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Four Highest Eight-Hour Ozone Concentrations in 2019
as of September 17

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 208/05/201911007508/28/201912007208/15/201910006809/01/2019100067
Keller C17208/05/201912008409/05/201912007508/02/201910007207/25/2019110071
Frisco C31/C680109/06/201912008809/05/201911008505/31/201913007806/18/2019110076
Midlothian OFW C52/A137106/17/201912006906/08/201911006406/13/201911006304/09/2019100063
Denton Airport South C56/A163/X157108/15/201911007908/02/201911007708/06/201912007107/31/2019110071
Arlington Municipal Airport C61106/17/201913007608/28/201912007306/13/201911006807/24/2019110064
Dallas North No.2 C63/C679109/06/201910008309/05/201911007908/05/201911007505/31/2019130073
Rockwall Heath C69109/05/201911007209/06/201910007106/06/201911006604/09/2019120064
Grapevine Fairway C70/A301/X182108/05/201912008109/06/201910007509/05/201910007508/15/2019110071
Kaufman C71/A304/X071104/09/201911006806/06/201912006506/12/201910006303/22/2019110063
Granbury C73/C681107/24/201912008007/27/201911006705/19/201912006708/14/2019130066
Eagle Mountain Lake C75 108/05/201913008207/25/201911008208/15/201910007809/03/2019110075
Parker County C76109/04/201913007008/15/201910007009/15/201911006807/27/2019110068
Cleburne Airport C77/C682107/12/201911008306/14/201911007607/24/201911007506/13/2019110073
Dallas Hinton St. C401/C60/AH161 308/05/201911007009/05/201911006906/17/201912006609/06/2019110065
Dallas Executive Airport C402106/17/201912007408/05/201911007008/28/201911006809/06/2019100067
Greenville C1006/A198104/09/201911006905/15/201910006309/06/201910006209/07/2019100061
Pilot Point C1032105/14/201911008009/06/201911007609/03/201910007305/16/2019100073
Italy C1044/A323103/22/201910006505/30/201912006204/09/201910006106/12/2019110060
Corsicana Airport C1051106/12/201911007004/09/201911006606/14/201910006203/22/2019120062
Tyler-Longview-Marshall
Longview C19/A127/C644204/09/201911007405/13/201911006909/06/201910006808/15/2019110067
Tyler Airport Relocated C82104/09/201911008008/15/201912006804/15/201915006704/10/2019120067
Karnack C85/AFHP303105/15/201910006709/07/201910006609/06/201910006404/27/2019110062
El Paso-Juarez
El Paso UTEP C12/A125/X151/G125208/05/201910008307/15/201910007907/26/201910007708/15/2019110075
Ascarate Park SE C37/A332/A172/X159108/15/201910007307/15/201910006707/27/201910006407/26/2019100064
Chamizal C41/AH126 108/05/201910007908/10/201910007507/15/201910007507/27/2019110073
Socorro Hueco C49/F312108/08/201910007107/18/201910006808/10/201910006708/05/2019100067
Skyline Park C72108/10/201910007808/05/201910007608/07/201909007507/26/2019110072
BRAVO Big Bend C67/C316/C656/C6913 N01/27/201908004801/28/201908004401/24/201913004401/26/2019100043
Ivanhoe C414/F514108/15/201911007408/07/201910007108/05/201909007108/22/2019100070
Waco
Waco Mazanec C1037109/06/201911006406/14/201911006403/22/201911006309/13/2019110062
Temple Georgia C1045104/09/201911006706/14/201910006404/27/201910006303/22/2019110063
Killeen Skylark Field C1047104/09/201911007206/14/201909007104/27/201911006804/10/2019110067
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 203/22/201911007006/14/201910006806/18/201911006509/06/2019100064
West Orange C9/A141203/22/201912006809/07/201910006404/20/201912006403/20/2019110064
Port Arthur West C28/A128/A228106/12/201911007103/20/201911006603/22/201911006506/14/2019090064
