Air quality
Air quality in Chelsea today
Updated
Moderate (US AQI 72) Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. Model estimate for Sun, Oct 25, 6:50 pm (22:50 UTC).
Live AQI, PM2.5, PM10 and ozone for Chelsea, Massachusetts, United States, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 72 Moderate
- PM2.5
- 14 µg/m³ 0.9× WHO 24-h guideline
- PM10
- 14 µg/m³
- Ozone
- 44 µg/m³
Air quality in Chelsea right now
Right now the modelled US Air Quality Index for Chelsea, Massachusetts, United States is 72, which falls in the "Moderate" band (up to 100). Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors.
PM2.5 is 14 µg/m³, within the WHO 24-hour guideline of 15 µg/m³; PM10 is 14 µg/m³ against a guideline of 45; ozone is 44 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 39 µg/m³ (above the 24-hour guideline of 25).
NASA FIRMS shows 7 fire hotspots within 300 km in the last day (nearest about 145 km), but particle levels are not elevated enough to point to smoke right now.
Chelsea vs the rest of United States
Across 619 United States cities we track, the average US AQI right now is 51 (Moderate). Chelsea at 72 is 21 points worse than average.
It ranks 565 of 619 from cleanest to most polluted; the cleanest is Hilo (18) and the most polluted Springfield, PA (131).
For context, the median across 3,556 cities worldwide is 58.
Air quality in cities near Chelsea
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Everett, MA | 3 km | 72 | Moderate | 14.1 |
| Boston | 4 km | 72 | Moderate | 14.1 |
| Cambridge, MA | 6 km | 72 | Moderate | 14.1 |
| Medford, MA | 7 km | 72 | Moderate | 14.1 |
| Arlington, MA | 10 km | 72 | Moderate | 14.1 |
| Lynn | 11 km | 72 | Moderate | 14.1 |
| Winchester, MA | 11 km | 72 | Moderate | 14.1 |
| Brighton, MA | 11 km | 72 | Moderate | 14.1 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Chelsea, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.
Advice for sensitive groups
At 72, most people are fine outdoors. If you are unusually sensitive to air pollution, keep long or intense workouts to the cleaner hours shown above.
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. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for Chelsea
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.