Researchers are beginning to quantify the negative impact on health from using wood as a primary heat source in residential homes. A recent study conducted in Canberra, Australia revealed that mortality rates from regular exposure to smoke emitted by wood-burning stoves are comparable to those during the extreme “black summer” wildfires of 2019/2020.
Professor Sotiris Vardoulakis, a member of the research team and leader of the National Research Network for Healthy Environments and Lives (Heal), spoke about winter in urban areas: “When I bring my two sons to play basketball outside during winter, or when we take our dog for a walk before dinner, there is always a noticeable scent of wood smoke in the air.”
The study conducted by Vardoulakis and colleagues revealed that wood-burning was responsible for approximately 25% of particle pollution in Canberra. Based on this data and the known health effects of air pollution, they concluded that wood smoke contributed to an estimated 17 to 63 deaths per year in the Australian Capital Territory, which has a population of around 450,000 people.
This shortening of life means an annual loss of A$92m to A$333m (£48m to £173m) to Australian society. The health impact of this regular winter burning was comparable to the deaths during the 2019-2020 “black summer” bushfires from smoke.
According to Vardoulakis, Canberra experiences high levels of pollution during the winter months, primarily caused by wood-burning heaters. This has resulted in numerous complaints from individuals with asthma and those without chronic health problems. These individuals feel helpless as they are unable to open their windows or spend time outside during the winter due to the presence of wood smoke.
“The most efficient method of decreasing smoke exposure in communities is by prohibiting new installations of wood heaters and gradually eliminating existing units. These results can be applied to other residential regions where wood burning occurs during the colder seasons.”
Studies have shown that approximately 284 individuals in London are experiencing premature death annually as a result of outdoor air pollution caused by solid-fuel heating. In Greece, there was a widespread transition from oil to wood heating during the winter of 2012-2013 due to the country’s financial crisis. Research conducted in Thessaloniki revealed an estimated 200 additional deaths attributed to the rise in air pollution resulting from this switch.
Studies have shown that stoves and fireplaces contribute to indoor particle pollution in homes, including those in the UK. This compounds with pollution from other sources such as cooking and tobacco smoking, but this area is not as extensively researched as outdoor exposure.
A recent research involving 50,000 American women found that those who utilized wood heating had a 43% higher risk of developing lung cancer compared to non-users. Additionally, individuals in various countries such as China and Ireland who use solid-fuel heating have shown increased cognitive impairment, which is a typical sign of dementia.
Two researchers from the University of Lisbon have been calculating the impact of using a wood stove or fireplace for heating on the lifespan of individuals, in order to gain a better understanding of its overall magnitude.
Dr. Nuno Martins described the inspiration for their study: “We were inspired by a podcast featuring Guardian columnist George Monbiot as a guest. Upon further investigation, we discovered limited data on the amount of particle pollution emitted by wood-burning equipment in households.”
Martins and his team initially assessed the air pollution levels emitted by stoves and fireplaces in a limited selection of residences. This information was then incorporated into computer models of three households located in north-west Europe: Birmingham, Groningen, and Copenhagen. The data was also paired with information on the impact of outdoor air pollution on human health.
Burning a fire in a living room fireplace for four hours every winter evening was predicted to decrease the resident’s lifespan by approximately one to 1.6 years. However, using a stove instead may result in a decrease of up to six months in overall life expectancy.
There are some important things to keep in mind about this information. The sources, chemical makeup, and level of exposure for indoor and outdoor air pollution are not the same. While we have limited knowledge on how to determine the effects of air pollution in our homes, further research could aid scientists in understanding the potential health consequences for individuals who use stoves and fireplaces, as well as potential solutions.
According to Martins, it is best to avoid using open fireplaces. A better alternative would be to switch to closed woodstoves or, ideally, replace all wood-burning equipment.