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Four Highest Eight-Hour Ozone Concentrations in 2020
as of October 31

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 208/04/202012008905/19/202011008308/21/202012007908/20/2020110075
Keller C17205/19/202011007408/21/202011007308/17/202012007106/12/2020110071
Frisco C31/C680108/17/202012008705/18/202011007310/06/202011007108/28/2020110070
Midlothian OFW C52/A137108/03/202012006408/17/202012006306/09/202011006208/02/2020100061
Denton Airport South C56/A163/X157108/17/202011007705/18/202011007506/01/202011007210/08/2020110071
Arlington Municipal Airport C61108/17/202012007108/04/202012007108/03/202012007105/06/2020110068
Dallas North No.2 C63/C679108/17/202012008005/19/202010007205/18/202012007107/03/2020110069
Rockwall Heath C69108/17/202013008004/30/202012006907/12/202011006407/03/2020110064
Grapevine Fairway C70/A301/X182108/17/202013008805/19/202010008608/21/202010007708/16/2020110077
Kaufman C71/A304/X071104/30/202011006705/01/202013006604/27/202014006606/13/2020110065
Granbury C73/C681106/11/202013007008/24/202012006505/01/202013006308/21/2020110062
Eagle Mountain Lake C75 108/21/202011007908/04/202011007806/12/202011007708/22/2020110076
Parker County C76108/05/202012007508/21/202013006905/06/202012006908/04/2020120068
Cleburne Airport C77/C682105/29/202011007206/11/202013007105/28/202010007005/01/2020110067
Dallas Hinton St. C401/C60/AH161 305/19/202011007508/17/202012006806/09/202011006405/18/2020110064
Dallas Executive Airport C402108/04/202012007306/08/202011007108/17/202012006806/09/2020110067
Greenville C1006/A198106/09/202012006604/27/202015006305/07/202016006208/17/2020110061
Pilot Point C1032105/18/202012007808/17/202011007708/28/202010007210/06/2020110071
Italy C1044/A323105/18/202010006208/02/202010006108/17/202011006005/01/2020110060
Corsicana Airport C1051106/13/202011006504/24/202010006406/12/202012006305/07/2020120063
Tyler-Longview-Marshall
Longview C19/A127/C644206/13/202010006208/21/202009005806/16/202009005610/13/2020100055
Tyler Airport Relocated C82106/13/202009006505/01/202015006506/12/202008006208/17/2020110060
Karnack C85/AFHP303102/29/202011006004/21/202010005705/01/202010005606/13/2020100055
El Paso-Juarez
El Paso UTEP C12/A125/X151/G125208/08/202011008507/25/202011008308/01/202010008107/07/2020100079
Ascarate Park SE C37/A332/A172/X159108/21/202011007708/14/202011007105/09/202011007008/22/2020100069
Chamizal C41/AH126 108/08/202010007308/01/202008007307/07/202010007305/09/2020110072
Socorro Hueco C49/F312108/21/2020110010208/14/202011007408/04/202011007408/01/2020080074
Skyline Park C72108/21/202010007908/04/202011007408/08/202011007308/19/2020100071
Ivanhoe C414/F514108/21/202011008208/19/202009007308/04/202011007109/03/2020110068
Waco
Waco Mazanec C1037108/04/202010006908/17/202011006408/18/202010006306/13/2020110063
Temple Georgia C1045105/18/202011006908/18/202009006806/13/202011006708/03/2020090064
Killeen Skylark Field C1047105/01/202011006708/18/202010006606/13/202011006508/17/2020110063
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 206/02/202010007208/07/202009006706/16/202010006506/01/2020110059
West Orange C9/A141206/02/202009007106/17/202009006610/14/202011006309/30/2020100062
Port Arthur West C28/A128/A228108/23/202009005806/16/202010005808/21/202009005706/13/2020090057
Hamshire C64/C654108/04/202010006506/02/202009006508/23/202009006305/26/2020120062
SETRPC Port Arthur C6281 N06/16/202010006705/25/202013006405/18/202016006408/20/2020090063
