Skip to main content

Four Highest Eight-Hour Ozone Concentrations in 2021
as of October 22

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 2021 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 206/16/2021110010206/15/202111009506/13/202112008007/29/2021110076
Keller C17206/16/2021110010007/29/202111007707/27/202112007709/25/2021110074
Frisco C31/C680109/07/202111008706/17/202110008506/19/202110008206/16/2021110081
Midlothian OFW C52/A137106/16/202109007206/19/202110006710/07/202110006410/06/2021100064
Denton Airport South C56/A163/X157106/16/202112009706/19/202111008507/30/202112008407/29/2021110081
Arlington Municipal Airport C61109/08/202112007606/15/202111007606/16/202109007307/21/2021110071
Dallas North No.2 C63/C679106/16/202110008809/07/202111007606/17/202110007607/30/2021100073
Rockwall Heath C69110/06/202112006606/17/202109006606/16/202109006606/19/2021100063
Grapevine Fairway C70/A301/X182106/16/202110009607/30/202111008207/29/202111007909/25/2021110075
Kaufman C71/A304/X071110/08/202110006506/19/202110006509/08/202111006410/07/2021100063
Granbury C73/C681106/15/202112007709/08/202112006807/21/202111006606/16/2021100065
Eagle Mountain Lake C75 106/16/2021120011407/29/202112008009/25/202111007807/07/2021120076
Parker County C76106/16/202113008106/15/202111006809/25/202110006709/09/2021110067
Cleburne Airport C77/C682109/08/202113008108/03/202111008006/15/202111007607/21/2021110075
Dallas Hinton St. C401/C60/AH161 306/16/202110009506/19/202110007606/17/202110007406/13/2021110074
Dallas Executive Airport C402106/16/202110007809/08/202111007006/19/202111007006/13/2021110070
Greenville C1006/A198110/07/202110006806/19/202111006810/08/202109006709/25/2021100065
Pilot Point C1032109/07/202111008906/19/202111008906/17/202111008506/16/2021110085
Italy C1044/A323110/08/202110006806/19/202109006809/08/202112006605/06/2021110064
Corsicana Airport C1051110/08/202110007010/07/202110006909/08/202111006906/19/2021100067
Tyler-Longview-Marshall
Longview C19/A127/C644206/17/202110006809/08/202110006709/25/202110006409/07/2021100064
Tyler Airport Relocated C82106/16/202110007009/25/202110006909/07/202111006909/24/2021100065
Karnack C85/AFHP303110/08/202110006308/06/202110006309/26/202110006109/25/2021090061
El Paso-Juarez
El Paso UTEP C12/A125/X151/G125207/27/202111008507/09/202110008406/22/202111008008/06/2021100073
Ascarate Park SE C37/A332/A172/X159105/05/202111006209/13/202110005805/29/202110005809/16/2021100056
Chamizal C41/AH126 107/27/202110007307/09/202110007306/22/202111007305/05/2021110069
Socorro Hueco C49/F312107/25/202111007507/17/202108007407/23/202109007309/14/2021090071
Skyline Park C72106/22/202111007407/27/202110007205/05/202111006906/19/2021100068
Ivanhoe C414/F514108/07/202110006608/04/202118006605/05/202111006607/25/2021110064
Ojo De Agua C1021/FG121/FG221107/27/202111008008/06/202111007209/13/202111007105/05/2021100071
Waco
Waco Mazanec C1037110/08/202110007009/08/202110006806/19/202109006810/07/2021100067
Temple Georgia C1045110/08/202110007310/07/202110006909/08/202111006706/19/2021100067
Killeen Skylark Field C1047110/08/202111007710/07/202111007709/08/202111007104/11/2021120070
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 208/06/202110007510/08/202110007109/11/202110006705/07/2021100065
West Orange C9/A141206/17/202110006409/11/202110006306/16/202110006309/26/2021100061
Port Arthur West C28/A128/A228108/25/202110006607/28/202110006606/17/202112006610/08/2021090065
Hamshire C64/C654109/11/202110006610/08/202109006405/07/202109006309/10/2021100062
