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.