Using a wood or coal burning stove or open fire at home may lead to a decline in lung function, suggests a new analysis from UCL researchers.
The study, presented at the European Respiratory Society Congress in Amsterdam, found that lung function among solid fuel users in England declined faster over eight years compared to non-users.
The use of solid fuels - such as wood, coal, and other burnable materials - for home heating has increased in parts of Europe, driven by rising fossil fuel prices and the promotion of wood as a renewable energy source.
In the UK, the proportion of harmful PM2.5 air pollution (fine particulate matter) caused by domestic solid fuel is now 20% of the total, compared with 4% for road vehicle exhaust emissions.
Annual emissions, specifically from domestic wood burning, almost doubled from 3,200 tonnes in 2009 to 6,000 tonnes in 2023.
Dr Laura Horsfall, based at the UCL Institute of Health Informatics, told the Congress: "We know wood burning at home emits harmful air pollution both indoors and outdoors including known carcinogens. Despite this, air pollution from this source has approximately doubled in the UK since 2009 as more people install and use wood stoves.
"However, the link with health outcomes in high-income countries is not well understood and residential areas with high emissions are hard to identify using existing air quality monitoring networks."
Building on a previous study that mapped the use of solid fuel burning stoves across the UK, the researchers used data from the English Longitudinal Study of Aging (ELSA) to study the connection between self-reported solid fuel use at home in England and lung function decline.
They assessed patients' lung function according to a measure called FEV1, which quantifies the amount of air a person can forcefully exhale in the first second of a breath.
Lower FEV₁ values are associated with increased risk of respiratory complications and poorer health outcomes, making FEV₁ a key objective marker in monitoring diseases like COPD and asthma.
Studying health impacts is challenging because wood-burning households tend to be wealthier and healthier overall. Dr Horsfall explained: "We found that people using solid fuel had lower rates of smoking and lung disease, which can mask the true effects of solid fuel exposure.
"However, using repeated lung function measurements over an eight-year period, we found that lung function declined faster among solid fuel users compared to non-users, even after adjusting for socioeconomic and housing factors. This suggests an important link between solid fuel use and respiratory decline, despite the healthier baseline of the exposed group.
"Our study suggests that high levels of particulate matter from stoves damage respiratory tissues, causing inflammation in a similar way to cigarette smoke," she added.
Dr Horsfall and her team now plan to investigate whether people living in or near areas with a high concentration of wood stoves, such as the wealthier parts of London, also show increased rates of respiratory issues, such as inhaler prescriptions and hospital visits for lung conditions.
Professor Ane Johannessen, Head of the European Respiratory Society's expert group on epidemiology and environment, based at the University of Bergen, Norway, who was not involved in the research, said: "In Europe, we are seeing a growing trend for using wood-burning stoves at home. Research in other parts of the world, where traditional wood burning is used in the home, has shown that this is harmful and causes asthma, COPD and lung cancer.
"These findings suggest that wood-burners used in European homes may have similar effects and should be considered a potential environmental risk factor when assessing respiratory health, especially in patients with unexplained lung function decline or chronic respiratory symptoms. Although new eco-design European wood-burners are generally considered cleaner and safer than more traditional wood stoves, many European homes still employ older wood-burners, and even the newer stoves may not be entirely risk-free.
"This study underscores the need for clearer public health guidance and regulation around domestic wood burning. People should be aware that these stoves could be harming them and their families, and doctors should be asking their patients about whether they are using stoves at home."
