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Peak Daily One-Hour Ozone Averages for April 2025

The table below lists the peak daily one-hour ozone concentrations measured in April 2025 in each community where the TCEQ measures ozone. Concentrations are color-highlighted based on the EPA-defined Air Quality Index colors. (See Interpreting the AQI.) All ozone measurements are in parts per billion, and are truncated to an integer number.

The values that go into this table are calculated at 3:30 am each morning. Therefore, the current day will almost always have very low hourly averages that are not truly representative of local conditions for the day. Because of this, the report does not display the current day's data.

Use the selection boxes below to customize this report. You may select a different month, a different year, a different report format, and whether or not to include time on the report. Click on the Generate Report button once you have made your selections.

Month:Year:Report Format: Include time:
Include time
Highlight using AQI colors
AreaMonitoring SitePOCApril 2025
12
Dallas-Fort Worth
Ft. Worth Northwest C13/AH302 25361
Keller C1725157
Frisco C31/C68014752
Denton Airport South C56/A163/X15714753
Arlington Municipal Airport C6114449
Dallas North No.2 C63/C67914752
Rockwall Heath C6913741
Grapevine Fairway C70/A301/X18214755
Kaufman C71/A304/X07113935
Granbury C73/C68115761
Eagle Mountain Lake C75 15456
Parker County C7615957
Cleburne Airport C77/C68214852
Dallas Executive Airport C40214339
Greenville C1006/A19814144
Pilot Point C103215157
Italy C1044/A32313843
Corsicana Airport C105113938
AreaMonitoring SitePOCApril 2025
12
Tyler-Longview-Marshall
Longview C19/A127/C64423527
Tyler Airport Relocated C8213731
Karnack C85/AFHP30313429
AreaMonitoring SitePOCApril 2025
12
El Paso-Juarez
Ascarate Park SE C37/A332/A172/X15915151
Chamizal C41/AH126 15252
Socorro Hueco C49/F31214750
Skyline Park C7215456
Ojo De Agua C1021/FG121/FG22114749
AreaMonitoring SitePOCApril 2025
12
Waco
Waco Mazanec C103714138
Temple Georgia C104513942
Killeen Skylark Field C104714545
AreaMonitoring SitePOCApril 2025
12
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 22325
West Orange C9/A14122120
Port Arthur West C28/A128/A22812422
Hamshire C64/C65412219
SETRPC 40 Sabine Pass C640/C165413221
SETRPC 43 Jefferson Co Airport C64312322
Nederland 17th Street C103512423
AreaMonitoring SitePOCApril 2025
12
Austin
Austin North Hills Drive C3/A32223744
Audubon C3813740
Dripping Springs School C6141 N4146
Lockhart C16041 N3134
St. Edwards University C16051 N4043
CAPCOG Bastrop CAMS16121 N3836
CAPCOG Elgin C16131 N3535
CAPCOG East Austin C16191 N3339
CAPCOG Round Rock Brushy Creek W C16201 N3242
CAPCOG Taylor Murphy Park C16291 N2227
CAPCOG Lake Kyle Park C16301 N3345
CAPCOG San Marcos Staples Road C16751 N5657
AreaMonitoring SitePOCApril 2025
12
Houston-Galveston-Brazoria
Houston East C1/G31622125
Houston Aldine C8/AF108/X150 22326
Channelview C15/AH115 32324
Northwest Harris Co. C26/A110/X15422828
Hou.DeerPrk2 C35/235/1001/AFH139FP23913023
Seabrook Friendship Park C4512823
Houston Bayland Park C53/A146 12829
Conroe Relocated C78/A32112428
Manvel Croix Park C8412325
Clinton C403/C304/AH113 31921
Houston North Wayside C405/C103311920
Houston Monroe C40612122
Lang C40822224
Houston Croquet C40922728
Houston Westhollow C410/C300312324
Park Place C41612324
Houston Harvard Street C41712324
Sheldon C5511 N2222
Baytown Wetlands Center C5521 N2322
Crosby Library C5531 N2122
West Houston C5541 N2626
La Porte Sylvan Beach C5561 N2920
Mercer Arboretum C5571 N2727
Tom Bass C5581 N2727
Katy Park C5591 N2524
Atascocita C5601 N2224
Meyer Park C5611 N2627
Bunker Hill Village C5621 N2324
Huffman Wolf Road C5631 N2427
Lynchburg Ferry C1015/A165 12827
Lake Jackson C1016 12927
Baytown Garth C101713029
Galveston 99th St. C1034/A320/X18313931
AreaMonitoring SitePOCApril 2025
12
San Antonio
San Antonio Northwest C23236NA
Camp Bullis C58 14252
Calaveras Lake C5914050
Elm Creek Elementary C5011 N3756
Fair Oaks Ranch C5021 N4446
Bulverde Elementary C5031 N3337
New Braunfels Airport C5041 N2834
AACOG City of Garden Ridge C505 1 N4051
Seguin Outdoor Learning Center C5061 N3139
Heritage Middle School C6221 N3949
CPS Pecan Valley C6781 N3549
Government Canyon C16101 N3951
AreaMonitoring SitePOCApril 2025
12
Corpus Christi-Victoria
Corpus Christi West C422533
Corpus Christi Tuloso C2112446
Victoria C8712625
AreaMonitoring SitePOCApril 2025
12
Lower Rio Grande Valley
Mission C43/AP14313044
Harlingen Teege C102312833
AreaMonitoring SitePOCApril 2025
12
Laredo
Laredo College C441 N4261
NA - Data not available.
 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.