Skip to main content

Four Highest Eight-Hour Ozone Concentrations in 2019
as of January 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 201/06/201910003701/07/201910003401/04/201909003201/05/2019100031
Keller C17201/06/201911004001/05/201912003801/09/201911003601/07/2019110036
Frisco C31/C680101/06/201910004101/09/201910003801/08/201911003801/07/2019100035
Midlothian OFW C52/A137101/06/201908004001/05/201919003801/07/201910003501/08/2019110034
Denton Airport South C56/A163/X157101/06/201911004001/07/201911003901/08/201910003501/09/2019100034
Arlington Municipal Airport C61101/06/201909003901/07/201910003601/05/201911003401/08/2019110032
Dallas North No.2 C63/C679101/06/201909004001/09/201910003501/08/201911003501/07/2019100034
Rockwall Heath C69101/08/201912004001/09/201910003901/06/201909003901/20/2019100036
Grapevine Fairway C70/A301/X182101/07/201911003801/06/201909003801/08/201912003601/09/2019100035
Kaufman C71/A304/X071101/06/201910004001/20/201911003901/08/201911003901/05/2019120038
Granbury C73/C681101/07/201911004001/06/201911003901/20/201911003601/08/2019110036
Eagle Mountain Lake C75 101/07/201911004101/06/201910004101/05/201912004101/04/2019110039
Parker County C76101/05/201912004401/07/201911004101/06/201910004001/08/2019110039
Cleburne Airport C77/C682101/06/201911004301/07/201911003901/05/201911003901/04/2019100038
Dallas Hinton St. C401/C60/AH161 301/06/201910004001/09/201910003701/08/201911003601/19/2019190032
Dallas Executive Airport C402101/06/201908003901/05/201911003801/08/201911003701/07/2019100037
Greenville C1006/A198101/06/201909004201/08/201912003801/05/201910003801/20/2019100037
Pilot Point C1032101/06/201910004101/08/201911003801/07/201911003801/09/2019090036
Italy C1044/A323101/08/201912003801/05/201911003801/09/201910003701/06/2019080036
Corsicana Airport C1051101/05/201912003901/06/201909003801/20/201910003701/09/2019110035
Tyler-Longview-Marshall
Longview C19/A127/C644201/06/201910004001/20/201910003801/09/201909003801/08/2019100038
Tyler Airport Relocated C82101/05/201912004701/09/201911004201/06/201913004201/08/2019120041
Karnack C85/AFHP303101/06/201910003801/09/201910003701/08/201911003501/20/2019100034
El Paso-Juarez
El Paso UTEP C12/A125/X151/G125201/18/201916004001/13/201909004001/19/201910003701/12/2019100037
Ascarate Park SE C37/A332/A172/X159101/18/201917004001/19/201909003801/13/201909003601/12/2019110033
Chamizal C41/AH126 101/18/201917004401/19/201910004101/13/201909003801/11/2019130038
Socorro Hueco C49/F312101/19/201910004001/20/201910003901/18/201917003901/13/2019100039
Skyline Park C72101/19/201909004201/18/201916004201/11/201911004101/07/2019080041
BRAVO Big Bend C67/C316/C656/C6913 N01/20/201919004301/19/201910004001/08/201915004001/06/2019090040
Ivanhoe C414/F514101/19/201910004101/18/201917004001/11/201912003801/13/2019100037
Waco
Waco Mazanec C1037101/05/201913003601/20/201911003501/09/201911003501/08/2019120035
Temple Georgia C1045101/20/201910003501/11/201910003501/06/201910003501/05/2019110035
Killeen Skylark Field C1047101/06/201910004301/05/201911004201/20/201910003801/10/2019110037
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 201/06/201910004401/08/201910004101/05/201911004101/11/2019120039
West Orange C9/A141201/05/201911004601/11/201912004301/06/201911004301/08/2019100041
Port Arthur West C28/A128/A228101/06/201910004201/05/201912004201/11/201911003901/07/2019100038
Hamshire C64/C654101/11/201912004701/06/201910004301/05/201911004201/08/2019100039
SETRPC Port Arthur C6281 N01/06/201910004601/11/201913004301/05/201912004201/07/2019090037
SETRPC 40 Sabine Pass C640/C1654101/06/201910004601/11/201913004201/05/201910004201/07/2019100041
SETRPC Mauriceville 42 C642/C311/C6651 N01/06/201911004601/05/201911004401/11/201912004101/08/2019100041
SETRPC 43 Jefferson Co Airport C643101/06/201910004601/05/201912004601/11/201912004401/07/2019080041
Nederland High School C1035 101/11/201913004201/06/201910004201/05/201911004001/07/2019100038
Austin
Austin Northwest C3/A322201/05/201911003501/20/201909003401/09/201910003401/06/2019110034
Audubon C38101/05/201913004001/06/201910003801/20/201909003501/09/2019100035
Houston-Galveston-Brazoria
