https://www.mercurynews.com/2020/08/19/real-time-map-find-air-quality-index-in-your-bay-area-city/

The map shows changes in air quality (ozone and particles): yellow is moderate, orange unsafe for sensitive groups, red unhealthful, purple very unhealthful and brown hazardous. Tilt your phone to landscape mode if you’re having trouble viewing the full map

Wildfire smoke is particularly heavy Wednesday morning on the Peninsula and around Vacaville, air quality index readings show.