Mention air pollution, and what comes to mind? Factories. Oil refineries. Auto tailpipes.

Now Bay Area smog regulators are trying to crack down on another source that they say is just as significant, even if beloved: home fireplaces.

Citing growing medical research that soot causes more severe health problems than was previously realized, the Bay Area Air Quality Management District is proposing a ban on all wood burning in fireplaces and wood stoves in the nine Bay Area counties during winter “Spare the Air” nights.

The agency’s statistics show that wood smoke is the largest source of particle pollution in the region. But its proposed crack down is sparking passionate debate.

If approved, fireplace police would enforce the rules, and neighbors would be encouraged to report neighbors.

Family tradition

“We understand a crackling fire is a longheld tradition of American family life,” said Jack Broadbent, executive officer of the air district, based in San Francisco.

“But traditions need to be changed when there is information showing that our health and our neighbors’ health are impacted.”

The district will hold 10 public meetings in March and April on the draft rules.

Supporters compare wood smoke dangers to that of cigarette smoke, and note natural gas fires are much cleaner. Critics call the proposal bureaucracy run amok.

Elevated levels of soot can cause asthma attacks, heart problems and respiratory ailments. Santa Clara County, with the largest population, emits more particle pollution than any Bay Area county.

Meeting EPA standards

Broadbent said the new rules are needed because the U.S. Environmental Protection Agency in 2006 set tough new national standards for fine particle air pollution. The Bay Area exceeded them 14 times last year.

There are an estimated 1.7 million fireplaces and woodstoves in the Bay Area. Some of them warm the heart. Others ignite concern.

Kathy Voss-Jensen and Joel Jensen favor the rules. Three years ago, the couple got a new neighbor who burns wood nearly every winter day despite their requests to limit it.

“It’s very noxious and irritating,” she said. “We have to keep our windows closed tight for several hours a day. And we have to keep them closed all night.”

Others say the proposal goes too far.

“I think this is a precursor to banning all wood burning. It is a camel’s nose under the tent,” said Steve Drenker, a sales manager whose 1950s ranch home has a fireplace.

Drenker burns only dry oak, he said, and his fires do not smoke up the neighborhood.

“It creates a real family-oriented centerpiece in the living room,” he said. “It’s very cozy, very warm, very inviting for my wife and kids.”

The air district’s 22-member board is expected to vote on the proposal this summer.

On cold winter nights with no breeze or rain, fireplace smoke can build up like a blanket over valleys and towns.

Under the draft rule, between November and February when the district forecasts that weather conditions are right for unhealthy levels of soot, officials would issue a “Spare the Air Tonight” alert to TV, radio and newspapers.

Those conditions have averaged about once a week in the winter, in recent years.

How to enforce the ban?

Broadbent said he has 60 inspectors, some of whom who would drive around looking for smoking chimneys. Neighbors also could phone a toll-free number to report violators. First-time offenders would be warned by a letter, with fines of $50 to $100 for second violations, and larger fines for later violations.

Similar programs recently passed by air districts in Sacramento and San Joaquin Valley allow violators to waive a $50 fine if they attend a 2-hour class on the health risks of wood smoke.

The proposed rule also would allow only dry, seasoned wood to be sold. And it would ban 365 days a year any excessively smoking chimneys. Recreational campfires would be exempt, as would homes with no other source of heat.

There would, however be no exception for burning wood in pellet stoves, or modern, EPA-certified stoves and inserts.

“I have a big problem with it. You are going to tell somebody they paid $3,500 for an EPA-certified wood stove and they can’t use it?” said Kevin McAndrews, manager of the California Window & Fireplace Outlet, in Campbell.

McAndrews also worries about enforcement.

“They are going to start neighborhood wars. I don’t want somebody coming to my door at 11 p.m.,” he said.

All nine Bay Area counties put an average of 178,000 pounds a day of soot and dust, known as “particulate matter,” or “PM 2.5,” for its size of 2.5 microns or less, into the air, district data shows. In winter, fireplace soot can make up one-third of all the particles in Bay Area air.

About 9,400 deaths per year are associated with long-term exposure to fine particle air pollution, a 2002 study by the state Air Resources Board and other agencies concluded. One study in 1997 found that emergency room visits in San Jose for asthma attacks increased up to 43 percent during the smokiest winter days.

Among the top advocates for a crackdown is the American Lung Association. It advocates more government incentives to help people buy natural gas fireplace inserts.

“We know how much people are fond of their fires,” said Jenny Bard, a spokeswoman for the American Lung Association. “There are ways to enjoy the fire without the smoke.”