Processed on 2024-03-04 13:25:00 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 Michigan spent in each AQI category during the the month of December.

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.

December in Michigan

December 2014 – 2 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 43 19 0 0 0 0 0
New 28 34 0 0 0 0 0

December 2015 – 2 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 47 13 0 0 0 0 2
New 33 27 0 0 0 0 2

December 2016 – 18 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 24 7 0 0 0 0 0
New 14 17 0 0 0 0 0

December 2017 – 1 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 20 11 0 0 0 0 0
New 10 21 0 0 0 0 0

December 2018 – 19 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 22 9 0 0 0 0 0
New 16 15 0 0 0 0 0

December 2019 – 2 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 27 18 0 0 0 0 17
New 14 31 0 0 0 0 17

December 2020 – 23 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 34 24 0 0 0 0 4
New 24 34 0 0 0 0 4

December 2021 – 20 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 291 139 0 0 0 0 159
New 208 222 0 0 0 0 159

December 2022 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 409 226 0 0 0 0 16
New 275 360 0 0 0 0 16

December 2023 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 418 194 0 0 0 0 18
New 330 282 0 0 0 0 18