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Peak Daily One-Hour Ozone Averages for March 2025

The table below lists the peak daily one-hour ozone concentrations measured in March 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 SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
Dallas-Fort Worth
Ft. Worth Northwest C13/AH302 2876841NANANA49364356575251514353622Ft. Worth Northwest C13/AH302
Keller C17283654345425149394255594850504351612Keller C17
Frisco C31/C680156543843414649364055584951484146571Frisco C31/C680
Denton Airport South C56/A163/X157155584143404545334152534747494147591Denton Airport South C56/A163/X157
Arlington Municipal Airport C61173604044424951354153574550504150591Arlington Municipal Airport C61
Dallas North No.2 C63/C679159554044404449363855574750474146571Dallas North No.2 C63/C679
Rockwall Heath C69153523544404446353750554849474148491Rockwall Heath C69
Grapevine Fairway C70/A301/X182169604347444450394360555151524352621Grapevine Fairway C70/A301/X182
Kaufman C71/A304/X071168634451486350363656605760534954581Kaufman C71/A304/X071
Granbury C73/C681171663747445146364554585151534550591Granbury C73/C681
Eagle Mountain Lake C75 179704146444947374454605049514451611Eagle Mountain Lake C75
Parker County C7616865364443504539435358545355NANANA1Parker County C76
Cleburne Airport C77/C682167693845445047334250624950494449611Cleburne Airport C77/C682
Dallas Executive Airport C402175614337424454364050584651474352611Dallas Executive Airport C402
Greenville C1006/A198152513747NA47513639555847NA524447561Greenville C1006/A198
Pilot Point C1032151543746454948354458605256NANANA741Pilot Point C1032
Italy C1044/A323158623945445041303950584848484448531Italy C1044/A323
Corsicana Airport C1051173654950485651333856595859545154591Corsicana Airport C1051
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
Tyler-Longview-Marshall
Longview C19/A127/C644259494348474944383752755250485148662Longview C19/A127/C644
Tyler Airport Relocated C82178554249475047373749604856505048581Tyler Airport Relocated C82
Karnack C85/AFHP303151454245424640343249575558505044611Karnack C85/AFHP303
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
El Paso-Juarez
Ascarate Park SE C37/A332/A172/X159151534942434344434344484644444445401Ascarate Park SE C37/A332/A172/X159
Chamizal C41/AH126 154585647454945454441NANANANANANA331Chamizal C41/AH126
Socorro Hueco C49/F312150544844484446424647554147454548421Socorro Hueco C49/F312
Skyline Park C72158565246524846474653565250484850521Skyline Park C72
Ivanhoe C414/F514139444036383537353537433640373539371Ivanhoe C414/F514
Ojo De Agua C1021/FG121/FG221154504841454340404243473941424239371Ojo De Agua C1021/FG121/FG221
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
Waco
Waco Mazanec C1037163674246465253324052625251504850571Waco Mazanec C1037
Temple Georgia C1045165633846445650284051684957484951601Temple Georgia C1045
Killeen Skylark Field C1047157624246435551314351634659474951601Killeen Skylark Field C1047
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
Beaumont-Port Arthur
Beaumont-Downtown C2/A112/C2002 258484447424647303250614753325247582Beaumont-Downtown C2/A112/C2002
West Orange C9/A141262524752454845293151604744295045602West Orange C9/A141
Port Arthur West C28/A128/A228164504449434342243048544443294943581Port Arthur West C28/A128/A228
Hamshire C64/C654172564952494946263263564649315251621Hamshire C64/C654
SETRPC Port Arthur C6281 N69534648464846273355614843305147NA1SETRPC Port Arthur C628
SETRPC 40 Sabine Pass C640/C1654180564752484946303566624841285748671SETRPC 40 Sabine Pass C640/C1654
SETRPC Mauriceville 42 C642/C311/C6651 N59534652475545303350604556295046NA1SETRPC Mauriceville 42 C642/C311/C665
SETRPC 43 Jefferson Co Airport C643163524352474843263351574448295247601SETRPC 43 Jefferson Co Airport C643
Nederland 17th Street C1035167544751464846273354584651305147611Nederland 17th Street C1035
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
Austin
Austin North Hills Drive C3/A322267594045445356334354595963444751552Austin North Hills Drive C3/A322
Audubon C38156583444425355314251625059414748551Audubon C38
Dripping Springs School C6141 N68623757556456425162735267536063621Dripping Springs School C614
Lockhart C16041 N67573748485347434360544657515053521Lockhart C1604
St. Edwards University C16051 NNANANANANANANANANANA504959415150491St. Edwards University C1605
CAPCOG Bastrop CAMS16121 N61594447465449384461565155565651531CAPCOG Bastrop CAMS1612
CAPCOG Elgin C16131 N71594449485649294461585062515054561CAPCOG Elgin C1613
CAPCOG East Austin C16191 N69553842425250304156545561414949531CAPCOG East Austin C1619
CAPCOG Round Rock Brushy Creek W C16201 N64604143425157284250575758414746541CAPCOG Round Rock Brushy Creek W C1620
CAPCOG Taylor Murphy Park C16291 N59543935344344193446474447413839451CAPCOG Taylor Murphy Park C1629
CAPCOG Lake Kyle Park C16301 N60563442NA5451434258545664444551551CAPCOG Lake Kyle Park C1630
CAPCOG San Marcos Staples Road C16751 N54493433325253474058515658494246501CAPCOG San Marcos Staples Road C1675
