The first three Spare the Air alerts of the winter season were announced Thursday for Friday through Sunday, Bay Area Air Quality Management District officials said.
The alert means residents are prohibited by law from burning wood, manufactured fire logs or other solid fuel either indoors or outdoors through midnight Sunday.
Air district officials said air quality is expected to be unhealthy because of weather conditions, which are expected to trap pollution close to the ground.
The pollution is especially harmful to children, the elderly, and people with respiratory conditions. Exposure to wood smoke, like cigarette smoke, has been linked to a higher risk of heart attacks, according to the air district.
During the alert, residents and visitors are prohibited from using fireplaces, woodstoves, pellet stoves, outdoor fire pits and any other wood-burning devices.
Exemptions exist for people whose only source of heat is a woodstove or fireplace, but people must use a U.S. Environmental Protection Agency-certified or pellet-fueled device that is registered with the air district.
No longer does an open-hearth fireplace qualify for an exemption.
Violators have an option of taking a wood smoke awareness class or pay a $100 ticket the first time they violate the rule.
A second violation results in a $500 fine and fines are higher for subsequent violations.
Air district officials said Bay Area residents and visitors must check to see whether a Spare the Air alert has been issued during the Winter Spare the Air Season, which runs from Nov. 1 through Feb. 28.
Several ways are available to check including text alerts, websites, a toll-free phone number and phone alerts.