New wood stoves, considered more environmentally friendly, still emit 750 times more tiny particle pollution than a modern heavy-duty truck, according to a report.
Only stoves that meet the ecodesign standard can be legally sold from early 2022 in the UK and the EU, but experts said the regulations were shockingly weak.
The report used data on emissions from stoves under perfect laboratory conditions and pollution could be even higher in daily use, the researchers said, with older stoves being much worse.
Pollution by tiny particles – called PM2.5 – is particularly harmful to health because it can pass through the lungs into the bloodstream, then be carried around the body and lodge in organs. At least 40,000 premature deaths per year are attributed to wood burning in Europe.
“The most surprising thing was the weakness of the ecodesign regulations, it was really shocking to me,” said Kåre Press-Kristensen, lead author of the analysis and lead advisor to the NGO Green Transition Denmark. “This means that a new wood stove, meeting the strictest regulations we have and burning only one kilogram of wood under optimal conditions, will pollute one million cubic meters of completely pure air up to the limit of the World Health Organization. [new] reference level.
The report said the use of wood-burning stoves should stop in order to tackle deadly air pollution and improve health, with heat pumps and district heating networks deployed instead. “The green transition is really about stopping the burning of things,” Press-Kristensen said.
Domestic wood burning is the largest source of PM2.5 air pollution in the UK, producing three times more pollution than road traffic. The situation is the same in the EU, with household stoves emitting around half of PM2.5 and soot. Only 8% of the UK population uses wood stoves and many are affluent people who choose a wood fire for aesthetic reasons, rather than to heat their homes.
The report, published by the European Environment Bureau, uses official data from Denmark produced in accordance with the requirements of a United Nations treaty on air pollution. The ecodesign standard was developed by the EU and allows wood stoves to emit 375g of PM2.5 for every gigajoule (GJ) of energy produced. In contrast, the latest standard for heavyweights is 0.5g per GJ.
“It is clear that particulate pollution from wood stoves and boilers is severely under-regulated compared to the regulation of trucks,” the report says. Nordic Swan, the official eco-label of the Nordic countries, allows wood stoves to emit 150g per GJ, which is 300 times more than a modern heavyweight.
The great disparity in pollution levels is due to the fact that combustion in heavy-duty engines is carefully controlled and technological solutions, including filters and catalytic converters that capture pollution, are required by law. In contrast, the burning of wood in stoves involves many uncontrolled factors such as air flow and the quantity and quality of fuel.
“Everyone’s been focused on traffic and power plants for the past 20-30 years and that’s great,” Press-Kristensen said. “But nothing has really been done to prevent pollution from wood stoves.”
Professor Alison Tomlin, University of Leeds, said: “This valuable report highlights the impact of household combustion of solid fuels on pollution. This shows that the very burning of dry wood and smokeless charcoal in an ecological stove results in particularly high PM2.5 emissions compared to other forms of home heating.
“At a time when gas prices are rising, households might be tempted to switch to solid fuels,” she said. However, this report shows that better insulation of our homes and a shift to cleaner heating methods are far more beneficial for health and the climate, ”said Tomlin.
Gary Fuller, Imperial College London and UKRI Clean Air Champion, said: “96% of UK homes that burn wood have other types of heating. Is it fair that vehicle and factory owners pay for technology to control air pollution while others add to it by burning solid fuels? “
A 2017 report from the Government’s Air Quality Expert Panel assessed the grams emitted per hour from eco-designed stoves and found them six times higher than heavy goods vehicles. “You’d be rightfully angry if six trucks were driving down your street every night, but we’ve standardized wood heating in the home,” Fuller said.
The UK government has no plans to restrict the use of wood stoves, but a retail ban on highly polluting wet wood came into effect in May.
“Air pollution has declined significantly since 2010, with PM2.5 emissions falling by 11%,” a spokesperson for the environment department said. She said the environmental bill currently in parliament “will make it easier for local authorities to tackle pollution caused by domestic fires by giving them powers to issue [fines] for smoke emissions.
Wood-burning stoves also triple the level of harmful pollution inside homes and should be sold with a health warning, the scientist behind a study published in December said. The researchers advised against using the stoves near the elderly or children.