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Four Highest Eight-Hour Ozone Concentrations in 2018
as of April 26

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 2018 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 204/24/201812007604/16/201811006104/11/201814006003/15/2018100059
Keller C17204/24/201812007704/16/201811006203/15/201810006104/11/2018120060
Frisco C31/C680101/04/201810003501/05/201810003301/01/201810003101/03/2018100029
Midlothian OFW C52/A137104/24/201812007304/16/201811006104/10/201811005903/24/2018120059
Denton Airport South C56/A163/X157103/15/201810006704/24/201810006403/22/201811006304/16/2018120062
Arlington Municipal Airport C61104/24/201812007704/16/201812006104/11/201812005903/15/2018100059
Dallas North No.2 C63/C679104/24/201811007504/16/201812006404/11/201813006103/15/2018100060
Rockwall Heath C69104/24/201811007103/03/201811006303/14/201810006103/22/2018130060
Grapevine Fairway C70/A301/X182104/24/201811007404/16/201811006103/15/201810006004/11/2018110058
Kaufman C71/A304/X071104/24/201810006703/22/201812006204/18/201810006003/15/2018100058
Granbury C73/C681104/24/201811006804/16/201811006004/11/201812006003/14/2018110059
Eagle Mountain Lake C75 104/24/201811007404/16/201812006404/11/201813006403/15/2018100062
Parker County C76104/24/201812007203/14/201811006004/16/201812005804/11/2018140058
Cleburne Airport C77/C682104/24/201811007104/16/201811006504/11/201813006404/10/2018120058
Dallas Hinton St. C401/C60/AH161 304/24/201811008104/16/201811006104/11/201813005903/15/2018100058
Dallas Executive Airport C402104/24/201811008104/16/201811006204/11/201812005903/15/2018100058
Greenville C1006/A198104/24/201810006403/22/201815006203/15/201809005904/16/2018130058
Pilot Point C1032104/24/201810006704/16/201812006404/11/201812006203/15/2018100060
Italy C1044/A323104/18/201810006103/14/201811006004/23/201811005804/11/2018120058
Corsicana Airport C1051104/24/201812006403/22/201812006204/18/201810006104/23/2018110059
Tyler-Longview-Marshall
Longview C19/A127/C644204/17/201812006403/15/201810005903/22/201811005803/14/2018110058
Tyler Airport Relocated C82104/12/201812006504/24/201810006404/17/201813006103/15/2018100061
Karnack C85/AFHP303103/15/201810006004/17/201810005703/22/201810005604/16/2018100055
El Paso-Juarez
El Paso UTEP C12/A125/X151204/10/201811006404/23/201809006304/18/201809006304/20/2018130062
Ascarate Park SE C37/A332/A172/X159104/18/201811005904/21/201809005604/10/201811005604/15/2018110054
Chamizal C41/AH126 104/23/201810006604/20/201813006504/18/201809006404/10/2018110063
Socorro Hueco C49/F312104/20/201813005804/21/201810005704/18/201810005704/16/2018110057
Skyline Park C72104/18/201810006504/23/201809006404/20/201813006404/10/2018110063
BRAVO Big Bend C67/C316/C656/C6913 N04/21/201812006904/17/201815006304/16/201811006204/18/2018110061
Ivanhoe C414104/23/201810006304/20/201814006304/18/201809006004/16/2018110060
Waco
Waco Mazanec C1037104/24/201811006404/18/201810006104/11/201811005804/10/2018110056
Temple Georgia C1045104/24/201810006404/18/201810006404/11/201812006204/16/2018100060
Killeen Skylark Field C1047104/16/201810006504/24/201810006304/18/201810006304/17/2018100061
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 204/25/201810007104/16/201810006403/14/201810005804/23/2018100056
West Orange C9/A141204/25/201810007504/16/201811006504/21/201815005703/03/2018110057
Port Arthur West C28/A128/A228104/25/201810006704/16/201811005804/24/201811005704/23/2018100056
