California wildfires have become more frequent and severe in recent years. According to a study conducted by the Lamont Doherty Earth Observatory at Columbia University, climate change has doubled the risk of extreme fire conditions in California since 1970. During the same period, the amount of annual acreage burned has increased eight-fold. As wildfires rise in frequency and severity, so too does the threat of wildfire smoke. 2020 represented a historic year for both wildfires and unhealthy air pollution days. The 2020 August Complex fire burned for more than 55 days, surpassing a million scorched acres and becoming the largest fire in California history.9 During this period, San Francisco air quality levels reached “unhealthy” or worse levels for more than 10 combined days.
When wildfires are burning, air quality can be fast changing, changing from “good” to “unhealthy” based on wind and weather conditions. Follow San Francisco’s forecast air quality data at the top of this page to discover when wildfire smoke will clear. The IQAir forecast model employs machine learning to analyze millions of air quality data points along with current and forecast weather conditions to provide the most accurate and up to date air quality predictions.