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Four Highest Eight-Hour Ozone Concentrations in 2019
as of March 19

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 203/06/201911004503/09/201909004402/24/201910004302/23/2019100043
Keller C17203/18/201911005303/17/201912005103/06/201912004703/16/2019110046
Frisco C31/C680103/18/201911005903/17/201910005203/13/201908004903/16/2019100048
Midlothian OFW C52/A137103/18/201910005403/17/201910005103/13/201904004903/16/2019100047
Denton Airport South C56/A163/X157103/18/201911005803/17/201911005403/13/201905004803/16/2019100046
Arlington Municipal Airport C61103/18/201911005203/17/201911004803/06/201911004803/13/2019040047
Dallas North No.2 C63/C679103/18/201911005703/17/201911005303/13/201908004803/06/2019110048
Rockwall Heath C69103/18/201911005803/17/201911005103/06/201910004803/16/2019110047
Grapevine Fairway C70/A301/X182103/18/201911005403/17/201911005203/16/201911004703/15/2019110046
Kaufman C71/A304/X071103/18/201910005603/17/201910005103/13/201905005103/09/2019110050
Granbury C73/C681103/18/201911005803/17/201911005403/16/201911004803/06/2019100048
Eagle Mountain Lake C75 103/18/201911005903/17/201911005503/06/201911005003/13/2019040049
Parker County C76103/18/201910006103/17/201912005603/16/201911005003/13/2019030050
Cleburne Airport C77/C682103/18/201910006003/17/201910005503/16/201911005103/06/2019110051
Dallas Hinton St. C401/C60/AH161 303/18/201911005403/17/201912005203/16/201911005003/09/2019100049
Dallas Executive Airport C402103/18/201910005502/23/201910005303/17/201911005203/06/2019110050
Greenville C1006/A198103/18/201910005603/17/201910004903/13/201905004803/06/2019100048
Pilot Point C1032103/18/201910005903/17/201911005403/13/201909005103/16/2019090047
Italy C1044/A323103/18/201910005603/17/201910005303/06/201911005203/16/2019100050
Corsicana Airport C1051103/18/201910005303/17/201910005203/13/201905005003/06/2019110050
Tyler-Longview-Marshall
Longview C19/A127/C644203/18/201911005903/17/201911005102/23/201913004903/14/2019090047
Tyler Airport Relocated C82103/18/201912006203/17/201910005703/09/201912005403/13/2019070052
Karnack C85/AFHP303103/18/201910005103/17/201910004802/23/201914004603/16/2019100044
El Paso-Juarez
El Paso UTEP C12/A125/X151/G125203/13/201912005302/17/201909005302/16/201911005302/26/2019090052
Ascarate Park SE C37/A332/A172/X159103/13/201919004902/16/201915004902/17/201909004802/11/2019130047
Chamizal C41/AH126 103/14/201910005603/13/201916005102/16/201912005102/11/2019130051
Socorro Hueco C49/F312103/14/201909005302/17/201909004903/18/201909004803/15/2019110048
Skyline Park C72103/14/201909005703/13/201916005203/12/201916005202/17/2019010052
BRAVO Big Bend C67/C316/C656/C6913 N01/27/201908004801/28/201908004401/24/201913004401/26/2019100043
Ivanhoe C414/F514102/11/201912005003/09/201908004902/17/201909004902/16/2019120049
Waco
Waco Mazanec C1037103/18/201911005203/17/201910005203/06/201913004903/16/2019100047
Temple Georgia C1045103/17/201911005503/18/201910005303/16/201910004903/06/2019100049
Killeen Skylark Field C1047103/17/201911005903/18/201911005603/16/201912005403/13/2019110053
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 203/18/201912005003/17/201910004603/14/201911004503/06/2019100045
West Orange C9/A141203/18/201911004903/06/201911004802/14/201909004801/28/2019100048
Port Arthur West C28/A128/A228103/18/201912005103/06/201912004702/14/201909004501/27/2019110045
Hamshire C64/C654103/18/201911005203/14/201911005003/17/201910004801/28/2019100047
SETRPC Port Arthur C6281 N03/18/201911005003/06/201910004801/27/201911004703/14/2019100046
SETRPC 40 Sabine Pass C640/C1654103/14/201911005003/06/201910004902/14/201909004901/27/2019110049
SETRPC Mauriceville 42 C642/C311/C6651 N03/18/201910005203/06/201911005003/14/201912004801/28/2019100048
SETRPC 43 Jefferson Co Airport C643103/18/201911005203/06/201914005102/14/201909004901/28/2019090049
Nederland High School C1035 103/18/201912004903/06/201911004602/14/201909004501/28/2019090045
Austin
Austin Northwest C3/A322203/17/201911005503/18/201911005203/16/201911005002/23/2019100050
Audubon C38103/17/201911005503/18/201909005203/16/201912005102/23/2019100049
Dripping Springs School C6141 N03/17/201910005103/18/201910004803/14/201908004803/13/2019110047
CAPCOG Lake Georgetown C6901 N03/17/201911005703/18/201910005303/16/201911005103/13/2019110049
Gorzycki Middle School C16031 N03/17/201911005203/18/201910004903/16/201911004703/14/2019090047
Lockhart C16041 N03/14/201909002903/15/201909002703/06/201912002703/18/2019110025
St. Edwards University C16051 N03/17/201911004903/18/201911004803/14/201909004803/16/2019110047
CAPCOG San Marcos Staples Road C16751 N03/18/201911005303/17/201911005303/16/201911005003/14/2019090049
CAPCOG Hutto College Street C66021 N03/17/201911005303/18/201910005003/16/201911005003/14/2019090047
