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Four Highest Eight-Hour Ozone Concentrations in 2023
as of September 29

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	08/31/2023	1100	92	08/25/2023	1000	92	09/02/2023	1100	86	08/16/2023	1200	84
	Keller C17	2	08/31/2023	1100	94	08/25/2023	1000	90	09/01/2023	1100	81	06/07/2023	1200	80
	Frisco C31/C680	1	08/18/2023	1100	87	08/17/2023	1000	87	09/06/2023	1200	82	08/31/2023	1000	82
	Denton Airport South C56/A163/X157	1	08/01/2023	1000	88	07/24/2023	1100	86	05/22/2023	1100	80	06/09/2023	1200	78
	Arlington Municipal Airport C61	1	08/16/2023	1100	84	08/25/2023	0900	82	06/07/2023	1000	76	08/31/2023	1100	74
	Dallas North No.2 C63/C679	1	09/06/2023	1200	84	08/31/2023	1100	83	08/26/2023	1000	83	08/25/2023	1000	80
	Rockwall Heath C69	1	09/08/2023	1100	70	06/08/2023	1000	69	09/07/2023	1100	68	08/26/2023	1000	67
	Grapevine Fairway C70/A301/X182	1	08/31/2023	1100	94	08/25/2023	1000	90	08/01/2023	0900	87	08/24/2023	1000	84
	Kaufman C71/A304/X071	1	09/19/2023	1100	80	06/07/2023	1000	73	09/03/2023	1000	71	09/02/2023	1100	71
	Granbury C73/C681	1	08/31/2023	1000	83	09/09/2023	1500	79	09/01/2023	1100	79	08/21/2023	1000	79
	Eagle Mountain Lake C75	1	08/31/2023	1200	89	09/01/2023	1100	85	09/27/2023	1200	81	08/25/2023	1200	81
	Parker County C76	1	08/21/2023	1000	82	09/02/2023	1100	79	09/01/2023	1300	78	08/25/2023	1300	78
	Cleburne Airport C77/C682	1	08/31/2023	1000	78	08/16/2023	1300	78	09/02/2023	1100	76	09/01/2023	1100	75
	Dallas Hinton St. C401/C60/AH161	3	06/07/2023	1100	94	08/25/2023	1000	82	08/26/2023	1100	81	08/31/2023	1100	79
	Dallas Executive Airport C402	1	06/07/2023	1100	91	08/16/2023	1100	81	08/31/2023	1100	79	08/25/2023	1000	79
	Greenville C1006/A198	1	06/08/2023	1000	76	09/19/2023	1000	74	09/08/2023	1100	70	09/07/2023	1100	69
	Pilot Point C1032	1	08/17/2023	1000	96	08/31/2023	1000	88	08/18/2023	1100	88	09/18/2023	1100	81
	Italy C1044/A323	1	09/19/2023	1000	74	09/12/2023	1100	71	09/01/2023	1000	70	08/31/2023	1100	70
	Corsicana Airport C1051	1	08/25/2023	1000	69	09/02/2023	1100	68	09/12/2023	1100	64	09/03/2023	1100	64
Tyler-Longview-Marshall
	Longview C19/A127/C644	2	09/02/2023	1100	86	08/17/2023	1100	78	05/23/2023	1000	68	08/25/2023	1000	67
	Tyler Airport Relocated C82	1	05/27/2023	1000	76	08/21/2023	1100	75	08/17/2023	1200	72	06/06/2023	1000	71
	Karnack C85/AFHP303	1	09/19/2023	1000	69	06/09/2023	1000	67	09/21/2023	1100	65	08/25/2023	0900	65
El Paso-Juarez
	Ascarate Park SE C37/A332/A172/X159	1	08/04/2023	1100	77	08/03/2023	1100	73	08/02/2023	1000	69	08/01/2023	1100	69
	Chamizal C41/AH126	1	08/04/2023	1100	77	07/04/2023	1100	70	08/03/2023	1000	69	08/01/2023	1100	68
	Socorro Hueco C49/F312	1	08/03/2023	0900	78	05/12/2023	1000	73	08/04/2023	1000	72	07/19/2023	1100	66
	Skyline Park C72	1	08/31/2023	1000	74	08/04/2023	1000	69	08/03/2023	1100	69	08/02/2023	0800	68
	Ivanhoe C414/F514	1	08/03/2023	1100	77	08/04/2023	1000	68	07/05/2023	1100	67	08/02/2023	0900	64
	Ojo De Agua C1021/FG121/FG221	1	08/04/2023	1200	78	08/31/2023	1000	75	08/03/2023	1100	74	07/04/2023	1100	74
