Stay updated with real-time air quality in Chelmsford, Massachusetts featuring accurate data on AQI, PM2.5, PM10, O3, NO2, SO2, and CO levels. Use our interactive map and detailed forecasts to monitor pollution trends, manage health risks, and plan your daily activities with confidence.
Live AQI (Air Quality Index)
32
Good
Chelmsford, Massachusetts
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
5.28 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
22.32 μg/m³
0
55
155
255
425
605+
34.90 ppb
0
55
71
86
201
201+
0.58 ppb
0
36
76
186
605
1005+
16.51 ppb
0
54
101
361
1250
2050+
0.17 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Moderate
Chelmsford, Massachusetts
Chelmsford, Massachusetts
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AQI 35
Good
4.76μg/m³
PM2.5
19.54μg/m³
PM10
38.44ppb
O3
0.64ppb
SO2
22.48ppb
NO2
0.17ppm
CO
AQI 31
Good
4.38μg/m³
PM2.5
15.79μg/m³
PM10
33.40ppb
O3
0.63ppb
SO2
17.36ppb
NO2
0.16ppm
CO
AQI 35
Good
4.69μg/m³
PM2.5
19.10μg/m³
PM10
38.08ppb
O3
0.64ppb
SO2
21.48ppb
NO2
0.17ppm
CO
AQI 34
Good
4.67μg/m³
PM2.5
18.52μg/m³
PM10
37.38ppb
O3
0.64ppb
SO2
21.08ppb
NO2
0.17ppm
CO
AQI 36
Good
4.73μg/m³
PM2.5
18.93μg/m³
PM10
38.74ppb
O3
0.62ppb
SO2
19.37ppb
NO2
0.17ppm
CO
AQI 31
Good
4.38μg/m³
PM2.5
15.47μg/m³
PM10
32.92ppb
O3
0.64ppb
SO2
16.59ppb
NO2
0.16ppm
CO
The air quality data for Massachusetts, USA is gathered from reliable sources such as satellites and monitoring stations, adhering to US EPA guidelines. With the help of advanced algorithms and machine learning, factors like traffic and population density are analyzed to deliver accurate and dependable results.
Source: Ambee Data Sources
Air quality updates for Chelmsford, Massachusetts are available every hour.
Chelmsford, Massachusetts experienced its worst air quality at 06:00:00, 2026-05-14.
The best air quality in Chelmsford, Massachusetts was observed at 03:00:00 on 2026-05-13.
The air quality in Chelmsford, Massachusetts right now is Good, with an AQI of 32.
In Chelmsford, Massachusetts, O3 is the most frequently found pollutant.
When air quality in Chelmsford, Massachusetts is compromised, staying indoors and wearing a mask can reduce health risks.
Chelmsford, Massachusetts currently has a PM2.5 concentration of 5.279 μg/m3.
Chelmsford, Massachusetts currently has a PM10 concentration of 22.325 μg/m3.
The current carbon monoxide (CO) level in Chelmsford, Massachusetts is 0.167 ppm.
The current sulfur dioxide (SO2) concentration in Chelmsford, Massachusetts is 0.583 ppb.
Chelmsford, Massachusetts currently has an ozone (O3) concentration of 34.898 ppm.
The current level of nitrogen dioxide (NO2) in Chelmsford, Massachusetts is 16.511 ppb.
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