Air quality in United States
Air quality in Maryland today
Updated
Moderate: average US AQI 63 across 8 cities in Maryland Worst now: Potomac (67); cleanest: St. Charles (58).
Live US AQI, PM2.5 and ozone for cities across Maryland, compared with the United States average.
- Average US AQI
- 63 Moderate
- United States average
- 48 747 cities
- Most polluted now
- Potomac AQI 67
- Cleanest now
- St. Charles AQI 58
- Cities above 100
- 0
Air quality in Maryland today
Right now the modelled air quality in Maryland averages a US AQI of 63 (Moderate) across the 8 cities we track. By category: 8 Moderate (of 8).
That is 15 points worse than the United States average of 48, ranking 45 of 51 states from cleanest to most polluted.
Potomac has the worst air at 67 (PM2.5 14 µg/m³), and St. Charles the cleanest at 58. No tracked city is above 100, so no group needs to change plans.
Maryland cities by AQI (most polluted first)
| City | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Potomac | 67 | Moderate | 14.1 | 18 | 92 |
| Baltimore | 66 | Moderate | 15.1 | 19 | 93 |
| Columbia | 66 | Moderate | 15.1 | 19 | 93 |
| Essex | 66 | Moderate | 15.1 | 19 | 93 |
| Frederick | 63 | Moderate | 12.1 | 15 | 93 |
| Pasadena | 62 | Moderate | 15.5 | 17 | 98 |
| Saint Charles | 58 | Moderate | 13.6 | 17 | 93 |
| St. Charles | 58 | Moderate | 13.6 | 17 | 93 |
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Modelled by CAMS (Copernicus) via Open-Meteo, refreshed twice a day; read hour by hour from the forecast.
Cities in Maryland
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Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS).