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Four Highest Eight-Hour Ozone Concentrations in 2025
as of April 28

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 2025 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.

Year	Report Format
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025	Tabular (Web Formatted) Comma-Delimited
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	2	04/10/2025	1100	72	03/01/2025	1200	70	04/12/2025	1200	68	04/09/2025	1200	65
	Keller C17	2	03/01/2025	1100	72	04/12/2025	1400	67	04/10/2025	1200	67	04/09/2025	1300	61
	Frisco C31/C680	1	04/09/2025	1100	68	04/10/2025	1100	63	04/12/2025	1200	62	03/25/2025	1100	62
	Denton Airport South C56/A163/X157	1	04/12/2025	1200	62	04/22/2025	1100	61	04/09/2025	1200	60	03/25/2025	1100	59
	Arlington Municipal Airport C61	1	04/10/2025	1100	70	04/12/2025	1500	67	04/09/2025	1200	66	03/01/2025	1200	62
	Dallas North No.2 C63/C679	1	04/09/2025	1100	67	04/12/2025	1500	62	04/13/2025	1100	61	04/10/2025	1200	61
	Rockwall Heath C69	1	04/08/2025	1200	58	04/07/2025	1100	57	04/09/2025	1100	56	04/10/2025	1200	54
	Grapevine Fairway C70/A301/X182	1	04/10/2025	1100	67	04/12/2025	1400	64	04/09/2025	1100	63	04/13/2025	1100	61
	Kaufman C71/A304/X071	1	04/09/2025	1100	67	04/08/2025	1100	67	04/07/2025	1100	67	03/01/2025	1000	61
	Granbury C73/C681	1	04/10/2025	1200	76	04/12/2025	1200	69	04/15/2025	1200	63	03/02/2025	1000	63
	Eagle Mountain Lake C75	1	04/12/2025	1300	68	03/01/2025	1100	68	04/10/2025	1200	65	04/09/2025	1400	63
	Parker County C76	1	04/10/2025	1100	68	04/12/2025	1400	66	03/01/2025	1200	64	04/21/2025	1100	61
	Cleburne Airport C77/C682	1	04/10/2025	1200	71	04/12/2025	1200	67	04/09/2025	1200	64	03/02/2025	1000	64
	Dallas Hinton St. C401/C60/AH161	3	02/02/2025	1200	54	02/03/2025	1100	42	02/01/2025	0900	42	01/13/2025	1000	40
	Dallas Executive Airport C402	1	04/09/2025	1100	69	04/10/2025	1100	68	04/12/2025	1500	65	03/01/2025	1100	65
	Greenville C1006/A198	1	04/09/2025	1100	65	04/10/2025	1100	59	04/16/2025	1000	58	04/22/2025	1000	57
	Pilot Point C1032	1	04/09/2025	1200	69	03/25/2025	1100	69	04/22/2025	1100	68	04/12/2025	1200	66
	Italy C1044/A323	1	04/12/2025	1500	64	04/09/2025	1100	64	04/08/2025	1000	64	04/07/2025	1100	60
	Corsicana Airport C1051	1	04/09/2025	1100	70	04/12/2025	1300	68	03/01/2025	1100	68	04/07/2025	1200	67
Tyler-Longview-Marshall
	Longview C19/A127/C644	2	04/09/2025	1300	75	04/08/2025	1000	67	04/13/2025	1300	62	03/17/2025	1500	61
	Tyler Airport Relocated C82	1	04/09/2025	1500	68	04/08/2025	1000	66	03/01/2025	1000	64	04/16/2025	1200	61
	Karnack C85/AFHP303	1	04/09/2025	1100	66	02/28/2025	1000	59	04/08/2025	1000	58	04/13/2025	1200	57
El Paso-Juarez
	Ascarate Park SE C37/A332/A172/X159	1	04/13/2025	1100	58	04/11/2025	1000	57	04/21/2025	1000	54	04/19/2025	1300	52
	Chamizal C41/AH126	1	04/13/2025	1100	63	04/12/2025	1200	56	03/02/2025	0900	56	04/19/2025	1200	53
	Socorro Hueco C49/F312	1	04/13/2025	1000	60	04/21/2025	1000	56	04/11/2025	1000	56	04/25/2025	1000	53
