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Four Highest Eight-Hour Ozone Concentrations in 2017
as of October 23

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 2017 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 St107/18/201711008306/15/201711007506/02/201710007206/09/2017100069
Ogden Dunes106/09/201711008007/18/201710007906/13/201709007206/02/2017100072
Michigan City-W. Michigan Blvd106/09/201711008406/13/201710008006/04/201712007906/15/2017110077
Valparaiso106/09/201711008106/03/201710007807/18/201709007706/15/2017110077
Gary-IITRI107/18/201710007906/09/201711007706/02/201710007506/03/2017090070
LaPorte-E. Lincolnway107/18/201710008106/09/201711008006/03/201710007307/19/2017090072
North Central
South Bend-Shields Dr106/09/201712008007/06/201711007306/10/201713007306/03/2017110072
Bristol106/09/201712007207/06/201711006706/10/201714006706/03/2017100064
Potato Creek State Park106/09/201713007907/19/201711006906/10/201714006806/03/2017100068
Granger-Beckley St106/09/201712007707/18/201712007006/10/201714007007/06/2017100068
North East
Fort Wayne-Beacon St106/10/201712007106/03/201710006905/16/201711006509/23/2017110062
Leo HS106/10/201713007206/03/201710007005/16/201712006806/11/2017110064
Roanoke Elem. School106/10/201712007006/03/201710006705/16/201712006506/11/2017110061
West Central
Terre Haute-Lafayette Ave106/05/201712007206/10/201710007106/16/201712006906/09/2017110068
Flora106/09/201711006306/04/201711006206/15/201712006105/16/2017100061
Sandcut106/10/201710007106/05/201712007106/09/201712006809/23/2017100066
West Union106/05/201711007106/02/201710006906/10/201708006806/09/2017100067
East Central
Indpls-E.16th St106/04/201711007106/10/201710006906/03/201711006906/02/2017110069
Emporia106/03/201710007206/02/201712007006/21/201712006806/10/2017090068
Albany106/03/201711007406/10/201710007006/09/201712006806/04/2017080063
Indpls-Washington Park106/04/201710006806/10/201710006706/05/201711006706/03/2017110067
Indpls-Harding St106/04/201711006706/10/201710006506/05/201712006506/09/2017120064
Indpls-Ft. Harrison106/04/201711007106/02/201711007106/03/201710007006/10/2017100068
Monrovia109/23/201710005906/09/201714005906/10/201711005806/05/2017120058
Trafalgar106/09/201712006406/05/201713006406/10/201710006305/16/2017110063
Whitestown106/10/201711007106/05/201711006906/04/201711006606/03/2017100066
Avon109/23/201710006806/10/201710006806/04/201711006806/05/2017120067
Fairland106/02/201712007306/10/201710006906/09/201713006906/04/2017100069
Noblesville-191st St106/10/201710007209/26/201711007106/03/201710006906/02/2017110069
Hope106/09/201712006805/15/201710006706/10/201709006506/16/2017100064
Indpls - I-70 E106/10/201711006706/04/201711006506/03/201712006505/15/2017120063
Helmsburg106/09/201711006706/10/201711006506/02/201710006205/14/2017110062
South West
Boonville106/02/201710007406/03/201710007305/15/201709007106/09/2017100068
Evansville-Buena Vista Rd106/02/201710007106/03/201710007006/09/201711006705/15/2017090064
Lynnville106/02/201711006906/03/201710006706/09/201710006606/16/2017100064
Inglefield106/02/201710007506/03/201710007106/09/201710006805/15/2017090068
St. Philips106/02/201710007806/03/201710007306/09/201710006905/14/2017090068
Leopold106/03/201709007106/09/201711006905/14/201710006805/15/2017090066
Dayville106/02/201710007406/03/201710007306/09/201710006805/15/2017090068
Plummer105/15/201711007106/04/201711007006/09/201711006906/05/2017130067
South East
New Albany106/04/201710007506/03/201711007507/17/201712007406/16/2017110074
Charlestown State Park106/03/201711007106/04/201710007005/15/201710007006/16/2017120068
Brownstown106/03/201711006806/09/201712006605/15/201711006506/04/2017090063
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.