Wood is used in more than 3 million Canadian homes as either a primary or secondary heat source. Woodstoves and fireplaces are not only used for heating purposes but also to create a “comforting and cosy” atmosphere in the home.

However, wood smoke pollutants can reduce the quality of our air and cause breathing difficulties and other health problems even at relatively low levels. In fact, residential wood burning is a major contributor to winter smog, and in areas of high use can result in poorer air quality in residential areas than in major city centres such as Montréal (see study).

If the combustion of wood were complete, only carbon dioxide (CO₂) and water would be emitted into the air. These conditions, however, are never reached. When wood is burning, the flames appear on one part of the log while smoke arises from several areas. This smoke results from the incomplete combustion of the wood. It contains a mix of hazardous particles and chemicals that are distilled out of the wood or formed during its combustion.

Some of the important pollutants found within wood smoke include:

• Particulate matter
• Nitrogen Oxides (NOx)
• Carbon Monoxide (CO)
• Volatile Organic Compounds (VOCs)
• Dioxins and Furans
• Polycyclic Aromatic Hydrocarbons (PAHs)

Also of concern, some of the unburned gases collect on the chimney walls as an oily residue known as creosote. A build-up of creosote can result in an increased risk of chimney fires.

Scientific research and the co-operative efforts between governments and industry have made wood burning appliances safer, less polluting and more efficient.

Still, it's important to stay informed as residential wood burning is at the centre of much discussion. Changes with regards to this issue may be coming your way soon. As these activities unfold, there are already many things that you can already do to take action and help reduce air pollution from wood heating.