	Skyline Park C72	1	04/11/2025	0900	66	04/13/2025	1200	65	04/21/2025	1000	61	03/30/2025	1600	59
	Ivanhoe C414/F514	1	04/21/2025	1000	52	04/13/2025	1100	52	04/11/2025	1000	49	04/12/2025	1100	48
	Ojo De Agua C1021/FG121/FG221	1	04/13/2025	1100	57	04/11/2025	0900	56	04/10/2025	2100	55	04/21/2025	1100	52
Waco
	Waco Mazanec C1037	1	04/09/2025	1100	72	04/10/2025	1100	69	04/08/2025	1000	69	04/14/2025	1100	64
	Temple Georgia C1045	1	04/09/2025	1100	70	04/12/2025	1100	68	04/10/2025	1100	66	04/08/2025	1100	63
	Killeen Skylark Field C1047	1	04/12/2025	1100	74	04/09/2025	1100	71	04/10/2025	1300	67	04/14/2025	1200	65
Beaumont-Port Arthur
	Beaumont-Downtown C2/A112/C2002	2	03/25/2025	1000	61	04/16/2025	1000	58	04/12/2025	1000	56	04/10/2025	0900	56
	West Orange C9/A141	2	04/10/2025	0900	57	03/17/2025	1100	57	03/01/2025	1100	57	04/16/2025	1000	55
	Port Arthur West C28/A128/A228	1	03/01/2025	1100	57	03/17/2025	1100	54	04/16/2025	0900	52	04/09/2025	1000	52
	Hamshire C64/C654	1	03/01/2025	1200	64	04/16/2025	1000	59	03/17/2025	1000	58	04/10/2025	0900	57
	SETRPC Port Arthur C628	1 N	03/01/2025	1200	64	03/17/2025	1100	59	03/11/2025	0900	53	02/02/2025	1000	53
	SETRPC 40 Sabine Pass C640/C1654	1	03/01/2025	1200	68	03/17/2025	1000	60	04/08/2025	1100	59	03/10/2025	1200	59
	SETRPC Mauriceville 42 C642/C311/C665	1 N	03/01/2025	1000	56	03/17/2025	1100	55	03/11/2025	1000	54	02/28/2025	1100	51
	SETRPC 43 Jefferson Co Airport C643	1	03/01/2025	1100	60	04/08/2025	0900	56	03/17/2025	1100	56	04/16/2025	0900	54
	Nederland 17th Street C1035	1	03/01/2025	1600	63	03/25/2025	1000	61	04/10/2025	0900	57	03/17/2025	1100	57
Austin
	Austin North Hills Drive C3/A322	2	04/10/2025	1100	65	04/12/2025	1000	63	04/21/2025	1100	61	04/11/2025	1100	61
	Audubon C38	1	04/09/2025	1000	66	04/12/2025	1000	65	04/10/2025	1100	64	04/11/2025	1000	63
	Dripping Springs School C614	1 N	04/11/2025	1100	77	04/09/2025	1100	77	04/08/2025	1200	76	04/21/2025	1100	75
	Lockhart C1604	1 N	04/09/2025	1200	74	04/08/2025	1000	71	04/12/2025	1100	67	04/11/2025	1100	67
	St. Edwards University C1605	1 N	04/11/2025	1100	71	04/08/2025	1100	71	04/09/2025	1100	70	04/12/2025	1100	68
	CAPCOG Bastrop CAMS1612	1 N	04/09/2025	1100	65	04/21/2025	1100	64	04/12/2025	1000	64	04/08/2025	1000	64
	CAPCOG Elgin C1613	1 N	04/08/2025	1000	66	03/01/2025	1100	66	04/09/2025	1200	65	04/11/2025	1000	63
	CAPCOG East Austin C1619	1 N	04/12/2025	1100	62	04/11/2025	1000	62	04/09/2025	1100	62	04/08/2025	1100	62
	CAPCOG Round Rock Brushy Creek W C1620	1 N	04/10/2025	1100	66	04/09/2025	1000	64	04/12/2025	1000	63	04/08/2025	1100	62
	CAPCOG Taylor Murphy Park C1629	1 N	04/09/2025	1100	78	04/12/2025	0900	77	04/08/2025	1000	77	04/10/2025	1100	75
	CAPCOG Lake Kyle Park C1630	1 N	04/11/2025	1100	65	04/08/2025	1100	65	04/12/2025	1100	64	04/09/2025	1100	63
	CAPCOG San Marcos Staples Road C1675	1 N	04/11/2025	1100	70	04/12/2025	1200	66	04/03/2025	1200	66	04/04/2025	1100	65
