Processed on 2024-03-04 13:20:37 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 Maryland 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 Maryland

October 2014 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 236 8 0 0 0 0 12
New 201 43 0 0 0 0 12

October 2015 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 262 13 0 0 0 0 13
New 224 51 0 0 0 0 13

October 2016 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 286 13 0 0 0 0 21
New 247 52 0 0 0 0 21

October 2017 – 10 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 266 12 0 0 0 0 10
New 199 79 0 0 0 0 10

October 2018 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 284 22 0 0 0 0 14
New 230 76 0 0 0 0 14

October 2019 – 10 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 302 5 0 0 0 0 13
New 282 25 0 0 0 0 13

October 2020 – 23 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 367 4 0 0 0 0 13
New 341 30 0 0 0 0 13

October 2021 – 12 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 358 5 0 0 0 0 21
New 318 45 0 0 0 0 21

October 2022 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 384 6 0 0 0 0 26
New 346 44 0 0 0 0 26

October 2023 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 386 13 0 0 0 0 17
New 350 49 0 0 0 0 17