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Four Highest Eight-Hour Ozone Concentrations in 2023
as of March 26

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 2023 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	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	03/05/2023	1000	54	03/15/2023	1400	51	03/25/2023	1000	49	03/04/2023	1000	48
	Keller C17	2	03/15/2023	1500	50	03/05/2023	1100	50	03/04/2023	1100	47	02/28/2023	1100	46
	Frisco C31/C680	1	03/06/2023	1100	56	03/04/2023	1200	56	03/05/2023	1100	54	03/15/2023	1600	51
	Denton Airport South C56/A163/X157	1	03/05/2023	1000	56	03/06/2023	1100	54	03/04/2023	1100	53	03/15/2023	1100	51
	Arlington Municipal Airport C61	1	03/05/2023	1100	51	03/04/2023	1200	51	03/15/2023	1400	49	03/25/2023	1100	48
	Dallas North No.2 C63/C679	1	03/04/2023	1200	52	03/05/2023	1000	49	03/25/2023	1000	48	03/15/2023	1600	48
	Rockwall Heath C69	1	03/04/2023	1100	47	03/19/2023	1000	45	03/15/2023	1600	45	03/05/2023	1000	45
	Grapevine Fairway C70/A301/X182	1	03/04/2023	1200	51	03/05/2023	0900	50	03/06/2023	1000	48	03/25/2023	1000	45
	Kaufman C71/A304/X071	1	03/05/2023	1100	55	03/04/2023	1100	54	02/28/2023	1100	54	03/26/2023	0800	52
	Granbury C73/C681	1	03/15/2023	1300	53	03/05/2023	1000	51	03/04/2023	1000	50	03/25/2023	1000	47
	Eagle Mountain Lake C75	1	03/05/2023	1100	54	03/04/2023	1000	52	03/15/2023	1300	51	02/28/2023	1100	51
	Parker County C76	1	03/15/2023	1300	53	02/27/2023	1500	53	02/28/2023	0900	51	03/05/2023	1000	49
	Cleburne Airport C77/C682	1	03/15/2023	1300	53	03/05/2023	1100	52	03/04/2023	1200	51	03/25/2023	1000	47
	Dallas Hinton St. C401/C60/AH161	3	03/04/2023	1200	51	03/05/2023	1000	48	03/15/2023	1600	46	03/25/2023	1100	45
	Dallas Executive Airport C402	1	03/25/2023	1000	49	03/26/2023	0800	46	02/05/2023	1100	43	01/27/2023	1000	43
	Greenville C1006/A198	1	03/25/2023	1000	57	03/05/2023	1000	56	03/06/2023	0900	51	03/04/2023	1100	51
	Pilot Point C1032	1	03/06/2023	1200	55	03/05/2023	1000	54	03/04/2023	1100	54	03/15/2023	1100	49
	Italy C1044/A323	1	03/04/2023	1100	55	03/15/2023	1300	53	02/28/2023	1100	52	03/05/2023	1000	50
	Corsicana Airport C1051	1	02/28/2023	1100	55	03/26/2023	0800	52	03/04/2023	1100	52	03/15/2023	1400	51
Tyler-Longview-Marshall
	Longview C19/A127/C644	2	03/05/2023	1100	53	03/25/2023	1100	52	02/28/2023	1100	52	03/26/2023	0800	48
	Tyler Airport Relocated C82	1	02/28/2023	1100	68	03/05/2023	1100	59	03/26/2023	0800	54	03/25/2023	1000	53
	Karnack C85/AFHP303	1	02/28/2023	1000	57	03/05/2023	1100	53	02/13/2023	1000	51	02/27/2023	1000	48
El Paso-Juarez
	Ascarate Park SE C37/A332/A172/X159	1	02/26/2023	1500	46	02/15/2023	1400	44	03/23/2023	1500	43	03/18/2023	1200	43
	Chamizal C41/AH126	1	03/24/2023	1000	52	02/26/2023	1800	52	03/23/2023	1500	51	03/05/2023	0900	51
	Socorro Hueco C49/F312	1	03/25/2023	1000	49	03/24/2023	0900	49	03/05/2023	1000	49	02/26/2023	1500	48
	Skyline Park C72	1	02/26/2023	1500	59	02/28/2023	1000	58	02/27/2023	1000	58	03/02/2023	0700	57
