Processed on 2024-03-04 13:22:39 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 Massachusetts 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 Massachusetts

October 2014 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 263 12 0 0 0 0 13
New 226 49 0 0 0 0 13

October 2015 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 257 14 0 0 0 0 17
New 226 45 0 0 0 0 17

October 2016 – 20 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 252 5 0 0 0 0 31
New 231 26 0 0 0 0 31

October 2017 – 10 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 277 16 0 0 0 0 27
New 233 60 0 0 0 0 27

October 2018 – 24 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 349 31 0 0 0 0 36
New 303 77 0 0 0 0 36

October 2019 – 14 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 400 5 0 0 0 0 43
New 368 37 0 0 0 0 43

October 2020 – 28 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 428 7 0 0 0 0 45
New 398 37 0 0 0 0 45

October 2021 – 17 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 503 0 0 0 0 0 41
New 471 32 0 0 0 0 41

October 2022 – 17 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 454 39 0 0 0 0 19
New 371 122 0 0 0 0 19

October 2023 – 19 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 518 34 3 0 0 0 53
New 458 94 3 0 0 0 53