The NOAA Hazard Mapping System Fire and Smoke Product shows a heavy concentration of smoke originating from Northern California.
The AirNow Map image above supports this claim as there is an increased concentration of PM from Northern California. The maximum air quality index reaches Hazardous levels (Dark Purple, 301-500).
The NOAA Aerosol Watch image above shows an increased level of AODs originating from Northern California.
INCIWEB reports that in Northern California there is the Dixie Fire that has burned over 490 thousand acres. The fire is currently 27 percent contained. CNN reports that the fire has burned over 900 structures and there are still 16,000 structures threatened by the fire.