Some people believe that wood smoke is only an issue if you have asthma or another lung disease. But wood smoke is bad for everyone, especially children. Wood smoke pollution has been linked to a wide range of health outcomes, including  heart attacks and dementia.

If you are not a smoker, breathing wood smoke is one of the most damaging things you can do to your health.

If you are a smoker, breathing wood smoke can reduce your lung function even more than from smoking alone, as well as increase your risk of smoking-related diseases such as chronic bronchitis and COPD.

Wood smoke particles are mostly in the fine and ultrafine size range that are most easily inhaled and most damaging to health.

…residential wood combustion has a relatively high health burden in terms of premature deaths, years of life lost, and decrease in life expectancy.
Orru, et al. Health impacts of PM2.5 originating from residential wood combustion in four Nordic cities.

Wood heating is linked to premature deaths

Pollution from residential wood burning is linked to premature deaths.

In Europe alone, for example, the burning of solid fuel (mostly wood) is estimated to contribute to the premature deaths of approximately 60,000 people a year (PDF).

A study centered on Nordic cities estimated that residential wood burning caused around 78 premature deaths each year in Copenhagen and 232 in Oslo.

In Armidale, Australia, a city with a population of around 24,500, it has been estimated that 14 people each year die prematurely from pollution caused by residential wood heating.

In a study in the Medical Journal of Australia, researchers estimated that each year a similar number of people die prematurely in the Australian Capital Territory (ACT) from PM2.5 emitted by wood stoves as were estimated to have died from the extreme smoke pollution of the 2019–20 Black Summer bushfires.

In Canada, an official government report issued in 2023 pointed out that home firewood burning was linked to more premature deaths nationwide than any other pollution sector considered, ending an estimated 2,300 lives a year.

A chart showing that home firewood burning is linked to 2,300 premature deaths in Canada annually, more than from any other source.
A chart from Health Impacts of Air Pollution from Transportation, Industry, and Residential Sources in Canada, an official government report by Health Canada (2023), showing that home firewood burning is linked to more premature deaths nationally than from any other sector.

Less wood smoke leads to a lower death rate

A community that reduced wood smoke pollution also lowered its death rate.

Launceston, Australia, conducted a wood smoke reduction program that encouraged residents to switch from wood stoves to electric heating. Wintertime deaths from respiratory disease dropped by 28%, and from cardiovascular disease by 20%. Year-round, for men, the reductions were 23% (respiratory), 18% (cardiovascular) and 11.4% (all deaths)

Based on a population of 100,000, the cost of cleaning up the air was less than A$21 per resident.

Wood burning and lung diseases

Wood smoke increases airway irritation that leads to coughing and difficulty breathing. It damages lung epithelial cells. It aggravates asthma and can increase its severity. It can decrease lung function and lead to the development of chronic bronchitis and conditions such as chronic obstructive pulmonary disease (COPD).

An older woman using an inhaler.
Breathing wood smoke is linked to increased risk of developing lung diseases such as COPD.

More wood stoves, more COPD

In 2015, an article in the Canadian Medical Association Journal suggested that an increase in cases of COPD may be due to an increased use of wood stoves. Dr. Kenneth Chapman, President of the Canadian Network for Respiratory Care and a professor of medicine at the University of Toronto stated:

Tiny particulates, produced from combusting wood are dangerous, especially for people with pre-existing respiratory issues. It’s the same thing that’s harmful about tobacco smoke—minus the nicotine. There are volatile gases that you don’t want to inhale and can irritate the airway and lungs.

A study of women hospitalized with COPD in Barcelona found “a strong association between wood or charcoal smoke exposure and chronic obstructive pulmonary disease, supporting its existence not only in developing countries, but also in European countries, such as Spain.

The message for policymakers and the public is clear. Wood heater smoke is not safe. Interventions to reduce exposure in homes and neighbourhoods should be a priority.
Prof. Fay Johnston of the Menzies Institute for Medical Research, quoted in Indoor Wood Burning Raises Women’s Lung Cancer Risk by 43%, Says US Study by Prof. Gary Fuller in The Guardian, October 6, 2023.

Allergies and altered immune function

Exposure to wood smoke, as well as to traffic pollution, has been linked to worsened allergic reactions. It is also associated with lower immune function. Animal studies have demonstrated that short-term, repeated exposure to wood smoke can compromise the lungs’ ability to fight off infections.

Wood smoke and heart attacks

As we mention on our Particle Pollution page, exposure to fine particle pollution is linked to heart attacks.

However, there is evidence that when the particulate matter comes from wood smoke, rather than from other sources, the risk is even higher.

Raised heart attack risk for seniors

A study found that when particle pollution from residential wood burning was at its highest, the risk of heart attacks in seniors rose by 19%.

According to McGill University professor Scott Weichenthal, lead author of the study:

We noticed that the association was stronger when more of the air pollution came from wood burning. This suggests that the source of pollution matters and that all particulate air pollution is perhaps not equally harmful when it comes to cardiovascular disease.
A red sign that says Emergency, pointing to a hospital emergency department.
Pollution from wood heating is linked to more heart attacks in seniors.

More symptoms in heart attack survivors

A study in Germany of air pollution constituents and symptoms in heart attack survivors found evidence that compounds related to wood burning are particularly harmful.

Wood smoke also stiffens arteries and reduces heart rate variability. Reduced heart rate variability has been associated with sudden cardiac death.

The risk of acute myocardial infarction for the elderly living in and around small cities is increased by air pollution caused by biomass burning from wood stoves.
McGill University press release, February 27, 2017.