Waco
	Waco Mazanec C1037	1	08/30/2023	1000	79	09/12/2023	1100	77	09/02/2023	1000	77	09/19/2023	1000	76
	Temple Georgia C1045	1	09/19/2023	1000	79	09/02/2023	1000	77	09/01/2023	1100	77	08/31/2023	1000	76
	Killeen Skylark Field C1047	1	09/01/2023	1100	80	09/19/2023	0800	77	08/31/2023	1100	77	09/02/2023	1100	76
Beaumont-Port Arthur
	Beaumont-Downtown C2/A112/C2002	2	09/02/2023	0900	71	07/24/2023	0900	71	08/17/2023	0900	68	05/19/2023	0800	68
	West Orange C9/A141	2	05/19/2023	0900	71	06/09/2023	1200	69	08/17/2023	1000	68	09/12/2023	1100	65
	Port Arthur West C28/A128/A228	1	05/01/2023	1100	67	05/26/2023	1000	64	09/01/2023	0900	63	06/09/2023	1100	63
	Hamshire C64/C654	1	09/01/2023	1000	69	09/18/2023	0900	67	08/31/2023	1100	67	08/17/2023	0900	67
	SETRPC Port Arthur C628	1 N	06/09/2023	1000	82	05/26/2023	1000	73	05/22/2023	1100	73	05/23/2023	0800	71
	SETRPC 40 Sabine Pass C640/C1654	1	05/23/2023	1000	75	05/22/2023	1100	74	09/09/2023	1100	68	06/09/2023	1100	68
	SETRPC Mauriceville 42 C642/C311/C665	1 N	07/24/2023	1000	66	06/01/2023	1000	66	05/04/2023	0900	64	05/02/2023	0900	64
	SETRPC 43 Jefferson Co Airport C643	1	05/01/2023	1100	72	08/01/2023	1000	67	09/11/2023	0900	66	08/16/2023	1000	65
	Nederland 17th Street C1035	1	05/01/2023	1000	77	08/01/2023	1000	72	09/02/2023	0800	70	08/16/2023	1000	70
Austin
	Austin North Hills Drive C3/A322	2	09/02/2023	1000	76	09/01/2023	1100	76	08/28/2023	1300	75	09/19/2023	1000	74
	Audubon C38	1	09/02/2023	1000	76	09/01/2023	1100	75	08/16/2023	1100	73	09/19/2023	1000	70
	Dripping Springs School C614	1 N	08/31/2023	1100	81	09/02/2023	1100	80	09/01/2023	1100	79	08/28/2023	1500	78
	CAPCOG Lake Georgetown C690	1 N	09/19/2023	1000	80	09/01/2023	1100	76	09/02/2023	1000	75	09/18/2023	1100	74
	Lockhart C1604	1 N	05/17/2023	1000	73	09/18/2023	1000	71	08/28/2023	1300	71	09/19/2023	1000	70
	St. Edwards University C1605	1 N	09/18/2023	1100	76	09/19/2023	0900	72	08/28/2023	1300	71	09/02/2023	1000	67
	CAPCOG Bastrop CAMS1612	1 N	09/19/2023	1000	69	09/18/2023	1000	69	09/12/2023	1000	69	09/01/2023	1100	69
	CAPCOG Elgin C1613	1 N	08/28/2023	1200	70	09/01/2023	1100	68	08/31/2023	1000	68	08/30/2023	1300	68
	CAPCOG East Austin C1619	1 N	08/28/2023	1200	84	08/25/2023	1100	79	08/16/2023	1100	78	08/30/2023	1100	75
	CAPCOG Round Rock Brushy Creek W C1620	1 N	08/28/2023	1200	74	09/01/2023	1000	73	09/02/2023	1000	72	09/19/2023	0800	71
	CAPCOG Taylor Murphy Park C1629	1 N	08/28/2023	1200	77	09/19/2023	1000	70	09/02/2023	1000	70	09/01/2023	1100	70
	CAPCOG Lake Kyle Park C1630	1 N	09/18/2023	1000	74	09/19/2023	1000	72	08/28/2023	1100	72	08/31/2023	1100	71
	CAPCOG San Marcos Staples Road C1675	1 N	09/19/2023	1000	73	09/18/2023	1000	73	08/31/2023	1100	70	09/01/2023	1100	69
Houston-Galveston-Brazoria
	Houston East C1/G316	2	05/18/2023	1000	110	09/11/2023	1100	91	05/01/2023	1100	91	09/12/2023	1000	90
	Houston Aldine C8/AF108/X150	2	06/09/2023	1000	81	05/18/2023	1100	79	09/12/2023	1100	78	08/01/2023	1000	78
