Air quality · ZIP 94131
Air quality in San Francisco (Twin Peaks), CA
ZIP 94131 (California) — air quality summary sourced from EPA AirNow. Data lands this week as the EPA AirNow ingestion pipeline rolls out.
Last verified 2026-04-24 · methodology
What lands here
Pages show the current AQI category (Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, Hazardous), the nearest reporting station, and historical averages.
Source & refresh
EPA AirNow. Refreshed hourly real-time / daily historical. Stale data is flagged, never silently served. Primary source →
Limitations specific to this source
Rural ZIPs may not have a nearby monitoring station; zipradar then reports the closest available station with distance context.
California context
Wildfire (WUI), seismic, water-supply variability
California carries the highest concentrated WUI wildfire risk in the US per USFS WHP, with FAIR Plan + non-renewal pressure intensifying since 2017 fires. FEMA NFHL coverage is strong; drinking-water systems vary from large urban (LADWP, EBMUD) to small disadvantaged community systems flagged in EPA SDWIS. Radon risk is mostly Zone 2-3.
See California state page for the full state-level rollup across all 12 dimensions.
Read more on air quality
Editorial deep-dives explaining the source data, its limits, and how to read it.
AQI explained — what 50, 100, 150 actually mean for your lungs
Plain-English guide to the EPA Air Quality Index (AQI) and the 6 categories from Good to Hazardous. When to take precautions and which pollutants matter.
Wildfire Hazard Potential — what the USFS scale means and how to defend your home
Plain-English guide to the USDA Forest Service's Wildfire Hazard Potential 1–5 scale, how to read your community's risk, and concrete home-defense measures.
AirNow + wildfire smoke — when AQI is a real-time tool
How EPA AirNow handles real-time wildfire smoke, what the colors mean during fire season, and where AirNow leaves gaps you should know about.
AQI thresholds — what 'unhealthy for sensitive groups' actually means for you
EPA's AQI uses six bands keyed to specific population groups. Here's what each band means at the personal-decision level — go outside, mask, stay home.
Full dashboard for ZIP 94131
Air quality is one of twelve dimensions zipradar federates per address. See the full federated summary for ZIP 94131:
Open San Francisco (Twin Peaks), CA dashboard →