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)
22
Good
San Mateo, California
Last updated: ... (Local time)
Good
Fine
Moderate
Poor
Very poor
Hazardous
4.37 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
19.14 μg/m³
0
55
155
255
425
605+
18.87 ppb
0
55
71
86
201
201+
0.67 ppb
0
36
76
186
605
1005+
4.54 ppb
0
54
101
361
1250
2050+
0.32 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Moderate
San Mateo, California
San Mateo, California
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AQI 22
Good
4.38μg/m³
PM2.5
23.28μg/m³
PM10
17.35ppb
O3
0.71ppb
SO2
4.69ppb
NO2
0.32ppm
CO
AQI 22
Good
3.71μg/m³
PM2.5
16.69μg/m³
PM10
17.54ppb
O3
0.71ppb
SO2
5.10ppb
NO2
0.25ppm
CO
AQI 22
Good
4.36μg/m³
PM2.5
23.26μg/m³
PM10
18.09ppb
O3
0.72ppb
SO2
4.80ppb
NO2
0.32ppm
CO
AQI 22
Good
3.67μg/m³
PM2.5
16.56μg/m³
PM10
17.63ppb
O3
0.71ppb
SO2
5.18ppb
NO2
0.25ppm
CO
AQI 22
Good
4.38μg/m³
PM2.5
23.28μg/m³
PM10
17.35ppb
O3
0.71ppb
SO2
4.69ppb
NO2
0.32ppm
CO
AQI 22
Good
3.56μg/m³
PM2.5
16.19μg/m³
PM10
17.81ppb
O3
0.72ppb
SO2
5.50ppb
NO2
0.24ppm
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 11:00:00 on 2025-07-29.
In the last 24 hrs, the best air quality in San Mateo, California was observed at 04:00:00 on 2025-07-30.
The current air quality in San Mateo, California is 22, 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 4.166 μg/m3.
The current PM10 concentration at San Mateo, California is 17.853 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 0.719 ppb.
The current ozone (O3) concentration at San Mateo, California is 17.842 ppm.
The current nitrogen dioxide (NO2) concentration at San Mateo, California is 4.936 ppb.
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