Worst air pollution Freedom Trail - Boston, today and tomorrow

Today (18 July): Air quality in Freedom Trail is medium. AQI and O3 are medium; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 1:00 PM (O3: 56.1/100).
Tomorrow (19 July 2026): Air quality in Freedom Trail is medium. All pollutants stay as today. Pollution peaks around 1:00 PM (O3: 59.4/100). Airmine updates local air quality forecasts four times daily.

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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team

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Boston's Freedom Trail air quality reflects the 2.5-mile urban walking route through historic Boston, with vehicle traffic on the surrounding arterials and the concentrated tourism character contributing variable local sources along the route. The Boston Harbour's maritime influence provides background ventilation at the waterfront end, while the trail's diverse urban character means air quality varies from the enclosed downtown street canyons to the more open Common and waterfront sections throughout the year.

Today - 18 July | Pollution peaks at 13:00

AQI:

Medium

56.1/100

PM2.5 (fine particles):

Good

16.0/100

PM10 (coarse particles):

Good

7.7/100

NO2 (nitrogen dioxide):

Good

12.0/100

O3 (ozone):

Medium

56.1/100

SO2 (sulfur dioxide):

Good

2.3/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

6.6/100

PM1 (ultrafine particles):

Good

17.6/100

Levels show the poorest local air quality during the day

Tomorrow - 19 July | Pollution peaks at 13:00

AQI:

Medium

59.4/100

PM2.5 (fine particles):

Good

14.3/100

PM10 (coarse particles):

Good

9.9/100

NO2 (nitrogen dioxide):

Good

16.7/100

O3 (ozone):

Medium

59.4/100

SO2 (sulfur dioxide):

Good

1.9/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

7.7/100

PM1 (ultrafine particles):

Good

16.8/100

Other Landmarks in Boston

Sports venues in Boston

Frequently Asked Questions

Is air quality bad in Freedom Trail right now?

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

Will air quality be worse tomorrow in Freedom Trail?

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

When is air pollution at its worst in Freedom Trail?

Air quality at Freedom Trail shifts across the year. In short, the cleanest conditions typically arrive with the more unsettled weather of spring and autumn, whereas the combination of local heat and imported regional haze peaks during summer. Coastal sea breezes can offer some relief from inland summer ozone buildup.

Are air quality levels in Freedom Trail 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.

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Data provided by Airmine — Last update: 18 July 2026 at 21:30 CEST (Data is updated four times daily.)

This forecast is produced independently using Airmine's own atmospheric data and models.

Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.

For long term forecasts and maps, see the Airmine app