Hamshire C64/C654104/25/201809007204/16/201810006004/23/201810005804/17/2018090057
SETRPC Port Arthur C6281 N04/25/201809006704/24/201811005704/23/201810005604/19/2018100054
SETRPC 40 Sabine Pass C640/C1654104/25/201811007604/16/201810006204/24/201810006104/23/2018100059
SETRPC Mauriceville 42 C642/C311/C6651 N04/25/201811007704/21/201816005904/23/201811005604/19/2018100055
SETRPC 43 Jefferson Co Airport C643104/25/201810007104/16/201810006103/14/201810005904/23/2018100058
Nederland High School C1035 104/25/201810006904/16/201811006404/21/201812005804/17/2018080058
Austin
Austin Northwest C3/A322204/24/201811006504/18/201812006504/11/201811006003/14/2018110060
Audubon C38104/24/201810006704/18/201811006304/11/201811006203/13/2018130059
Fayette County C6012 N04/24/201812006203/21/201811006004/25/201809005904/23/2018100059
Dripping Springs School C6141 N04/24/201812006904/18/201812006504/11/201811006304/16/2018100058
CAPCOG McKinney Roughs C6841 N04/18/201813005404/23/201811005304/24/201811005104/11/2018110051
CAPCOG Lake Georgetown C6901 N04/24/201810006904/18/201810006304/11/201811006104/16/2018100060
Gorzycki Middle School C16031 N04/11/201811006003/14/201811005504/10/201811005303/13/2018120053
Lockhart C16041 N04/18/201813006704/23/201810006504/24/201810005803/14/2018110058
St. Edwards University C16051 N04/18/201812006404/24/201811005904/23/201810005404/11/2018100054
CAPCOG San Marcos Staples Road C16751 N04/24/201811006604/18/201812006304/11/201810006103/14/2018110060
CAPCOG Hutto College Street C66021 N04/18/201811006604/24/201810006104/23/201811005904/11/2018110057
Houston-Galveston-Brazoria
Houston East C1/G316204/25/201810007304/24/201810006504/16/201810005903/21/2018100058
Houston Aldine C8/AF108/X150 204/25/201810007804/24/201811006904/23/201810006404/16/2018110062
Channelview C15/AH115 304/25/201809007104/24/201810006904/23/201811006204/15/2018090057
Northwest Harris Co. C26/A110/X154204/25/201809006704/24/201810006203/14/201811006004/23/2018100059
Hou.DeerPrk2 C35/235/1001/AFH139FP239104/24/201812007604/25/201809006904/23/201811006103/21/2018110059
Seabrook Friendship Park C45104/24/201812008404/25/201808006604/23/201811006003/21/2018100056
Houston Bayland Park C53/A146 104/25/201810007304/24/201810007003/14/201810006903/21/2018110063
Conroe Relocated C78/A321104/25/201808006604/16/201811006604/11/201811006604/24/2018100065
Manvel Croix Park C84104/24/201811007704/25/201809006603/14/201810006604/23/2018100061
Clinton C403/C304/AH113 304/24/201810006604/25/201810005903/21/201811005703/14/2018110056
Houston North Wayside C405104/25/201809006304/24/201810006103/14/201810005404/23/2018100053
Houston Monroe C406104/24/201812006904/25/201809006204/23/201811005704/15/2018090054
Lang C408204/25/201809007204/24/201811006604/23/201809005904/16/2018110059
Houston Croquet C409204/25/201809006704/24/201810006703/14/201811006303/21/2018110057
Houston Westhollow C410104/25/201809006904/24/201810006703/21/201811006303/14/2018110063
Park Place C416104/24/201812007204/25/201809007003/21/201811006103/14/2018110061
Baytown Wetlands Center C5521 N04/24/201812005604/25/201809005404/23/201811004804/16/2018120046
Crosby Library C5531 N04/25/201809008504/24/201810006404/23/201810006004/16/2018110059
La Porte Sylvan Beach C5561 N04/16/201813004204/15/201810004003/21/201813004003/22/2018140039
Tom Bass C5581 N04/16/201811005004/24/201814004903/22/201811004804/25/2018090047
Katy Park C5591 N04/25/201809005404/24/201810005304/19/201810005003/21/2018120050
