Sadiq Khan in U

Campaigners’ pressure sees London mayor withdraw approval for stoves billed as better for the environment

The mayor of London, Sadiq Khan, has withdrawn his endorsement of wood-burning stoves promoted as “environmentally friendly” after a surge in sales of the appliances, which contribute to harmful air pollution.

In 2018, Khan endorsed the Ecodesign stoves, which comply with new regulations in an EU directive on minimum energy efficiency standards that came into force on 1 January last year, in order to encourage householders to switch from open fires and older stoves to more modern technology. He said Londoners could make a big difference by using the “right kit”.

The mayor’s endorsement – along with the government’s clean air strategy, which also supported more efficient stoves – is used to promote the sales of modern wood-burning stoves, often bought primarily to enhance the attractiveness of a home.

Wood-burning stoves emit toxic particulate matter, known as PM2.5, which can be drawn deep into the lungs, increasing the risks from cardiovascular and respiratory disease. In 2019, exposure to these tiny toxic particles in the UK was linked to 33,100 premature deaths from all sources of pollution, including wood-burning stoves.

Emissions of PM2.5 from domestic wood burning increased by 124% between 2011 and 2021. Wood burning in homes now produces more small particle pollution than all road traffic in the UK.

Khan – who faces scrutiny over the extension of the ultra-low emission zone in London after Labour’s byelection defeat in Uxbridge and South Ruislip last Thursday – has confirmed he is withdrawing his endorsement of wood-burning stoves after being challenged by the Liberal Democrats over the issue.

A spokesperson for the mayor said: “The mayor has made it one of his top priorities to tackle the twin dangers of London’s air pollution and the climate crisis.

“Due to the increasing evidence of the harmful impacts of air pollution, including from wood-burning, the mayor no longer endorses Ecodesign wood-burning stoves or any other form of solid fuel burning.”

The Stove Industry Alliance, which promotes the wood-burning stove industry, has removed his recommendation from its website, but it still appears elsewhere. Marketing material for Schiedel, a leading manufacturer, stated last week: “Stoves are good!” and that they are “supported by ... the mayor of London”.

Data from the Stove Industry Alliance shows UK stove sales of its members rose from 143,160 in 2021 to 200,428 last year, a 40% increase.

Hina Bokhari, a Lib Dem London assembly member, said: “I’m grateful that the mayor has revoked his endorsement. Domestic wood-burning is one of the main sources of PM2.5, the most harmful of all pollutants that leads to a variety of respiratory and cardiac illnesses and has even been linked to dementia.”

One Ecodesign stove emits a volume of dirty pollution particles an hour equivalent to six modern diesel heavy good vehicles travelling at 20mph for an hour, according to an analysis in 2017 by the government’s air quality expert group. The stove industry says Ecodesign stoves emit a fraction of the polluting particles from an open wood fire or older stove.

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Jemima Hartshorn, founder of the campaign group Mums for Lungs, which was established in south London in 2017, said her group would like a ban on wood-burning stoves by 2032 unless they are the only source of heat in a home. “The levels of pollution from wood burning are very high already and are incredibly harmful,” she said.

Hazel Agombar, 53, from Winchester, a supporter of the Mums for Lungs group, said wood-burning stoves should be sold with warnings similar to those on cigarette packets. “Because it’s invisible and happens after dark, you’re not aware of the gradual build-up of wood smoke in your street,” she said. “Once you notice it, it becomes a big thing when you realise you’re breathing in harmful air.”

Chris Todd, 56, a transport campaigner from Brighton, said: “The woodsmoke has got worse the last few years. More people have put in stoves.

“I think some people just imagine the smoke goes out in the chimney and just is magicked away. People don’t understand that smoke doesn’t just go up in the air. It spreads out in a plume engulfing your closest neighbours.”

Gary Fuller, an air pollution scientist at Imperial College London, said: “The current messaging around the burning of wood seems to indicate it’s OK if you use a modern stove.

“Whether you use an open fire to burn wood, which is illegal in many of our urban areas, or invest in a stove for solid fuel, it is the most polluting way to heat your home.”

Ecodesign stoves are less polluting, but still emit 465 times more particle pollution than a gas-fired boiler, according to data in the chief medical officer’s report on air pollution.

The stove industry says data comparing emissions of Ecodesign stoves with vehicle emissions and other sources of energy is “deeply flawed”. It says these comparisons do not account for the fact that most stoves are only used for a few hours a day.

A spokesperson for the Stove Industry Alliance said: “Particulate matter comes from many different emissions sources and the UK stove industry is committed to continuing appliance improvement and innovation to drive down emissions and improve efficiency even further. Modern Ecodesign-compliant stoves burning dry wood account for less than 0.1% of total UK PM2.5 emissions and produce up to 90% less emissions than an open fire and up to 80% less than older, basic stove models. Wood is a sustainable and renewable fuel source.”

Schiedel said it had removed a reference to the mayor’s recommendation from its website.