Processed on 2024-03-04 13:26:25 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 Minnesota spent in each AQI category during the the month of September.

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.

September in Minnesota

September 2014 – 17 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 404 24 0 0 0 0 37
New 370 58 0 0 0 0 37

September 2015 – 18 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 460 27 0 0 0 0 71
New 401 86 0 0 0 0 71

September 2016 – 37 permanent monitors

Processing error: Unable to calculate tables.

September 2017 – 19 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 423 88 0 0 0 0 47
New 363 148 0 0 0 0 47

September 2018 – 40 permanent monitors

Processing error: Unable to calculate tables.

September 2019 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 596 3 0 0 0 0 52
New 580 19 0 0 0 0 52

September 2020 – 42 permanent monitors

Processing error: Unable to calculate tables.

September 2021 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 591 13 0 0 0 0 47
New 551 53 0 0 0 0 47

September 2022 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 556 25 0 0 0 0 70
New 501 80 0 0 0 0 70

September 2023 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 390 223 5 1 0 0 32
New 242 371 5 1 0 0 32