Air Quality in California
Live AQI readings for 13 cities in California. Click any city for real-time pollution data, PM2.5 levels and personalised health guidance.
13 Cities in California
Anaheim
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Bakersfield
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Chula Vista
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Fresno
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Irvine
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Los Angeles
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Riverside
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Sacramento
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San Diego
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San Francisco
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San Jose
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Santa Ana
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Stockton
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About Air Quality in California
Air quality in California is monitored by the US EPA AirNow network using certified government sensors. Data is updated hourly and reported using the US Air Quality Index (AQI) — a 0–500 scale where lower is better.
The AQI is calculated from six key pollutants: PM2.5, PM10, ground-level ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide. The dominant pollutant — whichever reads highest — sets the overall AQI for that city. Learn how AQI is calculated →