What is the air quality trend in Chelmsford?

Over the past 3 days, Chelmsford had an average AQI of 53 based on station measurements. The worst day was 2026-10-20 with AQI 93.

How is Chelmsford air quality measured?

Air quality in Chelmsford is measured by ground-level monitoring stations that report PM2.5 and PM10 concentrations hourly. CERNS.IO aggregates readings from nearby stations and converts PM2.5 to the US EPA Air Quality Index (AQI) scale.

Air Quality History for Chelmsford, United Kingdom

Name: Chelmsford Air Quality History
Creator: CERNS.IO
License: https://creativecommons.org/licenses/by/4.0/

Historical PM2.5 and AQI trend from monitoring stations near Chelmsford, United Kingdom.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

42h

PM2.5 Station

42h · 1 station

Temperature GFS model

8pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-10-21	14	4–29	3.3 µg/m³	3.7	10h	1
2026-10-20	93	20–125	32.1 µg/m³	35.7	24h	1
2026-10-19	54	25–89	16.3 µg/m³	18.2	8h	1

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