Four Highest Eight-Hour Ozone Concentrations in 2021
as of May 8

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	04/04/2021	1200	59	04/27/2021	1000	58	05/01/2021	1200	56	04/26/2021	1100	54
	Ogden Dunes	1	04/27/2021	1100	57	04/04/2021	1200	57	05/01/2021	1100	53	04/26/2021	1200	53
	Michigan City-W. Michigan Blvd	1	04/27/2021	1100	59	04/04/2021	1200	58	05/01/2021	1200	55	04/03/2021	1200	55
	Valparaiso	1	04/04/2021	1100	58	04/27/2021	1100	56	05/01/2021	1100	53	04/26/2021	1200	52
	Gary-IITRI	1	04/27/2021	1000	55	04/04/2021	1200	55	05/01/2021	1100	53	02/21/2021	1000	52
	LaPorte-E. Lincolnway	1	04/04/2021	1000	57	04/27/2021	1100	55	05/01/2021	1200	53	02/21/2021	1100	52
North Central
	South Bend-Shields Dr	1	04/27/2021	1300	57	04/04/2021	1200	57	05/01/2021	1300	53	04/26/2021	1300	52
	Bristol	1	04/27/2021	1300	57	02/21/2021	1300	53	04/23/2021	1100	52	04/04/2021	1200	52
	Potato Creek State Park	1	04/04/2021	1200	60	04/27/2021	1200	58	04/26/2021	1300	54	05/01/2021	1300	53
	Granger-Beckley St	1	04/27/2021	1300	61	04/04/2021	1100	59	05/01/2021	1400	57	04/03/2021	1200	57
North East
	Fort Wayne-Beacon St	1	04/04/2021	1100	55	04/27/2021	1200	53	04/05/2021	1100	53	04/23/2021	1100	52
	Leo HS	1	04/27/2021	1200	59	04/23/2021	1100	57	04/04/2021	1100	54	05/01/2021	1300	53
West Central
	Terre Haute-Lafayette Ave	1	04/27/2021	1100	58	04/26/2021	1200	54	05/01/2021	1200	53	04/09/2021	1100	52
	Flora	1	04/05/2021	1100	59	02/20/2021	1400	59	04/27/2021	1100	57	04/04/2021	1100	57
	Sandcut	1	04/04/2021	1200	59	04/27/2021	1100	58	04/05/2021	1100	57	03/09/2021	1300	56
	West Union	1	04/27/2021	0900	57	04/04/2021	1000	57	03/09/2021	1200	57	04/05/2021	1000	56
East Central
	Anderson-Eastside Elem. School	2	04/05/2021	1100	64	04/04/2021	1100	62	04/27/2021	1000	59	04/26/2021	1300	57
	Albany	1	04/05/2021	1100	65	04/04/2021	1100	59	04/27/2021	1100	58	04/23/2021	1100	55
	Indpls-Washington Park	1	04/05/2021	1100	59	04/04/2021	1100	58	04/27/2021	1100	55	04/09/2021	1200	52
	Indpls-Harding St	1	04/05/2021	1100	58	04/04/2021	1100	54	04/27/2021	1100	53	04/03/2021	1200	52
	Indpls-Ft. Harrison	1	04/05/2021	1100	63	04/04/2021	1100	62	04/27/2021	1000	58	04/09/2021	1200	56
	Whitestown	1	04/05/2021	1000	53	04/04/2021	1100	52	05/01/2021	1300	51	04/27/2021	1100	51
	Avon	1	04/05/2021	1100	59	04/04/2021	1200	57	04/27/2021	1100	56	04/09/2021	1200	54
	Fairland	1	04/05/2021	1100	58	04/04/2021	1100	54	03/09/2021	1100	52	04/09/2021	1200	51
	Noblesville-191st St	1	04/05/2021	1100	63	04/04/2021	1100	61	04/27/2021	1200	60	04/09/2021	1200	56
	Hope	1	04/05/2021	1100	62	04/04/2021	1100	60	04/27/2021	1100	56	04/26/2021	1100	56
	Indpls - I-70 E	1	04/27/2021	1100	54	04/05/2021	1100	53	04/04/2021	1100	51	03/09/2021	1200	50
	Kokomo - E. Vaile Ave.	1	04/05/2021	1100	62	04/27/2021	1100	59	04/04/2021	1100	58	04/26/2021	1200	56
	Helmsburg	1	04/05/2021	1100	63	04/04/2021	1100	61	04/27/2021	1100	59	04/09/2021	1200	58
South West
	Boonville	1	04/04/2021	1000	54	04/05/2021	0900	51	03/08/2021	1000	51	05/01/2021	1000	50
	Evansville-Buena Vista Rd	1	04/04/2021	1000	55	04/06/2021	1000	54	04/05/2021	1000	54	04/09/2021	1000	52
	Inglefield	1	04/04/2021	1100	58	04/06/2021	1000	56	04/05/2021	1000	56	04/09/2021	1000	55
	St. Philips	1	04/09/2021	1100	51	04/04/2021	1000	51	04/06/2021	1000	50	02/20/2021	1000	50
	Leopold	1	04/05/2021	1000	59	04/04/2021	1100	59	04/27/2021	1000	58	04/26/2021	1300	57
	Dayville	1	04/04/2021	1000	55	04/05/2021	0900	54	04/06/2021	0900	53	03/08/2021	1000	53
	Plummer	1	04/05/2021	1200	61	04/04/2021	1200	59	04/27/2021	1000	57	05/01/2021	1300	56
South East
	New Albany	1	04/04/2021	1100	57	04/27/2021	1100	56	04/05/2021	1000	56	04/09/2021	1200	54
	Charlestown State Park	1	04/04/2021	1100	58	04/05/2021	1100	57	04/27/2021	1100	56	04/09/2021	1100	55
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.