Hamshire C64/C654103/22/201910006606/18/201909006506/14/201909006503/20/2019090065
SETRPC Port Arthur C6281 N06/12/201911007906/13/201909006803/22/201912006806/14/2019100067
SETRPC 40 Sabine Pass C640/C1654106/12/201911008506/13/201911007203/22/201911006804/20/2019110067
SETRPC Mauriceville 42 C642/C311/C6651 N03/23/201911006603/22/201911006609/07/201910006406/18/2019110064
SETRPC 43 Jefferson Co Airport C643106/12/201910007503/22/201911007409/06/201910007306/14/2019100069
Nederland High School C1035 103/22/201911006506/12/201910006406/14/201910006309/06/2019100061
Austin
Austin Northwest C3/A322209/06/201910006908/16/201911006604/09/201911006603/22/2019130063
Audubon C38109/06/201911007407/26/201910006504/09/201911006504/27/2019100063
Dripping Springs School C6141 N07/26/201910007407/25/201910006704/09/201911006706/14/2019090064
CAPCOG Lake Georgetown C6901 N06/14/201909007008/16/201911006704/09/201910006706/09/2019090064
Gorzycki Middle School C16031 N07/26/201911007207/25/201911006506/12/201913006504/09/2019110064
Lockhart C16041 N07/26/201911006606/08/201911006105/21/201911006104/27/2019110061
St. Edwards University C16051 N03/21/201911006007/26/201911005903/22/201912005906/12/2019110058
CAPCOG Bastrop CAMS16121 N03/21/201911006307/26/201911006106/14/201910006006/08/2019100059
CAPCOG Elgin C16131 N06/14/201910006406/08/201910006303/21/201911006103/22/2019090060
CAPCOG San Marcos Staples Road C16751 N07/26/201910006606/12/201911006603/22/201910006403/21/2019100063
CAPCOG Hutto College Street C66021 N07/26/201911006203/21/201911006209/06/201910006006/14/2019090060
Houston-Galveston-Brazoria
Houston East C1/G316206/09/201909008806/17/201913007608/15/201910007409/06/2019110070
Houston Aldine C8/AF108/X150 209/05/201910009309/06/201911008506/17/201912008106/01/2019110081
Channelview C15/AH115 306/17/201913007604/09/201911007306/01/201912007106/09/2019090070
Northwest Harris Co. C26/A110/X154209/05/201911008603/27/201911007705/15/201911007608/29/2019120074
Hou.DeerPrk2 C35/235/1001/AFH139FP239108/15/2019100010706/12/201910007804/09/201912007606/09/2019090074
Seabrook Friendship Park C45108/15/201910009009/06/201911007406/12/201911006703/21/2019110064
Houston Bayland Park C53/A146 106/12/201911009106/09/201909008306/13/201911008005/13/2019110080
Conroe Relocated C78/A321106/14/201910008303/22/201911007804/21/201910007504/27/2019100074
Manvel Croix Park C84106/12/201911009006/11/201910008007/25/201910007906/13/2019100079
Clinton C403/C304/AH113 306/09/201909009208/15/201911007803/20/201910007706/12/2019100073
Houston North Wayside C405109/05/201910007409/06/201911007306/09/201909007306/17/2019130067
Houston Monroe C406108/15/201911008206/12/201911008106/13/201910007107/25/2019090069
Lang C408206/09/201909008809/05/201910007909/06/201911007506/17/2019130075
Houston Croquet C409206/12/201911008406/11/201909008307/25/201910007706/13/2019100075
Houston Westhollow C410105/13/201911007707/26/201910007606/09/201909007607/25/2019100073
Park Place C416106/09/201909008808/15/201911008606/12/201911008206/13/2019100072
Baytown Wetlands Center C5521 N08/15/201910006709/06/201911006404/09/201911006204/20/2019100061
Crosby Library C5531 N09/07/201910007409/06/201911006409/05/201910006207/26/2019110059
West Houston C5541 N09/05/201910007609/06/201911006908/15/201914006508/29/2019110062
La Porte Sylvan Beach C5561 N08/15/201910007209/06/201911006306/30/201911005206/14/2019090051
