What is the air quality trend in Redwood City?

Over the past 8 days, Redwood City had an average AQI of 29 based on station measurements. The worst day was 2026-07-16 with AQI 42.

How is Redwood City air quality measured?

Air quality in Redwood 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 Redwood City, United States

Name: Redwood 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 Redwood City, United States.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

167h

PM2.5 Station

167h · 108 stations

Temperature GFS model

28pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-07-22	21	21–21	5.0 µg/m³	1.1	1h	108
2026-07-21	29	23–51	7.0 µg/m³	4.9	24h	106
2026-07-20	22	17–64	5.5 µg/m³	2.8	24h	100
2026-07-19	25	20–30	6.1 µg/m³	4.3	24h	104
2026-07-18	27	22–32	6.5 µg/m³	3.4	24h	105
2026-07-17	36	31–43	8.6 µg/m³	8.7	24h	107
2026-07-16	42	30–220	14.9 µg/m³	6.8	24h	99
2026-07-15	35	30–58	8.5 µg/m³	6.0	22h	102

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