Processed on 2024-03-04 13:31:19 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 Montana spent in each AQI category during the the month of February.

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.

February in Montana

February 2014 – 18 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 51 33 0 0 0 0 0
New 42 42 0 0 0 0 0

February 2015 – 18 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 310 70 0 0 0 0 12
New 264 116 0 0 0 0 12

February 2016 – 36 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 324 77 4 0 0 0 1
New 288 113 4 0 0 0 1

February 2017 – 22 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 321 86 8 0 0 0 5
New 291 116 8 0 0 0 5

February 2018 – 45 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 413 61 0 0 0 0 30
New 368 106 0 0 0 0 30

February 2019 – 25 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 397 102 2 0 0 0 3
New 330 169 2 0 0 0 3

February 2020 – 46 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 467 44 0 0 0 0 11
New 439 72 0 0 0 0 11

February 2021 – 25 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 426 60 0 0 0 0 18
New 371 115 0 0 0 0 18

February 2022 – 28 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 467 63 0 0 0 0 2
New 421 109 0 0 0 0 2

February 2023 – 79 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 512 76 0 0 0 0 0
New 484 104 0 0 0 0 0