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Four Highest Eight-Hour Ozone Concentrations in 2020
as of July 11

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 2020 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 205/19/202011008306/12/202011007005/30/202011006906/13/2020110068
Keller C17205/19/202011007406/12/202011007106/13/202011006305/30/2020110063
Frisco C31/C680105/18/202011007304/30/202013006805/01/202011006706/22/2020110065
Midlothian OFW C52/A137106/09/202011006205/19/202011006106/11/202011006005/06/2020110060
Denton Airport South C56/A163/X157105/18/202011007506/01/202011007206/13/202011007106/12/2020100069
Arlington Municipal Airport C61105/06/202011006805/19/202011006706/09/202011006605/01/2020110064
Dallas North No.2 C63/C679105/19/202010007205/18/202012007107/03/202011006906/09/2020110068
Rockwall Heath C69104/30/202012006907/03/202011006406/09/202009006405/27/2020120064
Grapevine Fairway C70/A301/X182105/19/202010008606/12/202010007306/01/202011007206/13/2020110071
Kaufman C71/A304/X071104/30/202011006705/01/202013006604/27/202014006606/13/2020110065
Granbury C73/C681106/11/202013007005/01/202013006306/09/202010006205/06/2020110062
Eagle Mountain Lake C75 106/12/202011007705/19/202010007405/30/202011007306/13/2020110070
Parker County C76105/06/202012006905/30/202012006405/01/202014006406/14/2020110063
Cleburne Airport C77/C682105/29/202011007206/11/202013007105/28/202010007005/06/2020100068
Dallas Hinton St. C401/C60/AH161 305/19/202011007506/09/202011006405/18/202011006405/01/2020110063
Dallas Executive Airport C402106/08/202011007106/09/202011006705/19/202011006605/01/2020110064
Greenville C1006/A198106/09/202012006604/27/202015006305/07/202016006204/24/2020110061
Pilot Point C1032105/18/202012007806/17/202010007006/13/202010007005/01/2020110068
Italy C1044/A323105/18/202010006205/01/202011006004/24/202010006004/23/2020110060
Corsicana Airport C1051106/13/202011006504/24/202010006406/12/202012006305/07/2020120063
Tyler-Longview-Marshall
Longview C19/A127/C644206/13/202010006206/16/202009005606/12/202008005504/27/2020140055
Tyler Airport Relocated C82106/13/202009006505/01/202015006506/12/202008006205/07/2020140060
Karnack C85/AFHP303102/29/202011006004/21/202010005705/01/202010005606/13/2020100055
El Paso-Juarez
El Paso UTEP C12/A125/X151/G125207/07/202010007906/25/202010007505/09/202011007505/06/2020100074
Ascarate Park SE C37/A332/A172/X159105/09/202011007007/07/202010006905/26/202010006405/18/2020100064
Chamizal C41/AH126 107/07/202010007305/09/202011007205/06/202010006906/25/2020100064
Socorro Hueco C49/F312105/09/202011007306/02/202011007006/22/202011006306/03/2020100063
Skyline Park C72105/09/202010007005/06/202010006806/25/202010006604/30/2020100066
Ivanhoe C414/F514105/09/202012006807/07/202010006706/02/202011006405/18/2020100064
Waco
Waco Mazanec C1037106/13/202011006305/18/202011006205/01/202011006204/24/2020100062
Temple Georgia C1045105/18/202011006906/13/202011006705/01/202011006406/14/2020090060
Killeen Skylark Field C1047105/01/202011006706/13/202011006505/18/202012006205/19/2020110060
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 206/02/202010007206/16/202010006506/01/202011005905/25/2020120058
West Orange C9/A141206/02/202009007106/17/202009006605/25/202013006106/16/2020090059
Port Arthur West C28/A128/A228106/16/202010005806/13/202009005706/02/202009005705/25/2020120057
Hamshire C64/C654106/02/202009006505/26/202012006205/25/202010005906/13/2020090058
