A "Spare the Air" alert is in effect today, the sixth of this winter's season.
The alert by the Bay Area Air Quality Management District bans burning of wood, manufactured fire logs or any other solid fuel, both indoors and outdoors for 24 hours.
Three consecutive alerts have been called this week because of a regional high-pressure system that continues to build across the West Coast and likely will stay in place until early next week.
Light, offshore winds and cold overnight temperatures are expected to trap wood smoke pollution near the ground, creating unhealthy air quality in the region.
"Like cigarette smoke, wood smoke has immediate health impacts for both residents inside the home and surrounding neighbors as well," said Jack Broadbent, executive officer of the air district.
It is illegal for Bay Area residents and businesses to use their fireplaces, woodstoves, pellet stoves, outdoor fire pits, or any other wood-burning devices during a Winter Spare the Air Alert. Homes without permanently installed heating, where woodstoves or fireplaces are the only source of heat, are exempt.