SETRPC Port Arthur C6281 N07/28/202110006906/17/202112006809/09/202109006509/10/2021100063
SETRPC 40 Sabine Pass C640/C1654108/25/202110006506/17/202112006310/08/202109006109/07/2021110060
SETRPC Mauriceville 42 C642/C311/C6651 N09/11/202110007409/26/202110006805/07/202110006810/08/2021100062
SETRPC 43 Jefferson Co Airport C643106/15/202110007110/08/202109006706/16/202110006708/06/2021090066
Nederland High School C1035 106/16/202110006810/08/202110006706/15/202108006506/17/2021110064
Austin
Austin North Hills Drive C3/A322210/08/202110007109/25/202110006709/10/202110006710/06/2021110066
Audubon C38109/24/202110006609/23/202110006609/10/202111006604/11/2021110065
Dripping Springs School C6141 N09/10/202110007510/08/202111007204/11/202112007110/07/2021100069
CAPCOG Lake Georgetown C6901 N10/08/202110007610/07/202110006910/06/202110006709/08/2021110065
Lockhart C16041 N10/08/202110006809/10/202110006609/08/202111006404/11/2021110063
St. Edwards University C16051 N09/10/202110006304/11/202112006009/08/202110005909/23/2021100057
CAPCOG Bastrop CAMS16121 N09/25/202110007009/10/202110006503/26/202113006510/08/2021100064
CAPCOG Elgin C16131 N10/08/202110006609/25/202110006606/18/202110006409/10/2021100063
CAPCOG East Austin C16191 N10/08/202110006909/10/202110006509/25/202111006310/07/2021110062
CAPCOG Round Rock Brushy Creek W C16201 N10/08/202110007610/07/202110006810/06/202110005909/25/2021100059
CAPCOG San Marcos Staples Road C16751 N10/08/202110007109/10/202110007010/07/202110006410/06/2021100063
Houston-Galveston-Brazoria
Houston East C1/G316205/29/202111008607/26/202111007810/08/202110007706/19/2021090076
Houston Aldine C8/AF108/X150 204/11/202111008610/08/202110008410/07/202110007706/19/2021100075
Channelview C15/AH115 305/29/202112009007/26/202112008110/08/202109007407/27/2021120068
Northwest Harris Co. C26/A110/X154210/08/202110007109/11/202111007104/11/202112007009/26/2021110069
Hou.DeerPrk2 C35/235/1001/AFH139FP239107/26/202111009706/19/202109008910/07/202110008405/29/2021100074
Seabrook Friendship Park C45110/07/202110008306/19/202109007907/26/202111007106/18/2021100060
Houston Bayland Park C53/A146 110/07/202112009206/18/202111008609/08/202110008307/28/2021110078
Conroe Relocated C78/A321110/08/202110008610/09/202110007304/12/202110007304/08/2021110070
Manvel Croix Park C84109/08/202111008910/07/202111008309/09/202111007907/28/2021100077
Clinton C403/C304/AH113 307/26/202111007805/29/202111007506/19/202109007004/11/2021100070
Houston North Wayside C405/C1033104/11/202111007506/19/202109007110/08/202110006705/29/2021110065
Houston Monroe C406110/07/202111007804/20/202110007109/08/202110006806/16/2021100068
Lang C408204/11/202111008910/08/202111007710/07/202110007409/08/2021090071
Houston Croquet C409206/17/202109008710/07/202112008606/16/202110008509/08/2021100083
Houston Westhollow C410/C3003106/18/202111008207/28/202112007409/08/202111007310/07/2021120071
Park Place C416110/07/202111007906/18/202110007906/17/202109007806/16/2021100078
Houston Harvard Street C417110/07/202110008610/08/202111008409/08/202110008106/15/2021090079
Sheldon C5511 N10/08/202110007304/20/202111006309/11/202110005706/19/2021120057
Baytown Wetlands Center C5521 N07/26/202111007410/07/202110006906/19/202109006704/20/2021110063
Crosby Library C5531 N10/08/202109006904/20/202111006607/27/202112006505/29/2021120064
West Houston C5541 N06/18/202109008109/24/202111008006/15/202108007809/08/2021100077
La Porte Sylvan Beach C5561 N06/19/202109008110/07/202110007607/26/202111007304/20/2021120062
