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Four Highest Eight-Hour Ozone Concentrations in 2020
as of April 4

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 2020 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 203/25/202011005402/29/202011005003/28/202010004703/31/2020100043
Keller C17203/25/202011005302/29/202012005203/28/202010004603/29/2020100044
Frisco C31/C680103/25/202011006102/29/202012005603/28/202010004904/01/2020090046
Midlothian OFW C52/A137103/25/202011005903/31/202011005503/28/202011005503/24/2020110053
Denton Airport South C56/A163/X157103/25/202012005502/29/202012005403/28/202010004801/08/2020110046
Arlington Municipal Airport C61103/25/202011005403/28/202011004803/24/202011004802/29/2020110048
Dallas North No.2 C63/C679103/25/202011005902/29/202012005403/28/202011004803/24/2020110047
Rockwall Heath C69102/29/202011005503/25/202011005303/28/202011004803/24/2020110046
Grapevine Fairway C70/A301/X182103/25/202011005402/29/202012005103/28/202010004703/29/2020110045
Kaufman C71/A304/X071102/29/202011005503/25/202011005403/24/202013005101/08/2020120047
Granbury C73/C681102/29/202012005203/25/202010004903/28/202010004504/01/2020140044
Eagle Mountain Lake C75 103/25/202011005602/29/202012005603/28/202009004901/08/2020110047
Parker County C76103/25/202010005302/29/202012005203/28/202010004801/08/2020110048
Cleburne Airport C77/C682102/29/202011005501/08/202011004903/28/202010004704/01/2020140046
Dallas Hinton St. C401/C60/AH161 303/25/202011005402/29/202011005103/28/202011004503/31/2020110044
Dallas Executive Airport C402103/25/202011005602/29/202012005303/24/202011004903/31/2020110048
Greenville C1006/A198103/25/202012005702/29/202011005403/28/202010004803/24/2020110046
Pilot Point C1032103/25/202011006402/29/202012005503/28/202010004903/26/2020100048
Italy C1044/A323103/25/202010005302/29/202011005203/28/202009004701/08/2020110045
Corsicana Airport C1051103/25/202011005502/29/202011005501/08/202012004504/01/2020100044
Tyler-Longview-Marshall
Longview C19/A127/C644203/25/202011005003/27/202013004804/02/202009004604/01/2020100044
Tyler Airport Relocated C82102/29/202013006003/25/202010005203/24/202014005003/05/2020120047
Karnack C85/AFHP303102/29/202011006003/08/202011005104/01/202010005004/02/2020110049
El Paso-Juarez
El Paso UTEP C12/A125/X151/G125203/31/202011005703/23/202011005303/30/202009005203/22/2020090051
Ascarate Park SE C37/A332/A172/X159103/31/202011005403/30/202009005203/22/202010005203/29/2020100050
Chamizal C41/AH126 103/31/202010005703/23/202011005703/22/202010005703/24/2020100055
Socorro Hueco C49/F312103/31/202010005403/30/202010005303/22/202010005303/23/2020100052
Skyline Park C72103/31/202010005503/23/202011005403/30/202009005303/22/2020100053
Ivanhoe C414/F514103/30/202009005403/23/202011005403/31/202010005303/22/2020100053
Waco
Waco Mazanec C1037102/29/202012005501/08/202012005004/01/202012004903/28/2020100048
Temple Georgia C1045103/25/202011005302/29/202011005304/01/202012004903/28/2020100047
Killeen Skylark Field C1047103/25/202011005702/29/202011005404/01/202011005103/28/2020110050
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 202/29/202010005804/02/202014005404/01/202011005303/01/2020070051
West Orange C9/A141202/29/202010005704/02/202011005303/25/202010005304/01/2020100052
Port Arthur West C28/A128/A228102/29/202010005204/01/202010004903/29/202010004902/02/2020110048
