Worst air pollution Chelmsford, today and tomorrow
Today (9 August): Air quality in Chelmsford is fair. NO2 and PM1 are fair; AQI and O3 are medium; PM2.5, PM10, SO2, CO, and HCHO are good. Pollution peaks around 3:00 PM (O3: 58.4/100).
Tomorrow (10 August 2026): Air quality in Chelmsford is fair. AQI worsens to fair; NO2 decreases to good; O3 increases to fair; PM1 decreases to good; all other pollutants stay as today. Pollution peaks around 4:00 PM (O3: 26.4/100). 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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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 - 9 August | Pollution peaks at 15:00
AQI:
Medium
58.4/100
PM2.5 (fine particles):
Good
17.8/100
PM10 (coarse particles):
Good
5.0/100
NO2 (nitrogen dioxide):
Fair
35.6/100
O3 (ozone):
Medium
58.4/100
SO2 (sulfur dioxide):
Good
5.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
7.4/100
PM1 (ultrafine particles):
Fair
22.5/100
Levels show the poorest local air quality during the day
Tomorrow - 10 August | Pollution peaks at 16:00
AQI:
Fair
26.4/100
PM2.5 (fine particles):
Good
6.3/100
PM10 (coarse particles):
Good
2.4/100
NO2 (nitrogen dioxide):
Good
8.3/100
O3 (ozone):
Fair
26.4/100
SO2 (sulfur dioxide):
Good
1.6/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
3.3/100
PM1 (ultrafine particles):
Good
5.5/100
Pollen forecast in Chelmsford
View pollen forecastFrequently Asked Questions
Is air quality bad in Chelmsford right now?
On 9 August 2026, overall air quality in Chelmsford is fair. NO2 is the main pollutant at 35.6/100. Pollution peaks around 3:00 PM (O3: 58.4/100).
Will air quality be worse tomorrow in Chelmsford?
On 10 August 2026, air quality conditions in Chelmsford will be similar to today, with AQI forecast at fair at 26.4/100. Pollution peaks around 4:00 PM (O3: 26.4/100).
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.
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: 9 August 2026 at 20:27 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.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
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