Wood burning stoves and air pollution

Wood burning stoves are in the news. They make a significant contribution to air pollution according to a recent government report. Wood burners and open fires together account for more than one-third (38%) of the tiny particles known as PM2.5 that are among the most damaging types of emissions for human health. That is more than any other source. Road traffic, by contrast, accounts for only 12%.

I’m not sure what to make of this. I like to fire up our stove on cold days, to supplement the oil-fired central heating, and we are thinking of adding a second stove elsewhere in the house to reduce our reliance on oil. Surely it is better to burn wood than fossil fuels? 

Well it’s not that simple. Wood is a renewable energy source as burning it is carbon neutral and doesn’t increase carbon dioxide emissions. But those PM2.5 emissions are a problem, both inside and outside the home. Open fires are worse than burners on that front, but many burners with doors are poor too. A recent study by the University of Sheffield showed that people who open the door to load a stove twice or more in an evening are exposed to pollution spikes two to four times higher than those who refuel once or not at all.

The problem is compounded by burning the wrong type of wood. Emissions from wood treated with chemicals or containing glue are seriously carcinogenic. Wet wood is also more polluting because it produces more smoke. A ban on sales of wet wood for households came into force in England in February.

Biomass boilers tend to be less of a problem than wood burning stoves, especially those that burn wood pellets. They are also more an informed choice than a nice-to-have accessory as you can’t sit around them enjoying the comforting warmth and glow.

I’m happy to take the indoor pollution risk of using a wood burner. But what about the particulates escaping up the chimney? Is air quality in Newton Abbot affected by that? Judging by a pollution map based on the National Atmospheric Emissions Inventory, the answer is yes. Domestic wood burning is the biggest source of air pollution due to PM2.5 in all the local towns.

This surprising fact has to be seen in the context of the huge reduction in air pollution over the past 50 years and the way the government measures it. Annual emissions of PM2.5 have fallen by 80% since 1970, mainly due to the falling use of coal and higher emission standards for transport and industry. The decline has levelled off in recent years though, as decreases in emissions from some sectors are largely offset by increases in emissions from domestic wood burning and use of biofuels by industry.

Wood burning stoves have become fashionable in recent years. They have also become more efficient and less polluting (in terms of outdoor pollution at least). The government’s report assumes stoves in use are mostly of the old polluting type, and that they are being used for 40 hours a week in winter and 20 hours a week in summer. This is based on a 2015 survey that also forms the basis of the NAEI. The government admits its estimates could be wrong by a factor of 10, so wood burning stoves could be making a much smaller (or larger) contribution to air pollution than the 38% attributed.

Whatever the numbers, Gary Fuller, an air pollution scientist at Imperial College and author of ‘The Invisible Killer – the rising global threat of air pollution and how we fight back’, is clear that burning wood, especially as a fashion statement, is not acceptable. In an interview with Environmental Protection Scotland he said even stoves that meet the eco-design standards that will apply from 2022 “emit the same amount of particles as the emissions from six heavy goods vehicles”.

That doesn’t sound like a neighbourly thing to do, even in my semi-rural village. In a city, it is definitely hard to justify when we know that air pollution is a killer. So my search for a clean alternative to burning oil to heat my house is leading in the direction of a heat pump, although that will be more expensive to install and run than another wood burning stove. If I was a more cynical person, I would suspect this demonisation of wood burning stoves to be a campaign aimed at prolonging our reliance on fossil fuels. That’s just mad though, isn’t it?

6 thoughts on “Wood burning stoves and air pollution”

