Four Highest Eight-Hour Ozone Concentrations in 2021
as of February 26

Use this form to retrieve the four highest eight-hour ozone concentration averages from data collected at IDEM 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 2021 in each community where the IDEM 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
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021	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
North West
	Hammond-141st St	1	02/21/2021	1000	49	02/22/2021	0100	45	02/20/2021	1000	44	01/31/2021	1500	41
	Ogden Dunes	1	02/21/2021	1100	51	02/20/2021	1200	51	02/22/2021	0900	47	01/31/2021	1700	42
	Michigan City-W. Michigan Blvd	1	02/21/2021	1000	51	02/20/2021	1300	51	02/22/2021	1100	48	02/26/2021	0900	42
	Valparaiso	1	02/20/2021	1400	52	02/21/2021	0900	50	02/22/2021	1000	49	02/23/2021	1100	44
	Gary-IITRI	1	02/21/2021	1000	52	02/20/2021	1300	51	02/22/2021	0900	47	01/31/2021	1700	44
	LaPorte-E. Lincolnway	1	02/21/2021	1100	52	02/20/2021	1200	49	02/22/2021	1000	47	02/24/2021	1100	42
North Central
	South Bend-Shields Dr	1	02/21/2021	1400	50	02/22/2021	1200	44	02/20/2021	1200	42	02/23/2021	1300	39
	Bristol	1	02/21/2021	1300	53	02/22/2021	1000	47	02/20/2021	2200	46	02/23/2021	1600	44
	Potato Creek State Park	1	02/21/2021	1200	53	02/20/2021	1700	53	02/22/2021	0900	49	02/23/2021	1400	47
	Granger-Beckley St	1	02/21/2021	1200	51	02/20/2021	1200	45	02/22/2021	0800	44	02/23/2021	1500	40
North East
	Fort Wayne-Beacon St	1	02/21/2021	1200	52	02/22/2021	0800	48	02/24/2021	1000	45	02/20/2021	1200	45
	Leo HS	1	02/22/2021	0900	46	02/19/2021	1200	45	02/24/2021	1000	42	02/23/2021	1300	42
West Central
	Terre Haute-Lafayette Ave	1	02/20/2021	1000	49	02/21/2021	1200	48	02/22/2021	0900	43	02/19/2021	1100	42
	Flora	1	02/20/2021	1400	59	02/22/2021	0600	52	02/21/2021	1100	52	02/24/2021	1200	49
	Sandcut	1	02/20/2021	1200	54	02/21/2021	1200	51	02/22/2021	0800	46	02/19/2021	1000	45
	West Union	1	02/20/2021	1100	55	02/21/2021	1100	51	02/22/2021	0900	48	02/19/2021	1000	47
East Central
	Anderson-Eastside Elem. School	2	02/20/2021	1200	51	02/24/2021	1200	48	02/22/2021	0800	48	02/19/2021	1100	48
	Albany	1	02/21/2021	1200	53	02/20/2021	1200	52	02/22/2021	0900	49	02/24/2021	1200	48
	Indpls-Washington Park	1	02/20/2021	1200	46	02/21/2021	1100	45	02/24/2021	1200	43	02/22/2021	0700	43
	Indpls-Harding St	1	02/20/2021	1100	48	02/21/2021	1100	46	02/19/2021	1000	42	02/24/2021	1100	40
	Indpls-Ft. Harrison	1	02/24/2021	1200	44	02/22/2021	0900	44	02/19/2021	1000	44	02/12/2021	1200	41
	Whitestown	1	02/20/2021	1000	45	02/22/2021	0800	41	02/19/2021	1000	41	02/21/2021	1000	40
	Avon	1	02/20/2021	1000	49	02/21/2021	1100	47	02/22/2021	1200	44	02/19/2021	0900	44
	Fairland	1	02/20/2021	1100	49	02/19/2021	1200	44	02/22/2021	0800	42	02/21/2021	1000	42
	Noblesville-191st St	1	02/20/2021	1200	48	02/21/2021	1000	47	02/24/2021	1300	45	02/22/2021	0700	45
	Hope	1	02/20/2021	1000	50	02/19/2021	1200	49	02/24/2021	1000	46	02/21/2021	1200	46
	Indpls - I-70 E	1	02/21/2021	1200	44	02/20/2021	1200	44	02/22/2021	1500	36	02/26/2021	1000	34
	Kokomo - E. Vaile Ave.	1	02/20/2021	1100	54	02/22/2021	0700	51	02/21/2021	1000	51	02/24/2021	1100	50
	Helmsburg	1	02/20/2021	1200	48	02/19/2021	1200	47	02/22/2021	1300	46	02/21/2021	1600	46
South West
	Boonville	1	02/20/2021	1000	48	02/21/2021	1200	45	02/19/2021	1100	45	02/18/2021	1400	45
	Evansville-Buena Vista Rd	1	02/24/2021	1000	45	02/23/2021	0900	41	02/25/2021	1000	40	02/11/2021	1100	39
	Inglefield	1	01/23/2021	1000	32	01/20/2021	0900	32	01/14/2021	1000	32	01/22/2021	0900	30
	St. Philips	1	02/20/2021	1000	50	02/19/2021	1100	46	02/18/2021	1300	44	02/21/2021	1100	43
	Leopold	1	02/24/2021	0800	50	02/21/2021	1400	49	02/20/2021	1000	48	02/19/2021	1100	48
	Dayville	1	02/20/2021	1100	52	02/21/2021	1100	48	02/18/2021	1300	48	02/19/2021	1000	47
	Plummer	1	02/20/2021	1200	53	02/19/2021	1400	52	02/21/2021	1200	50	02/22/2021	1000	49
South East
	New Albany	1	02/24/2021	1000	47	02/19/2021	1100	46	02/22/2021	0900	43	02/23/2021	1000	42
	Charlestown State Park	1	02/19/2021	1300	48	02/24/2021	1100	47	02/20/2021	1200	47	02/23/2021	1200	45
POC (Parameter Occurrence Code): a code used to correctly separate data from multiple instruments at one site.

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	0.201 - 0.2011
401 - 500	0.505 - 0.604	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 IDEM 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 IDEM 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.