What is the air quality trend in Palo Alto?

Over the past 8 days, Palo Alto had an average AQI of 27 based on station measurements. The worst day was 2026-10-18 with AQI 34.

How is Palo Alto air quality measured?

Air quality in Palo Alto 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 Palo Alto, United States

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

Historical PM2.5 and AQI trend from monitoring stations near Palo Alto, United States.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

165h

PM2.5 Station

165h · 109 stations

Temperature GFS model

28pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-10-21	31	28–34	7.6 µg/m³	1.7	3h	106
2026-10-20	19	16–32	4.6 µg/m³	5.4	24h	93
2026-10-19	23	20–29	5.5 µg/m³	11.7	24h	106
2026-10-18	34	24–41	8.0 µg/m³	20.3	24h	98
2026-10-17	30	24–35	7.1 µg/m³	12.8	24h	109
2026-10-16	30	23–36	7.3 µg/m³	12.3	24h	104
2026-10-15	28	25–34	6.8 µg/m³	12.3	24h	111
2026-10-14	25	22–29	5.9 µg/m³	12.1	18h	112

Back to Palo Alto Air Quality