Wood heater smoke estimated to kill up to 63 in ACT each year, prompting calls for national ban

Researchers are calling for new wood heaters to be banned from urban areas and existing ones to be phased out after their study showed wood heaters could be killing up to 63 people a year in the ACT alone.

The study published on Monday in the Medical Journal of Australia found there were a similar number of deaths attributed to domestic wood heaters in the ACT each year as they estimated died prematurely in the territory due to the extreme smoke from the 2019-20 Black Summer bushfires.

Wood smoke has previously been estimated to cause 269 premature deaths a year in the Sydney Greater Metropolitan Area and 65 deaths annually in Tasmania.

While the ACT has already moved to ban the heaters, the study's findings have prompted its authors to call on environmental regulators and public health authorities in other states to urgently ban the heaters as well.

In the study, the researchers measured the amount of microscopic particulates, known as PM 2.5, at three research stations in the capital including Tuggeranong Valley, Belconnen and central Canberra.

These tiny particles are small enough to enter the bloodstream through the lungs, and long-term exposure can exacerbate respiratory conditions such as asthma and it also leads to a higher risk of heart attacks, strokes and some types of cancer.

Their modelling found the higher number of these particulates in the air during cold years – 2017, 2018 and 2021 – would conservatively likely be responsible for 17 to 26 premature deaths in the ACT.

The excess number of particulates during milder years — 2016 and 2022 — would be responsible for 11 to 15 deaths in the capital.

When they used the least conservative approach, these estimates jumped to 43 to 63 deaths a year during colder years and 26 to 36 deaths annually during the milder years.

They estimated costs of the deaths ranged from $57 million to $333 million.

A dangerous form of air pollution

Fay Johnston from the Menzies Institute for Medical Research co-authored the study and said it showed policies to address wood heater use were urgently needed.

"They're highly polluting, which means only a few of them can affect entire neighbourhoods," she said.

"Policies to improve air quality, including addressing the burden that comes from wood heaters, are important all around Australia."

Professor Johnston said wood smoke was a particularly dangerous form of air pollution because wood heaters burn wood under highly variable conditions.

As a result, it undergoes what is known as "incomplete combustion", which leads to more dangerous by-products.

"There are increasing risks to wood heater owners, in addition to the burden on the community from pollution in general," she said.

"Some very big recent studies from the United States found higher rates of cancer, for example, in people who use wood heaters even seasonally."

Peter Irga, who lectures in air and noise pollution at the University of Technology Sydney, said while the study was limited by the use of only three air-monitoring sites, overall it was sound.

"Alarmingly, the estimated deaths and costs could in fact be underestimates, if you take into account the potential increased toxicity from PM 2.5 derived from domestic wood heater smoke," he said.

Across the country, the distribution and impact of wood heaters is varied.

An estimated 2.7 million Australians have asthma, and for one in four of them smoke is a trigger for asthma attacks, with 455 dying nationally in 2022 from their asthma.

In NSW about 10 per cent of homes use wood heaters for heating, but towns such as Armidale use it extensively.

In Sydney, the heaters are responsible for up to 24 per cent of wintertime air pollution from 4 per cent of homes.

A 2021 government inquiry in Victoria found wood heating was a "significant contributor" to air pollution in built-up areas and made recommendations for reform.

"It's the cumulative effect of the hundreds of thousands of chimneys that are going throughout a city," Professor Johnston said.

Topography plays a role in the impact of wood smoke. In Launceston and Armidale in NSW, smoke more easily accumulates in their lower-lying town centres.

The ACT government is moving to phase out household wood-fired heaters by 2045 except in rural areas.

It came after a report by ACT Commissioner for Sustainability and the Environment Sophie Lewis found there was "no safe level of air pollution for human health" and the heaters had no place in the territory’s renewables future.

Up to 40,000 wood heaters are sold in Australia each year and they are estimated to be in 900,000 homes.

The industry has long argued new-model woodfire heaters have lower emissions.