California Air Quality Map
See air quality in your area in real time. This map shows ratings for the Bay Area and California, updated every 10 minutes. Go here for more information on PurpleAir vs. AirNow and how to read air quality readings near you. Read here about why California ranks worst in nation for air pollution.
Key
- Good
- Moderate
- Unhealthy for some
- Unhealthy for all
- Very unhealthy
- Hazardous
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Recent Air Quality News
About this data
Air Quality
Most mapped air quality sensors are from PurpleAir, updated every 10 minutes.
We also publish data from 19 Clarity air quality sensors , concentrated in the Tenderloin and South of Market neighborhoods in San Francisco and installed by environmental justice nonprofit Brightline Defense.
The sensors detect real-time fine-particulate matter (PM2.5 - particulates that are less than 2.5 microns in diameter) concentrations. PM2.5 is a primary concern for people's health at high levels.
The descriptions of the pollutant levels follow the guidance the EPA provides using its Air Quality Index rating for surface level PM2.5 concentrations. In the legend, we label Good (< 12 μg/m³), Moderate (< 35.5 μg/m³), Unhealthy for some (< 55.5 μg/m³), Unhealthy for all (< 150.5 μg/m³) and Very unhealthy (150.5 μg/m³ or greater).
Smoke Forecast
The smoke layer is an experimental forecast from NOAA's High Resolution Rapid Refresh forecast product. Currently displayed imagery is forecast ahead of time. When this layer and the sensors differ, the sensors should be trusted, as that information is delivered in real time.