Worst air pollution Waltham, today and tomorrow
Today (16 July): Air quality in Waltham is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 1:00 PM (O3: 36.3/100).
Tomorrow (17 July 2026): Air quality in Waltham is fair. All pollutants stay as today. Pollution peaks around 1:00 PM (O3: 38.8/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Waltham's air quality reflects the Charles River valley in the Boston western metropolitan area, with vehicle emissions from I-95 and the surrounding Brandeis University and pharmaceutical and technology manufacturing corridor contributing local sources. The broader Boston metropolitan regional ozone burden on prevailing southwesterlies elevates background pollution, while the Charles River provides limited ventilation and the flat eastern Massachusetts terrain generally allows reasonable dispersal throughout the year.
Today - 16 July | Pollution peaks at 13:00
AQI:
Fair
36.3/100
PM2.5 (fine particles):
Good
10.7/100
PM10 (coarse particles):
Good
8.6/100
NO2 (nitrogen dioxide):
Good
2.4/100
O3 (ozone):
Fair
36.3/100
SO2 (sulfur dioxide):
Good
0.4/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
5.1/100
PM1 (ultrafine particles):
Good
4.8/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 13:00
AQI:
Fair
38.8/100
PM2.5 (fine particles):
Good
8.9/100
PM10 (coarse particles):
Good
7.2/100
NO2 (nitrogen dioxide):
Good
2.7/100
O3 (ozone):
Fair
38.8/100
SO2 (sulfur dioxide):
Good
0.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
8.0/100
PM1 (ultrafine particles):
Good
5.2/100
Pollen forecast in Waltham
View pollen forecastFrequently Asked Questions
Is air quality bad in Waltham right now?
On 16 July 2026, overall air quality in Waltham is fair. AQI is the main air quality indicator at 36.3/100. Pollution peaks around 1:00 PM (O3: 36.3/100).
Will air quality be worse tomorrow in Waltham?
On 17 July 2026, air quality conditions in Waltham will be similar to today, with AQI forecast at fair at 38.8/100. Pollution peaks around 1:00 PM (O3: 38.8/100).
When is air pollution at its worst in Waltham?
Air quality across Waltham rises and falls with the seasons — the shoulder seasons bring the most consistently clean air of the year, whereas the combination of local heat and imported regional haze peaks during summer. Winter cold fronts tend to clear the air quickly, so extended pollution episodes are relatively uncommon.
Are air quality levels in Waltham 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.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 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