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Four Highest Eight-Hour Ozone Concentrations in 2018
as of February 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 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 201/25/201809004401/31/201810004001/06/201811003902/01/2018110038
Keller C17201/25/201811004601/06/201811004401/31/201810004001/05/2018110040
Frisco C31/C680101/04/201810003501/05/201810003301/01/201810003101/03/2018100029
Midlothian OFW C52/A137101/25/201811004601/06/201811004501/05/201811004201/31/2018110040
Denton Airport South C56/A163/X157101/31/201812004001/06/201811003902/01/201811003801/25/2018120038
Arlington Municipal Airport C61101/25/201812004501/06/201811004301/31/201810004101/05/2018100040
Dallas North No.2 C63/C679101/25/201812004401/06/201813004401/31/201810004101/28/2018100039
Rockwall Heath C69101/25/201812004601/06/201813004602/01/201812004402/02/2018110042
Grapevine Fairway C70/A301/X182101/25/201811004301/06/201813004101/31/201810004001/22/2018100040
Kaufman C71/A304/X071101/06/201813004801/25/201810004501/31/201811004102/01/2018120040
Granbury C73/C681101/25/201811004701/06/201811004302/01/201811004201/31/2018100042
Eagle Mountain Lake C75 101/25/201810004801/05/201811004501/31/201810004401/06/2018100044
Parker County C76101/25/201812004701/06/201810004301/05/201812004202/01/2018110041
Cleburne Airport C77/C682101/25/201811004901/06/201811004501/24/201811004401/05/2018110044
Dallas Hinton St. C401/C60/AH161 301/06/201811004201/25/201811004101/31/201811004002/01/2018110038
Dallas Executive Airport C402101/25/201810004401/06/201813004202/01/201812003801/31/2018100037
Greenville C1006/A198101/06/201812004801/25/201811004401/31/201810004102/01/2018120039
Pilot Point C1032101/31/201810004101/06/201814004101/25/201811004001/28/2018100038
Italy C1044/A323101/06/201811004501/05/201810004201/31/201811004002/01/2018120039
Corsicana Airport C1051101/06/201812004801/25/201810004701/05/201811004402/01/2018130042
Tyler-Longview-Marshall
Longview C19/A127/C644201/31/201814005001/25/201811004501/06/201811004401/05/2018100042
Tyler Airport Relocated C82101/25/201811004801/31/201812004601/06/201812004601/05/2018110045
Karnack C85/AFHP303101/25/201811004201/31/201811004101/06/201811004101/24/2018100038
El Paso-Juarez
El Paso UTEP C12/A125/X151201/29/201809004402/09/201810004301/27/201811004301/21/2018090043
Ascarate Park SE C37/A332/A172/X159102/08/201811004202/07/201809004201/24/201810003801/11/2018100037
Chamizal C41/AH126 101/21/201810004702/03/201811004601/29/201809004602/07/2018090045
Socorro Hueco C49/F312102/08/201810004301/29/201810004302/07/201810004201/21/2018090041
Skyline Park C72101/29/201809005002/08/201810004802/09/201810004702/05/2018090046
BRAVO Big Bend C67/C316/C656/C6913 N01/30/201803004901/29/201822004801/27/201814004601/22/2018100046
Ivanhoe C414102/08/201810004602/09/201810004302/07/201809004302/06/2018210043
Waco
Waco Mazanec C1037101/25/201811004401/06/201811004201/31/201812004101/05/2018120040
Temple Georgia C1045101/25/201811004402/01/201812004301/31/201812004201/06/2018110042
Killeen Skylark Field C1047101/25/201811004702/01/201813004601/31/201810004501/23/2018100043
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 201/31/201810004201/29/201811003801/15/201810003801/24/2018100037
West Orange C9/A141201/06/201810004201/25/201810003901/20/201811003901/15/2018110039
Port Arthur West C28/A128/A228101/06/201810004201/31/201810004101/25/201810004101/29/2018100039
Hamshire C64/C654101/25/201811004501/26/201811004401/31/201810004301/21/2018090042
SETRPC 40 Sabine Pass C640/C1654101/25/201811004501/06/201810004401/29/201810004301/31/2018100041
SETRPC 43 Jefferson Co Airport C643101/31/201810004401/25/201810004301/06/201810004301/26/2018100042
Nederland High School C1035 101/25/201811004201/06/201811004201/26/201810004101/29/2018100040
Austin
Austin Northwest C3/A322202/01/201813004401/25/201812004301/31/201812004101/28/2018110041
Audubon C38101/25/201811004501/31/201812004302/01/201813004201/28/2018120042
St. Edwards University C16051 N02/01/201814003901/28/201812003901/25/201812003901/29/2018100037
Houston-Galveston-Brazoria
Houston East C1/G316201/31/201810004402/01/201810003601/06/201810003601/21/2018070035
