Processed on 2024-03-04 13:06:29 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 August.

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.

August in Illinois

August 2014 – 11 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 135 173 0 0 0 0 44
New 58 250 0 0 0 0 44

August 2015 – 12 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 228 129 0 0 0 0 27
New 138 219 0 0 0 0 27

August 2016 – 26 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 279 50 0 0 0 0 55
New 202 127 0 0 0 0 55

August 2017 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 336 70 0 0 0 0 42
New 205 201 0 0 0 0 42

August 2018 – 40 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 310 263 2 0 0 0 65
New 137 436 2 0 0 0 65

August 2019 – 23 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 536 62 0 0 0 0 74
New 389 209 0 0 0 0 74

August 2020 – 43 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 541 106 0 0 0 0 89
New 365 282 0 0 0 0 89

August 2021 – 23 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 434 257 2 0 0 0 43
New 195 495 3 0 0 0 43

August 2022 – 24 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 671 31 0 0 0 0 34
New 501 201 0 0 0 0 34

August 2023 – 26 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 402 336 0 0 0 0 30
New 270 468 0 0 0 0 30