SETRPC 40 Sabine Pass C640/C1654105/26/202012006908/20/202010006208/03/202013006206/13/2020100062
SETRPC Mauriceville 42 C642/C311/C6651 N10/14/202011007206/02/202010006806/17/202009006705/01/2020090067
SETRPC 43 Jefferson Co Airport C643106/16/202010006608/23/202009006208/21/202009006210/05/2020100060
Nederland High School C1035 106/16/202010006406/02/202010006008/23/202010005704/20/2020110057
Austin
Austin North Hills Drive C3/A322202/02/202012004601/08/202012004601/05/202010004501/21/2020120041
Audubon C38108/18/202008006505/18/202011006406/13/202012006305/01/2020100063
Dripping Springs School C6141 N05/18/202011007205/01/202010006806/13/202011006705/06/2020110066
CAPCOG Lake Georgetown C6901 N08/18/202010006910/06/202010006810/01/202011006406/13/2020120064
Lockhart C16041 N08/18/202011006610/01/202011006404/23/202010006205/01/2020100059
St. Edwards University C16051 N08/18/202009006604/24/202008006008/17/202010005805/18/2020110056
CAPCOG Bastrop CAMS16121 N08/18/202010006810/01/202011006305/01/202010006210/06/2020100059
CAPCOG Elgin C16131 N08/18/202009006806/13/202011006305/01/202010006204/30/2020100061
CAPCOG East Austin C16191 N08/18/202010007308/17/202010006604/24/202009006405/18/2020110063
CAPCOG San Marcos Staples Road C16751 N08/18/202011007808/19/202010006510/07/202010006208/17/2020110062
CAPCOG Hutto College Street C66021 N08/18/202008006505/18/202010006304/24/202008006306/13/2020110061
Houston-Galveston-Brazoria
Houston East C1/G316205/18/202010008608/21/202009007310/05/202011007208/18/2020100067
Houston Aldine C8/AF108/X150 206/16/202010007505/18/202011007404/20/202012006908/21/2020100068
Channelview C15/AH115 305/18/202010008108/21/202009006908/04/202010006708/07/2020100059
Northwest Harris Co. C26/A110/X154206/16/202010008410/03/202011007605/11/202011007406/02/2020120071
Hou.DeerPrk2 C35/235/1001/AFH139FP239108/18/202010008105/18/202010008108/21/202009007410/04/2020100073
Seabrook Friendship Park C45105/18/202010007508/03/202011007404/30/202011006808/18/2020110064
Houston Bayland Park C53/A146 108/18/202010008210/05/202011008108/20/202011007308/17/2020110073
Conroe Relocated C78/A321106/17/202011007908/07/202011007708/06/202011007705/01/2020100075
Manvel Croix Park C84108/18/202010009810/04/202010008008/20/202010007008/19/2020100070
Clinton C403/C304/AH113 308/18/202010007210/05/202011007108/21/202009007105/18/2020100071
Houston North Wayside C405106/16/202010006505/18/202010006408/21/202009006206/02/2020100061
Houston Monroe C406108/18/202011008010/04/202010006808/20/202009006710/13/2020090062
Lang C408206/16/202009007306/02/202010007308/18/202008007010/05/2020110069
Houston Croquet C409210/13/202011008208/18/202011008108/20/202011006910/05/2020110066
Houston Westhollow C410108/18/202010007404/20/202012007110/05/202011007008/20/2020110066
Park Place C416108/18/202011008010/13/202010007710/05/202011007210/04/2020090070
Sheldon C5511 N05/07/202011005604/30/202010005604/24/202010005604/23/2020100056
Baytown Wetlands Center C5521 N05/18/202010008508/03/202011006608/21/202009006508/18/2020100063
Crosby Library C5531 N10/14/202010006206/17/202009006109/26/202010005805/27/2020080057
West Houston C5541 N08/18/202010006906/14/202009006510/05/202011006408/17/2020110062
La Porte Sylvan Beach C5561 N05/18/202010007908/03/202010006704/30/202011006408/18/2020100060
Mercer Arboretum C5571 N06/16/202010007108/07/202011006906/17/202010006508/06/2020100062
