The heavy smoke that hung over Sacramento on Monday came from a fire burning on Grizzly Island in Solano County, according to Sacramento County's Regional Fire Dispatch Center.
Sacramento-area fire dispatchers were inundated with calls from residents wondering about the location of the fire.
Several fires also have been burning in areas north of Sacramento, which could have contributed to smoke in the area.
They include the 3,000-acre Wye fire and 2,000-acre Walker fire, which are burning in Lake and Colusa counties. The Chips fire also continues to burn in the Plumas National Forest.
The Sacramento Air Quality Management District has declared today to be a Spare the Air Day, urging residents to limit their driving due to ground-level ozone pollution. Officials also warn that smoke may be present throughout the Sacramento Valley due to wildfires in the surrounding area.
Conditions are considered unhealthy for sensitive groups. For updates on air quality, see the website at www.sparetheair.com.