Processed on 2024-03-04 13:04:34 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 Idaho 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 Idaho

September 2014 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 167 7 0 0 0 0 12
New 152 22 0 0 0 0 12

September 2015 – 17 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 220 6 0 0 0 0 22
New 200 26 0 0 0 0 22

September 2016 – 32 permanent monitors

Processing error: Unable to calculate tables.

September 2017 – 19 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 209 113 25 29 0 0 27
New 181 141 25 27 2 0 27

September 2018 – 37 permanent monitors

Processing error: Unable to calculate tables.

September 2019 – 22 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 493 15 0 0 0 0 19
New 449 59 0 0 0 0 19

September 2020 – 34 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 18 12 0 0 0 0 1
New 16 14 0 0 0 0 1

September 2021 – 19 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 274 139 32 3 0 0 17
New 203 209 33 3 0 0 17

September 2022 – 23 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 275 124 24 22 0 0 20
New 190 209 24 20 2 0 20

September 2023 – 17 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 499 8 0 0 0 0 20
New 471 36 0 0 0 0 20