Processed on 2024-03-04 13:22:08 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 July.

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.

July in Massachusetts

July 2014 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 189 66 0 0 0 0 33
New 113 142 0 0 0 0 33

July 2015 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 206 70 0 0 0 0 12
New 151 125 0 0 0 0 12

July 2016 – 20 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 238 24 0 0 0 0 26
New 187 75 0 0 0 0 26

July 2017 – 10 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 250 23 0 0 0 0 15
New 208 65 0 0 0 0 15

July 2018 – 24 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 304 85 0 0 0 0 27
New 224 165 0 0 0 0 27

July 2019 – 14 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 350 84 0 0 0 0 14
New 232 202 0 0 0 0 14

July 2020 – 28 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 356 29 0 0 0 0 63
New 278 107 0 0 0 0 63

July 2021 – 17 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 384 81 13 2 0 0 64
New 300 164 14 2 0 0 64

July 2022 – 17 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 435 37 0 0 0 0 40
New 335 137 0 0 0 0 40

July 2023 – 19 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 397 141 12 1 0 0 25
New 289 247 13 2 0 0 25