Processed on 2024-03-04 13:54:35 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 Oregon 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 Oregon

September 2014 – 26 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 638 73 5 0 0 0 28
New 564 147 5 0 0 0 28

September 2015 – 30 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 789 20 0 0 0 0 28
New 739 70 0 0 0 0 28

September 2016 – 70 permanent monitors

Processing error: Unable to calculate tables.

September 2017 – 32 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 560 166 58 89 20 4 64
New 498 228 56 80 28 7 64

September 2018 – 78 permanent monitors

Processing error: Unable to calculate tables.

September 2019 – 37 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1101 8 1 0 0 0 37
New 1081 28 1 0 0 0 37

September 2020 – 106 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 242 74 12 29 49 31 59
New 216 98 14 22 49 38 59

September 2021 – 67 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1463 267 69 96 13 4 72
New 1382 345 71 88 22 4 72

September 2022 – 72 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1489 411 58 34 6 2 139
New 1303 595 60 32 7 3 139

September 2023 – 79 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1923 162 24 11 0 0 143
New 1807 277 25 10 1 0 143