Worst air pollution Brookline & Chestnut Hill - Boston, today and tomorrow

On 18 July 2026, overall air quality in Brookline & Chestnut Hill is medium. AQI is the main air quality indicator at 56.1/100. Pollution peaks around 1:00 PM (O3: 56.1/100).

On 19 July 2026, air quality conditions in Brookline & Chestnut Hill will be similar to today, with AQI forecast at medium at 59.4/100. Pollution peaks around 1:00 PM (O3: 59.4/100).

Like the rest of Boston, Brookline & Chestnut Hill sees air quality change through the year — spring and autumn generally bring the cleanest air, helped by more active weather patterns, whereas summer heat and regional haze drifting up from the Midwest and South drive ozone spikes. Winter cold fronts tend to clear the air quickly, so extended pollution episodes are relatively uncommon.

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.

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.