Houston-Galveston-Brazoria
	Houston East C1/G316	2	03/25/2025	1000	76	04/12/2025	1100	63	03/01/2025	1100	62	04/10/2025	0900	61
	Houston Aldine C8/AF108/X150	2	03/25/2025	1000	81	04/12/2025	1000	71	04/09/2025	1000	70	04/10/2025	1000	69
	Channelview C15/AH115	3	03/25/2025	0900	62	04/08/2025	1100	60	04/10/2025	0800	58	04/09/2025	1000	58
	Northwest Harris Co. C26/A110/X154	2	03/25/2025	1200	77	04/09/2025	1000	76	04/12/2025	1100	74	04/10/2025	1000	71
	Hou.DeerPrk2 C35/235/1001/AFH139FP239	1	03/01/2025	1100	66	03/24/2025	1100	63	04/08/2025	1100	62	04/12/2025	1100	60
	Seabrook Friendship Park C45	1	03/01/2025	1200	68	04/08/2025	1200	60	04/11/2025	1100	57	03/24/2025	1100	56
	Houston Bayland Park C53/A146	1	03/25/2025	1100	68	04/11/2025	1100	67	03/24/2025	1200	65	04/12/2025	1000	64
	Conroe Relocated C78/A321	1	04/12/2025	1100	80	04/10/2025	1100	80	04/09/2025	1000	78	03/25/2025	1100	76
	Manvel Croix Park C84	1	03/01/2025	1100	69	04/11/2025	1100	66	03/24/2025	1200	62	04/12/2025	1000	59
	Clinton C403/C304/AH113	3	03/01/2025	1100	60	04/08/2025	1100	57	04/12/2025	1000	56	04/11/2025	1000	56
	Houston North Wayside C405/C1033	1	03/25/2025	1000	67	04/12/2025	1100	57	04/09/2025	0900	57	04/16/2025	1000	53
	Houston Monroe C406	1	03/01/2025	1100	61	03/24/2025	1200	60	04/08/2025	1100	57	03/25/2025	1100	57
	Lang C408	2	03/25/2025	1100	75	04/09/2025	1000	64	04/12/2025	1000	62	04/10/2025	1000	62
	Houston Croquet C409	2	03/01/2025	1100	70	04/11/2025	1100	66	04/09/2025	1000	65	04/12/2025	1000	64
	Houston Westhollow C410/C3003	1	03/01/2025	1200	65	04/11/2025	1000	63	04/09/2025	1000	63	03/25/2025	1000	63
	Park Place C416	1	03/25/2025	1100	65	03/01/2025	1100	65	03/24/2025	1100	63	04/12/2025	1100	60
	Houston Harvard Street C417	1	03/25/2025	1100	72	03/24/2025	1200	64	04/09/2025	1000	61	03/01/2025	1100	61
	Sheldon C551	1 N	03/25/2025	0900	69	04/10/2025	0800	59	03/01/2025	1100	59	04/08/2025	1000	58
	Baytown Wetlands Center C552	1 N	03/01/2025	1000	61	04/08/2025	1200	57	02/01/2025	1100	56	04/16/2025	0900	55
	Crosby Library C553	1 N	04/10/2025	0800	71	04/12/2025	0900	59	03/01/2025	1000	59	04/16/2025	0900	58
	West Houston C554	1 N	03/25/2025	1000	74	04/09/2025	0900	72	04/12/2025	0900	70	03/01/2025	1100	70
	La Porte Sylvan Beach C556	1 N	03/01/2025	1200	60	04/08/2025	1300	59	04/16/2025	0900	55	04/09/2025	0900	54
	Mercer Arboretum C557	1 N	03/25/2025	1000	86	04/10/2025	0900	79	04/09/2025	1000	78	04/12/2025	0900	77
	Tom Bass C558	1 N	03/01/2025	1200	77	04/11/2025	1000	68	04/12/2025	0900	66	04/09/2025	0900	66
	Katy Park C559	1 N	04/09/2025	0900	64	04/12/2025	0900	60	04/11/2025	0900	59	04/10/2025	0900	58
	Atascocita C560	1 N	03/25/2025	0900	71	04/12/2025	0900	66	04/09/2025	0900	65	04/10/2025	0900	64
	Meyer Park C561	1 N	03/25/2025	1000	85	04/10/2025	1000	75	04/12/2025	0900	74	04/09/2025	0900	73
	Bunker Hill Village C562	1 N	03/25/2025	1000	69	04/12/2025	1000	67	04/09/2025	0900	67	03/01/2025	1100	67
