For most of us, a fireplace means a quiet evening spent relaxing in front of the fire, watching the dancing flames and listening to the crackling logs.
But at what cost?
Whether the smoke released comes from a woodstove, a fireplace or a campfire, it is not as “environmentally safe” as you might think. According to Environment Canada, a woodstove that is not certified emits as many fine particles into the air in nine hours as does a certified woodstove in 60 hours or a mid-size automobile traveling 18,000 km.
Heating with wood represents a major source of contaminant discharge in the air: carbon monoxide (CO), volatile organic compounds (VOC), fine particles (PM2.5), nitrogen oxides (NOx) and polycyclic aromatic hydrocarbons (PAH). Smoke from the combustion of wood is present both inside and outside the home.
In residential neighbourhoods where wood heating is common, exposure to contaminants from chimney smoke can have a significant impact on health.
In Québec, wood-fire home heating is responsible for half of the fine particle emissions associated with human activities. At the local level, wood combustion may contribute far more severely to pollution. For example, a wood-heating sampling campaign carried out in Montréal in 1999 (in french) by the Montréal Urban Community has shown that, in winter, the concentrations of fine particles, VOC and PAH were often higher in residential neighbourhoods than in downtown Montréal. Under certain weather conditions, the concentration of contaminants in the ambient air can reach high levels in certain neighbourhoods. This type of situation can occur in many places in Québec.
The number of wood-heating systems is increasing in Quebec. Statistics Canada data indicate that the number of dwellings using wood heating increased by about 60% from 1987 to 2000. During the same period, the number of dwellings increased by less than 20%.
Number of dwellings using wood heating in Québec
Health Effects of Smoke
The particles emitted when heating with wood are very small, less than 2.5 microns, allowing them to penetrate deep into the respiratory tract, affecting breathing.
Potential health impacts of certain contaminants from high concentration of wood smoke in the air
The magnitude of these effects depends upon people’s sensitivity. Very young children, the elderly and individuals who suffer from asthma, emphysema or heart problems are among the most sensitive to air pollution.
In addition to emitting contaminants outdoors, wood combustion units may alter the quality of the air inside the home when a portion of the combustion gases and fine particles make their way back indoors. These leaks inside the home will vary in importance according to the type of unit used, the quality of its installation and the way in which the homeowner operates the unit. A study carried out by the Direction de la santé publique de Montréal-Centre showed that people using a woodstove had higher concentrations of contaminants in their urine than people without woodstoves. The combustion of wood thus represents an additional source of exposure to toxic substances in the home.
What Should You Do?
A few simple things you can do to limit your exposure to pollutants:
To Find Out More…
Many sites deal with the issue of wood heating:
Brochure - Heating with wood : How harmless is it? (PDF file, 518 Kb)