Stay updated with real-time air quality in Waltham, 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)
31
Good
Waltham, Massachusetts
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
3.57 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
16.03 μg/m³
0
55
155
255
425
605+
34.34 ppb
0
55
71
86
201
201+
0.40 ppb
0
36
76
186
605
1005+
6.25 ppb
0
54
101
361
1250
2050+
0.19 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Waltham, Massachusetts
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AQI 24
Good
3.65μg/m³
PM2.5
14.68μg/m³
PM10
25.68ppb
O3
0.62ppb
SO2
8.23ppb
NO2
0.19ppm
CO
AQI 27
Good
3.51μg/m³
PM2.5
13.09μg/m³
PM10
29.06ppb
O3
0.51ppb
SO2
7.52ppb
NO2
0.20ppm
CO
AQI 24
Good
3.66μg/m³
PM2.5
14.80μg/m³
PM10
25.77ppb
O3
0.62ppb
SO2
8.20ppb
NO2
0.19ppm
CO
AQI 30
Good
3.58μg/m³
PM2.5
13.09μg/m³
PM10
31.66ppb
O3
0.47ppb
SO2
7.34ppb
NO2
0.20ppm
CO
AQI 31
Good
3.09μg/m³
PM2.5
15.50μg/m³
PM10
33.04ppb
O3
0.45ppb
SO2
6.37ppb
NO2
0.20ppm
CO
AQI 24
Good
3.67μg/m³
PM2.5
14.94μg/m³
PM10
25.91ppb
O3
0.62ppb
SO2
8.16ppb
NO2
0.19ppm
CO
Air quality and pollutant data for Massachusetts, USA are sourced from ground-based monitors and satellites, adhering to US EPA standards. Machine learning and advanced algorithms enhance the data by incorporating local variables like traffic and population density, ensuring high accuracy and dependability.
Source: Ambee Data Sources
The air quality information for Waltham, Massachusetts is updated every hour for accuracy.
In the past 24 hours, the air quality in Waltham, Massachusetts was at its worst at 04:00:00 on 2026-02-11.
In the last 24 hours, the best air quality in Waltham, Massachusetts was observed at 01:00:00 on 2026-02-12.
As of now, the AQI in Waltham, Massachusetts is 31, indicating Good conditions.
Waltham, Massachusetts air has the highest levels of O3.
Poor air quality in Waltham, Massachusetts means it's advisable to stay indoors and wear a mask for your protection.
PM2.5 levels in Waltham, Massachusetts are currently 3.566 μg/m3.
The PM10 concentration in Waltham, Massachusetts is 16.028 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Waltham, Massachusetts is 0.19 ppm.
Currently, Waltham, Massachusetts has a sulfur dioxide (SO2) concentration of 0.4 ppb.
The current ozone (O3) level in Waltham, Massachusetts at the moment is 34.345 ppm.
Nitrogen dioxide (NO2) level in Waltham, Massachusetts at the moment is 6.245 ppb.
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