Hamshire C64/C654102/29/202010005703/29/202011005404/01/202010005204/02/2020100051
SETRPC Port Arthur C6281 N02/29/202010005903/01/202008005002/28/202010005003/08/2020100049
SETRPC 40 Sabine Pass C640/C1654102/29/202010005704/02/202015005404/03/202015005004/01/2020090050
SETRPC Mauriceville 42 C642/C311/C6651 N02/29/202010006503/25/202011006004/02/202011005804/01/2020100058
SETRPC 43 Jefferson Co Airport C643102/29/202010005804/02/202015005504/01/202010005203/29/2020110052
Nederland High School C1035 102/29/202010005604/02/202014005202/02/202011004904/01/2020120047
Austin
Austin Northwest C3/A322202/02/202012004601/08/202012004601/05/202010004501/21/2020120041
Audubon C38102/29/202011005404/01/202010005203/25/202011005203/29/2020100050
Dripping Springs School C6141 N04/01/202011005203/29/202011005203/25/202010005103/28/2020110050
CAPCOG Lake Georgetown C6901 N04/01/202011005102/29/202010005103/29/202010004903/25/2020130048
Lockhart C16041 N04/01/202011005203/29/202010004903/31/202011004403/28/2020120044
St. Edwards University C16051 N04/01/202011004603/29/202010004602/29/202010004603/24/2020130045
CAPCOG Bastrop CAMS16121 N04/01/202010004902/29/202010004803/29/202010004702/28/2020100042
CAPCOG Elgin C16131 N04/01/202011004703/29/202010004603/06/202010004403/24/2020120042
CAPCOG East Austin C16191 N03/12/202011005104/01/202012005003/11/202012005003/14/2020110049
CAPCOG San Marcos Staples Road C16751 N04/01/202011005503/29/202010005302/29/202010005302/28/2020120052
CAPCOG Hutto College Street C66021 N03/29/202010005004/01/202011004903/28/202011004603/24/2020120045
Houston-Galveston-Brazoria
Houston East C1/G316203/29/202011005202/29/202010005204/01/202011005102/02/2020110048
Houston Aldine C8/AF108/X150 204/01/202010005703/29/202011005202/29/202010005203/25/2020110050
Channelview C15/AH115 303/29/202011005002/29/202010005002/28/202011004902/25/2020120046
Northwest Harris Co. C26/A110/X154204/01/202011006103/25/202011005303/08/202010005104/03/2020090050
Hou.DeerPrk2 C35/235/1001/AFH139FP239103/29/202012005904/01/202010005302/29/202010005304/02/2020070049
Seabrook Friendship Park C45103/29/202012005002/29/202012004804/02/202006004602/28/2020100046
Houston Bayland Park C53/A146 103/29/202012006104/01/202011005903/06/202011005302/29/2020110053
Conroe Relocated C78/A321103/25/202011006504/01/202011005602/29/202011005303/26/2020100048
Manvel Croix Park C84103/29/202011005702/29/202010005202/28/202010005204/01/2020100051
Clinton C403/C304/AH113 303/29/202011005304/01/202010005102/29/202011004803/08/2020110045
Houston North Wayside C405104/01/202010004603/29/202011004502/29/202011004503/08/2020100042
Houston Monroe C406103/29/202011005304/01/202009005002/29/202010004602/28/2020100046
Lang C408204/01/202010005403/29/202011005102/29/202011005103/25/2020100047
Houston Croquet C409203/29/202011005604/01/202010005002/29/202010004902/28/2020100047
Houston Westhollow C410103/29/202012005704/01/202011005602/29/202011004902/28/2020100049
Park Place C416103/29/202011005504/01/202010005102/29/202010004704/02/2020100046
Sheldon C5511 N02/29/202011005202/28/202011005104/01/202011005003/29/2020110049
Baytown Wetlands Center C5521 N03/29/202011005704/01/202010005104/02/202013004902/29/2020110049
Crosby Library C5531 N03/25/202010004702/28/202010004701/08/202011004704/01/2020100046
West Houston C5541 N04/01/202012005101/08/202011004004/02/202009003903/08/2020110038
La Porte Sylvan Beach C5561 N03/29/202011005604/01/202011005202/16/202011005104/02/2020100050
