'Like having a truck idling in your living room': the toxic cost of wood-fired heaters

A lesser known source of pollution costs health systems billions each year.

smoke from wood heaters fills the sky

Peter Irga, University of Technology Sydney; Brian Oliver, University of Technology Sydney, and Fraser R Torpy, University of Technology Sydney

Australians are accustomed to having fresh air, and our clean atmosphere is a source of pride for many.

Last summer’s bushfires, however, brought air quality to the public’s attention, as millions of Australians breathed some of the world’s worst quality air.

But there’s a lesser-known source of pollution causing billions of dollars’ worth of health costs every year: indoor wood-fired heaters.

This week, the Victorian branch of the Australian Medical Association endorsed calls to remove these heaters via a buyback or subsidy scheme. But will it work?

Wood heater smoke is a huge pollution source
In winter, wood heater smoke is the single biggest air pollutant in New South Wales and the ACT. Similarly, in Victoria, wood smoke on cool winter days is responsible for most breaches of air quality standards.

Wood heater smoke is generated from both open fireplaces and wood-fired heaters. Wood-fired heaters are controlled-combustion, domestic heating appliances. In order to discharge emissions, they use a metal pipe called a flue, while open fireplaces use chimneys.

Around 10 per cent of Australian households – roughly 900,000 homes – use wood as their main source of heating, according to the ABS.

Based on NSW guidelines, burning 10kg of wood (an average day) in a modern, low-emitting wood heater can produce around 15g of ‘particulate matter’.

This is composed of tiny particles, which can penetrate into the respiratory system, potentially causing lung and heart diseases. It is one of the most dangerous components of smoke, and a carrier for many of its cancer-causing chemicals.

By contrast, a truck travelling on congested urban roads can produce just 0.03g of particulate matter per kilometre travelled. A truck would therefore have to travel 500km in heavy traffic – roughly the distance from Melbourne to Mildura – to produce the same particulate matter emissions as one average day of using a wood heater.

So, a wood-fired heater is like having a truck idling in your living room all day (albeit with the bulk of the emissions escaping via the chimney).

Smoke is toxic
The smoke from wood fires is very similar to that generated by bushfires, and is also detrimental to our health.

Australia’s wood-fired heaters are estimated to cause health costs of around A$3,800 per wood heater each year.

Given the roughly 900,000 wood heaters used as primary household heating sources in Australia, this could be as high as $3.4 billion annually across the country.

One study published in May estimated 69 deaths, 86 hospital admissions, and 15 asthma emergency department visits in Tasmania were attributable to biomass smoke each year – the smoke that comes from burning wood, crops and manure. More than 74 per cent of these impacts were attributed to wood heater smoke, with average associated yearly costs of $293 million.

Another study modelled the effects of air pollution on over-45-year-olds in Sydney over seven years. It found chronic exposure to low levels of particulate matter was linked with an increased risk of death. Depending on the model used, it found between a 3–16 per cent increased risk of dying occurred with each extra microgram (one millionth of a gram) of particulate matter per cubic metre of air.

All of this assumes wood heater users follow the law and use clean, dry hardwood as fuel. Problems become far worse when treated wood is used as the fuel source.

Treated timber offcuts from construction or demolition activities are freely available and, therefore, continue to be used as fuel for wood heaters, against recommendations.

Much of this timber is treated with an antifungal chemical called copper chrome arsenate. Breathing the emissions when this wood is burned can increase incidents of liver, bladder, and lung cancers, and reduce the production of red and white blood cells, leading to fatigue, abnormal heart rhythm, and blood-vessel damage.

There is no safe level of indoor or outdoor air pollution. This is an ideal time to consider the hidden dangers associated with our ‘clean’ air.

Wood heater smoke has been linked with increased hospitalisations and deaths from asthma. www.shutterstock.com

Change is difficult
Standard testing for new stoves is one way authorities try to reduce wood smoke emissions. Australian heaters must be designed to pass strict standards, however this system may not reflect the way heaters are actually operated in the home environment, because this varies so much between households.

For example, in New Zealand, testing on five heaters installed in people’s homes recorded particulate matter levels more than 15 times higher than their predicted average calculated during testing.