Atascocita C5601 N04/25/201810007704/24/201810006104/16/201811006103/14/2018110058
Meyer Park C5611 N04/25/201809004503/14/201811004303/22/201811004204/16/2018110041
Bunker Hill Village C5621 N04/25/201810005604/24/201811005403/14/201811005304/19/2018100051
Huffman Wolf Road C5631 N04/25/201810004803/29/201811003604/16/201811003504/23/2018110034
HRM-3 Haden Road C603/A114 1 N04/25/201810006803/21/201810005904/23/201810005704/16/2018100056
Wallisville Road C617 1 N04/25/201809007804/24/201811006704/23/201810006304/16/2018110062
Danciger C618 1 N01/05/201811003901/04/201810003201/03/201810003101/01/2018100030
Texas City 34th St. C620 1 N04/24/201811008804/23/201811006604/25/201808006504/15/2018100059
UH Moody Tower C6951 N04/25/201810007404/24/201811007203/14/201811006403/21/2018110062
UH WG Jones Forest C6981 N04/25/201809006704/16/201812006603/22/201811006404/24/2018110063
UH West Liberty C6991 N04/25/201809008004/16/201810006203/29/201811006104/11/2018100056
Lynchburg Ferry C1015/A165 104/25/201810006404/24/201810005803/21/201811005604/23/2018100055
Lake Jackson C1016 104/24/201810006904/25/201808006303/14/201810006104/23/2018100059
Baytown Garth C1017104/25/201809008104/24/201811006604/23/201810006204/16/2018100062
Galveston 99th St. C1034/A320/X183104/24/201812008304/25/201810006904/23/201812006904/15/2018110062
Oyster Creek C1607 1 N04/24/201811007004/25/201808006404/23/201811006104/19/2018110060
San Antonio
San Antonio Northwest C23204/23/201812007304/24/201811006703/14/201812006204/18/2018150061
Camp Bullis C58 104/23/201812007704/24/201809007304/11/201810006403/14/2018110062
Calaveras Lake C59104/24/201811006603/14/201811006504/23/201811006204/11/2018090061
Elm Creek Elementary C5011 N04/23/201811006204/24/201809006103/14/201810005904/11/2018090058
Fair Oaks Ranch C5021 N04/24/201811006904/23/201813006703/21/201812006204/11/2018110060
Bulverde Elementary C5031 N04/24/201811006904/23/201812006804/11/201811006304/18/2018140059
New Braunfels Airport C5041 N04/24/201811006304/18/201814005804/11/201810005803/14/2018110058
City of Garden Ridge C5051 N04/23/201812007104/24/201811006704/18/201815006504/11/2018100062
Seguin Outdoor Learning Center C5061 N04/24/201810006104/23/201811005904/11/201810005903/14/2018110059
Heritage Middle School C6221 N04/24/201812006304/23/201811006203/14/201811006204/11/2018090058
CPS Pecan Valley C6781 N03/14/201811005203/06/201811004703/08/201811004603/13/2018120045
Government Canyon C16101 N04/24/201811006704/23/201811006604/11/201809006004/19/2018100057
Corpus Christi-Victoria
Corpus Christi West C4204/25/201807006004/19/201812005903/14/201811005704/24/2018100056
Corpus Christi Tuloso C21104/25/201808006604/24/201811005803/14/201810005804/19/2018110057
Victoria C87104/24/201810006404/25/201808006303/14/201811005704/23/2018110055
Holly Road C6601 N01/15/201811003201/14/201811003201/10/201811003201/09/2018130032
Violet C6641 N03/08/201811005103/19/201811005003/14/201811005001/09/2018140045
Ingleside C6851 N03/30/201811005403/31/201808005303/23/201801005103/29/2018110048
Lower Rio Grande Valley
Mission C43/AP143104/23/201812005903/14/201810005904/15/201811005703/21/2018120055
Brownsville C80/AGP180101/04/201817003201/03/201810002501/02/201815002101/01/2018180020
Harlingen Teege C1023104/25/201808006404/23/201813006004/24/201810005903/14/2018090058
Laredo
Laredo Vidaurri C44/AFGP144/P244104/22/201811005703/21/201815005403/20/201811005304/19/2018200052
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.