Mercer Arboretum C5571 N07/01/2019210010307/02/201901009309/05/201911007209/06/2019110067
Tom Bass C5581 N06/12/201912009107/25/201910008206/13/201910008006/11/2019100079
Katy Park C5591 N07/26/201910008109/05/201910007405/14/201910007406/09/2019090071
Atascocita C5601 N06/14/201910005903/22/201911005806/17/201913005607/26/2019110054
Meyer Park C5611 N09/05/201911009009/06/201912008003/27/201911006906/14/2019090068
Bunker Hill Village C5621 N09/05/201910006809/06/201911006508/31/201910005808/15/2019110055
Huffman Wolf Road C5631 N09/07/201911007709/06/201911006409/05/201911006407/26/2019110064
HRM-3 Haden Road C603/A114 1 N06/09/201909008606/17/201913007503/20/201910007204/09/2019110071
Wallisville Road C617 1 N06/17/201913007604/09/201911007404/20/201911007009/07/2019100068
Danciger C618 1 N08/29/201911007506/13/201910007204/26/201910007007/25/2019110066
Texas City 34th St. C620 1 N08/15/2019110010706/12/201913008306/13/201919007706/09/2019100074
UH Moody Tower C6951 N06/09/201909009308/15/201911008806/12/201911008306/17/2019140077
UH WG Jones Forest C6981 N06/14/201910008309/05/201913007803/22/201911007709/06/2019130072
UH West Liberty C6991 N09/07/201910007203/22/201910006606/14/201910006504/15/2019100064
Lynchburg Ferry C1015/A165 106/17/201913007706/01/201909007006/09/201909006908/15/2019100068
Lake Jackson C1016 106/13/201911006807/25/201911006306/10/201909006303/20/2019100063
Baytown Garth C1017106/17/201913007604/09/201911007309/07/201910007004/20/2019110069
Galveston 99th St. C1034/A320/X183108/15/201912008106/13/201917008106/08/201915008103/22/2019130079
Oyster Creek C1607 1 N03/22/201910007304/26/201911007103/20/201910006903/21/2019100066
San Antonio
San Antonio Northwest C23206/13/201911007806/08/201911007607/26/201910007507/25/2019110074
Camp Bullis C58 107/26/201910007606/13/201911007004/09/201911007007/25/2019100069
Calaveras Lake C59107/26/201912006406/13/201910006306/07/201911006304/09/2019110063
Elm Creek Elementary C5011 N06/13/201910007007/26/201910006906/08/201911006906/12/2019110068
Fair Oaks Ranch C5021 N07/26/201910006704/09/201910006707/27/201911006207/25/2019110060
Bulverde Elementary C5031 N04/09/201911006707/26/201910006404/27/201910005904/20/2019110059
New Braunfels Airport C5041 N04/09/201911006306/12/201911005904/27/201910005807/26/2019110057
City of Garden Ridge C5051 N06/13/201910006604/09/201911006604/27/201911006107/26/2019100060
Seguin Outdoor Learning Center C5061 N03/22/201911006204/27/201910005904/09/201911005907/26/2019110057
Heritage Middle School C6221 N07/26/201911006006/07/201911005806/13/201910005706/08/2019110057
CPS Pecan Valley C6781 N06/08/201911006806/13/201910006207/26/201909006107/25/2019110059
Government Canyon C16101 N07/25/201911007206/08/201911007206/13/201911007104/09/2019110062
Corpus Christi-Victoria
Corpus Christi West C4206/13/201910006803/22/201909006703/21/201911006404/26/2019100062
Corpus Christi Tuloso C21107/26/201909006307/25/201912006107/24/201913005803/22/2019090058
Victoria C87103/22/201910006607/26/201910006509/14/201912006206/13/2019100062
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/AP143104/08/201911006504/26/201910005607/13/201910005506/13/2019120053
Harlingen Teege C1023103/21/201911006304/26/201911006104/20/201909006004/19/2019110059
Laredo
Laredo Vidaurri C44/AFGP144/P244107/25/201909006407/14/201911006307/24/201912006007/13/2019120059
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.