Wood heating | The health of residents in high-risk areas

Exposure to pollution from residential wood heating has a more devastating effect on the health of regional residents than that from road transport or industries. The findings of a new study by the Institut national de santé publique du Québec (INSPQ) are such that it recommends that municipalities on the outskirts of major centres tighten regulations on heating appliances.

Published at 1:30 a.m. Updated at 9:00 a.m.

What you need to know

In 2023, a report made public by Health Canada revealed that fine particles from residential combustion cause more premature deaths in Quebec than all other pollutants.

In Quebec, since 2009, all heating appliances on sale must be EPA or CSA certified, to emit fewer fine particles.

Between 2015 and 2020, the standard in Quebec went from 4.5 grams of fine particles per hour to 2.5 g/h.

Fine particles (PM2.5 microns in diameter) in the air are the main culprits, both summer and winter.

At the request of the Ministry of the Environment, the Fight against Climate Change, Wildlife and Parks (MELCCFP), INSPQ researchers modeled the annual impact of air pollutants in eight sectors: Québec-Limoilou, Sherbrooke-Estrie, Trois-Rivières and Bécancour, Sorel, Saint-Hyacinthe, Témiscamingue, Rouyn-Noranda and Saguenay. Although controlling emissions from industries remains necessary, reducing emissions caused by residential wood heating would be “more beneficial for populations,” concludes the centre of expertise and reference for public health in Québec.

“Locally, residential wood combustion (PM2.5) continues to be responsible for half of air pollution,” he summarized in an interview with The Press the study’s principal investigator, Audrey Smargiassi, of the Quebec Department of Environmental Health at Work and Toxicology, also a full professor at the University of Montreal.

The INSPQ research report, published in December 2023, was produced at the request of the MELCCFP. It was obtained by The Press under the Access to Information Act. Through various graphs, the experts dissect scenarios of emissions from residential wood heating, its abolition, and the elimination of emissions associated with agriculture, off-road vehicles and industrial activities. The data analyzed are taken from satellite imagery and measurements from sampling stations.

Possible reduction

The research team found that it would be possible to reduce average daily PM2.5 concentrations by 30% if there were a widespread shift to EPA-certified devices. Only Témiscamingue would have a less pronounced reduction, estimated all the same at 15%, it is indicated.

« The health impact of fine particles has long been demonstrated. Wood heating contributes to the risks. By reducing it, we will effectively improve air quality. I would say that even by completely eliminating residential wood heating, 50% of fine particles in the region would remain in the air,” says expert Smargiassi.

Particles travel with air masses. They can come from very distant sources, for example from transport in large American cities or from northern Ontario.

Audrey Smargiassi, principal investigator of the study

Along the way, the experts analyzed deaths associated with chronic exposure to PM2.5 in the eight targeted sectors. They studied other associated effects, such as respiratory symptoms of asthma, chronic bronchitis in adults and acute bronchitis in children, emergency room visits and hospitalizations for respiratory and cardiac problems. Like a Health Canada report, the researchers conclude that the annual mortality rates associated with chronic exposure to fine particles from wood combustion are higher in the region than those linked to other pollutants (O3, NO2 and SO2), including sulphur dioxide from fossil fuel combustion.

In Montreal and Laval, it is prohibited to use a device that emits more than 2.5 grams of particles per hour. Quebec City followed suit this year by requiring owners of wood stoves and fireplaces to register them. Starting in September 2026, only certified devices will be permitted. Starting in 2030, the national capital will prohibit the use of ambient fireplaces.

“Certification is not a panacea”

Elsewhere in Quebec, regulations regarding wood stoves remain permissive. The cities of Sherbrooke, Trois-Rivières, Sorel, Saint-Hyacinthe, Témiscamingue, Rouyn-Noranda and Saguenay have confirmed that there are no mandatory certifications for the appliances.

In the City of Saguenay, for example, communications advisor Dominic Arseneau explained that wood heating is “totally permitted,” but that there are “safety standards” issued by the regional fire department that must be respected.

In Trois-Rivières, the communications department clarified by email that it “has not adopted any specific regulations since the standards for manufacturing and using wood-burning appliances are the responsibility of governments, and the installation is governed by the Building Code.”

Daniel Vézina founded the group Families for Clean Air. “We are a small group, the poor child of the environment,” he says. According to him, we must ask ourselves questions about the social norm of normalizing indoor fires for ambiance and campfires in the summer.

“Certification is not a panacea,” he said. “New gas fireplaces also pollute. We should subsidize the removal of old appliances. I can understand people’s emotional attachment, but we have to understand the health issues.”

With the collaboration of William Leclerc, The Press