My first instinct is to rush to the attack against any think tank which calls for stuff to be banned. But in the case of a proposal by Bright Blue that wood-burners should come with a health warning, and that their use should be prohibited on certain days when pollution is high, I will make an exception. For far too long, wood-burners have been pushed at us as if they were an environmentally-friendly alternative to burning gas and oil. A whole generation of dinner parties has been thrown by smug hosts showing off their eco-credentials in front of a roaring wood-burner. Yet the sad truth is that they are just about the filthiest way you could choose to heat your home, and the biggest single contribution to foul air in our towns, cities and countryside.

Where is the impetus to cut pollution by the smug, middle-class wood-burning brigade?

Wood-burners in 2019 were responsible for 38 per cent of all the PM2.5 pollution in England (that is particles less than 2.5 microns in diameter), according to a study by Imperial College in 2021. What’s more, the pollution from this source has doubled over the past 20 years, while it has fallen for most other sources. According to the European Environmental Bureau, a typical wood-burner will spew out up to 375 grammes of PM2.5 per gigajoule of energy – compared with around 6 grams for an oil boiler and just 0.1 grams for a boiler powered by natural gas. Diesel vehicles have been targeted for their contribution to air pollution, yet the European environmental standard for wood-burners allows them to emit over 700 times as much particulate pollution, unit of energy for unit of energy, as a modern HGV truck.

Motorists on low incomes have been driven off the road by Sadiq Khan’s Ultra Low Emission Zone expansion. Yet where is the impetus to cut pollution by the smug, middle-class wood-burning brigade? Not only are the polluting habits of the wood-burning classes tolerated, but in some cases they have been heavily subsidised: right up until March 2022, the government’s Renewable Heat Incentive (RHI) was accepting applications from householders who wanted to replace a clean oil or gas boiler with a wood-burning one. The RHI promised payments for thousands of pounds (based on how much wood you burned) for seven years, so taxpayers will still be funding it until 2029.

The smog of the 1950s showed the devastating effect of particulate pollution. The Clean Air Acts are among the most successful pieces of legislation of modern times. Since 1970, particulate pollution has fallen by 85 per cent – yet by 1970 there had already been a huge improvement in air quality since the 1950s, for when there is rather less data on PM2.5s. But you only have to walk around towns today to sniff how lax the policing of clean air zones has become. What’s more, clean air zones do not generally extend to countryside. The air in my village is often foul on cold nights, thanks to wood-burners and people burning coal-based fuels (the sale of ordinary house coal was banned from 1 May this year). So often environmental rules seem fixated on carbon emissions to the exclusion of everything else. In this case, encouraging wood-burning has made air quality worse. It is high time that the tide turned against wood-burners.