What is the air quality trend in San Francisco?

Over the past 3 days, San Francisco had an average AQI of 57 based on station measurements. The worst day was 2026-05-27 with AQI 83.

How is San Francisco air quality measured?

Air quality in San Francisco 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 Francisco, El Salvador

Name: San Francisco 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 Francisco, El Salvador.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

19h

PM2.5 Station

19h · 1 station

Temperature GFS model

8pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-05-29	53	3–109	16.0 µg/m³	17.3	8h	1
2026-05-28	37	5–86	10.8 µg/m³	11.3	10h	1
2026-05-27	83	83–83	27.4 µg/m³	29.3	1h	1

Back to San Francisco Air Quality