What is the air quality trend in Foster City?

Over the past 3 days, Foster City had an average AQI of 24 based on station measurements. The worst day was 2026-08-08 with AQI 36.

How is Foster City air quality measured?

Air quality in Foster City 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 Foster City, United States

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

Historical PM2.5 and AQI trend from monitoring stations near Foster City, United States.

Current AQI
Moderate CAMS model

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

44h

PM2.5 Station

44h · 1 station

Temperature GFS model

8pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-08-08	36	16–56	8.9 µg/m³	11.2	4h	1
2026-08-07	19	4–41	4.5 µg/m³	5.5	22h	1
2026-08-06	19	13–25	4.7 µg/m³	5.3	18h	1

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