Mercer Arboretum C5571 N04/01/202010005303/25/202010005102/29/202011005003/06/2020100048
Tom Bass C5581 N03/29/202011005604/01/202011005402/29/202010005002/28/2020110048
Katy Park C5591 N04/01/202011005503/29/202010005102/29/202011005003/06/2020100048
Atascocita C5601 N02/29/202011005004/01/202010004903/25/202010004904/02/2020100046
Meyer Park C5611 N04/01/202011005903/25/202011005602/29/202012005404/03/2020090050
Bunker Hill Village C5621 N04/01/202011005303/29/202011005102/29/202011004903/06/2020110047
Huffman Wolf Road C5631 N03/25/202010005902/29/202011005504/01/202010005202/28/2020110051
HRM-3 Haden Road C603/A114 1 N03/29/202011005202/29/202010004603/08/202011004502/28/2020100045
Wallisville Road C617 1 N02/29/202010005403/29/202010005302/28/202010005204/02/2020090051
Danciger C618 1 N01/08/202011004902/08/202012004802/07/202011004701/25/2020110046
Texas City 34th St. C620 1 N03/29/202011006002/29/202010005802/25/202013005804/01/2020090057
UH Moody Tower C6951 N03/29/202012005702/29/202010005202/28/202011005103/08/2020090048
UH WG Jones Forest C6981 N03/25/202011006104/01/202011005602/02/202012005004/03/2020090048
UH West Liberty C6991 N03/25/202010005304/01/202010005002/29/202010005002/28/2020120047
Lynchburg Ferry C1015/A165 104/01/202010005003/29/202010005002/29/202013004904/02/2020080045
Lake Jackson C1016 102/25/202011006303/29/202011005802/28/202011005502/29/2020100053
Baytown Garth C1017102/29/202010005203/29/202010005104/01/202010005004/02/2020090048
Galveston 99th St. C1034/A320/X183102/29/202012005704/03/202023005303/29/202010005302/28/2020120053
Oyster Creek C1607 1 N03/29/202010005502/28/202011005203/06/202010005102/25/2020110051
San Antonio
San Antonio Northwest C23204/01/202011005403/29/202010005103/25/202012005102/29/2020100050
Camp Bullis C58 104/01/202011005803/29/202009005402/29/202011005302/28/2020100053
Calaveras Lake C59104/01/202010005402/29/202010005203/29/202009005102/22/2020110051
Elm Creek Elementary C5011 N04/01/202011004902/29/202010004802/28/202010004803/29/2020100047
Fair Oaks Ranch C5021 N04/01/202011005503/25/202011005503/29/202010004902/29/2020110048
Bulverde Elementary C5031 N04/01/202011005703/25/202011005503/29/202010005103/26/2020110048
New Braunfels Airport C5041 N04/01/202011004902/29/202010004902/28/202011004703/29/2020100045
City of Garden Ridge C5051 N04/01/202011005803/29/202010005303/25/202011005103/28/2020110050
Seguin Outdoor Learning Center C5061 N04/01/202011005403/24/202011005103/29/202010004902/29/2020090048
Heritage Middle School C6221 N01/27/202011004501/08/202011004402/02/202011004201/21/2020110042
CPS Pecan Valley C6781 N02/28/202011004804/01/202010004702/29/202011004703/29/2020100046
Government Canyon C16101 N04/01/202011004703/25/202011004603/29/202009004502/29/2020100045
Corpus Christi-Victoria
Corpus Christi West C4203/06/202011004902/29/202009004803/29/202014004702/28/2020100047
Corpus Christi Tuloso C21103/06/202011005202/29/202009005002/28/202009005002/25/2020110050
Victoria C87102/28/202011005503/29/202010005303/06/202010005202/29/2020100051
Lower Rio Grande Valley
Mission C43/AP143104/01/202009005203/31/202011005103/06/202011005103/07/2020100049
Harlingen Teege C1023103/31/202011004903/06/202011004802/28/202011004602/29/2020090045
Laredo
Laredo Vidaurri C44/AFGP144/P244103/31/202011005603/06/202011005504/01/202010005403/07/2020110048
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.