Inflammation and blood clotting

Short-term exposure to wood smoke in healthy adults has been linked to increased levels of inflammation and effects on blood clotting. “Relatively low levels” of wood smoke exposure have also been associated with raised biomarkers in blood, breath and urine indicating effects on airways.

It has also been shown in a laboratory experiment that the free radicals in wood smoke remain chemically active forty times longer than those from cigarette smoke. (Free radicals play a major part in the development of chronic and degenerative illnesses such as cancer, autoimmune disorders, cataracts, rheumatoid arthritis, cardiovascular diseases and neurodegenerative diseases.)

Wood burning linked to dementia

As we note elsewhere, exposure to fine particle pollution is recognized as a risk factor in the development of dementia.

Researchers in Sweden studied a population living in an area where PM2.5 came mostly from residential wood burning. They found that those who lived in an area with a 1 µg/m3 increase in PM2.5 due to residential wood burning had a 55% higher likelihood of developing dementia compared to those who were not living in an area polluted by wood smoke. Those who had a wood stove in their home and lived in neighborhoods where wood burning was common were 74% more likely to develop dementia over the course of the study.

It is well established that biomass burning emits health-damaging pollutants, including several carcinogenic compounds.
Oudin, et al. Association between air pollution from residential wood burning and dementia incidence in a longitudinal study in northern Sweden.

Wood smoke particles generate DNA damage

Wood smoke has been found to produce high levels of free radicals and DNA damage, as well as to promote inflammatory and oxidative stress response gene expression in human cells.

Compared to diesel exhaust particles, wood smoke particles were found to increase levels of DNA strand breaks in a laboratory study.

Another study similarly found that particulate matter from wood smoke “generates more DNA damage than traffic-generated (particulate matter) per unit mass in human cell lines, possibly due to the high level of polycyclic aromatic hydrocarbons” in wood smoke.

According to the authors of the study:

This suggests that exposure to wood smoke particulate matter might be more hazardous than particulate matter collected from vehicle exhaust with respect to development of lung cancer.
A patient's perspective view looking out over a blurred foot at a hospital cancer infusion ward.
Wood stoves and fireplaces are a surprisingly large source of cancer-related pollutants in our air.

Wood smoke and cancer risk

Wood smoke contains chemicals that are listed as known and suspected carcinogens by the International Agency for Research on Cancer (IARC), as well as other chemicals that are classified as hazardous air pollutants. (For more information on chemicals in wood smoke, see our Toxins page).

More carcinogenic than cigarette smoke

Extracts of particulate matter containing “substantial quantities of wood smoke” have been found to be 30 times more potent at inducing tumors than cigarette smoke condensate (PDF) in an animal study.

Wood smoke has been found to be genotoxic, inducing DNA damage and mutations.
S. Mehta, et al. Indoor wood-burning from stoves and fireplaces and incident lung cancer among Sister Study participants.

Carcinogenic pollution linked to wood burning

A study in Athens, Greece, found that residential wood burning is “a considerable source of carcinogenic PAHs in one of the most populated regions of the Mediterranean,” responsible for nearly half the annual carcinogenic potential from these compounds in the air. “This can result in a large number of excess cancer cases due to biomass burning-related high PM levels.”

The researchers involved in the study pointed out that while the analysis was done in Athens, the results were not unusual. Carcinogenic pollution from residential wood heating is a significant problem in cities throughout Europe.

A primary airborne cancer risk

Pollution from wood stoves and fireplaces has been found to be the top cancer risk in Oregon’s air.

A study from Seattle found, as well, that pollution from wood burning is a primary airborne cancer risk. The situation is likely similar in other places where wood stove use is common.

Focus on wood heating to lower cancer risk

A report in Canada found that wood smoke from residential wood heating, more than emissions from industrial sources, was “an important source of cancer-related pollutants” and recommended that, in some regions of the country, pollution reduction efforts should focus on residential wood burning for heat in order to lower cancer risk.

Wood smoke increases lung cancer risk

Wood smoke is associated with the development of lung cancer. For example, in an article on the Medical Journal of Australia’s InSight+ website, respiratory physician Dr. James Markos said of breathing air polluted by wood stoves:

It is identical to the risk of lung cancer from passive smoking. So, if you live in a smoky hollow, you are playing Russian roulette with whether you might end up with lung cancer after 20 or more years.

Wood stove and fireplace use linked to lung cancer

A study published in 2023 by researchers with the US National Institute of Environmental Health Sciences found that, overall, women who used a wood stove or fireplace more than 30 days each year had a 68% higher rate of lung cancer, compared with those who did not heat with wood.

Even occasional wood burning (less than 30 days a year) was linked to increased risk.

The study authors concluded:

…in this large prospective study of US women, we provide evidence consistent with prior case-control studies that even infrequent exposure to indoor wood smoke is associated with a higher incidence of lung cancer, including among never smokers.

Oral and throat cancers

An association has also been found with wood smoke and carcinomas of the mouth, pharynx, and larynx.

A young child is wearing a hooded towel while standing in front of a lit wood stove.
Children absorb more of the carcinogenic PAHs in wood smoke than adults due to their size and physiological differences.

Children absorb more carcinogens

It has also been noted that children, who absorb more of the carcinogenic polycyclic aromatic hydrocarbons (PAHs) from wood smoke than adults due to their size and physiological differences, have a higher lifetime risk of lung cancer from inhaling wood smoke than adults.