The fourth consecutive "Winter Spare the Air" alert has been issued for Thursday (Dec. 26).
The Bay Area Air Quality Management District's announcement Wednesday means that wood, logs or other solid fuels cannot be burned in fireplaces, fire pits or any other wood-burning device indoors or outdoors for 24 hours.
The only exception is for households that depend on wood burning as a heat source.
A Christmas Day ban on burning wood that was in place meant no fireplaces could be lit during the winter holiday.
The dry, mild weather this week has contributed to the buildup of pollutants that make the air unhealthy to breathe, according to the air district.
Those with respiratory conditions, children and elderly residents are advised to limit outdoor activity during Spare the Air days.
Residents who violate the ban will be levied a $100 fine or can take a wood-smoke awareness classes. Repeat violators will receive a fine of $500 or more.
This is the season's 19th alert. The season runs until Feb. 28.