Skip to main content

Four Highest Eight-Hour Ozone Concentrations in 2019
as of May 21

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 2019 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 204/10/201911006204/09/201911006105/14/201909006004/26/2019100058
Keller C17205/14/201910006203/22/201912006105/16/201910006005/15/2019100060
Frisco C31/C680105/14/201911007505/15/201910007105/16/201910007005/13/2019110069
Midlothian OFW C52/A137104/09/201910006303/22/201911006205/19/201910006105/14/2019100059
Denton Airport South C56/A163/X157105/14/201910006904/09/201912006505/15/201910006404/10/2019110064
Arlington Municipal Airport C61105/19/201910006003/22/201911006005/14/201910005805/15/2019100057
Dallas North No.2 C63/C679105/15/201910006704/09/201912006503/22/201911006505/13/2019100063
Rockwall Heath C69104/09/201912006403/22/201910006203/18/201911005805/15/2019100057
Grapevine Fairway C70/A301/X182105/14/201911006605/16/201909006004/09/201912006005/13/2019100058
Kaufman C71/A304/X071104/09/201911006803/22/201911006305/15/201909006103/28/2019140061
Granbury C73/C681105/19/201912006704/10/201912006304/09/201912006103/22/2019120061
Eagle Mountain Lake C75 104/10/201912006804/09/201911006603/22/201912006505/14/2019100062
Parker County C76104/26/201911006704/10/201913006404/09/201911006103/27/2019120061
Cleburne Airport C77/C682105/19/201911007304/10/201911006604/09/201911006503/22/2019100064
Dallas Hinton St. C401/C60/AH161 305/14/201910006203/22/201911006104/09/201912006005/15/2019100059
Dallas Executive Airport C402105/14/201909006503/22/201911006405/19/201910006305/15/2019100063
Greenville C1006/A198104/09/201911006905/15/201910006303/22/201910006003/19/2019110058
Pilot Point C1032105/14/201911008005/16/201910007305/15/201910007205/13/2019110069
Italy C1044/A323103/22/201910006504/09/201910006104/20/201911005904/15/2019110059
Corsicana Airport C1051104/09/201911006603/22/201912006205/15/201910006105/14/2019100060
Tyler-Longview-Marshall
Longview C19/A127/C644204/09/201911007405/13/201911006903/22/201911006404/27/2019150063
Tyler Airport Relocated C82104/09/201911008004/15/201915006703/22/201911006504/27/2019110063
Karnack C85/AFHP303105/15/201910006704/27/201911006204/21/201910006104/15/2019100060
El Paso-Juarez
El Paso UTEP C12/A125/X151/G125204/19/201911006605/14/201911006505/15/201910006405/18/2019120060
Ascarate Park SE C37/A332/A172/X159105/14/201910006405/15/201910006105/19/201909005905/18/2019110058
Chamizal C41/AH126 104/19/201911006705/18/201911006405/19/201909006204/10/2019110062
Socorro Hueco C49/F312105/14/201911006605/13/201911006305/19/201909006104/19/2019110061
Skyline Park C72105/15/201910006605/18/201913006505/14/201911006404/19/2019110064
BRAVO Big Bend C67/C316/C656/C6913 N01/27/201908004801/28/201908004401/24/201913004401/26/2019100043
Ivanhoe C414/F514105/18/201912006405/14/201911006405/19/201909006305/15/2019090061
Waco
Waco Mazanec C1037103/22/201911006304/27/201910005903/19/201911005804/15/2019100057
Temple Georgia C1045104/09/201911006704/27/201910006303/22/201911006304/10/2019110062
Killeen Skylark Field C1047104/09/201911007204/27/201911006804/10/201911006703/22/2019100067
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 203/22/201911007003/20/201911006303/23/201913006204/21/2019100061
West Orange C9/A141203/22/201912006804/20/201912006403/20/201911006403/23/2019110063
