Bad Air Days in Anne Arundel County, Maryland: 5 a Year
5 bad air days a year
More bad air days than three quarters of monitored counties. Ranked 199 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (0% particle days).
The bad-air season here
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in July and June and May. Averaged over 2016 to 2025.
What actually helps here
- Ozone drives many bad days here. Purifiers and filters do not remove ozone, so do not buy one for that. Ozone peaks on hot afternoons: exercise outside in the morning.
The worst days on file
In 2000 to 2009 this county averaged 37 bad days a year; in 2016 to 2025, 5. The air has improved. The worst recent year was 2018, with 9 bad days on 261 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2023-06-29 | 150 | Ozone |
| 2019-06-28 | 143 | Ozone |
| 2016-08-29 | 140 | Ozone |
| 2018-06-18 | 140 | Ozone |
| 2017-05-17 | 129 | Ozone |
An ordinary day in Anne Arundel
Across 2,597 monitored days from 2016 to 2025, the air in Anne Arundel County rated Good on 81% of them, more often than the 72% typical of monitored counties, and Moderate on 18%. The median day sat at AQI 41; one day in ten went above 64.
The pollutant setting the AQI on an ordinary day here:
- ozone90%2,333 days
- coarse dust (PM10)8%195 days
- fine particles (PM2.5)3%69 days
Anne Arundel County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 259 | 227 | 30 | 2 | 0 | 40 | 119 |
| 2024 | 231 | 186 | 44 | 1 | 0 | 40 | 129 |
| 2023 | 263 | 225 | 36 | 2 | 0 | 40 | 150 |
| 2022 | 263 | 247 | 16 | 0 | 0 | 38 | 93 |
| 2021 | 262 | 222 | 39 | 1 | 0 | 38 | 101 |
| 2020 | 262 | 235 | 25 | 2 | 0 | 39 | 108 |
| 2019 | 264 | 179 | 78 | 7 | 0 | 45 | 143 |
| 2018 | 261 | 193 | 59 | 9 | 0 | 42 | 140 |
| 2017 | 265 | 216 | 43 | 6 | 0 | 41 | 129 |
| 2016 | 267 | 166 | 93 | 8 | 0 | 44 | 140 |
| 2015 | 264 | 177 | 83 | 4 | 0 | 45 | 119 |
| 2014 | 264 | 186 | 77 | 1 | 0 | 44 | 133 |
| 2013 | 258 | 168 | 86 | 4 | 0 | 45 | 119 |
| 2012 | 262 | 146 | 99 | 17 | 6 | 49 | 192 |
| 2011 | 264 | 151 | 96 | 17 | 4 | 47 | 172 |
| 2010 | 360 | 158 | 182 | 20 | 4 | 53 | 185 |
*2025 may be a partial year in EPA's file.
Maryland compared
- Baltimore County8/yr
- Harford County7/yr
- Prince George's County5/yr
- Cecil County4/yr
- Baltimore City4/yr
- Kent County2/yr
- Frederick County2/yr
- Charles County2/yr
How this is counted
A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day, and on why a purifier does not touch ozone in smoke vs ozone.