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Peak Daily One-Hour Ozone Averages for May 2021

The table below lists the peak daily one-hour ozone concentrations measured in May 2021 in each community where the IDEM measures ozone. Concentrations are color-highlighted based on the EPA-defined Air Quality Index colors. (See Interpreting the AQI.) All ozone measurements are in parts per billion, and are truncated to an integer number.

The values that go into this table are calculated at 3:30 am each morning. Therefore, the current day will almost always have very low hourly averages that are not truly representative of local conditions for the day. Because of this, the report does not display the current day's data.

Use the selection boxes below to customize this report. You may select a different month, a different year, a different report format, and whether or not to include time on the report. Click on the Generate Report button once you have made your selections.

Month:Year:Report Format: Include time:
Include time
Highlight using AQI colors
AreaMonitoring SitePOCMay 2021
North West
Hammond-141st St159513529354447
Ogden Dunes158493530364246
Michigan City-W. Michigan Blvd159514231354044
LaPorte-E. Lincolnway157504135353646
AreaMonitoring SitePOCMay 2021
North Central
South Bend-Shields Dr156524134343045
Potato Creek State Park157523832362946
Granger-Beckley St160564236363046
AreaMonitoring SitePOCMay 2021
North East
Fort Wayne-Beacon St151503831353743
Leo HS156564335384149
AreaMonitoring SitePOCMay 2021
West Central
Terre Haute-Lafayette Ave156473628414049
West Union157473829434451
AreaMonitoring SitePOCMay 2021
East Central
Anderson-Eastside Elem. School255554034384551
Indpls-Washington Park152493730404249
Indpls-Harding St155493925394047
Indpls-Ft. Harrison157534031414551
Noblesville-191st St158534133384251
Indpls - I-70 E15045322425NANA
Kokomo - E. Vaile Ave.157543936383853
AreaMonitoring SitePOCMay 2021
South West
Evansville-Buena Vista Rd154414034404249
St. Philips152394234384449
AreaMonitoring SitePOCMay 2021
South East
New Albany154454348424751
Charlestown State Park152464249414749
NA - Data not available.

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.