Worst air pollution Chelmsford, today and tomorrow
Today (16 July): Air quality in Chelmsford is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 3:00 PM (O3: 33.1/100).
Tomorrow (17 July 2026): Air quality in Chelmsford is fair. All pollutants stay as today. Pollution peaks around 3:00 PM (O3: 39.6/100). 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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Being part of Essex, Chelmsford sees an air quality profile that's largely down to traffic and general town-centre activity. The A46 generates consistent traffic-related NO₂ and PM2.5, particularly during peak commuting hours. The region's typical south-westerlies offer a degree of natural ventilation, keeping pollution broadly in line with comparable UK towns.
Today - 16 July | Pollution peaks at 15:00
AQI:
Fair
33.1/100
PM2.5 (fine particles):
Good
9.4/100
PM10 (coarse particles):
Good
3.1/100
NO2 (nitrogen dioxide):
Good
8.8/100
O3 (ozone):
Fair
33.1/100
SO2 (sulfur dioxide):
Good
1.2/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.9/100
PM1 (ultrafine particles):
Good
8.4/100
Levels show the poorest local air quality during the day
Tomorrow - 17 July | Pollution peaks at 15:00
AQI:
Fair
39.6/100
PM2.5 (fine particles):
Good
11.4/100
PM10 (coarse particles):
Good
3.9/100
NO2 (nitrogen dioxide):
Good
11.5/100
O3 (ozone):
Fair
39.6/100
SO2 (sulfur dioxide):
Good
1.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
4.1/100
PM1 (ultrafine particles):
Good
10.5/100
Pollen forecast in Chelmsford
View pollen forecastFrequently Asked Questions
Is air quality bad in Chelmsford right now?
On 16 July 2026, overall air quality in Chelmsford is fair. AQI is the main air quality indicator at 33.1/100. Pollution peaks around 3:00 PM (O3: 33.1/100).
Will air quality be worse tomorrow in Chelmsford?
On 17 July 2026, air quality conditions in Chelmsford will be similar to today, with AQI forecast at fair at 39.6/100. Pollution peaks around 3:00 PM (O3: 39.6/100).
When is air pollution at its worst in Chelmsford?
The shoulder seasons generally bring the mildest readings of the year. Ask a local in Chelmsford and they'll tell you air quality changes noticeably from season to season. The coldest months usually bring the worst readings, as heating and temperature inversions keep A46 emissions from dispersing normally. Warmer months swap one problem for another — less smoke and heating pollution, but more ozone on the sunniest days.
Are air quality levels in Chelmsford 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