Dear Asking For a Friend,
I have an old house with a lovely wood-burning fireplace. Recently a friend told me that burning wood in the house, even with good ventilation can cause cancer. Wondering if this is a real risk? And then her comment made me think of those “logs” that apparently “burn clean” — are these a better option?
Signed, Don’t Want To Go Electric
Dear Don’t Want To Go Electric,
Getting cozy by a wood-burning fireplace has a lot of appeal in colder weather, especially when you’re likely spending more time at home because of the pandemic. No question, it’s nice to feel warm and safe.
The problem is, wood-burning fires are not safe — despite the common perception that because wood is natural, the wood smoke that’s created when you burn it is harmless.
Smoke from burning wood has been linked to cardiac disease
In fact, the smoke from wood burning is made up of a complex mixture of gases and fine particles called particle pollution or particulate matter that has been linked to aggravated cardiac and respiratory diseases. These microscopic particles can get into your eyes and respiratory system, causing a runny nose and burning eyes. They can also trigger asthma attacks and heart attacks.
So if you already have asthma, bronchitis and emphysema or any type of heart disease, fireside experiences are not helping you.
An alarming 2020 study in the U.K. found that wood-burning stoves tripled harmful indoor air pollution and should be sold with health warnings. The researchers warn that exposure to high intensities of small particles over much shorter periods of time can cause a range of health issues, especially in older people with weakened immunity or the very young, whose immune systems are still developing.
Hours, not just days, by your wood-burning stove or fireplace can impact your health. And each time you’re opening the door to put on another log, you’re getting that intensified exposure.
On top of the dangerous particles, wood smoke contains several toxic air pollutants, including benzene and formaldehyde, which are considered carcinogenic.
Research scientist Michael Brauer, a professor of occupational and environmental health at the University of British Columbia, has been at the forefront of research on air pollution and human health for 20 years, including as the author of a review of wood smoke health effects published in Inhalation Toxicology.
The review explains that wood smoke contains at least five chemical groups classified as known human carcinogens by the International Agency for Research on Cancer (IARC), others categorized by IARC as probable or possible human carcinogens, and at least 26 chemicals listed by the U.S. Environmental Protection Agency as hazardous air pollutants.
Smoke affects your immune response
“What’s happening is the smoke tends to affect your immune response,” Brauer says, putting people with existing conditions or compromised immunity at higher risk of serious effects.
While there’s no direct evidence of the link to cancer in developed countries, he says the 40 to 45 per cent of the global population who cook over an open fire at home has shown increased incidence of lung cancer. The assumption is that if something is carcinogenic, there’s no safe level of exposure.
“We’ve also looked at some severe respiratory infections, one called bronchiolitis, which is one of the main reasons that kids under the age of two are hospitalized,” he says. “It’s not a super common thing, but it can be quite severe.”
Wood smoke pollution raises the risk of bronchiolitis, as well as rates of hospitalization for childhood pneumonia and bronchitis.
Brauer’s research has found adults with lung disease whose condition worsens with exposure, as well as evidence of increased risk of heart attack and stroke. What’s more, the effects can be long-lasting as studies where people who have been exposed to wildfire smoke in the summer experience more flu during the following winter.
“The more we look at it, it’s just as bad as general air pollution,” he says.
He cautions that good ventilation in your home won’t lessen the impact and clean-burning logs on the market can be cleaner-burning, but there’s still significant risk.
The best advice is to save your wood-burning fireplace experience for a remote cabin or cottage when you’re on vacation. And for your home, gas-burning fireplaces give you some of the same warm, fuzzy feel and are much cleaner and better for heat and energy-savings.
Oh, and what about the neighbours?
The other point often missed is that people who are enjoying their wood-burning fireplaces are jeopardizing the health of their neighbours.
“You can have one fireplace going and you’ll smell it all the way around the block,” says Brauer. “It’s really affecting a lot of people and they have no choice.”