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)
27
Good
Waltham, Massachusetts
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
5.29 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
11.92 μg/m³
0
55
155
255
425
605+
29.23 ppb
0
55
71
86
201
201+
0.52 ppb
0
36
76
186
605
1005+
8.03 ppb
0
54
101
361
1250
2050+
0.21 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Waltham, Massachusetts
Waltham, Massachusetts
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AQI 33
Good
6.21μg/m³
PM2.5
23.84μg/m³
PM10
7.11ppb
O3
0.33ppb
SO2
20.24ppb
NO2
0.57ppm
CO
AQI 38
Good
7.13μg/m³
PM2.5
25.30μg/m³
PM10
16.95ppb
O3
0.34ppb
SO2
17.55ppb
NO2
0.55ppm
CO
AQI 33
Good
6.22μg/m³
PM2.5
24.11μg/m³
PM10
7.13ppb
O3
0.33ppb
SO2
20.19ppb
NO2
0.58ppm
CO
AQI 38
Good
6.93μg/m³
PM2.5
25.19μg/m³
PM10
16.89ppb
O3
0.32ppb
SO2
15.73ppb
NO2
0.53ppm
CO
AQI 33
Good
5.78μg/m³
PM2.5
18.95μg/m³
PM10
19.39ppb
O3
0.31ppb
SO2
17.29ppb
NO2
0.58ppm
CO
AQI 33
Good
6.22μg/m³
PM2.5
24.42μg/m³
PM10
7.16ppb
O3
0.33ppb
SO2
20.10ppb
NO2
0.58ppm
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 2025-11-03.
In the last 24 hours, the best air quality in Waltham, Massachusetts was observed at 01:00:00 on 2025-11-02.
As of now, the AQI in Waltham, Massachusetts is 33, 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 6.133 μg/m3.
The PM10 concentration in Waltham, Massachusetts is 26.461 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Waltham, Massachusetts is 0.533 ppm.
Currently, Waltham, Massachusetts has a sulfur dioxide (SO2) concentration of 0.475 ppb.
The current ozone (O3) level in Waltham, Massachusetts at the moment is 8.526 ppm.
Nitrogen dioxide (NO2) level in Waltham, Massachusetts at the moment is 17.623 ppb.
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