Port Arthur West C28/A128/A228103/20/201911006603/22/201911006503/23/201912006204/20/2019110061
Hamshire C64/C654103/22/201910006603/20/201911006404/03/201914006303/27/2019100063
SETRPC Port Arthur C6281 N03/22/201912006803/20/201911006604/20/201911006504/21/2019110064
SETRPC 40 Sabine Pass C640/C1654103/22/201911006804/20/201911006704/09/201911006604/26/2019120064
SETRPC Mauriceville 42 C642/C311/C6651 N03/23/201911006603/22/201911006604/27/201910006405/14/2019100063
SETRPC 43 Jefferson Co Airport C643103/22/201911007403/20/201911006803/23/201913006704/20/2019110066
Nederland High School C1035 103/22/201911006503/20/201911006004/21/201912005903/23/2019120059
Austin
Austin Northwest C3/A322204/09/201911006603/22/201913006304/27/201910006203/21/2019110062
Audubon C38104/09/201911006504/27/201910006303/22/201911006204/10/2019100061
Dripping Springs School C6141 N04/09/201911006704/27/201910006204/20/201911006204/10/2019110061
CAPCOG Lake Georgetown C6901 N04/09/201910006703/22/201911006304/27/201911006203/25/2019130061
Gorzycki Middle School C16031 N04/09/201911006404/27/201910006003/22/201913006004/20/2019110059
Lockhart C16041 N04/27/201911006105/05/201911005405/14/201910005005/04/2019090049
St. Edwards University C16051 N03/21/201911006003/22/201912005904/09/201910005604/27/2019100054
CAPCOG Bastrop CAMS16121 N03/21/201911006303/20/201910005904/27/201910005704/09/2019110055
CAPCOG Elgin C16131 N03/21/201911006103/22/201909006004/09/201910005904/27/2019100056
CAPCOG San Marcos Staples Road C16751 N03/22/201910006403/21/201910006304/27/201911006204/26/2019110059
CAPCOG Hutto College Street C66021 N03/21/201911006204/09/201909006003/22/201911006004/20/2019110058
Houston-Galveston-Brazoria
Houston East C1/G316204/09/201911007004/20/201911006503/22/201911006403/21/2019100060
Houston Aldine C8/AF108/X150 204/09/201911007403/27/201910007303/22/201910007103/20/2019110071
Channelview C15/AH115 304/09/201911007303/20/201911006503/22/201911006403/21/2019090064
Northwest Harris Co. C26/A110/X154205/15/201911007603/22/201910007204/09/201910006704/15/2019110064
Hou.DeerPrk2 C35/235/1001/AFH139FP239104/09/201912007603/20/201912007303/21/201910006604/20/2019100064
Seabrook Friendship Park C45103/21/201911006403/22/201912006103/20/201913006104/20/2019100060
Houston Bayland Park C53/A146 105/13/201911008004/26/201912007605/14/201910006904/09/2019100067
Conroe Relocated C78/A321103/22/201911007804/21/201910007504/27/201910007404/15/2019110072
Manvel Croix Park C84104/26/201911007503/20/201911007104/09/201911006704/02/2019110066
Clinton C403/C304/AH113 303/20/201910007704/09/201911006104/26/201911005804/20/2019110057
Houston North Wayside C405104/20/201910005804/09/201910005804/27/201910005703/27/2019110057
Houston Monroe C406103/20/201910006104/09/201911006004/26/201910005405/16/2019100051
Lang C408205/14/201909006504/09/201910006403/22/201910006403/27/2019100062
Houston Croquet C409204/26/201911007005/13/201911006603/20/201910006604/09/2019100065
Houston Westhollow C410105/13/201911007705/14/201908006904/09/201910006704/26/2019110065
Park Place C416104/09/201911007204/26/201912006705/13/201911006604/20/2019110061
Baytown Wetlands Center C5521 N04/09/201911006204/20/201910006103/21/201911005803/22/2019100053
Crosby Library C5531 N03/22/201911005903/20/201911005404/20/201911005304/09/2019100053
La Porte Sylvan Beach C5561 N05/16/201917003805/15/201916003605/14/201914003505/06/2019110035