Banning wood stoves altogether is inequitable, as some people cannot afford any other source of heating, and many people employed in the wood-fire heater industry could lose their jobs. But changing economic incentives could work. An intervention method currently being proposed in Victoria is a wood stove buyback or subsidy scheme, which is now supported by the Victorian branch of the Australian Medical Association.

However, a similar rebate scheme did not have much impact in Canberra. Since November 2015, residents have been able to claim a subsidy of up to $1250 if they replace their wood heater with a ducted electric reverse cycle system. Just five households took up this rebate in the first six months. Meanwhile, 40,000–50,000 wood heaters are sold in Australia each year.

Another option is fines. Tasmanians can be fined $1680 if their chimney emits smoke that is visible for more than 10 minutes. However, when these regulations were announced, the laws were considered by many Tasmanians to be heavy-handed and the government was met with community resistance.

Many attempts at reducing the number of indoor wood heaters in Australia have been ineffective. www.shutterstock.com

A way forward?
In 2001, Launceston established several strategies to encourage use of electric heaters instead of wood heaters, including a grant of $500 to those switching over.

Following this, wood heater prevalence fell from 66 per cent to 30 per cent of all households, corresponding to a 40 per cent reduction in particulate air pollution during winter.

Education could also help. If people knew the concentrations of air pollutants in their homes, they might be motivated to change their wood-burning behaviour. Often residents are unaware of the concentrations of smoke generated by their activity, with many considering opening a window reduces the level of wood smoke in their home. Controlling indoor pollution is difficult, especially if the major source of the pollution is outdoors – opening the window would actually let more pollution in.

We suggest that together with the proposed rebate schemes, one way forward could be to provide affordable access (through subsidies or otherwise) to air-quality sensors. At the lower end of the scale, prices range from $100–500, with more accurate devices in the range of $1000–5000.

Despite the expense, they can improve awareness of levels of air pollution among those with wood-fired heaters, and may provide the impetus for people to work together and change community perceptions around wood-burning appliances.

This article is supported by the Judith Neilson Institute for Journalism and Ideas.The Conversation

Peter Irga, Chancellor's Postdoctoral Research Fellow and Lecturer in Air and Noise Pollution, School of Civil and Environmental Engineering, University of Technology Sydney; Brian Oliver, Research Leader in Respiratory cellular and molecular biology at the Woolcock Institute of Medical Research and Professor, Faculty of Science, University of Technology Sydney, and Fraser R Torpy, Director, Plants and Environmental Quality Research Group, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons licence. Read the original article.

Do you have a wood-fired heater in your home? Would you be happy to switch it over as part of a buyback scheme?

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    To make a comment, please register or login
    19th Jun 2020
    A scheme like this can't come soon enough for me. I am sick of all the air pollution in my neighbourhood from the pot belly stoves and wood heaters. Let's face it it is very rarely cold enough in Brisbane to warrant a fireplace or one of these heaters but people seem to put them on simply because it is winter. They are no different from the old incinerators in the back yard which were banned years ago because they polluted the air. I know some areas are colder than others like Canberra, which is freezing, but we should be building under floor heating etc. for the colder areas.
    30th Jun 2020
    I lived in Childers Qld for three years. Beautiful weather, BUT, As of 4pm each day in winter, you could feel the "chill" move in.....it was a sudden, and dramatic temperature drop. Overnight it was cold, cold, so cold! This in a centre which was claimed to have the most temperate weather in Qld. I battled through the first winter, as I had no idea I would need heating......but a combustion heater was installed before the next winter hit. Perhaps I should have settled further north, in tropical Qld.
    19th Jun 2020
    The researchers have not provided any research materials, just vague summaries, and they have not taken into account that the electricity to provide the heat if not coming from wood, is still mainly coming from Coal Fired Electricity generators, - which have no restrictions on their particulate matter output, so don't care.

