As soon as Bay Area revelers clink their champagne glasses and toot their noisemakers at midnight, they must also shut off their fireplaces for New Year's Day, regional air quality regulators have ordered.
Burning wood, fire logs or pellets will be illegal all day Tuesday in the nine-county region, the Bay Area Air Quality Management District announced Monday. Those who defy the ban face possible fines.
Chilly and still air is creating a health hazard by trapping soot, about a third of which on a typical winter night comes from the Bay Area's more than 1 million wood stoves and fireplaces.
"We have warmer air above that's trapping colder air below," said district spokeswoman Kristine Roselius. "It also traps wood smoke, condenses it down and makes it denser."
Also contributing to the respiratory dangers are smoky New Year's Eve fireworks, but Roselius said the weather conditions are what triggered the mandatory order.
The district forecasts that the unhealthiest air conditions Tuesday will be in the Santa Clara Valley and the North Bay, but the fireplace ban applies to the entire Bay Area.
Heavy rain and wind over the past several weeks have kept the air cleaner by pushing out pollution, delaying the onset of the annual "Spare the Air" alerts for a longer period than usual.
Tuesday marks the first winter wood-burning ban since Jan. 14 and the first of this winter season.
"Last year by this time we had 11," Roselius said.