Does wood smoke health risk warrant regulation?
On the evening of Dec. 8 last year, Butte County residents hurried home from work, eager to reach the warmth of their homes. The area was in the grip of a cold snap, with highs in the mid-40s for several days and overnight temperatures in the low 20s.
As soon as they arrived home, in thousands of those dwellings fires were lit in fireplaces or wood-burning stoves to drive off the chill. Smoke began drifting out of numerous chimneys.
The smoke was mostly carbon monoxide, with some carbon dioxide, other gases and water vapor. Suspended in the mix were microscopic bits of ash and tar, residue from the burned wood.
And while warmth spread inside, pollution levels outside rose above federal health standards.
The gases and vapor from the smoke had dissipated quickly, but the microscopic particles took a while to drift to the ground. The tiniest ones would float for hours. And they were a form of pollution the Environmental Protection Agency has found to be dangerous.
For the rest of the night in Chico, with the county's largest and densest concentration of wood stoves, as much as 38 pounds of those tiny bits would hang in the air at the level where Chicoans were breathing it, based on readings at the California Air Resources Board's Chico pollution monitor. Roughly another 12 pounds of similar-sized bits from other sources also would be in the mix.
Dec. 8 turned out to be the winter's biggest violation, but the clean air stanwas violated an average of 33 days each winter. This year's improvement is attributed to an increase of rain, which washed the bits out of the air more quickly.
The violations were common enough that in December 2009, the EPA set a three-year deadline to clean it up. With the timing of pollution spikes and the chemical signature of the microscopic bits pointing to wood stoves as the main source of the problem, a bitter controversy has resulted, dividing residents, politicians and health professionals.
Many local residents don't see a problem. They enjoy the warmth, ambiance and economy of their wood fire, they say, without any dire health effects. They resent government intrusion into the sanctity of their homes, and fear having a crucial source of heat taken from them.
But for some other Chico residents — especially children, the elderly and those who suffer from breathing or heart issues — doctors and medical experts agree the particles in wood smoke pose a risk.
Dr. Norman McCann, a Chico allergist, said his patients with persistent asthma can have inflamed bronchial tubes, and that soot from wood smoke can make that inflammation worse. He recalls seeing patients with asthma so severe that he advised them to switch to another form of heat.
Today's stoves are better sealed, so that people using them are less affected by the smoke, he said.
"But what's coming out of their chimneys affects other people," he said. "I think for the benefit of the health of society, it behooves them to regulate it."
The weight of federal law stands behind those who see wood smoke as a health problem.
The Clean Air Act charges EPA scientists with determining at what level a variety of pollutants become health risks. That finding becomes a limit all local air quality districts are required to stay within. In districts that exceed the standard, a plan has to be prepared to eliminate enough of the pollutant to get below the limit.
The EPA has set such standards for a number of pollutants, including the "small particulate" pollution linked to wood smoke.
In most districts that have faced wood smoke problems similar to Butte County's, part of the solution has been to legislate some form of mandatory wood-burning prohibition on bad air days. That's the case in Sacramento, the Bay Area, the San Joaquin Valley and 13 other of the state's 35 air districts. Reno, Nev., has had similar regulations since 1986.
The Butte County district has tried voluntary wood-burning advisories since the winter of 2005-06, using public service announcements and e-mail notifications asking people not to burn when bad air quality was expected. But even with that, there have been 113 violations in that past half-decade.
So last September, the Butte County Air Quality Management District staff presented a proposal to its governing board for a mandatory rule to reduce wood burning on days when bad air is forecast.
The measure failed to get the six votes necessary to pass.
"There's a limit on what we can do to keep people safe," Air Quality Board member and county Supervisor Bill Connelly of Oroville told the Enterprise-Record. "Common sense has left the process.
"Some of their figures are just pulled out of the air, and then they run with them ... If you don't go along, they call you anti-health of people," said Connelly.