    A proper analysis comparing the pollution from coal fired heating and everything else at the same time, - cooking, light, hot water, etc. so that we may sensibly compare, I would listen to, but not this vague one sided aphorisms approach.
    I concede it may be a problem in big industrial suburbs in England, but seriously doubt it is a problem in Australia.
    19th Jun 2020
    Au contraire Lookfar, it is a problem, in suburban Melbourne at least. To compare household wood heating with coal fired power stations is like comparing apples and oranges. If Horace Cope is correct, and I hope he is, there is no smoke from coal fired power stations "because there have been arrestors installed and most pollutants collected and stored, not allowed into the atmosphere". In any case coal is a far superior fuel than wood in respect to release of pollutants. Any smoke from a power station is along way away from my house, I would like to walk about my suburb without having to breathe in smoke from wood fires and my wife would like to be able to hang out the washing without having it contaminated by smoke.
    20th Jun 2020
    Lookfar, I agree. Given that still the main source of power is dirty brown coal generation, any negative comparison of wood heater emissions needs to be made against polluting brown coal. We only think electric heaters and air cons are 'clean' because the dirt is created in someone else's back yard. In most cases unless burning recycled industrial wood which is usually softwood or treated so unsuitable anyway, the only places where its economical to burn wood is near where the wood is growing which by definition is not in cities so the contribution to city polution is minimal.
    19th Jun 2020
    It is interesting, considering many homes not only use wood fires for heating (watch interviews with Bob Brown from his timber home in Tasmania), but it is essential for cooking meals and heating hot water.

    For those who consider those areas of Australia bad, I suggest you go to Cambodia, and about each afternoon about 4 to 5 pm it becomes very smokey because everyone is cooking.

    Not everyone has access to costly gas and electricity, nor can they afford costly solar panels, batteries, and inverters, together with the regular replacement costs, and the disposal costs.

    Many affluent people living in cities, don't understand that many working families are living on less than $50,000.00 pa, and even pensioner couples on around $35000.00 pa. Then they either have to pay rent, or rates and insurance.

    Think about all others, and their circumstances before being critical. Look at what YOU can do to help, not others, Governments (taxpayers), try and be constructive not destructive.

    Look for solutions that are cost effective without subsidies. I am.
    19th Jun 2020
    I agree, I cannot afford to run an electric heater, the rental I live in is impossible to keep warm without a wood fire which I can only just afford if I use it only in the evening. With an electric heater i would just about have to sit on top of it. Would be better to use incentive for landlords to make energy efficient housing first.
    22nd Jun 2020
    Agree 45er, approx 3 billion people on our planet cook with wood but a lot are moving away from the 3 stone fire to special 'can be made locally' Gasifier woodstoves that heat the wood until the gases leave and burn those gases directly under the pot, - no smoke, 30% more heat from the same wood, and a bit of charcoal left over to put in the compost which makes it better.
    They are called T-Lud, - Top Lit Up Draft, many on the Net, and there is a whole mob of people all over the world helping, developing, teaching villagers how to make etc, called "stovers"- Annual conventions etc, - no secret passwords though, - usually done for free.
    19th Jun 2020
    No I do not and I hate the smell of the wood fire in the winter in and around my are AND many other areas -- I have a few friends with wood fires and they love them and say they like the atmosphere as well -- give me an A/C any day -- cheaper AND I just press the button --
    19th Jun 2020
    My landlord will not provide me with an A/C to costly for them to install. So some of us have no choice.
    19th Jun 2020
    Firstly the picture used to illustrate article is clearly not in Australia but appears to be from an industrialised town situated in a smoke trapping valley in Europe, probably in Germanic or Eastern Europe. Furthermore, judging from the size of the building from which the main smoke is being emitted, it is from an industrial building rather than a residence. So yet more exagerated or fake news from YLC.

    I think the carbon dioxide benefits of the more than one hundred trees growing on my rural property more than compensate for the burning of a few fallen eucalypt branches during the weeks of winter. I'd rather burn potential bushfire fuel in my wood burner under control rather than out of control because if my property and home go up in smoke there will be far more particles floating around.

    Still the main source of Australian power generation is from burning dirty, brown coal so the electricity and pollution saving from this source need to be weighed up in the source of heating fuel.
    19th Jun 2020
    Not everyone has an efficient heater installed in a rental, I have the option of using a portable money guzzler or and ancient heater that has not been tested for who knows how long or the wood heater. The wood heater is the only thing that keeps me warm in this old house with insufficient insulation and I only can afford the wood if I only use it in the evenings.

    An incentive for landlords to make rentals more energy efficient would have to happen first for me to swap to electric and that would have to be run off solar to make it affordable and i don't have that either.

