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)
21
Good
San Mateo, California
Last updated: ... (Local time)
Good
Fine
Moderate
Poor
Very poor
Hazardous
2.76 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
9.68 μg/m³
0
55
155
255
425
605+
23.06 ppb
0
55
71
86
201
201+
0.57 ppb
0
36
76
186
605
1005+
1.24 ppb
0
54
101
361
1250
2050+
0.31 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
San Mateo, California
San Mateo, California
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AQI 23
Good
1.85μg/m³
PM2.5
10.95μg/m³
PM10
25.00ppb
O3
0.53ppb
SO2
2.44ppb
NO2
0.32ppm
CO
AQI 21
Good
3.09μg/m³
PM2.5
15.30μg/m³
PM10
22.91ppb
O3
0.56ppb
SO2
4.08ppb
NO2
0.23ppm
CO
AQI 24
Good
2.25μg/m³
PM2.5
19.60μg/m³
PM10
26.46ppb
O3
0.54ppb
SO2
2.48ppb
NO2
0.33ppm
CO
AQI 21
Good
3.18μg/m³
PM2.5
15.84μg/m³
PM10
22.86ppb
O3
0.57ppb
SO2
4.22ppb
NO2
0.23ppm
CO
AQI 23
Good
1.85μg/m³
PM2.5
10.95μg/m³
PM10
25.00ppb
O3
0.53ppb
SO2
2.44ppb
NO2
0.32ppm
CO
AQI 21
Good
3.41μg/m³
PM2.5
17.35μg/m³
PM10
22.70ppb
O3
0.58ppb
SO2
4.63ppb
NO2
0.23ppm
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 07:00:00 on 2025-07-16.
In the last 24 hrs, the best air quality in San Mateo, California was observed at 02:00:00 on 2025-07-16.
The current air quality in San Mateo, California is 21, categorized as Good based on real-time data.
The most common pollutant in San Mateo, California is O3.
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 0.829 μg/m3.
The current PM10 concentration at San Mateo, California is 15.056 μg/m3.
The current carbon monoxide (CO) concentration at San Mateo, California is 0.327 ppm.
The current sulfur dioxide (SO2) concentration at San Mateo, California is 0.63 ppb.
The current ozone (O3) concentration at San Mateo, California is 23.211 ppm.
The current nitrogen dioxide (NO2) concentration at San Mateo, California is 1.648 ppb.
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