SETRPC Port Arthur C6281 N06/16/202010006706/02/202011006006/13/202008005905/01/2020080059
SETRPC 40 Sabine Pass C640/C1654105/26/202012006906/13/202010006205/25/202012006106/16/2020100059
SETRPC Mauriceville 42 C642/C311/C6651 N06/02/202010006806/17/202009006705/01/202009006702/29/2020100065
SETRPC 43 Jefferson Co Airport C643106/16/202010006606/02/202009006005/25/202012005902/29/2020100058
Nederland High School C1035 106/16/202010006406/02/202010006004/20/202011005705/25/2020120056
Austin
Austin Northwest C3/A322202/02/202012004601/08/202012004601/05/202010004501/21/2020120041
Audubon C38105/18/202011006406/13/202012006305/01/202010006306/14/2020090061
Dripping Springs School C6141 N05/18/202011007205/01/202010006806/13/202011006705/06/2020110066
CAPCOG Lake Georgetown C6901 N06/13/202012006406/14/202009006106/17/202010005806/08/2020130056
Lockhart C16041 N04/23/202010006205/01/202010005904/30/202010005905/18/2020100057
St. Edwards University C16051 N04/24/202008006005/18/202011005606/13/202011005505/01/2020100055
CAPCOG Bastrop CAMS16121 N05/01/202010006204/30/202010005906/13/202010005805/18/2020110058
CAPCOG Elgin C16131 N06/13/202011006305/01/202010006204/30/202010006106/14/2020080058
CAPCOG East Austin C16191 N04/24/202009006405/18/202011006305/01/202010006204/30/2020110062
CAPCOG San Marcos Staples Road C16751 N06/08/202001006006/14/202009005906/13/202011005906/07/2020230059
CAPCOG Hutto College Street C66021 N05/18/202010006304/24/202008006306/13/202011006105/01/2020100061
Houston-Galveston-Brazoria
Houston East C1/G316205/18/202010008606/02/202010006606/16/202009006506/14/2020080062
Houston Aldine C8/AF108/X150 206/16/202010007505/18/202011007404/20/202012006906/02/2020100064
Channelview C15/AH115 305/18/202010008106/16/202009005906/02/202009005906/17/2020090057
Northwest Harris Co. C26/A110/X154206/16/202010008405/11/202011007406/02/202012007104/21/2020110070
Hou.DeerPrk2 C35/235/1001/AFH139FP239105/18/202010008104/30/202011006706/16/202010006306/13/2020110062
Seabrook Friendship Park C45105/18/202010007504/30/202011006804/23/202010005806/13/2020120057
Houston Bayland Park C53/A146 104/20/202012007205/18/202010006706/14/202008006604/26/2020100065
Conroe Relocated C78/A321106/17/202011007905/01/202010007504/24/202011007205/07/2020100069
Manvel Croix Park C84106/12/202010006706/13/202010006505/18/202010006504/26/2020100065
Clinton C403/C304/AH113 305/18/202010007106/14/202008006106/02/202010006106/16/2020090059
Houston North Wayside C405106/16/202010006505/18/202010006406/02/202010006104/20/2020110058
Houston Monroe C406106/16/202009006004/30/202011005606/13/202010005505/10/2020110055
Lang C408206/16/202009007306/02/202010007305/18/202009006706/14/2020080066
Houston Croquet C409205/18/202010006404/26/202009006305/10/202012006106/14/2020080060
Houston Westhollow C410104/20/202012007106/14/202008006506/12/202009006206/02/2020100061
Park Place C416106/16/202009006204/30/202011005904/26/202010005906/14/2020080056
Sheldon C5511 N05/07/202011005604/30/202010005604/24/202010005604/23/2020100056
Baytown Wetlands Center C5521 N05/18/202010008505/01/202010005904/30/202012005905/07/2020100057
Crosby Library C5531 N07/10/202010006206/17/202009006105/27/202008005705/01/2020090057
West Houston C5541 N06/14/202009006506/16/202009006106/12/202009006006/13/2020100057
La Porte Sylvan Beach C5561 N05/18/202010007904/30/202011006405/07/202010005804/23/2020100057
Mercer Arboretum C5571 N06/16/202010007106/17/202010006505/07/202009006205/01/2020090062
