The report below displays data on the total number of days in Illinois with an Air Quality Index Value of
over 100. This data has been compiled from 1990-2007. Some states have multiple monitoring stations and each will be listed in the reports below.
Other states do not have any monitoring stations in which case we have selected the closest station available.
Year
Chicago
St. Louis
1990
13
30
1991
36
33
1992
13
23
1993
8
20
1994
11
49
1995
29
46
1996
14
35
1997
15
32
1998
20
45
1999
27
45
2000
17
30
2001
38
36
2002
34
49
2003
19
29
2004
13
11
2005
29
47
2006
9
22
2007
23
34
According to the EPA, an Air Quality Index Value of over 100 presents some level of health concern. The higher the number, the
higher the level of concern. The EPA provides the following table and more information on Air Quality Index can be found at
WikiPedia.