    More pollution comes from cars IMO.
    19th Jun 2020
    Not everyone has an efficient heater installed in a rental, I have the option of using a portable money guzzler or and ancient heater that has not been tested for who knows how long or the wood heater. The wood heater is the only thing that keeps me warm in this old house with insufficient insulation and I only can afford the wood if I only use it in the evenings.

    An incentive for landlords to make rentals more energy efficient would have to happen first for me to swap to electric and that would have to be run off solar to make it affordable and i don't have that either.

    More pollution comes from cars IMO.
    20th Jun 2020
    What utter bullshit!

    We did have a wood burning heater for 35 years in our previous house with zero ill effects for the whole family of 5. The "experts above don't know what they're talking about! Even though my wife suffered from emphysemia she hardly ever coughed during those years. If one observes some simple rules, the heaters are perfectly safe.

    Firstly, a slow combustion heater must not be operated with the main door open.
    Secondly, WFHs must have a proper flue fitted which always creates negative air pressure within the heater. No poisonous gases are emitted within the room if fitted properly in the first place.
    Thirdly, the heater must not be opened during the warm up phase, and topped up when there is zero or very low visible smoke.
    Fourthly, to reduce any pollution into the room, the heater must be kept shut and on as low a setting as possible.
    Fifthly, the heater should have an air circulating fan to make it extremely efficient at distributing heat. This also counteracts the effects of air currents generated with Cathedral Ceilings.
    Finally, treated wood must not be used.

    In our case, our heater produced 4 times (32,000 Kilowatts) as much heat energy as our 8.4 Kw a/c inverter and it ran 24 hours night and day in winter. It was also 3 times more efficiently than our gas wall furnace, and at 1/3rd the cost. As long as these precautions were observed, we never had a problem!

    Finally, there was nothing comparable to come home to a warm house with a wood fire on display. The effect was mesmerizing. Last but not least, the heater was as good after 35 years as the day we bought it. No electrically driven heater lasted this long. Also, it heated a 48 square house at low cost. Other advantages were that it could warm up dinner plates before serving meals and dry clothes on clothes racks for free (distance to be as appropriate for clothes in front of heater. We found 3 metres was ideal.

    So how come these "experts" never did any on site tests?
    20th Jun 2020
    Jo, it is not so much the smoke and such IN the home it is the smoke coming out of the chimneys into the fresh air

    My friends homes are never smokey but I can smell the smoke outside
    20th Jun 2020
    Plan B, and what about the thousands of people living around and downstream of the brown coalfield power stations? In Eastern Europe and Germany (from where I expect the above photo was taken) where they burn coal, the acid rain has killed off millions of trees and polluted waterways in the Carpathian and Hartz mountains amongst others. In Sweden they complain about the radio active effects from the British atomic power stations blown across to them. Electricity may seem clean for the user but unless its green (but ever seen the toxic garbage from a phootoelectric cell factory, an abandoned nuclear power station or a used solar panel dump) it's far from clean where it's made or generated. I'm all for clean energy but no one seems keen to publish the total life-cycle data for each method.
    20th Jun 2020
    Excellent tips JoJo, pity there is no fan on mine though, thanks.
    20th Jun 2020
    Plan B, you're right, I forgot to mention our circumstances where we lived. We had an acre property in a suburb full of gum trees. It was necessary to keep the property clean and free of dropped limbs and trunks of these trees (some were massive with limbs 500-600mm in diameter) and processing and storing the wood was a monthly exercise in winter.

    If we had left these wood offcuts piled up in summer, we could have easily lost the suburb to massive bushfires. In the 50 years we lived there, we never had a fire of more than one tree or branch at a time, because everyone kept their fuel load to the bare minimum.

    Yes there was the smell of smoke when the wind was still, but this occurred maybe once a week in winter. Most other times, the wind cleared out the smoke in the valley.