	Huffman Wolf Road C563	1 N	03/25/2025	1000	80	04/10/2025	0900	74	04/09/2025	0900	67	04/12/2025	0900	64
	HRM-3 Haden Road C603/A114	1 N	03/01/2025	1000	63	03/17/2025	1000	54	03/21/2025	0900	52	03/13/2025	1100	50
	Wallisville Road C617	1 N	03/01/2025	1000	56	03/17/2025	1000	51	02/01/2025	1100	48	03/21/2025	0900	47
	Texas City 34th St. C620	1 N	03/01/2025	1200	75	03/17/2025	1000	56	03/16/2025	1100	54	02/01/2025	1100	53
	Lynchburg Ferry C1015/A165	1	03/17/2025	1000	60	04/09/2025	0900	58	03/01/2025	1000	58	04/16/2025	0900	57
	Lake Jackson C1016	1	03/01/2025	1100	67	04/11/2025	1100	66	04/08/2025	1100	61	03/24/2025	1200	61
	Baytown Garth C1017	1	03/25/2025	1000	71	04/10/2025	0800	64	04/16/2025	1000	59	04/12/2025	1100	59
	Galveston 99th St. C1034/A320/X183	1	03/01/2025	1600	97	02/01/2025	1200	82	04/11/2025	1200	66	03/24/2025	1300	63
	Oyster Creek C1607	1 N	04/11/2025	1100	68	03/24/2025	1100	64	04/08/2025	1100	62	04/12/2025	0900	60
San Antonio
	San Antonio Northwest C23	2	04/21/2025	1100	64	04/11/2025	1200	64	04/12/2025	1100	60	04/10/2025	1100	59
	Camp Bullis C58	1	04/11/2025	1100	75	04/10/2025	1100	70	04/21/2025	1100	69	04/12/2025	1100	69
	Calaveras Lake C59	1	04/11/2025	1100	68	04/12/2025	1100	66	04/08/2025	1000	65	04/21/2025	1000	64
	Elm Creek Elementary C501	1 N	04/21/2025	1100	71	04/11/2025	1100	70	04/12/2025	1000	64	04/08/2025	1000	62
	Fair Oaks Ranch C502	1 N	04/11/2025	1200	72	04/10/2025	1100	71	04/12/2025	1000	68	04/21/2025	1100	66
	Bulverde Elementary C503	1 N	03/01/2025	1100	61	04/10/2025	1100	58	02/28/2025	1100	58	04/12/2025	1000	57
	New Braunfels Airport C504	1 N	03/01/2025	1000	65	02/28/2025	1100	61	03/10/2025	1200	54	03/02/2025	0900	54
	AACOG City of Garden Ridge C505	1 N	04/11/2025	1100	71	04/21/2025	1200	68	04/12/2025	1100	66	04/08/2025	1200	62
	Seguin Outdoor Learning Center C506	1 N	03/01/2025	1100	66	02/28/2025	1100	62	03/13/2025	1200	60	04/11/2025	1200	59
	Heritage Middle School C622	1 N	04/21/2025	1100	73	04/11/2025	1100	72	04/08/2025	1100	69	04/12/2025	1100	67
	CPS Pecan Valley C678	1 N	04/21/2025	1100	62	04/11/2025	1100	62	04/08/2025	1100	60	04/12/2025	1100	59
	Government Canyon C1610	1 N	04/21/2025	1100	74	04/11/2025	1100	74	04/12/2025	1000	68	04/08/2025	1000	66
Corpus Christi-Victoria
	Corpus Christi West C4	2	04/08/2025	1000	67	04/09/2025	0900	59	02/28/2025	1200	58	04/12/2025	1000	56
	Corpus Christi Tuloso C21	1	04/08/2025	1000	66	04/09/2025	0800	60	04/11/2025	1100	59	02/28/2025	1200	58
	Victoria C87	1	04/08/2025	0900	65	04/09/2025	0900	64	02/28/2025	1300	63	04/11/2025	1300	61
Lower Rio Grande Valley
	Mission C43/AP143	1	04/08/2025	1000	71	04/09/2025	1100	58	03/10/2025	1100	58	04/11/2025	1000	57
	Harlingen Teege C1023	1	04/08/2025	1000	60	04/09/2025	1000	57	04/12/2025	1100	55	04/07/2025	1100	55
Laredo
	Laredo College C44	1 N	04/08/2025	1100	69	04/20/2025	1200	62	04/12/2025	1100	61	04/09/2025	1000	61
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

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.