Processed on 2024-03-04 14:14:54 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 Washington spent in each AQI category during the the month of October.

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.

October in Washington

October 2014 – 30 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 856 28 0 0 0 0 44
New 789 95 0 0 0 0 44

October 2015 – 41 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1007 90 0 0 0 0 87
New 852 245 0 0 0 0 87

October 2016 – 112 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1164 37 0 0 0 0 143
New 1072 129 0 0 0 0 143

October 2017 – 52 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1184 151 0 1 0 0 104
New 1052 283 0 1 0 0 104

October 2018 – 130 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1253 302 1 4 0 1 103
New 1047 508 1 4 0 1 103

October 2019 – 67 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1594 159 0 0 0 0 135
New 1401 352 0 0 0 0 135

October 2020 – 129 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1495 190 1 0 0 0 106
New 1278 407 1 0 0 0 106

October 2021 – 71 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1902 71 0 0 0 0 107
New 1800 173 0 0 0 0 107

October 2022 – 83 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1254 716 83 76 4 1 138
New 960 1006 87 73 7 1 138

October 2023 – 106 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 2103 192 5 0 0 0 292
New 1872 423 5 0 0 0 292