  1. Good Evening,
    Thank you for your very clear article. I totally agree, wood smoke inhalation is very unhealthy. I think the only reason anyone would/should want to burn logs, or even pellets today, is when that is only means they have to heat their home. We have installed an excellent heat pump and it’s done well for 2 winters now, and you can claim RHI, but yes, the initial outlay is a bit pricey. I can’t cope now with any amount of wood smoke in the air. Several years in a smoky street some time ago, ruined my lungs and gave me COPD. I’ve had plenty of hospital tests and I have never smoked cigarettes – so be warned, please. Those doctors and scientists who speak out against all these fancy wood stoves are not making it up, nor are they seeking to promote the continuance of fossil fuel energy. They are trying to protect the health of the next generation. I’ve looked into this mater for almost 20 years and have collected literally hundreds of scientific studies, published in reputable peer-reviewed journals, all saying the same thing – woodsmoke damages human health and can even kill you. I’d be more than happy to send my list to you. Diesel vehicles certainly do emit these very harmful fine particles too, but here in the UK (indeed across the whole of Europe and beyond) the largest source is from industrial/municipal biomass burning and domestic combustion. Also, from everything I’ve read and all those I’ve spoke to, here and abroad, I’d say that wood burning is only going to add to the CO2 catastrophe. It is not carbon-neutral, or even low-carbon (I can tell you more, if you wish …) Wood burning is not green, it is black, dirty and toxic – even though a warm glowing fireplace IS cosy, I do agree – it’s just when you go into the science, and when you, or someone dear to you, coughs and wheezes painfully because of the smoke, that you find out the truth. I’m pleased to know that you are supporting action against the climate crisis. Please include wood burning as part of that.

  2. Prolonging our reliance on fossil fuels AND fuelling (!) another industry making new things to sell to everyone…. Every method of heating/cooling causes some pollution – I am not convinced that rolling out millions of ‘new’ machines is the way forward…..

  3. The emissions from wood burners are mixed up with the emissions from all solid fuel burning, including open fires, BBQs, fire pits and bonfires. Those gunning for wood burners should also want to ban BBQs in particular, especially as those are used in hot weather when everyone has their doors and windows open.

  4. Fuel companies stand to lose income and governments revenue if significant numbers of people start to use wood for their home heating. Wood is generally free and much cheaper than electricity gas or oil. It is therefore in the interests of government and suppliers to protect their profits by making the argument that burning wood is evil.  Thus we get not so much a debate as the rollout of a propaganda machine to control the agenda.  Shame on those ‘scientists’ who get well paid to distort the facts.  

    Recently reported was a survey which found that the winemaking industry generated more CO² than the emissions of airliners and motor vehicles combined, no doubt commissioned by the petroleum industry? 

    In the USA some states have made going off-grid illegal, not because of environmental concerns but to ensure that there is no loss of revenue.

    The official demonisation of the woodburner appears to be part of the plan to maintain the status quo, in many cases buying off ‘expert’ opinion to push the agenda.
    The privatised fuel industry has got a lot to answer for in its obscenely excessive prices which cause fuel poverty and the necessity for people to seek alternative ways of heating.
    They shouldn’t be allowed to have it both ways.

  5. Thanks for the comments. Interesting to see another article in the Guardian quoting a report by a Danish NGO called Green Transition Denmark which finds that new wood burning stoves billed as more environmentally friendly still emit 750 times more tiny particle pollution than a modern HGV truck. https://www.theguardian.com/environment/2021/oct/09/eco-wood-stoves-emit-pollution-hgv-ecodesign.
    There were also a couple of letters in response taking issue with the findings:
    https://www.theguardian.com/environment/2021/oct/11/wood-burner-debate-stoked-up-by-scientists
    We are installing our second woodburner, one of the new type obviously. I hope we will be able to install an air or ground source heat pump eventually too. We have plenty of wood from our own trees – most of the ash trees will be coming down over the next few years due to ash dieback.
    I note the government plans to put nuclear power at the centre of its decarbonising plans to reach its net zero target. Seems like another example of the energy companies getting people to pay over the odds for power. Not good!

  6. I find it more than a little coincidental that at the moment gas and electricity prices reach record levels, wood burning stove owners are demonised as “Public Enemy #1”.

    The government report quoted assumes “stoves in use are mostly of the old polluting type, and that they are being used for 40 hours a week in winter and 20 hours a week in summer.” I’m sorry, but in the six years we have had a wood burning stove we have never used it for 40 hours a week in the winter, and never in the summer!

    Even in 2021 electricity supplies are far from 100% reliable, and likely to get worse as the government haven’t invested in securing supplies as older power stations, both fossil fuel and nuclear, haven’t been replaced in a timely fashion. With that in mind wood burning stoves aren’t going to be a “fashion statement” for many, they are going to become the primary way of heating the house when the electricity fails, something we have found on more than one occasion.

    Still, the individual is such a soft target compared to big business.

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