	Channelview C15/AH115	3	06/09/2023	1000	91	09/12/2023	1100	89	05/18/2023	1100	87	08/01/2023	1000	85
	Northwest Harris Co. C26/A110/X154	2	09/19/2023	1000	89	06/02/2023	0900	82	05/31/2023	1000	82	08/25/2023	1000	79
	Hou.DeerPrk2 C35/235/1001/AFH139FP239	1	09/11/2023	1000	95	05/18/2023	1100	93	06/07/2023	1000	89	09/01/2023	1000	83
	Seabrook Friendship Park C45	1	05/23/2023	1000	75	08/28/2023	1100	74	08/15/2023	1000	74	05/22/2023	1200	73
	Houston Bayland Park C53/A146	1	09/18/2023	1100	97	09/11/2023	1100	97	05/18/2023	1100	97	09/01/2023	1000	87
	Conroe Relocated C78/A321	1	06/02/2023	1100	77	05/19/2023	1200	77	08/18/2023	1200	74	06/22/2023	1100	72
	Manvel Croix Park C84	1	09/01/2023	1000	88	09/11/2023	1000	85	08/31/2023	1000	84	08/16/2023	1000	82
	Clinton C403/C304/AH113	3	05/18/2023	1100	108	09/11/2023	1100	88	05/01/2023	1100	86	09/12/2023	1000	82
	Houston North Wayside C405/C1033	1	05/18/2023	1100	84	06/09/2023	1000	81	09/12/2023	1100	75	06/02/2023	1000	74
	Houston Monroe C406	1	09/11/2023	0900	83	05/18/2023	1000	81	06/07/2023	1000	79	08/16/2023	1000	78
	Lang C408	2	05/18/2023	1200	96	09/12/2023	1000	85	09/11/2023	1100	83	05/01/2023	1100	83
	Houston Croquet C409	2	09/18/2023	1100	92	09/11/2023	1000	85	05/18/2023	1100	82	09/01/2023	1000	80
	Houston Westhollow C410/C3003	1	09/18/2023	1100	86	09/09/2023	1100	82	09/11/2023	1100	81	09/01/2023	1000	77
	Park Place C416	1	05/18/2023	1100	101	09/11/2023	1100	92	09/18/2023	1000	88	05/27/2023	1000	85
	Houston Harvard Street C417	1	05/18/2023	1100	108	09/11/2023	1100	86	09/12/2023	1000	84	09/02/2023	1000	78
	Sheldon C551	1 N	09/12/2023	1000	83	08/01/2023	1000	77	06/09/2023	1000	77	09/11/2023	1000	71
	Baytown Wetlands Center C552	1 N	05/18/2023	1100	89	09/12/2023	0900	81	09/11/2023	1000	74	08/01/2023	0900	72
	Crosby Library C553	1 N	09/12/2023	1000	85	06/09/2023	1000	76	08/01/2023	1000	73	06/03/2023	0900	70
	West Houston C554	1 N	09/18/2023	1000	89	09/19/2023	1000	86	09/09/2023	1000	85	09/11/2023	1000	84
	La Porte Sylvan Beach C556	1 N	06/07/2023	1000	75	06/04/2023	0900	72	09/12/2023	0900	69	09/11/2023	1000	69
	Mercer Arboretum C557	1 N	06/09/2023	1000	83	09/12/2023	1000	82	08/18/2023	1000	79	08/02/2023	1000	78
	Tom Bass C558	1 N	09/11/2023	1000	89	09/18/2023	1000	86	09/01/2023	0900	85	05/23/2023	0900	85
	Katy Park C559	1 N	09/09/2023	1000	84	09/18/2023	1000	83	05/27/2023	0900	76	09/01/2023	0900	75
	Atascocita C560	1 N	09/12/2023	1000	76	08/01/2023	1000	71	07/31/2023	1000	71	08/02/2023	0900	70
	Meyer Park C561	1 N	08/02/2023	1000	89	06/02/2023	1000	83	09/19/2023	0900	81	09/11/2023	1000	77
	Bunker Hill Village C562	1 N	05/18/2023	1000	93	05/27/2023	0900	81	09/01/2023	0900	77	05/23/2023	0900	76
	Huffman Wolf Road C563	1 N	06/03/2023	0900	74	05/19/2023	0900	74	06/09/2023	1000	72	09/12/2023	0900	71
	HRM-3 Haden Road C603/A114	1 N	05/18/2023	1100	105	09/12/2023	1000	92	05/01/2023	1100	90	09/11/2023	1100	86
	Wallisville Road C617	1 N	09/12/2023	1100	97	06/09/2023	1000	91	08/01/2023	1100	90	09/11/2023	1100	78