	Ivanhoe C414/F514	1	03/14/2023	1000	45	03/25/2023	1000	43	03/05/2023	0900	43	02/26/2023	1700	43
	Ojo De Agua C1021/FG121/FG221	1	02/26/2023	1500	48	02/27/2023	1100	47	03/18/2023	1300	46	03/05/2023	0900	46
Waco
	Waco Mazanec C1037	1	03/04/2023	1100	62	02/28/2023	1100	59	03/15/2023	1200	55	03/05/2023	1000	54
	Temple Georgia C1045	1	03/04/2023	1100	64	02/27/2023	1000	62	02/28/2023	1100	58	03/15/2023	1100	53
	Killeen Skylark Field C1047	1	02/27/2023	1000	68	03/04/2023	1100	59	02/28/2023	1000	58	03/05/2023	1000	55
Beaumont-Port Arthur
	Beaumont-Downtown C2/A112/C2002	2	03/25/2023	1100	55	03/05/2023	1000	52	03/04/2023	1100	51	03/15/2023	1100	47
	West Orange C9/A141	2	03/25/2023	1100	54	03/05/2023	1100	54	03/15/2023	1100	51	01/06/2023	1100	51
	Port Arthur West C28/A128/A228	1	03/25/2023	1100	57	03/05/2023	1100	48	01/06/2023	1000	47	03/04/2023	1100	46
	Hamshire C64/C654	1	03/25/2023	1100	54	03/05/2023	1100	54	03/04/2023	1000	52	01/06/2023	1000	51
	SETRPC Port Arthur C628	1 N	03/05/2023	1200	55	03/15/2023	1100	51	03/04/2023	1000	51	01/06/2023	1100	51
	SETRPC 40 Sabine Pass C640/C1654	1	03/25/2023	1000	55	03/05/2023	1100	53	03/20/2023	1500	50	03/15/2023	1100	48
	SETRPC Mauriceville 42 C642/C311/C665	1 N	03/05/2023	1000	58	01/06/2023	1100	56	03/15/2023	1200	53	03/04/2023	1100	52
	SETRPC 43 Jefferson Co Airport C643	1	03/25/2023	1100	59	03/04/2023	1100	52	03/05/2023	1100	49	03/20/2023	1200	45
	Nederland 17th Street C1035	1	03/25/2023	1100	63	03/04/2023	1100	56	03/05/2023	1100	53	01/06/2023	1100	49
Austin
	Austin North Hills Drive C3/A322	2	03/04/2023	1100	72	02/27/2023	1000	67	03/05/2023	1000	58	03/03/2023	1000	53
	Audubon C38	1	03/04/2023	1100	62	02/27/2023	1000	61	02/28/2023	1100	54	03/05/2023	1000	51
	Dripping Springs School C614	1 N	03/04/2023	1200	62	03/05/2023	1100	49	03/25/2023	1000	46	03/03/2023	1000	45
	CAPCOG Lake Georgetown C690	1 N	02/27/2023	1300	64	03/04/2023	1100	57	03/05/2023	1000	51	02/28/2023	1000	50
	Lockhart C1604	1 N	03/04/2023	1000	59	03/19/2023	1100	49	03/05/2023	1100	49	03/25/2023	1000	48
	St. Edwards University C1605	1 N	03/04/2023	1100	54	02/27/2023	1000	49	03/25/2023	1000	46	03/19/2023	1000	45
	CAPCOG Bastrop CAMS1612	1 N	02/27/2023	1000	58	03/04/2023	1100	56	03/25/2023	1000	48	03/05/2023	1100	48
	CAPCOG Elgin C1613	1 N	02/27/2023	1000	62	03/04/2023	1100	57	03/25/2023	1100	54	03/05/2023	1100	49
	CAPCOG East Austin C1619	1 N	03/04/2023	1100	66	02/27/2023	1100	62	03/25/2023	1100	57	03/05/2023	1100	55
	CAPCOG Round Rock Brushy Creek W C1620	1 N	03/13/2023	0700	68	03/04/2023	1200	63	02/27/2023	1000	61	03/05/2023	1100	53
	CAPCOG San Marcos Staples Road C1675	1 N	03/04/2023	1000	61	03/05/2023	1100	52	03/25/2023	1000	51	03/03/2023	1000	51
Houston-Galveston-Brazoria
	Houston East C1/G316	2	03/04/2023	1100	67	03/25/2023	1100	65	03/05/2023	1000	60	03/15/2023	1100	51
	Houston Aldine C8/AF108/X150	2	03/04/2023	1100	64	03/25/2023	1100	55	03/05/2023	1000	55	02/27/2023	1100	52
