Processed on 2024-03-04 13:06:18 PST.


Disclaimer: Data presented here come from a variety of sources and do not represent official EPA measurements. Please visit AirNow for official measurements.


Cumulative exposure to smoke is an important public health metric. This report summarizes the cumulative number of days air quality monitors in Illinois spent in each AQI category during the the month of July.

The tables below include only permanent monitors measuring PM2.5 and show cumulative exposure under existing NAAQS (National Ambient Air Quality Standards) and under the 2024 revised standards for PM2.5.

In the tables and plots below, ‘Old’ designates cumulative days calculated using the 2023 PM2.5 NAAQS while ‘New’ is calculated using the 2024 revised PM2.5 NAAQS. The impact of the NAAQS revision is quite clear.

July in Illinois

July 2014 – 11 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 197 108 0 0 0 0 47
New 126 178 1 0 0 0 47

July 2015 – 12 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 162 139 2 6 0 0 43
New 87 214 2 6 0 0 43

July 2016 – 26 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 253 71 0 0 0 0 60
New 163 161 0 0 0 0 60

July 2017 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 340 50 1 0 0 0 57
New 229 161 1 0 0 0 57

July 2018 – 40 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 475 123 0 0 0 0 42
New 324 274 0 0 0 0 42

July 2019 – 23 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 399 204 1 0 0 0 68
New 228 375 1 0 0 0 68

July 2020 – 43 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 468 136 7 1 0 0 124
New 375 229 7 1 0 0 124

July 2021 – 23 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 317 349 7 0 0 0 63
New 190 476 7 0 0 0 63

July 2022 – 24 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 576 129 0 0 0 0 31
New 414 291 0 0 0 0 31

July 2023 – 26 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 446 224 28 6 0 0 64
New 293 376 29 6 0 0 64