Houston East C1/G316201/11/201911003801/05/201910003701/06/201910003601/20/2019100033
Houston Aldine C8/AF108/X150 201/11/201912004801/05/201911004201/06/201910003801/08/2019100037
Channelview C15/AH115 301/11/201911004001/20/201911003301/07/201910003301/09/2019090032
Northwest Harris Co. C26/A110/X154201/05/201910004501/11/201911004301/06/201910003901/20/2019100035
Hou.DeerPrk2 C35/235/1001/AFH139FP239101/11/201912004601/05/201911004201/06/201910003901/10/2019110036
Seabrook Friendship Park C45101/11/201912004401/10/201913003901/06/201911003501/07/2019090034
Houston Bayland Park C53/A146 101/05/201911004001/11/201912003701/20/201909003001/10/2019110029
Conroe Relocated C78/A321101/11/201913005101/05/201911004501/06/201910004301/10/2019100039
Manvel Croix Park C84101/11/201911004601/05/201910004601/06/201909003801/10/2019100036
Clinton C403/C304/AH113 301/11/201912003901/05/201912003901/06/201910003601/09/2019090033
Houston North Wayside C405101/06/201910003101/05/201910003001/09/201909002901/10/2019100025
Houston Monroe C406101/11/201912003701/05/201911003501/06/201910003001/10/2019100028
Lang C408201/11/201912003801/05/201910003701/06/201910003301/20/2019090031
Houston Croquet C409201/05/201911004401/11/201911004201/06/201910003701/08/2019100033
Houston Westhollow C410101/05/201910004501/11/201911004401/06/201910003701/20/2019100033
Park Place C416101/05/201911004301/11/201913004201/06/201910003501/10/2019100032
Baytown Wetlands Center C5521 N01/11/201911003901/10/201910003001/09/201909002901/20/2019100028
Crosby Library C5531 N01/11/201911004001/05/201911003601/10/201910003101/06/2019100031
Katy Park C5591 N01/11/201912003601/05/201910003101/06/201910002701/09/2019090025
Atascocita C5601 N01/11/201912003501/06/201910002901/05/201910002801/20/2019100027
Meyer Park C5611 N01/11/201911002601/05/201911002501/06/201911002301/20/2019100021
Huffman Wolf Road C5631 N01/11/201911002401/06/201910002001/20/201910001901/10/2019100019
HRM-3 Haden Road C603/A114 1 N01/11/201911004401/05/201910003601/06/201909003301/09/2019090032
Wallisville Road C617 1 N01/11/201912004801/05/201911004101/06/201910004001/09/2019090037
Danciger C618 1 N01/05/201910004901/11/201910004601/10/201911004301/09/2019090039
Texas City 34th St. C620 1 N01/11/201910004801/05/201921004501/06/201909004201/10/2019100040
UH Moody Tower C6951 N01/05/201911004901/11/201911004601/06/201910004101/10/2019110036
UH WG Jones Forest C6981 N01/11/201912004901/05/201911004801/06/201911004101/20/2019110036
UH West Liberty C6991 N01/11/201912004601/05/201911004301/06/201910003901/10/2019100037
Lynchburg Ferry C1015/A165 101/11/201911004301/07/201909003501/10/201910003101/20/2019110030
Lake Jackson C1016 101/05/201910004501/11/201909004401/10/201911004101/09/2019100038
Baytown Garth C1017101/11/201911004801/06/201910004001/05/201911003901/10/2019110037
Galveston 99th St. C1034/A320/X183101/11/201912004901/05/201917004601/10/201913004101/07/2019070038
Oyster Creek C1607 1 N01/05/201911005601/11/201909005001/06/201909004901/10/2019100043
San Antonio
San Antonio Northwest C23201/05/201911004501/06/201911004101/10/201914003901/04/2019100036
Camp Bullis C58 101/05/201910004201/06/201910004101/04/201910004001/10/2019120036
Calaveras Lake C59101/10/201913004501/05/201911004201/06/201911003901/20/2019100037
Heritage Middle School C6221 N01/05/201912004101/10/201913003701/06/201910003201/04/2019110032
Corpus Christi-Victoria
Corpus Christi West C4201/05/201911004601/10/201911004501/09/201912004401/20/2019100038
Corpus Christi Tuloso C21101/05/201910004001/11/201909003901/10/201912003801/04/2019100036
Victoria C87101/05/201910004101/11/201909004001/10/201911004001/06/2019110036
Violet C6641 N01/10/201911004301/05/201911004301/11/201908004201/04/2019110041
Ingleside C6851 N01/11/201907004501/10/201911004501/05/201910004501/09/2019110042
Lower Rio Grande Valley
Mission C43/AP143101/10/201910003701/09/201916003701/05/201911003601/20/2019110035
Harlingen Teege C1023101/05/201911004801/10/201910004201/11/201903004001/06/2019100040
Laredo
Laredo Vidaurri C44/AFGP144/P244101/10/201910003801/06/201909003701/20/201910003601/05/2019100036
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.