Processed on 2024-03-04 13:19:56 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 June.

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.

June in Maryland

June 2014 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 200 63 0 0 0 0 16
New 137 126 0 0 0 0 16

June 2015 – 9 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 193 48 0 0 0 0 38
New 150 91 0 0 0 0 38

June 2016 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 235 24 0 0 0 0 51
New 175 84 0 0 0 0 51

June 2017 – 10 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 220 23 0 0 0 0 36
New 170 73 0 0 0 0 36

June 2018 – 21 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 268 28 0 0 0 0 14
New 224 72 0 0 0 0 14

June 2019 – 10 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 269 21 0 0 0 0 20
New 215 75 0 0 0 0 20

June 2020 – 23 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 340 11 0 0 0 0 21
New 302 49 0 0 0 0 21

June 2021 – 12 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 306 12 0 0 0 0 54
New 273 45 0 0 0 0 54

June 2022 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 325 18 0 0 0 0 60
New 273 70 0 0 0 0 60

June 2023 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 187 144 14 36 0 0 22
New 153 177 15 34 2 0 22