Unless Mother Nature changes her pattern, the Bay Area — including most of Sonoma County — is headed for a record number of high-pollution days when home wood fires are banned.
The ceaseless dry cold weather has led to atmospheric conditions that have trapped pollutants close to the ground, resulting thus far in 10 so-called Spare the Air bans. That's more than the past two winter seasons and about as many alerts as there were during the first season three years ago when the crackdown started.
And the current pollution-alert season is only half over.
"We're on pace to possibly have the most winter Spare the Air alerts since the wood-burning rule has been in effect," said Aaron Richardson, a spokesman for the Bay Area Air Quality Management District, which administers the rule.
Complaints of violations are rolling in.
On Christmas Eve and Christmas Day, 400 people in the nine-county Bay Area tipped off air district officials about neighbors who were illegally burning wood in fireplaces.
That's a big share of the complaints usually filed during the cold-weather season, which runs from Nov. 1 through the end of February. There were 1,453 complaints in 2008-2009 season, 2,355 in 2009-2010 season and 1,373 complaints a year ago.
District officials said Wednesday they do not yet know how many of the 400 complaints came from Sonoma County residents, but if history is a guide, many came from the North Coast.
When district officials catch someone violating the rule, a warning letter is issued. A second instance will result in a notice of violation and a $400 fine.
A little less than 10 percent of all Spare the Air complaints have historically come from Sonoma County. But the county's share of warning letters is far greater.
Last year, almost half of the 59 warning letters involved Sonoma County residents. During the 2009-2010 season, 77 of the 310 warning letters came from local residents — more than any of county in the Bay Area.
Air district officials said there's a lot of wood burning in Sonoma County and that the large number of warning letters could be the result of confusion about air district boundaries. Northern Sonoma County, which is not included in the Bay Area air district's boundaries, does not have a similar wood burning rule, she said.
The region of Sonoma County that falls within Bay Area district runs as far north as Windsor and includes Sebastopol and its environs to the west.
Richardson said this is the driest December since 1989, and that without wind or stormy weather to clear the air, levels of small-particle pollution can quickly reach unhealthy levels.
It is anticipated that each winter season will have 15-to-20 Spare the Air alerts, "and we're well on our way to that number this year," Richardson said.
He said that wood smoke complaints are logged by the district enforcement staff, and that an inspector is sent to investigate whenever possible.
Spare the Air alerts may have put a damper on wood fires over the Christmas weekend, but officials said that the New Year's weekend is "looking good."
"Right now, Saturday isn't looking too bad and Sunday looks like it will be moderate all across the Bay Area," said Jones, the air district spokeswoman.