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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
1
Dallas-Fort Worth
Ft. Worth Northwest C13/AH302 253
Keller C17251
Frisco C31/C680147
Denton Airport South C56/A163/X157147
Arlington Municipal Airport C61144
Dallas North No.2 C63/C679147
Rockwall Heath C69137
Grapevine Fairway C70/A301/X182147
Kaufman C71/A304/X071139
Granbury C73/C681157
Eagle Mountain Lake C75 154
Parker County C76159
Cleburne Airport C77/C682148
Dallas Executive Airport C402143
Greenville C1006/A198141
Pilot Point C1032151
Italy C1044/A323138
Corsicana Airport C1051139
AreaMonitoring SitePOCApril 2025
1
Tyler-Longview-Marshall
Longview C19/A127/C644235
Tyler Airport Relocated C82137
Karnack C85/AFHP303134
AreaMonitoring SitePOCApril 2025
1
El Paso-Juarez
Ascarate Park SE C37/A332/A172/X159151
Chamizal C41/AH126 152
Socorro Hueco C49/F312147
Skyline Park C72154
Ojo De Agua C1021/FG121/FG221147
AreaMonitoring SitePOCApril 2025
1
Waco
Waco Mazanec C1037141
Temple Georgia C1045139
Killeen Skylark Field C1047145
AreaMonitoring SitePOCApril 2025
1
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 223
West Orange C9/A141221
Port Arthur West C28/A128/A228124
Hamshire C64/C654122
SETRPC 40 Sabine Pass C640/C1654132
SETRPC 43 Jefferson Co Airport C643123
Nederland 17th Street C1035124
AreaMonitoring SitePOCApril 2025
1
Austin
Austin North Hills Drive C3/A322237
Audubon C38137
Dripping Springs School C6141 N41
Lockhart C16041 N31
St. Edwards University C16051 N40
CAPCOG Bastrop CAMS16121 N38
CAPCOG Elgin C16131 N35
CAPCOG East Austin C16191 N33
CAPCOG Round Rock Brushy Creek W C16201 N32
CAPCOG Taylor Murphy Park C16291 N22
CAPCOG Lake Kyle Park C16301 N33
CAPCOG San Marcos Staples Road C16751 N56
AreaMonitoring SitePOCApril 2025
1
Houston-Galveston-Brazoria
Houston East C1/G316221
Houston Aldine C8/AF108/X150 223
Channelview C15/AH115 323
Northwest Harris Co. C26/A110/X154228
Hou.DeerPrk2 C35/235/1001/AFH139FP239130
Seabrook Friendship Park C45128
Houston Bayland Park C53/A146 128
Conroe Relocated C78/A321124
Manvel Croix Park C84123
Clinton C403/C304/AH113 319
Houston North Wayside C405/C1033119
Houston Monroe C406121
Lang C408222
Houston Croquet C409227
Houston Westhollow C410/C3003123
Park Place C416123
Houston Harvard Street C417123
Sheldon C5511 N22
Baytown Wetlands Center C5521 N23
Crosby Library C5531 N21
West Houston C5541 N26
La Porte Sylvan Beach C5561 N29
Mercer Arboretum C5571 N27
Tom Bass C5581 N27
Katy Park C5591 N25
Atascocita C5601 N22
Meyer Park C5611 N26
Bunker Hill Village C5621 N23
Huffman Wolf Road C5631 N24
Lynchburg Ferry C1015/A165 128
Lake Jackson C1016 129
Baytown Garth C1017130
Galveston 99th St. C1034/A320/X183139
AreaMonitoring SitePOCApril 2025
1
San Antonio
San Antonio Northwest C23236
Camp Bullis C58 142
Calaveras Lake C59140
Elm Creek Elementary C5011 N37
Fair Oaks Ranch C5021 N44
Bulverde Elementary C5031 N33
New Braunfels Airport C5041 N28
AACOG City of Garden Ridge C505 1 N40
Seguin Outdoor Learning Center C5061 N31
Heritage Middle School C6221 N39
CPS Pecan Valley C6781 N35
Government Canyon C16101 N39
AreaMonitoring SitePOCApril 2025
1
Corpus Christi-Victoria
Corpus Christi West C4225
Corpus Christi Tuloso C21124
Victoria C87126
AreaMonitoring SitePOCApril 2025
1
Lower Rio Grande Valley
Mission C43/AP143130
Harlingen Teege C1023128
AreaMonitoring SitePOCApril 2025
1
Laredo
Laredo College C441 N42
 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.