Air quality · ZIP 94920
Air quality in Tiburon (Marin), CA
ZIP 94920 (California) — air quality summary sourced from EPA Air Quality System (AQS), annual county summary. Refreshed on the cadence of the primary regulator with every claim cited to the source record.
Marin County, California · 2025 annual summary
Median AQI 21 — Good
Air quality is satisfactory, and air pollution poses little or no risk.
- Good days
- 87
- Moderate days
- 8
- Unhealthy for sensitive groups
- 0
- Unhealthy+ days
- 0
- Max AQI
- 66
- 90th percentile AQI
- 49
This is a county-level ANNUAL SUMMARY for 2025, not a live current reading. For today's air quality, check a real-time monitor at airnow.gov. Categories follow EPA's official AQI breakpoints.
What lands here
The 2025 annual EPA Air Quality System summary for this ZIP's county — shown above.
Source & refresh
EPA Air Quality System (AQS), annual county summary. Refreshed annual (epa aqs publication). Stale data is flagged, never silently served. Primary source →
Limitations specific to this source
This is a county-level ANNUAL SUMMARY, not a live current reading and not an address-level measurement — for today's AQI, EPA's real-time AirNow feed is the correct source (not yet federated here). Not every county operates an EPA monitor; absence of data for a ZIP's county means no 2025 EPA reading exists, not that air is good.
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.
EPA AQI categories explained — what 0–50 Good through 301–500 Hazardous mean
Plain-English guide to the six EPA Air Quality Index categories: 0–50 Good, 51–100 Moderate, 101–150 Unhealthy for Sensitive Groups, 151–200 Unhealthy, 201–300 Very Unhealthy, 301–500 Hazardous — what each level means and who is at risk.
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.
The other dimensions for ZIP 94920
Air quality is one of twelve public-records dimensions zipradar indexes per address. See the ZIP 94920 index for the other eleven — each with its own regulator, source and link:
All dimensions for Tiburon (Marin), CA →Frequently asked questions
What is the air quality for ZIP 94920?
Marin County, California (which covers ZIP 94920) had a 2025 median AQI of 21 — Good, per EPA's Air Quality System. Over the year: 87 Good days, 8 Moderate, 0 Unhealthy for Sensitive Groups. This is a county-level ANNUAL SUMMARY for 2025, not a live current reading. For today's air quality, check a real-time monitor at airnow.gov. Categories follow EPA's official AQI breakpoints.
Where does the air quality data come from?
EPA Air Quality System (AQS), annual county summary (primary regulator). zipradar federates air quality on the regulator's published cadence: annual (epa aqs publication). Every claim cites the source record; stale data is flagged, never silently served. The primary source URL: https://aqs.epa.gov/aqsweb/airdata/download_files.html.
What are the limitations of air quality data?
This is a county-level ANNUAL SUMMARY, not a live current reading and not an address-level measurement — for today's AQI, EPA's real-time AirNow feed is the correct source (not yet federated here). Not every county operates an EPA monitor; absence of data for a ZIP's county means no 2025 EPA reading exists, not that air is good.
Is ZIP 94920 (Tiburon (Marin)) data current?
Last verified 2026-09-07. Air quality for ZIP 94920 refreshes annual (epa aqs publication) per EPA Air Quality System (AQS), annual county summary cadence. See the full ZIP dashboard at /zip/94920/ for all 12 dimensions side-by-side.