Mercer Arboretum C5571 N06/19/202112006005/07/202110006004/12/202110005904/20/2021100058
Tom Bass C5581 N10/07/202111008309/25/202110008109/08/202110008106/16/2021100076
Katy Park C5591 N09/25/202111007009/24/202111007009/26/202110006909/08/2021110067
Atascocita C5601 N10/08/202110007908/23/202111006108/24/202111005908/05/2021110059
Meyer Park C5611 N10/08/202111008204/11/202112007109/11/202110006608/06/2021090066
Bunker Hill Village C5621 N10/07/202111007609/08/202110007506/18/202110007506/15/2021080073
Huffman Wolf Road C5631 N10/08/202110007304/20/202110006508/24/202111006308/05/2021100062
HRM-3 Haden Road C603/A114 1 N05/29/202111008907/26/202111008210/08/202110007804/11/2021100074
Wallisville Road C617 1 N05/29/202111007607/26/202112007504/20/202111007310/08/2021090067
Texas City 34th St. C620 1 N10/07/202109008710/08/202109007509/09/202110007503/23/2021110074
UH Moody Tower C6951 N06/15/202109008010/07/202111007706/17/202109007606/18/2021100075
UH WG Jones Forest C6981 N10/08/202112008404/12/202110007105/07/202110007004/26/2021100070
UH West Liberty C6991 N01/19/202109004401/18/202111004401/14/202111004202/03/2021100041
Lynchburg Ferry C1015/A165 107/26/202112007605/29/202111007210/07/202110006606/19/2021090065
Lake Jackson C1016 109/09/202111007909/08/202110007405/05/202111007009/07/2021110069
Baytown Garth C1017107/26/202112008505/29/202111008104/20/202111007509/19/2021100071
Galveston 99th St. C1034/A320/X183106/14/202111007709/09/202109007110/06/202111007010/07/2021090069
UH Smith Point C16061 N10/07/202110007706/19/202109007709/18/202110007409/19/2021100072
Oyster Creek C1607 1 N09/09/202110008109/07/202111007207/28/202110007109/08/2021100070
UH Launch Trailer C16111 N06/15/202109007810/07/202110007604/11/202111007606/17/2021090075
San Antonio
San Antonio Northwest C23209/10/202111007604/11/202111007209/23/202111007006/18/2021090070
Camp Bullis C58 110/06/202110008409/10/202111008410/08/202110008009/23/2021110078
Calaveras Lake C59109/10/202111006804/11/202111006710/06/202110006609/09/2021100066
Elm Creek Elementary C5011 N09/10/202111007909/23/202110007209/09/202110007206/15/2021100069
Fair Oaks Ranch C5021 N10/06/202111007410/08/202111006807/29/202110006505/07/2021100063
Bulverde Elementary C5031 N10/08/202111007304/11/202111007210/07/202110006710/06/2021120067
New Braunfels Airport C5041 N04/11/202111006209/10/202110005906/18/202108005906/17/2021100057
City of Garden Ridge C5051 N10/08/202111006910/06/202111006909/10/202111006804/11/2021110067
Seguin Outdoor Learning Center C5061 N10/08/202110006609/10/202110006210/06/202110006004/11/2021110060
Heritage Middle School C6221 N09/10/202110006509/09/202110006404/11/202111006304/25/2021110062
CPS Pecan Valley C6781 N04/11/202111005809/10/202111005403/26/202111005209/23/2021110051
Government Canyon C16101 N09/23/202111006809/10/202110006807/29/202110006705/20/2021110067
Corpus Christi-Victoria
Corpus Christi West C4209/09/202112006810/06/202111006709/08/202113006710/07/2021120065
Corpus Christi Tuloso C21110/06/202110007209/09/202111006910/07/202110006609/08/2021130064
Victoria C87110/07/202111006909/09/202109006506/18/202113006306/17/2021100061
Lower Rio Grande Valley
Mission C43/AP143109/09/202110007210/06/202111006809/11/202109006309/10/2021090062
Harlingen Teege C1023110/06/202110006009/09/202108005910/05/202110005809/08/2021150056
Laredo
Laredo Vidaurri C44/AFGP144/P244105/03/202111006905/20/202111006106/18/202108006005/06/2021090060
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.