    The point is, the advantages far outweigh the negatives.
    22nd Jun 2020
    I am very aware of others having to have fireplaces such as yourself and Incognito -- and yes I agree with the pollution that the coal /oil and ESPECIALLY the nuclear are downright unacceptable
    Does make one wonder where the hell we will be very soon
    22nd Jun 2020
    Excellent article! We moved into a new home here in WA 4 years ago and next doors fires smokes and the sw winds blow it directly into our alfresco area. When in winter we have a lovely sunny day as we face north, we have to run inside when next door light their fires, yes the Council knows about it, they say that it is allowed to smoke for 15 minutes! The damage is done by then, I think also people throw fire lighters on their burning fires to boost up the heat in winter and of course the putrid smell comes into our home if we are not quick enough to close all the windows and doors. I am sure this is why my husband now has leukemia. We are totally fed up with fires burning and the smoke they produce.
    23rd Jun 2020
    I had the same thing happen from my neighbour who I spoke to today about it and she admitted it was the firelighters, but I know they are also burning wood from a building site too. There are more natural firelighters and non-toxic if you look out for them and maybe suggest they get that or use kindling.
    At $2.50 buy them some and drop it in their letterbox with a not and ask them kindly to use these instead.


    I am very careful about what I burn and where the wind is blowing but I usually wait until dark before lighting the fire and everyone is indoors anyway.
    30th Jun 2020
    I asked for a company to recommend and install a GAS heater in my home. I started to get very ill, dull thumping headache, nausea, muddled thinking, etc. etc. When I complained, the company checked it, said the "gases" were within accepted levels and left. I continued to get ill, worsening the longer the heater was on. I called the brand maker, and discussed the issue with him.......he told me that I had an unflued appliance, and I should have it removed immediately. He advised me that the heater I had been recommended was banned in some of the other states. I had the heater removed by the company, and they recommended I opt for another unit.........at greater expense of course. I had this new unit installed....flued to outside. It did not take long to realise that I was still getting ill. I did as much research as I could as to why this was so. I had had gas heating in many homes in the past and had never experienced this problem. I can only assume that, as I am now older, I may have developed an "allergy" to the gasses which are emitted......regardless of the "accepted levels". I was told some time back that I had developed "adult asthma", so perhaps that is the reason I am now reacting so badly to gas heating. I am now considering going to combustion wood heating.......I have arthritis which screams in this cold weather... and must do something. I have a reverse cycle a/c but cannot afford to run that as needed. I have just purchased an air purifier...awaiting delivery....it is a German built unit which is supposed to also capture "gases" , so when that arrives I will try the gas heater again and see how I get on. Failing that.........a wood heater it will be!
    30th Jun 2020
    Tarabelle, You could well be right about your allergy to gas fumes. I grew up with largely kerosene heating during long European winters. While I have a fascination with kero lamps, my chest now becomes congested after a short exposure to kero fumes. Have you tried alternating periods of gas and reverse air con to give your body a break while still keeping costs moderate?
    You say that reverse cycle air con is too expensive but it will probably cost around $3,000 or so to buy and install a good wood heater. I don't know your access to good hard wood timber but living in a sub-tropical area with short winters we use around 2 cubic meters of chopped and split timber per year which comes from trees on our own property. (the chopping and splitting saves gym fees!) I have no idea what this would cost to buy in your area but this might give you some basic info to consider.
    30th Jun 2020
    Many years ago I got very sick from a gas heater too, I was renting and ended up moving out, have used wood ever since, but like Viking says it can be expensive to install, I rent and it was already here but has no fan and not very efficient, I mostly have it on in the evening to save the costs, some very cold days if I am home will get it going earlier.

    I would make sure you are on a better rate for electricity and keep the temperature on your reverse cycle on a steady temperature I think it is 18 - 21 degrees and where more clothing (must be wool) get some thermal wear made from wool too, you will be very warm and chuck a beanie on your head.
    1st Jul 2020
    Incognito, good stuff especially on the indoor clothing, dress for winter!

    How do you go for wood fuel?
    1st Jul 2020
    I have to buy it unfortunately, so use it sparingly, and pick up what I can around the yard, have had a couple of tree's drop branches and there is always heaps of kindling. I bought a reciprocating saw so I can cut up the branches. Annoying thing is when you buy it and it might not be seasoned enough, always have the odd piece that smokes.
    3rd Jul 2020
    Hi Tarabelle it may be worth your while to look at a stove/heater/hot water wood unit, they are up a bit over that $3,000; mark, and I was told you can get REC's for them.
    Interesting, we all worry about electricity being the biggest contributor to climate change, (unless it is generated by renewables) but heating is the biggest, so a full job wood fire is the most environmentally active you can be.
    A company called Wise Living, in Albury is one I know of, doubtless there are others.

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