Houston Aldine C8/AF108/X150 201/31/201810004201/06/201810004201/24/201810003802/01/2018100037
Channelview C15/AH115 301/31/201810004101/29/201811003601/22/201810003601/06/2018100036
Northwest Harris Co. C26/A110/X154201/06/201811004401/31/201811004201/24/201810004201/22/2018100039
Hou.DeerPrk2 C35/235/1001/AFH139FP239101/31/201810004201/06/201810004101/25/201810003902/01/2018100036
Seabrook Friendship Park C45101/06/201812003801/31/201810003701/25/201812003701/24/2018100034
Houston Bayland Park C53/A146 101/31/201810004101/15/201810003801/24/201810003701/06/2018110037
Conroe Relocated C78/A321101/06/201812005001/31/201811004401/25/201811004301/24/2018100043
Manvel Croix Park C84101/31/201810004501/06/201811004501/15/201810004201/29/2018110040
Clinton C403/C304/AH113 301/06/201811004001/24/201810003601/25/201812003401/15/2018100034
Houston North Wayside C405101/06/201810003601/31/201810003501/24/201810003501/22/2018090031
Houston Monroe C406101/31/201810003901/06/201810003701/25/201810003602/01/2018100035
Lang C408201/31/201810004001/24/201810003701/06/201811003702/01/2018100035
Houston Croquet C409201/31/201810004002/01/201809003901/06/201811003901/15/2018100038
Houston Westhollow C410101/06/201812004301/31/201810004201/15/201810004001/25/2018110038
Park Place C416101/06/201811004001/31/201811003601/25/201810003601/15/2018100036
Baytown Wetlands Center C5521 N01/06/201813003601/15/201811003301/25/201810003201/26/2018100031
La Porte Sylvan Beach C5561 N02/19/201801001602/18/201823001602/09/201811001502/15/2018110014
Tom Bass C5581 N01/31/201810003801/15/201810003501/21/201809003101/25/2018100030
Katy Park C5591 N01/06/201812003501/31/201810003101/26/201811003001/25/2018120030
Atascocita C5601 N01/06/201810004401/31/201810004001/25/201810003801/24/2018100038
Meyer Park C5611 N01/06/201811003201/31/201811003101/24/201810002902/01/2018100026
HRM-3 Haden Road C603/A114 1 N01/25/201816006401/31/201810004001/06/201810003701/29/2018100035
Wallisville Road C617 1 N01/31/201810004401/06/201810004401/26/201811004201/23/2018100042
Danciger C618 1 N01/05/201811003901/04/201810003301/03/201810003101/01/2018100030
Texas City 34th St. C620 1 N01/06/201811004801/25/201811004501/05/201811004301/15/2018080041
UH Moody Tower C6951 N01/31/201810004301/06/201810004101/25/201810003801/15/2018090038
UH WG Jones Forest C6981 N01/06/201811004901/31/201811004601/24/201810004302/01/2018120042
UH West Liberty C6991 N01/06/201811004301/31/201810004201/24/201811003901/15/2018100039
Lynchburg Ferry C1015/A165 101/31/201811004101/06/201810003601/25/201813003401/29/2018110033
Lake Jackson C1016 101/31/201810004501/06/201811004501/25/201811004401/26/2018100041
Baytown Garth C1017101/06/201812004501/31/201810004301/15/201810004201/29/2018100039
Galveston 99th St. C1034/A320/X183101/06/201811004401/25/201812004101/05/201812004101/31/2018080040
Oyster Creek C1607 1 N01/06/201811004501/25/201811004401/31/201809004301/26/2018090042
San Antonio
San Antonio Northwest C23202/04/201811004701/31/201810004201/14/201811004201/10/2018120042
Camp Bullis C58 102/04/201811004401/10/201812004302/01/201813004201/31/2018100042
Calaveras Lake C59101/30/201811004401/25/201811004401/10/201812004401/14/2018110043
Heritage Middle School C6221 N02/04/201811004801/05/201814004301/14/201812004201/10/2018120042
Corpus Christi-Victoria
Corpus Christi West C4201/09/201812004501/10/201810004401/29/201810004301/31/2018100042
Corpus Christi Tuloso C21101/10/201811004102/01/201810004001/31/201810004001/29/2018100040
Victoria C87101/29/201811004001/06/201811004001/31/201811003901/25/2018120039
Holly Road C6601 N01/15/201811003201/14/201811003201/10/201811003201/09/2018130032
Violet C6641 N01/09/201814004501/06/201811004201/10/201812004101/08/2018100041
Lower Rio Grande Valley
Mission C43/AP143101/29/201811004102/01/201810004001/10/201810004001/04/2018120040
Brownsville C80/AGP180101/04/201817003201/03/201810002501/02/201815002101/01/2018180020
Harlingen Teege C1023101/05/201810004501/04/201812004401/10/201810004301/30/2018110042
Laredo
Laredo Vidaurri C44/AFGP144/P244101/29/201811003501/10/201810003502/01/201811003401/31/2018100033
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.