	Texas City 34th St. C620	1 N	05/23/2023	1000	98	06/04/2023	1000	90	08/28/2023	1100	89	06/07/2023	0900	83
	UH Moody Tower C695	1 N	05/18/2023	1100	108	09/11/2023	1100	90	06/07/2023	1000	80	09/18/2023	1000	79
	UH WG Jones Forest C698	1 N	06/02/2023	1000	83	08/02/2023	1100	80	06/01/2023	1100	80	08/18/2023	1100	79
	Lynchburg Ferry C1015/A165	1	05/18/2023	1100	99	09/12/2023	1000	88	06/09/2023	1100	88	08/01/2023	1100	82
	Lake Jackson C1016	1	08/28/2023	1000	80	08/31/2023	1000	75	05/24/2023	1000	74	08/30/2023	1000	73
	Baytown Garth C1017	1	06/09/2023	1000	104	08/01/2023	1100	100	05/18/2023	1200	84	08/18/2023	1000	83
	Galveston 99th St. C1034/A320/X183	1	08/28/2023	1300	89	09/26/2023	1000	86	09/17/2023	1300	83	08/31/2023	1000	81
	UH Smith Point C1606	1 N	05/18/2023	1200	78	08/31/2023	1100	76	05/03/2023	1300	75	05/26/2023	1000	74
	Oyster Creek C1607	1 N	08/28/2023	1100	82	09/17/2023	1100	78	08/31/2023	1100	78	08/30/2023	1000	74
	UH Launch Trailer C1611	1 N	05/18/2023	1100	114	09/11/2023	1100	93	05/01/2023	1100	83	06/07/2023	1000	82
	Liberty Sam Houston Library C1626	1 N	05/19/2023	1000	85	08/17/2023	0900	69	05/03/2023	1400	65	09/12/2023	1100	63
San Antonio
	San Antonio Northwest C23	2	09/01/2023	1000	78	08/31/2023	1100	78	09/18/2023	1100	74	09/11/2023	1000	74
	Camp Bullis C58	1	09/01/2023	1000	81	08/31/2023	1100	77	09/02/2023	1100	76	06/21/2023	1000	76
	Calaveras Lake C59	1	08/31/2023	1000	77	08/29/2023	1100	77	09/01/2023	1100	73	09/02/2023	1100	71
	Elm Creek Elementary C501	1 N	08/31/2023	1100	78	09/01/2023	1100	72	09/02/2023	1100	71	08/29/2023	1000	68
	Fair Oaks Ranch C502	1 N	06/21/2023	1000	75	09/11/2023	1000	71	09/19/2023	1000	67	09/18/2023	1100	66
	Bulverde Elementary C503	1 N	09/01/2023	1000	80	08/31/2023	1100	76	09/19/2023	1000	74	09/18/2023	1000	74
	New Braunfels Airport C504	1 N	09/27/2023	1000	60	03/04/2023	1000	60	09/01/2023	1100	59	02/27/2023	1000	57
	AACOG City of Garden Ridge C505	1 N	09/27/2023	1100	77	09/01/2023	1100	76	08/31/2023	1100	76	09/02/2023	1000	74
	Seguin Outdoor Learning Center C506	1 N	09/19/2023	1000	71	08/31/2023	1100	63	09/01/2023	1100	62	09/27/2023	1000	61
	Heritage Middle School C622	1 N	08/31/2023	1000	82	08/29/2023	1000	82	09/01/2023	1100	78	09/02/2023	1100	75
	CPS Pecan Valley C678	1 N	09/18/2023	1000	65	08/31/2023	1100	65	09/01/2023	1100	64	09/02/2023	1000	62
	Government Canyon C1610	1 N	08/31/2023	1000	66	09/27/2023	1000	63	09/01/2023	1000	63	09/28/2023	1000	62
Corpus Christi-Victoria
	Corpus Christi West C4	2	08/29/2023	1000	69	05/25/2023	0900	68	08/28/2023	1300	64	03/25/2023	1500	64
	Corpus Christi Tuloso C21	1	08/29/2023	0900	71	05/25/2023	1000	71	05/24/2023	1000	66	08/30/2023	1000	65
	Victoria C87	1	09/01/2023	0900	62	08/31/2023	1000	62	06/07/2023	1000	61	09/18/2023	1000	59
Lower Rio Grande Valley
	Harlingen Teege C1023	1	08/30/2023	0900	71	08/31/2023	0900	61	08/29/2023	1200	60	06/08/2023	1100	60
Laredo
	Laredo College C44	1 N	08/29/2023	1100	80	08/31/2023	1000	79	09/01/2023	1000	68	08/28/2023	1100	64
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.