Tom Bass C5581 N04/26/201911007405/13/201911006305/04/201910005904/20/2019110059
Katy Park C5591 N05/14/201910007405/13/201911006705/15/201910006204/09/2019100062
Atascocita C5601 N03/22/201911005804/09/201910005004/21/201908004904/27/2019090048
Meyer Park C5611 N03/27/201911006905/15/201910006603/22/201911006605/05/2019110063
Huffman Wolf Road C5631 N03/22/201910004104/27/201909003804/09/201910003804/20/2019110037
HRM-3 Haden Road C603/A114 1 N03/20/201910007204/09/201911007104/20/201910006603/21/2019100064
Wallisville Road C617 1 N04/09/201911007404/20/201911007003/20/201910006704/15/2019090065
Danciger C618 1 N04/26/201910007003/21/201910006403/22/201910006303/20/2019110063
Texas City 34th St. C620 1 N04/09/201910007203/21/201911007103/22/201913006903/20/2019110068
UH Moody Tower C6951 N03/20/201911007704/09/201911007505/13/201910007204/26/2019120072
UH WG Jones Forest C6981 N03/22/201911007704/27/201910007204/09/201911007104/15/2019100069
UH West Liberty C6991 N03/22/201910006604/15/201910006404/09/201910006304/20/2019110060
Lynchburg Ferry C1015/A165 104/20/201910006203/22/201912006204/09/201911006003/20/2019110059
Lake Jackson C1016 103/20/201910006304/09/201910006203/21/201910006203/22/2019100061
Baytown Garth C1017104/09/201911007304/20/201911006903/20/201911006604/15/2019100065
Galveston 99th St. C1034/A320/X183103/22/201913007905/04/201911007003/20/201912006604/25/2019110064
Oyster Creek C1607 1 N03/22/201910007304/26/201911007103/20/201910006903/21/2019100066
San Antonio
San Antonio Northwest C23204/09/201911006303/21/201911006004/20/201911005903/20/2019110059
Camp Bullis C58 104/09/201911007004/20/201911006404/27/201910006304/10/2019110060
Calaveras Lake C59104/09/201911006303/22/201911006104/27/201910006004/02/2019110060
Elm Creek Elementary C5011 N04/09/201911006004/26/201911005903/21/201910005903/22/2019120057
Fair Oaks Ranch C5021 N04/09/201910006704/27/201910005904/20/201910005904/10/2019110057
Bulverde Elementary C5031 N04/09/201911006704/27/201910005904/20/201911005904/10/2019110056
New Braunfels Airport C5041 N04/09/201911006304/27/201910005804/20/201910005703/22/2019100056
City of Garden Ridge C5051 N04/09/201911006604/27/201911006104/20/201911005903/22/2019100058
Seguin Outdoor Learning Center C5061 N03/22/201911006204/27/201910005904/09/201911005903/21/2019110057
Heritage Middle School C6221 N03/22/201912005504/27/201910005304/26/201911005304/02/2019110053
CPS Pecan Valley C6781 N05/05/201911004705/04/201911004403/22/201914003803/20/2019110038
Government Canyon C16101 N04/09/201911006204/27/201911005805/15/201911005605/14/2019100055
Corpus Christi-Victoria
Corpus Christi West C4203/22/201909006703/21/201911006404/26/201910006205/04/2019100057
Corpus Christi Tuloso C21103/22/201909005803/21/201910005804/26/201910005604/20/2019080051
Victoria C87103/22/201910006604/08/201910005904/27/201909005804/26/2019110058
Violet C6641 N01/10/201911004301/05/201911004301/25/201910004201/21/2019100042
Ingleside C6851 N01/25/201909004601/11/201907004501/10/201911004501/05/2019100045
Lower Rio Grande Valley
Mission C43/AP143104/08/201911006504/26/201910005604/09/201910005103/21/2019120051
Harlingen Teege C1023103/21/201911006304/26/201911006104/20/201909006004/19/2019110059
Laredo
Laredo Vidaurri C44/AFGP144/P244102/15/201910005404/19/201910005204/11/201911005204/07/2019100052
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.