/2023100065
Victoria C87109/01/202309006208/31/202310006206/07/202310006109/18/2023100059
Lower Rio Grande Valley
Harlingen Teege C1023108/30/202309007108/31/202309006108/29/202312006006/08/2023110060
Laredo
Laredo College C441 N08/29/202311008008/31/202310007909/01/202310006808/28/2023110064
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.