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)
39
Good
Waltham, Massachusetts
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
2.54 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
10.62 μg/m³
0
55
155
255
425
605+
42.31 ppb
0
55
71
86
201
201+
0.84 ppb
0
36
76
186
605
1005+
4.03 ppb
0
54
101
361
1250
2050+
0.18 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Waltham, Massachusetts
Waltham, Massachusetts
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AQI 38
Good
2.68μg/m³
PM2.5
11.05μg/m³
PM10
40.53ppb
O3
1.05ppb
SO2
5.12ppb
NO2
0.19ppm
CO
AQI 39
Good
2.54μg/m³
PM2.5
10.64μg/m³
PM10
42.37ppb
O3
0.81ppb
SO2
4.15ppb
NO2
0.18ppm
CO
AQI 38
Good
2.69μg/m³
PM2.5
11.09μg/m³
PM10
40.66ppb
O3
1.05ppb
SO2
5.11ppb
NO2
0.19ppm
CO
AQI 38
Good
2.51μg/m³
PM2.5
10.74μg/m³
PM10
41.02ppb
O3
0.73ppb
SO2
4.03ppb
NO2
0.17ppm
CO
AQI 38
Good
2.77μg/m³
PM2.5
10.76μg/m³
PM10
41.00ppb
O3
0.69ppb
SO2
4.16ppb
NO2
0.21ppm
CO
AQI 38
Good
2.70μg/m³
PM2.5
11.14μg/m³
PM10
40.85ppb
O3
1.04ppb
SO2
5.08ppb
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 08:00:00 on 2026-06-14.
In the last 24 hours, the best air quality in Waltham, Massachusetts was observed at 01:00:00 on 2026-06-15.
As of now, the AQI in Waltham, Massachusetts is 39, 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 2.539 μg/m3.
The PM10 concentration in Waltham, Massachusetts is 10.616 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Waltham, Massachusetts is 0.178 ppm.
Currently, Waltham, Massachusetts has a sulfur dioxide (SO2) concentration of 0.839 ppb.
The current ozone (O3) level in Waltham, Massachusetts at the moment is 42.311 ppm.
Nitrogen dioxide (NO2) level in Waltham, Massachusetts at the moment is 4.033 ppb.
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