Stay updated with real-time air quality in San Mateo, California 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)
33
Good
San Mateo, California
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
6.37 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
31.23 μg/m³
0
55
155
255
425
605+
35.09 ppb
0
55
71
86
201
201+
0.84 ppb
0
36
76
186
605
1005+
3.39 ppb
0
54
101
361
1250
2050+
0.32 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Very high
San Mateo, California
San Mateo, California
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AQI 38
Good
7.16μg/m³
PM2.5
32.79μg/m³
PM10
32.50ppb
O3
0.87ppb
SO2
3.46ppb
NO2
0.32ppm
CO
AQI 38
Good
7.34μg/m³
PM2.5
32.23μg/m³
PM10
37.33ppb
O3
0.81ppb
SO2
1.97ppb
NO2
0.31ppm
CO
AQI 38
Good
7.01μg/m³
PM2.5
30.72μg/m³
PM10
33.86ppb
O3
0.86ppb
SO2
3.40ppb
NO2
0.32ppm
CO
AQI 38
Good
7.11μg/m³
PM2.5
31.32μg/m³
PM10
37.15ppb
O3
0.81ppb
SO2
1.81ppb
NO2
0.31ppm
CO
AQI 38
Good
7.16μg/m³
PM2.5
32.79μg/m³
PM10
32.50ppb
O3
0.87ppb
SO2
3.46ppb
NO2
0.32ppm
CO
AQI 34
Good
6.38μg/m³
PM2.5
28.41μg/m³
PM10
37.13ppb
O3
0.79ppb
SO2
1.34ppb
NO2
0.30ppm
CO
Air quality data and pollutant measurements for California, USA adhere to strict US EPA standards. The data is collected from multiple reliable sources, including satellites and ground-based monitoring stations. This data is further analyzed and enhanced using machine learning and advanced algorithms that factor in elements such as traffic and population density, ensuring accurate and reliable results.
Source: Ambee Data Sources
The air quality for San Mateo, California is updated every hour.
The worst air quality in San Mateo, California in the last 24 hours was observed at 12:00:00 on 2026-04-25.
In the last 24 hrs, the best air quality in San Mateo, California was observed at 11:00:00 on 2026-04-25.
The current air quality in San Mateo, California is 33, categorized as Good based on real-time data.
The most common pollutant in San Mateo, California is PM2.5.
If the air quality in San Mateo, California is poor, consider staying indoors and wearing a mask to protect yourself.
The current PM2.5 concentration at San Mateo, California is 6.374 μg/m3.
The current PM10 concentration at San Mateo, California is 31.225 μg/m3.
The current carbon monoxide (CO) concentration at San Mateo, California is 0.318 ppm.
The current sulfur dioxide (SO2) concentration at San Mateo, California is 0.845 ppb.
The current ozone (O3) concentration at San Mateo, California is 35.085 ppm.
The current nitrogen dioxide (NO2) concentration at San Mateo, California is 3.387 ppb.
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