Processed on 2024-03-04 13:19:25 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 March.

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.

March in Maryland

March 2014 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 180 64 0 0 0 0 4
New 113 131 0 0 0 0 4

March 2015 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 182 79 0 0 0 0 18
New 119 142 0 0 0 0 18

March 2016 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 247 61 0 0 0 0 2
New 187 121 0 0 0 0 2

March 2017 – 10 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 249 27 0 0 0 0 3
New 207 69 0 0 0 0 3

March 2018 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 292 14 0 0 0 0 4
New 255 51 0 0 0 0 4

March 2019 – 10 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 282 26 0 0 0 0 2
New 241 67 0 0 0 0 2

March 2020 – 23 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 306 1 0 0 0 0 3
New 291 16 0 0 0 0 3

March 2021 – 12 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 328 35 0 0 0 0 9
New 307 56 0 0 0 0 9

March 2022 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 389 9 0 0 0 0 5
New 340 58 0 0 0 0 5

March 2023 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 385 16 0 0 0 0 2
New 359 42 0 0 0 0 2