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Four Highest Eight-Hour Ozone Concentrations in 2020
as of January 21

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 2020 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.

YearReport Format
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 St101/11/202012003201/09/202011003001/04/202013003001/01/2020170029
Ogden Dunes101/20/202020003401/11/202013003401/09/202013003101/08/2020020031
Michigan City-W. Michigan Blvd101/20/202019004101/11/202013003701/04/202016003701/19/2020160036
LaPorte-E. Lincolnway101/20/202009003201/04/202016003201/09/202016003101/08/2020010031
North Central
South Bend-Shields Dr101/09/202017003301/04/202018003201/01/202020003201/21/2020080031
Potato Creek State Park101/20/202011003801/09/202017003401/04/202015003301/21/2020080032
Granger-Beckley St101/04/202019003401/20/202012003101/09/202018003101/08/2020010031
North East
Fort Wayne-Beacon St101/20/202011004001/21/202007003501/04/202020003301/09/2020170032
Leo HS101/20/202011004301/21/202008003901/04/202022003701/05/2020010035
Roanoke Elem. School101/01/2020210033No DataNo DataNo Data
West Central
Terre Haute-Lafayette Ave101/09/202011003201/01/202013003101/05/202012002901/10/2020010028
West Union101/09/202010003501/01/202011003301/10/202001003201/05/2020100031
East Central
Indpls-Washington Park101/20/202013003301/10/202002003301/09/202013003301/01/2020120033
Indpls-Harding St101/01/202012003201/10/202018003101/09/202013003101/05/2020090029
Indpls-Ft. Harrison101/01/202013003301/20/202013003201/09/202014003201/05/2020120031
Noblesville-191st St101/20/202013003201/09/202013003201/01/202012003201/04/2020210031
Indpls - I-70 E101/09/202013003101/01/202013003101/10/202002003001/05/2020090027
Kokomo - E. Vaile Ave.101/10/202001003101/09/202016003101/04/202020003101/01/2020210031
South West
Evansville-Buena Vista Rd101/09/202011003601/01/202011003601/08/202008003301/05/2020110033
St. Philips101/09/202012003801/01/202011003601/10/202011003301/08/2020090031
South East
New Albany101/08/202009003401/21/202007003301/07/202011003201/01/2020100032
Charlestown State Park101/09/202019003701/08/202011003701/10/202001003501/01/2020110034
Brownstown101/01/2020110034No DataNo DataNo Data
POC (Parameter Occurrence Code): a code used to correctly separate data from multiple instruments at one site.

Interpreting the AQI

Air Quality Index

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

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.