Maryland(MD)
Air quality overview and monitoring data — 2025
299
Monitoring Sites
4,592
Active Monitors
20
Counties with Data
83
Cities Monitored
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County Air Quality
| County | Median AQI ▲ | 90th %ile | Max AQI | Good | Moderate | USG | Unhealthy |
|---|---|---|---|---|---|---|---|
| Howard | 36 | 54 | 78 | 211 | 63 | 0 | 0 |
| Calvert | 38 | 48 | 77 | 227 | 13 | 0 | 0 |
| Carroll | 38 | 50 | 90 | 215 | 23 | 0 | 0 |
| Charles | 38 | 49 | 97 | 218 | 18 | 0 | 0 |
| Anne Arundel | 40 | 58 | 119 | 217 | 30 | 2 | 0 |
| Dorchester | 40 | 52 | 84 | 255 | 47 | 0 | 0 |
| Kent | 40 | 57 | 129 | 249 | 49 | 1 | 0 |
| Cecil | 41 | 61 | 129 | 246 | 56 | 2 | 0 |
| Frederick | 41 | 58 | 93 | 203 | 34 | 0 | 0 |
| Garrett | 41 | 55 | 80 | 256 | 47 | 0 | 0 |
| Montgomery | 41 | 54 | 90 | 253 | 50 | 0 | 0 |
| Prince George's | 41 | 61 | 126 | 254 | 47 | 3 | 0 |
| Washington | 42 | 59 | 90 | 235 | 69 | 0 | 0 |
| Harford | 43 | 61 | 143 | 226 | 74 | 3 | 0 |
| Baltimore | 44 | 65 | 129 | 214 | 87 | 3 | 0 |
| Baltimore (City) | 44 | 64 | 136 | 208 | 93 | 2 | 0 |
Pollutant Trends
Ozone
No data available
PM2.5
No data available
PM10
No data available
CO
No data available
NO2
No data available
SO2
No data available