Tom Bass C5581 N08/18/202010008710/04/202010007708/20/202011007105/18/2020100067
Katy Park C5591 N08/18/202010006606/14/202009006606/02/202010006504/20/2020130064
Atascocita C5601 N05/18/202011006708/07/202010006106/16/202010006006/17/2020100059
Meyer Park C5611 N06/16/202011008010/03/202011007705/11/202011007005/01/2020090065
Bunker Hill Village C5621 N08/18/202010006910/05/202011006806/14/202008006308/20/2020110061
Huffman Wolf Road C5631 N06/17/202009007205/18/202012007110/14/202011007008/05/2020100068
HRM-3 Haden Road C603/A114 1 N05/18/202010007908/21/202009007110/05/202010006210/04/2020100061
Wallisville Road C617 1 N05/18/202011008108/21/202009007105/27/202009006505/26/2020110065
Danciger C618 1 N01/08/202011004902/08/202012004802/07/202011004701/25/2020110046
Texas City 34th St. C620 1 N05/18/202010008806/13/202010008008/18/202010007804/23/2020100075
UH Moody Tower C6951 N08/18/202010008010/05/202011007905/18/202010007708/21/2020090071
UH WG Jones Forest C6981 N08/07/202011008106/16/202011007808/06/202011007606/17/2020110075
UH West Liberty C6991 N10/14/202010006408/05/202010006305/18/202012006306/17/2020100061
Lynchburg Ferry C1015/A165 105/18/202010007608/21/202009007208/03/202011006308/04/2020100061
Lake Jackson C1016 108/19/202010007308/18/202009007306/10/202011007005/10/2020110065
Baytown Garth C1017105/18/202011008108/04/202010007608/21/202009007110/14/2020110066
Galveston 99th St. C1034/A320/X183108/19/202015008005/18/202010007608/02/202010006904/23/2020110068
UH Smith Point C16061 N08/03/202010008908/18/202013006608/17/202009006510/01/2020110064
Oyster Creek C1607 1 N08/19/202010009308/18/202012007906/10/202010007310/06/2020100071
UH Launch Trailer C16111 N10/05/202011007808/21/202011007508/18/202010007505/18/2020100075
San Antonio
San Antonio Northwest C23210/07/202010007108/20/202009007110/13/202011007004/30/2020110069
Camp Bullis C58 104/30/202011008110/06/202010007710/13/202011007510/07/2020100074
Calaveras Lake C59108/19/202010007308/18/202011006810/07/202009006604/30/2020110066
Elm Creek Elementary C5011 N10/07/202010006908/19/202010006608/20/202010006304/30/2020110063
Fair Oaks Ranch C5021 N04/30/202012007010/06/202010006105/01/202010006108/04/2020110059
Bulverde Elementary C5031 N04/20/202011006904/30/202012006810/06/202010006210/05/2020110060
New Braunfels Airport C5041 N08/18/202010006808/19/202010006104/30/202011005805/01/2020100057
City of Garden Ridge C5051 N08/18/202010006404/30/202011006310/07/202010006210/05/2020110062
Seguin Outdoor Learning Center C5061 N08/18/202010006210/01/202011005905/18/202011005804/20/2020100058
Heritage Middle School C6221 N08/19/202010006708/18/202010006610/07/202009006108/20/2020090059
CPS Pecan Valley C6781 N08/19/202010006508/18/202010006510/07/202010006008/20/2020100060
Government Canyon C16101 N10/13/202010006310/07/202010006304/30/202011006306/14/2020080061
Corpus Christi-Victoria
Corpus Christi West C4206/10/202013006610/06/202011006410/05/202011006204/23/2020140061
Corpus Christi Tuloso C21106/10/202014006906/13/202012006604/30/202010006506/14/2020110064
Victoria C87106/12/202013007006/13/202013006504/26/202011006108/19/2020100060
Lower Rio Grande Valley
Mission C43/AP143104/30/202010005810/02/202010005610/05/202011005506/13/2020110055
Harlingen Teege C1023110/06/202012005710/02/202010005610/05/202011005410/04/2020100053
Laredo
Laredo Vidaurri C44/AFGP144/P244105/26/202011006410/02/202011006206/13/202009006006/11/2020100060
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.