Tom Bass C5581 N05/18/202010006704/26/202011006606/12/202010006305/10/2020110063
Katy Park C5591 N06/14/202009006606/02/202010006504/20/202013006406/12/2020100063
Atascocita C5601 N05/18/202011006706/16/202010006006/17/202010005905/01/2020090059
Meyer Park C5611 N06/16/202011008005/11/202011007005/01/202009006504/21/2020110065
Bunker Hill Village C5621 N06/14/202008006306/02/202010006004/20/202012006005/18/2020100059
Huffman Wolf Road C5631 N06/17/202009007205/18/202012007105/01/202009006604/24/2020100063
HRM-3 Haden Road C603/A114 1 N05/18/202010007906/02/202009006006/16/202009005904/30/2020100058
Wallisville Road C617 1 N05/18/202011008107/04/202011007305/27/202009006505/26/2020110065
Danciger C618 1 N01/08/202011004902/08/202012004802/07/202011004701/25/2020110046
Texas City 34th St. C620 1 N05/18/202010008806/13/202010008004/23/202010007506/14/2020090068
UH Moody Tower C6951 N05/18/202010007706/16/202009006806/14/202008006406/02/2020100064
UH WG Jones Forest C6981 N06/16/202011007806/17/202011007505/01/202010007105/07/2020100070
UH West Liberty C6991 N05/18/202012006306/17/202010006105/27/202008006005/01/2020090060
Lynchburg Ferry C1015/A165 105/18/202010007605/07/202011005806/16/202010005706/17/2020080055
Lake Jackson C1016 106/10/202011007005/10/202011006506/13/202010006304/23/2020100063
Baytown Garth C1017105/18/202011008104/09/202011006305/27/202008006205/26/2020120062
Galveston 99th St. C1034/A320/X183105/18/202010007604/23/202011006806/12/202013006506/13/2020100062
UH Smith Point C16061 N06/13/202010006406/17/202009006006/01/202011005706/16/2020110056
Oyster Creek C1607 1 N06/10/202010007304/23/202011006906/13/202009006806/12/2020110068
UH Launch Trailer C16111 N05/18/202010007506/16/202009006506/14/202008006106/02/2020090061
San Antonio
San Antonio Northwest C23204/30/202011006906/13/202011006506/12/202010006506/11/2020100065
Camp Bullis C58 104/30/202011008104/20/202011007205/18/202010007005/01/2020100070
Calaveras Lake C59104/30/202011006604/23/202012006406/13/202011006304/20/2020110063
Elm Creek Elementary C5011 N04/30/202011006306/12/202010006104/23/202011006106/13/2020090060
Fair Oaks Ranch C5021 N04/30/202012007005/01/202010006104/20/202011005906/14/2020080057
Bulverde Elementary C5031 N04/20/202011006904/30/202012006805/18/202010006005/01/2020090059
New Braunfels Airport C5041 N04/30/202011005805/01/202010005705/18/202010005606/14/2020080055
City of Garden Ridge C5051 N04/30/202011006306/08/202010006005/18/202010006004/20/2020110059
Seguin Outdoor Learning Center C5061 N05/18/202011005804/20/202010005805/01/202009005704/30/2020110057
Heritage Middle School C6221 N06/13/202011005606/14/202008005405/18/202011005306/12/2020090052
CPS Pecan Valley C6781 N04/30/202011005804/20/202011005806/13/202011005305/01/2020100053
Government Canyon C16101 N04/30/202011006306/14/202008006106/13/202010006106/12/2020100060
Corpus Christi-Victoria
Corpus Christi West C4206/10/202013006604/23/202014006106/13/202012006006/14/2020100058
Corpus Christi Tuloso C21106/10/202014006906/13/202012006604/30/202010006506/14/2020110064
Victoria C87106/12/202013007006/13/202013006504/26/202011006106/14/2020110060
Lower Rio Grande Valley
Mission C43/AP143104/30/202010005806/13/202011005505/17/202010005504/29/2020110055
Harlingen Teege C1023104/30/202011005305/01/202008005204/29/202012005204/25/2020170050
Laredo
Laredo Vidaurri C44/AFGP144/P244105/26/202011006406/13/202009006006/11/202010006004/30/2020100059
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.