Because wood is natural and trees can be replanted, some people believe that burning wood is better for the environment than using fossil fuels. However, wood burning emits high levels of harmful particulate pollution, toxins, short-lived climate pollutants and other compounds. As we’ve noted , even though wood is a natural substance, it is neither healthy nor good for the environment.
Wood burning creates large quantities of localized outdoor air pollution, which has a Group 1 human carcinogen by the International Agency for Research on Cancer. It also emits such as PAHs, dioxins, benzene, mercury, formaldehyde and arsenic into our environment, to name a few. Many of these are harmful persistent chemicals that don’t readily break down in the environment and build up inside human and animal body tissues.
Tobacco smoke is, like wood smoke, a natural biomass smoke, but few people argue that cigarette smoke is harmless. Wood smoke contains many of the same harmful chemical compounds as tobacco smoke, but in much greater quantities. Heating a home with wood for a week can create more toxic chemicals than in the smoke from (PDF).
The Puget Sound Clean Air Agency estimates that heating a home with a correctly-operated US EPA-certified wood stove results in the emission of 97 lbs of PM2.5 annually. According to the Australian Air Quality Group, this makes the average wood stove 2,200 gasoline-fueled passenger cars.
the California Air Resources Board, wood stoves and fireplaces contributed an average of 50.4 tons a day of PM2.5 in the state in 2012, compared to 43.07 tons for all motor vehicles on the road combined — passenger cars, diesels, heavy-duty trucks, RVs, commercial and municipal buses, school buses, etc.
Carried through the air on microscopic particles of wood, the toxins in wood smoke either make their way into the lungs, brains and bloodstreams of humans and animals, or they eventually wind up on the ground and in our waterways, where they become part of our environment and our food chain. It doesn't matter if a carcinogen such as benzene comes from a factory or from wood smoke. It is the same, harmful chemical.
While in the atmosphere, some of the toxins in wood smoke chemically change and may become even more harmful. Some also contribute to ozone formation, worsening air pollution.
Wood burning also emits short-lived climate pollutants such as black carbon, brown carbon, methane and carbon monoxide, and levels of atmospheric CO2 during the immediate crucial time frame when controlling CO2 emissions matters most.
Trees are environmentally friendly and green. But burning them is not. Burning wood harms our health and our environment.