"This air quality stuff is so invasive, intrusive on people's freedom," he continued. "It just doesn't seem that bad."
The Air Quality Board vote didn't stop the clock ticking toward the EPA's December 2012 deadline for completion of a plan.
After the measure's defeat, the city of Chico took up the issue of mandatory restrictions on bad-air days. The City Council in January directed its staff to prepare an ordinance based on the Air Quality District's rejected rule. Its proponents hope to pass the measure and have it in place by November.
Even if the city's effort were to fail, wood-burning restrictions eventually could still come to Chico, and even most of Butte County, because the EPA has declared a large swath of the county to be out of compliance with the Clean Air Act.
If the EPA isn't presented a cleanup plan it finds sufficient to solve the problem, it can impose its own. That action would also come with a cut-off of federal highway dollars.
But EPA officials say that's unlikely.
"The sanctions are so big we never get there. The state won't let it happen," said Kerry Drake, associate director of the Air Division in the EPA's Pacific Southwest Region, which includes California, Nevada, Arizona, Hawaii and the Pacific Island territories.
Under state law, the local Air Quality District would prepare rules for stationary sources — like wood stoves — and send it on to the state. The state would add rules for cars and trucks and forward it to the EPA.
He said the EPA has a year after the state plan is presented to decide whether it's acceptable. If not, 18 months after that, one level of sanctions could be imposed, and six months later — which could be as late as 2015 — the agency could impose its own plan for Butte County and cut off highway funding.
Drake pointed out the schedule allows plenty of time to get a Butte County plan prepared, which is what he expects to happen.
"It's a healthy conversation to have that the Clean Air Act does allow sanctions," he said, "but we're not even close to being in a threatening posture with Butte County."
Is wood smoke really the source of Chico's particulate pollution? Skeptics point to cars and trucks, agricultural burning and burning of prunings and yard waste — still allowed outside the Chico city limits — as more likely sources.
Air quality officials agree all those sources do contribute to a base level of Chico's particulate pollution in winter.
From the chemical composition of the particles found in the Chico monitoring station, the CARB has determined that on an average day, the breakdown looks like this:
- "Mobile sources" — cars and trucks — are responsible for 8 percent of the particulates.
- "Managed burning" — agricultural and yard waste burning — adds another 14 percent.
- Industrial processes contribute 15 percent.
- Farm equipment operation and construction are responsible for another 5 percent.
- Road dust from paved and unpaved roads amounts to 8 percent.
But residential burning is pegged for 47 percent — almost half — of the particles on a daily basis. And that's on an average day, when the federal health standard isn't exceeded.
On days when Chico's air is determined to be unhealthy, the CARB monitors find virtually all the additional particles that put the city over the standard are organic carbon — the byproduct of wood combustion. On the days when the standard is exceeded, organic carbon rises as high as 75 percent of the total pollution.
That could be from agriculture or yard burning, except that it happens at night and first thing in the morning, when the only fires that are burning are warming homes.
Even before new regulations are enacted, some residents have already made changes — often reluctantly.
A wood stove is the only source of heat in Patty Betonte's old house in Butte Creek Canyon. Out of guilt, Betonte said, she and her husband bought a new EPA-approved stove last year.
"They make you feel guilty," she said. "A guy wrote in to the paper about how the smoke was killing him. It does make you feel guilty."
Betonte, 62, is retired after a career of working many different jobs. She was born in Chico and raised in Orland and comes from "a farm family."
She added she's not sure about reports that wood smoke hurts people's health. On the one hand, it seems many people use wood stoves and suffer no ill effects. But it may be that at some point conclusive evidence will be found that wood smoke is harmful, she said.
Betonte's quite sure of one thing, however.
"I want to be warm," she said. "I hate being cold."
Tomorrow: Health and wood smoke.
City Editor Steve Schoonover can be reached at 530-896-7750 or email@example.com.
Staff writer Larry Mitchell and Deborah Schoch of the Center for Health Reporting contributed to this report.