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)
44
Good
Waltham, Massachusetts
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
7.91 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
29.64 μg/m³
0
55
155
255
425
605+
11.05 ppb
0
55
71
86
201
201+
0.65 ppb
0
36
76
186
605
1005+
25.36 ppb
0
54
101
361
1250
2050+
0.40 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Waltham, Massachusetts
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AQI 49
Good
9.05μg/m³
PM2.5
43.98μg/m³
PM10
7.19ppb
O3
0.61ppb
SO2
21.04ppb
NO2
0.40ppm
CO
AQI 44
Good
7.91μg/m³
PM2.5
29.64μg/m³
PM10
12.11ppb
O3
0.65ppb
SO2
22.59ppb
NO2
0.40ppm
CO
AQI 49
Good
9.06μg/m³
PM2.5
43.82μg/m³
PM10
7.21ppb
O3
0.61ppb
SO2
21.04ppb
NO2
0.40ppm
CO
AQI 44
Good
8.14μg/m³
PM2.5
38.02μg/m³
PM10
12.45ppb
O3
0.62ppb
SO2
19.36ppb
NO2
0.40ppm
CO
AQI 44
Good
8.11μg/m³
PM2.5
29.57μg/m³
PM10
11.86ppb
O3
0.60ppb
SO2
16.66ppb
NO2
0.48ppm
CO
AQI 49
Good
9.08μg/m³
PM2.5
43.64μg/m³
PM10
7.23ppb
O3
0.61ppb
SO2
21.03ppb
NO2
0.40ppm
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 03:00:00 on 2026-03-09.
In the last 24 hours, the best air quality in Waltham, Massachusetts was observed at 01:00:00 on 2026-03-09.
As of now, the AQI in Waltham, Massachusetts is 44, indicating Good conditions.
Waltham, Massachusetts air has the highest levels of PM2.5.
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 7.907 μg/m3.
The PM10 concentration in Waltham, Massachusetts is 29.64 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Waltham, Massachusetts is 0.397 ppm.
Currently, Waltham, Massachusetts has a sulfur dioxide (SO2) concentration of 0.652 ppb.
The current ozone (O3) level in Waltham, Massachusetts at the moment is 11.049 ppm.
Nitrogen dioxide (NO2) level in Waltham, Massachusetts at the moment is 25.365 ppb.
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