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)
38
Good
Chelmsford, Massachusetts
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
6.96 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
28.20 μg/m³
0
55
155
255
425
605+
13.33 ppb
0
55
71
86
201
201+
0.38 ppb
0
36
76
186
605
1005+
16.09 ppb
0
54
101
361
1250
2050+
0.22 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Chelmsford, Massachusetts
Chelmsford, Massachusetts
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AQI 33
Good
6.39μg/m³
PM2.5
28.58μg/m³
PM10
3.02ppb
O3
0.54ppb
SO2
9.51ppb
NO2
0.46ppm
CO
AQI 44
Good
7.58μg/m³
PM2.5
32.00μg/m³
PM10
2.06ppb
O3
0.51ppb
SO2
13.35ppb
NO2
0.45ppm
CO
AQI 38
Good
6.58μg/m³
PM2.5
28.77μg/m³
PM10
2.83ppb
O3
0.56ppb
SO2
10.60ppb
NO2
0.46ppm
CO
AQI 38
Good
6.69μg/m³
PM2.5
29.33μg/m³
PM10
2.77ppb
O3
0.53ppb
SO2
10.58ppb
NO2
0.45ppm
CO
AQI 38
Good
6.66μg/m³
PM2.5
29.64μg/m³
PM10
3.06ppb
O3
0.56ppb
SO2
11.56ppb
NO2
0.47ppm
CO
AQI 44
Good
7.60μg/m³
PM2.5
31.49μg/m³
PM10
2.03ppb
O3
0.49ppb
SO2
13.70ppb
NO2
0.44ppm
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 12:00:00, 2025-11-03.
The best air quality in Chelmsford, Massachusetts was observed at 02:00:00 on 2025-11-02.
The air quality in Chelmsford, Massachusetts right now is Good, with an AQI of 44.
In Chelmsford, Massachusetts, PM2.5 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 7.588 μg/m3.
Chelmsford, Massachusetts currently has a PM10 concentration of 32.79 μg/m3.
The current carbon monoxide (CO) level in Chelmsford, Massachusetts is 0.45 ppm.
The current sulfur dioxide (SO2) concentration in Chelmsford, Massachusetts is 0.522 ppb.
Chelmsford, Massachusetts currently has an ozone (O3) concentration of 1.807 ppm.
The current level of nitrogen dioxide (NO2) in Chelmsford, Massachusetts is 13.018 ppb.
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