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Daily Maximum Eight-Hour Ozone Averages for May 2021

The table below lists the peak daily maximum eight-hour ozone concentrations measured in May 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.) All ozone measurements are in parts per billion.

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 with AQI colors
AreaMonitoring SitePOCMay 2021
North West
Hammond-141st St15647302630384233
Ogden Dunes15346302833384235
Michigan City-W. Michigan Blvd15549342933374235
LaPorte-E. Lincolnway15347312732294130
AreaMonitoring SitePOCMay 2021
North Central
South Bend-Shields Dr15348322732254127
Potato Creek State Park15348312732244127
Granger-Beckley St15752342834244229
AreaMonitoring SitePOCMay 2021
North East
Fort Wayne-Beacon St14847282933314027
Leo HS15352323135344423
AreaMonitoring SitePOCMay 2021
West Central
Terre Haute-Lafayette Ave15343302337344724
West Union15343332439394932
AreaMonitoring SitePOCMay 2021
East Central
Anderson-Eastside Elem. School25352363135414930
Indpls-Washington Park15046322636394528
Indpls-Harding St15145292234374324
Indpls-Ft. Harrison154NVNA2837424825
Noblesville-191st St1555035303640NVNA
Indpls - I-70 E14841NV20NVNANANA
Kokomo - E. Vaile Ave.15450363135345030
AreaMonitoring SitePOCMay 2021
South West
Evansville-Buena Vista Rd15039352838384732
St. Philips14734362636384732
AreaMonitoring SitePOCMay 2021
South East
New Albany15042404239444930
Charlestown State Park15042394138434731
POC (Parameter Occurrence Code): a code used to correctly separate data from multiple instruments at one site.
NV - There are not enough valid eight-hour averages for this day (there must be eighteen valid eight-hour averages).
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.