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
Houston-Galveston-Brazoria
Houston East C1/G316269534651425148343258574963385051612Houston East C1/G316
Houston Aldine C8/AF108/X150 272554552495747423758625365415251602Houston Aldine C8/AF108/X150
Channelview C15/AH115 364504348434946273455554763365050553Channelview C15/AH115
Northwest Harris Co. C26/A110/X154266604252495548523754655061435152572Northwest Harris Co. C26/A110/X154
Hou.DeerPrk2 C35/235/1001/AFH139FP239176544750465346313357534659364852591Hou.DeerPrk2 C35/235/1001/AFH139FP239
Seabrook Friendship Park C45175554654465143283258534351334956581Seabrook Friendship Park C45
Houston Bayland Park C53/A146 1NANA4751475547373955594860405251561Houston Bayland Park C53/A146
Conroe Relocated C78/A321164575351496149423452655260465149601Conroe Relocated C78/A321
Manvel Croix Park C84178514449465045303850514454375352561Manvel Croix Park C84
Clinton C403/C304/AH113 367494140424636313347433646314548443Clinton C403/C304/AH113
Houston North Wayside C405/C10331NANA3739384536312947483951314144491Houston North Wayside C405/C1033
Houston Monroe C406172524145414541283351474150354446501Houston Monroe C406
Lang C408271514247424842363553534456364646532Lang C408
Houston Croquet C409278534648455143333652534446364949522Houston Croquet C409
Houston Westhollow C410/C3003170544452475445363653544458375351521Houston Westhollow C410/C3003
Park Place C416171504546425044333347494352354547511Park Place C416
Houston Harvard Street C417166544344394841333150504354354346501Houston Harvard Street C417
Sheldon C5511 N654841NANA434429345656455934NANA521Sheldon C551
Baytown Wetlands Center C5521 N78494648NA4938253252514353294948561Baytown Wetlands Center C552
Crosby Library C5531 N65515049495345263457614965364949631Crosby Library C553
West Houston C5541 N76624753505948423958634963405753561West Houston C554
La Porte Sylvan Beach C5561 N69504246425041273156494244324650551La Porte Sylvan Beach C556
Mercer Arboretum C5571 N75594551506248433867645365445452621Mercer Arboretum C557
Tom Bass C5581 N89584952485648364058574859395253581Tom Bass C558
Katy Park C5591 N65523748NANA46363450554351365249501Katy Park C559
Atascocita C5601 N66514247465341303255594766354848591Atascocita C560
Meyer Park C5611 N72594651495748473868625061425352581Meyer Park C561
Bunker Hill Village C5621 N76564548455442333654554458354949561Bunker Hill Village C562
Huffman Wolf Road C5631 N645150NA505549303059695674445552681Huffman Wolf Road C563
HRM-3 Haden Road C603/A114 1 N72514250435046353256544863365051NA1HRM-3 Haden Road C603/A114
Wallisville Road C617 1 N60474647464841293251524565324746NA1Wallisville Road C617
Texas City 34th St. C620 1 N89604953465048333556484542354860NA1Texas City 34th St. C620
Lynchburg Ferry C1015/A165 174514851465550293354585158394949641Lynchburg Ferry C1015/A165
Lake Jackson C1016 173545054465249363757524240394851541Lake Jackson C1016
Baytown Garth C1017162515149485146323457585070365048621Baytown Garth C1017
Galveston 99th St. C1034/A320/X1831104795255485250384059524839375066651Galveston 99th St. C1034/A320/X183
Oyster Creek C1607 1 NNA6955574954503539NANANANANANANANA1Oyster Creek C1607
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
San Antonio
San Antonio Northwest C23260492742414759453950494147404445492San Antonio Northwest C23
Camp Bullis C58 171603348465468544457584054455053581Camp Bullis C58
Calaveras Lake C59161543048505248554458545154474749521Calaveras Lake C59
Elm Creek Elementary C5011 N62553148505350484461564855484750511Elm Creek Elementary C501
Fair Oaks Ranch C5021 N70593248435467554457594555455155581Fair Oaks Ranch C502
Bulverde Elementary C5031 N70583247445361494455614856445054371Bulverde Elementary C503
New Braunfels Airport C5041 N73593548465648434263535362514751521New Braunfels Airport C504
AACOG City of Garden Ridge C505 1 N66563045424956454357575459464851541AACOG City of Garden Ridge C505
Seguin Outdoor Learning Center C5061 N72633751486150514464595465574954591Seguin Outdoor Learning Center C506
Heritage Middle School C6221 N67572951515552554661565259525155561Heritage Middle School C622
CPS Pecan Valley C6781 N59492738404549403749474144364140451CPS Pecan Valley C678
Government Canyon C16101 N63522848455265544660594356485155571Government Canyon C1610
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
Corpus Christi-Victoria
Corpus Christi West C4259583552515450404452495042424754522Corpus Christi West C4
Corpus Christi Tuloso C21164503355495247454654505046434854491Corpus Christi Tuloso C21
Victoria C87161533449505544444350634751474955641Victoria C87
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
Lower Rio Grande Valley
Mission C43/AP143152342948484651564765454971674853491Mission C43/AP143
Harlingen Teege C1023146382639444139383843444459465147501Harlingen Teege C1023
AreaMonitoring SitePOCMarch 2025POCMonitoring Site
1234567891011121314151617
Laredo
Laredo College C441 N52503656505047505054575959455056531Laredo College C44
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.