Houston-Galveston-Brazoria
Houston East C1/G316202/14/201910004901/28/201910004603/17/201911004503/18/2019100043
Houston Aldine C8/AF108/X150 203/18/201911005303/17/201911005003/14/201910004901/28/2019100048
Channelview C15/AH115 303/14/201911004803/17/201910004502/14/201909004503/18/2019100044
Northwest Harris Co. C26/A110/X154203/18/201911005403/14/201911005003/17/201910004903/16/2019100047
Hou.DeerPrk2 C35/235/1001/AFH139FP239103/18/201912004703/14/201911004703/06/201911004601/11/2019120046
Seabrook Friendship Park C45103/06/201912004603/18/201912004503/17/201910004401/27/2019130044
Houston Bayland Park C53/A146 103/06/201911004803/17/201910004703/14/201910004703/18/2019120045
Conroe Relocated C78/A321103/06/201913005403/18/201910005303/14/201910005101/11/2019130051
Manvel Croix Park C84103/14/201910005003/17/201910004903/18/201911004803/06/2019100047
Clinton C403/C304/AH113 303/17/201911004503/14/201910004203/15/201909004003/05/2019090040
Houston North Wayside C405103/18/201911004503/17/201910004303/06/201911004003/14/2019100039
Houston Monroe C406103/18/201912004003/06/201910003803/17/201910003703/14/2019100037
Lang C408203/17/201911004703/18/201911004603/16/201911004403/14/2019100043
Houston Croquet C409203/06/201912004603/18/201911004403/17/201911004403/14/2019100044
Houston Westhollow C410103/17/201911005003/14/201910004703/06/201912004703/18/2019120045
Park Place C416103/17/201911004401/05/201911004303/14/201910004203/06/2019110042
Baytown Wetlands Center C5521 N03/18/201911004203/06/201912004103/17/201911004003/14/2019110040
Crosby Library C5531 N03/18/201911004503/17/201910004103/14/201910004103/06/2019110041
Katy Park C5591 N03/17/201911004903/06/201912004803/18/201911004703/14/2019100046
Atascocita C5601 N03/18/201911003903/14/201911003703/06/201912003703/17/2019100036
Meyer Park C5611 N03/18/201911004903/17/201910004403/16/201910004303/15/2019100041
Huffman Wolf Road C5631 N03/18/201911003003/14/201910002903/06/201911002803/17/2019100027
HRM-3 Haden Road C603/A114 1 N03/17/201910004703/18/201910004503/14/201911004501/27/2019100045
Wallisville Road C617 1 N03/18/201911005103/14/201910005003/06/201912004903/17/2019100048
Danciger C618 1 N03/17/201910005302/24/201911005103/18/201911005003/06/2019110049
Texas City 34th St. C620 1 N01/27/201912005503/18/201913005303/06/201912005303/17/2019110052
UH Moody Tower C6951 N03/17/201911005003/14/201910004901/05/201911004903/06/2019110047
UH WG Jones Forest C6981 N03/18/201911005203/17/201911005003/16/201911004903/06/2019120049
UH West Liberty C6991 N03/18/201911005103/17/201910004903/06/201912004802/14/2019090046
Lynchburg Ferry C1015/A165 103/18/201911004603/06/201912004501/28/201910004402/14/2019090043
Lake Jackson C1016 103/17/201911005102/24/201911005103/18/201911004903/14/2019100049
Baytown Garth C1017103/18/201911005203/06/201912005003/14/201910004901/11/2019110048
Galveston 99th St. C1034/A320/X183103/06/201913005201/27/201913005203/18/201914005103/17/2019110049
Oyster Creek C1607 1 N01/05/201911005603/17/201911005403/06/201912005403/18/2019120053
San Antonio
San Antonio Northwest C23203/18/201912005203/17/201911005103/14/201909005103/13/2019110048
Camp Bullis C58 103/18/201910005103/17/201910005103/14/201909005103/13/2019110050
Calaveras Lake C59103/18/201911005403/14/201910005303/17/201911004903/06/2019100049
Elm Creek Elementary C5011 N03/14/201910005003/18/201911004903/17/201911004803/06/2019100046
Fair Oaks Ranch C5021 N03/18/201910004903/17/201910004903/13/201910004903/14/2019090048
Bulverde Elementary C5031 N03/18/201910004903/17/201910004903/14/201909004803/13/2019110048
New Braunfels Airport C5041 N03/18/201911004603/14/201909004503/06/201911004503/17/2019110043
City of Garden Ridge C5051 N03/18/201911005003/14/201909004903/17/201911004703/06/2019100045
Seguin Outdoor Learning Center C5061 N03/18/201911004903/06/201910004703/14/201910004603/17/2019110045
Heritage Middle School C6221 N03/18/201911004703/14/201909004603/17/201911004303/06/2019100043
CPS Pecan Valley C6781 N03/06/201911003203/14/201910003102/24/201910003003/15/2019110028
Government Canyon C16101 N03/18/201910004803/17/201910004803/14/201908004703/13/2019100046
Corpus Christi-Victoria
Corpus Christi West C4203/18/201912005303/06/201911005103/14/201910005001/27/2019110047
Corpus Christi Tuloso C21103/18/201911004603/14/201911004603/17/201912004303/06/2019110042
Victoria C87103/14/201910005103/06/201911004603/15/201913004402/24/2019100044
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/AP143103/17/201911004303/14/201919004302/24/201911004202/13/2019110042
Harlingen Teege C1023103/18/201913005203/14/201914004902/13/201910004801/05/2019110048
Laredo
Laredo Vidaurri C44/AFGP144/P244102/15/201910005403/18/201912005103/14/201911005102/24/2019120046
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.