City comparison
Los Angeles vs San Francisco air quality
Live AQI comparison between Los Angeles and San Francisco. Data updates every 15 minutes.
Los Angeles and San Francisco differ by 24 AQI points right now. San Francisco has cleaner air at this moment.
What drives air quality in Los Angeles and San Francisco
Los Angeles
Los Angeles is shaped by basin geography, high vehicle activity, and strong sunlight, a combination that supports persistent smog dynamics. Nitrogen dioxide is elevated near freeways and major freight routes, while ozone can become the dominant afternoon pollutant across broad areas. Topographic trapping often worsens conditions inland relative to coastal zones.
San Francisco
San Francisco often benefits from Pacific airflow, yet Bay Area air quality varies sharply by neighbourhood and season. Bridge approaches and dense urban corridors can show elevated nitrogen dioxide, while regional wildfire smoke may push PM2.5 into unhealthy bands across the entire metro.
Both cities are shaped by different combinations of traffic density, terrain, weather patterns, and seasonal events, which is why the same AQI band can feel different on the ground. Checking live readings rather than relying on reputation or past visits is the most reliable way to plan travel, exercise, or outdoor time between the two.
Live AQI from Open-Meteo (CAMS). Conditions change hourly — refresh for the latest readings. South African cities may show WAQI station data on their dedicated pages.