What is the air quality trend in San Mateo?

Over the past 3 days, San Mateo had an average AQI of 8 based on station measurements. The worst day was 2026-06-09 with AQI 12.

How is San Mateo air quality measured?

Air quality in San Mateo is measured by ground-level monitoring stations that report PM2.5 and PM10 concentrations hourly. CERNS.IO aggregates readings from nearby stations and converts PM2.5 to the US EPA Air Quality Index (AQI) scale.

Air Quality History for San Mateo, United States

Name: San Mateo Air Quality History
Creator: CERNS.IO
License: https://creativecommons.org/licenses/by/4.0/

Historical PM2.5 and AQI trend from monitoring stations near San Mateo, United States.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

39h

PM2.5 Station

39h · 1 station

Temperature GFS model

8pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-06-09	12	2–23	2.9 µg/m³	4.0	11h	1
2026-06-08	9	1–18	2.0 µg/m³	3.7	19h	1
2026-06-07	4	2–10	1.0 µg/m³	2.5	9h	1

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