	Channelview C15/AH115	3	03/25/2023	1000	60	03/04/2023	1000	58	03/05/2023	1100	54	03/19/2023	1100	46
	Northwest Harris Co. C26/A110/X154	2	03/05/2023	1100	70	03/04/2023	1200	63	02/27/2023	1000	61	03/25/2023	1000	55
	Hou.DeerPrk2 C35/235/1001/AFH139FP239	1	03/25/2023	1200	68	03/05/2023	1100	56	03/04/2023	1100	56	02/12/2023	1100	52
	Seabrook Friendship Park C45	1	03/25/2023	1100	57	03/20/2023	1100	46	03/14/2023	1200	46	03/03/2023	1000	45
	Houston Bayland Park C53/A146	1	03/25/2023	1100	65	03/04/2023	1100	65	03/05/2023	1100	59	02/27/2023	1200	55
	Conroe Relocated C78/A321	1	02/27/2023	1000	64	03/05/2023	1100	62	03/04/2023	1100	60	03/15/2023	1100	57
	Manvel Croix Park C84	1	03/25/2023	1100	63	03/04/2023	1100	59	03/05/2023	1000	54	03/15/2023	1100	49
	Clinton C403/C304/AH113	3	03/25/2023	1200	67	03/04/2023	1100	62	03/05/2023	1100	59	03/15/2023	1100	49
	Houston North Wayside C405/C1033	1	03/04/2023	1000	62	03/25/2023	1100	55	03/05/2023	1000	53	03/15/2023	1100	42
	Houston Monroe C406	1	03/25/2023	1200	58	03/04/2023	1000	51	03/05/2023	1000	49	03/15/2023	1100	45
	Lang C408	2	03/04/2023	1100	65	03/05/2023	1000	61	03/25/2023	1000	58	02/27/2023	1100	57
	Houston Croquet C409	2	03/25/2023	1200	59	03/04/2023	1100	59	03/05/2023	1100	54	03/15/2023	1100	50
	Houston Westhollow C410/C3003	1	03/04/2023	1100	55	03/25/2023	1000	49	03/05/2023	1100	49	02/27/2023	1000	46
	Park Place C416	1	03/04/2023	1100	60	03/05/2023	1000	57	03/15/2023	1100	50	02/12/2023	1200	48
	Houston Harvard Street C417	1	03/04/2023	1100	68	03/25/2023	1200	64	03/05/2023	1100	63	03/15/2023	1100	52
	Sheldon C551	1 N	03/04/2023	1000	61	03/25/2023	1000	55	02/27/2023	1300	54	03/05/2023	1100	51
	Baytown Wetlands Center C552	1 N	03/25/2023	1000	55	03/05/2023	1100	48	03/04/2023	1100	48	03/20/2023	1300	44
	Crosby Library C553	1 N	03/04/2023	1100	59	02/27/2023	1200	54	03/25/2023	1000	53	03/05/2023	1100	52
	West Houston C554	1 N	03/04/2023	1200	67	03/05/2023	1100	61	02/27/2023	1100	58	03/25/2023	0900	53
	La Porte Sylvan Beach C556	1 N	03/05/2023	1300	52	03/15/2023	1000	48	03/20/2023	1100	47	03/14/2023	1100	45
	Mercer Arboretum C557	1 N	03/04/2023	1100	67	03/05/2023	1100	62	02/27/2023	1100	59	03/25/2023	1000	54
	Tom Bass C558	1 N	03/25/2023	1100	64	03/04/2023	1100	59	03/05/2023	1100	55	03/15/2023	1000	50
	Katy Park C559	1 N	03/04/2023	1200	60	03/05/2023	1100	55	02/27/2023	1100	54	03/15/2023	1000	49
	Atascocita C560	1 N	03/04/2023	1100	62	02/27/2023	1200	49	03/25/2023	1000	47	03/15/2023	1000	45
	Meyer Park C561	1 N	03/05/2023	1100	67	03/04/2023	1100	67	02/27/2023	1100	62	03/15/2023	1000	53
	Bunker Hill Village C562	1 N	03/04/2023	1200	62	03/05/2023	1100	57	02/27/2023	1100	51	02/13/2023	1100	42
	Huffman Wolf Road C563	1 N	03/04/2023	1100	57	02/27/2023	1200	56	03/05/2023	1100	53	03/15/2023	1000	49
	HRM-3 Haden Road C603/A114	1 N	02/12/2023	1200	49	02/27/2023	1100	44	02/13/2023	1000	44	02/18/2023	1000	42
