Processed on 2024-03-04 13:53:56 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 May.

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.

May in Oregon

May 2014 – 26 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 667 1 0 0 0 0 36
New 663 5 0 0 0 0 36

May 2015 – 30 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 623 2 0 0 0 0 47
New 614 11 0 0 0 0 47

May 2016 – 70 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 663 1 0 0 0 0 40
New 660 4 0 0 0 0 40

May 2017 – 32 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 699 2 0 1 0 0 34
New 696 5 0 1 0 0 34

May 2018 – 78 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 577 3 1 0 0 0 219
New 576 4 1 0 0 0 219

May 2019 – 37 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 872 7 1 0 0 0 80
New 836 43 1 0 0 0 80

May 2020 – 106 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 975 0 0 0 0 0 49
New 973 2 0 0 0 0 49

May 2021 – 67 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1749 4 0 1 0 0 102
New 1743 10 0 1 0 0 102

May 2022 – 72 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1937 8 0 1 0 0 134
New 1934 11 0 1 0 0 134

May 2023 – 79 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1999 35 1 2 0 1 106
New 1967 67 1 1 1 1 106