Inner Belt, Somerville, Massachusetts Air Quality Forecast - Today, Tomorrow
Air Quality Today
Today (10 October): Air quality in Inner Belt is fair. AQI and NO2 are fair; PM2.5, PM10, O3, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 4:00 PM (NO2: 21.1/100).
Air Quality Tomorrow
Tomorrow (11 October 2026): Air quality in Inner Belt is good. AQI improves to good; NO2 decreases to good; all other pollutants stay as today. Pollution peaks around 4:00 PM (NO2: 17.4/100).
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Air Quality
Today - 10 October
| Pollutant | Level | Value |
|---|---|---|
| AQI | Fair | 21.1/100 |
| PM2.5 (fine particles) | Good | 7.3/100 |
| PM10 (coarse particles) | Good | 4.1/100 |
| NO2 (nitrogen dioxide) | Fair | 21.1/100 |
| O3 (ozone) | Good | 15.2/100 |
| SO2 (sulfur dioxide) | Good | 0.2/100 |
| CO (carbon monoxide) | Good | 0.4/100 |
| HCHO (formaldehyde) | Good | 2.4/100 |
| PM1 (ultrafine particles) | Good | 11.0/100 |
Tomorrow - 11 October
| Pollutant | Level | Value |
|---|---|---|
| AQI | Good | 17.4/100 |
| PM2.5 (fine particles) | Good | 7.5/100 |
| PM10 (coarse particles) | Good | 3.9/100 |
| NO2 (nitrogen dioxide) | Good | 17.4/100 |
| O3 (ozone) | Good | 16.7/100 |
| SO2 (sulfur dioxide) | Good | 0.2/100 |
| CO (carbon monoxide) | Good | 0.4/100 |
| HCHO (formaldehyde) | Good | 1.9/100 |
| PM1 (ultrafine particles) | Good | 11.0/100 |
Local Environmental Conditions
This location in Somerville is largely built up, so vehicle exhaust and urban activity dominate the local air pollution sources. Home heating, especially wood stoves and fireplaces, adds smoke and fine particles in the colder months. Air arriving from elsewhere in the region adds to what is produced locally. Exhaust from nearby roads is usually highest close to busy streets and junctions.
Ozone is the main concern from July to August, when sunny days averaging 23°C turn traffic and other emissions into ozone by mid-afternoon. From November to March, temperatures near -2°C, with winds of around 10 km/h, let smoke and particles from home heating and traffic build up, especially on cold, still mornings.
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Frequently Asked Questions About Air Quality in Massachusetts
Is air quality bad in Inner Belt right now?
On 10 October 2026, overall air quality in Inner Belt is fair. AQI is the main air quality indicator at 21.1/100. Pollution peaks around 4:00 PM (NO2: 21.1/100).
Will air quality be worse tomorrow in Inner Belt?
On 11 October 2026, air quality conditions in Inner Belt will be better than today, with AQI forecast at good at 17.4/100. Pollution peaks around 4:00 PM (NO2: 17.4/100).
When is air pollution at its worst in Inner Belt?
Ozone is the main concern from July to August, when sunny days averaging 23°C turn traffic and other emissions into ozone by mid-afternoon. From November to March, temperatures near -2°C, with winds of around 10 km/h, let smoke and particles from home heating and traffic build up, especially on cold, still mornings.
Are air quality levels in Inner Belt based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
Understanding the Scale
The 0–100 air quality scores represent risk levels, not direct air pollutant concentrations. Higher scores indicate higher risk.
Air Quality
| Good | 0-20 | Low air quality risk. Air quality is expected to be good, with low levels of pollution. |
| Fair | 20-40 | Generally low air quality risk. Air quality is expected to be acceptable, with some pollution present. |
| Moderate | 40-60 | Moderate air quality risk. Air pollution is elevated and air quality may be less favorable. |
| Poor | 60-80 | High air quality risk. Air pollution is high and air quality is expected to be poor. |
| Very Poor | 80-100 | Very high air quality risk. Air pollution is very high and air quality is expected to be very poor. |