	Wallisville Road C617	1 N	02/12/2023	1100	54	02/13/2023	1100	47	01/05/2023	1100	47	01/06/2023	1000	46
	Texas City 34th St. C620	1 N	03/05/2023	1200	64	03/04/2023	1100	63	03/15/2023	1100	59	03/03/2023	1000	56
	UH Moody Tower C695	1 N	03/25/2023	1300	68	03/04/2023	1100	60	03/05/2023	1100	57	02/27/2023	1300	55
	UH WG Jones Forest C698	1 N	02/27/2023	1300	72	03/04/2023	1200	67	03/05/2023	1100	65	03/15/2023	1100	58
	Lynchburg Ferry C1015/A165	1	03/05/2023	1200	54	03/25/2023	1100	52	03/04/2023	1100	50	03/15/2023	1000	47
	Lake Jackson C1016	1	03/25/2023	1100	66	03/05/2023	1000	61	03/04/2023	1100	60	02/12/2023	1100	53
	Baytown Garth C1017	1	03/25/2023	1100	64	03/05/2023	1100	64	03/04/2023	1000	60	02/12/2023	1200	60
	Galveston 99th St. C1034/A320/X183	1	03/25/2023	1400	64	03/05/2023	1600	62	02/12/2023	1400	57	03/04/2023	1100	56
	Oyster Creek C1607	1 N	03/05/2023	1000	58	03/04/2023	1000	57	02/12/2023	1200	55	03/15/2023	1400	51
	Liberty Sam Houston Library C1626	1 N	03/05/2023	1000	56	02/27/2023	1100	54	03/04/2023	1100	53	02/13/2023	1000	52
San Antonio
	San Antonio Northwest C23	2	03/04/2023	1100	61	03/05/2023	1000	58	02/27/2023	0800	54	03/25/2023	1100	51
	Camp Bullis C58	1	03/04/2023	1000	63	03/05/2023	1000	60	02/27/2023	0900	56	03/25/2023	1100	51
	Calaveras Lake C59	1	02/27/2023	1000	65	03/04/2023	1000	64	03/03/2023	1100	63	03/05/2023	1100	56
	Elm Creek Elementary C501	1 N	03/04/2023	1000	57	02/27/2023	0900	54	03/25/2023	1100	53	03/05/2023	1000	51
	Fair Oaks Ranch C502	1 N	03/04/2023	1100	54	03/05/2023	0900	50	02/27/2023	0900	48	02/28/2023	1200	44
	Bulverde Elementary C503	1 N	03/04/2023	1100	52	03/05/2023	1000	45	02/27/2023	0900	45	03/25/2023	1100	41
	New Braunfels Airport C504	1 N	03/04/2023	1000	60	02/27/2023	1000	57	03/05/2023	1000	51	03/03/2023	0900	50
	AACOG City of Garden Ridge C505	1 N	03/04/2023	1100	59	02/27/2023	0900	53	03/05/2023	1100	49	03/25/2023	1100	47
	Seguin Outdoor Learning Center C506	1 N	03/04/2023	1100	55	02/27/2023	1100	52	03/05/2023	1100	47	03/25/2023	1200	46
	Heritage Middle School C622	1 N	02/27/2023	1100	60	03/04/2023	1000	57	03/03/2023	1100	56	03/25/2023	1100	52
	CPS Pecan Valley C678	1 N	03/04/2023	1000	43	02/27/2023	1100	42	03/03/2023	1100	38	03/05/2023	1100	37
	Government Canyon C1610	1 N	03/04/2023	1000	56	02/27/2023	0700	51	03/05/2023	1000	48	03/03/2023	1000	45
Corpus Christi-Victoria
	Corpus Christi West C4	2	03/25/2023	1500	64	03/03/2023	1100	57	03/04/2023	1100	56	03/05/2023	0900	52
	Corpus Christi Tuloso C21	1	03/25/2023	1500	62	03/04/2023	1000	58	03/03/2023	1000	58	03/05/2023	0900	52
	Victoria C87	1	03/04/2023	1100	56	03/03/2023	1200	52	03/05/2023	1000	51	03/25/2023	1000	49
Lower Rio Grande Valley
	Harlingen Teege C1023	1	03/04/2023	1000	56	03/05/2023	0800	53	03/25/2023	1300	51	03/03/2023	1000	51
Laredo
	Laredo College C44	1 N	03/04/2023	1100	58	03/25/2023	1100	57	03/05/2023	0900	54	02/23/2023	1100	52
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.