‘Debilitating’: health impacts of smoke from Australia’s black summer bushfires revealed in study

The film-maker Shaun Humphreys vividly remembers the miserable summer of the 2019-20 bushfires.

His house, in a north Canberra suburb, was far from the burning fires, but the surrounding smoke was thick and stifling.

“When it first hit and we weren’t so savvy at managing the house and making sure that every window was completely airtight … you could see the smoke inside.”

Hunkered down with his partner, the film-maker Vivienne O’Connell, and teenage children, Humphreys and his family bought air purifiers and watched “movies that remind[ed] us of the cold”.

“We just found it completely debilitating,” he recalled. “It got so bad that we ended up going and sleeping in our little film studio for a couple of nights, because it had air conditioning.”

While the impact of directly surviving bushfires that threaten life and property has been reasonably well researched, less is known about the effects of exposure to bushfire smoke, said Prof Iain Walker of the Australian National University.

Walker is the co-author of a new study that has found the physical and mental impacts of exposure to smoke from the black summer fires was likely greatly underestimated by official health statistics.

The study, published in the journal Frontiers in Public Health, surveyed 2,084 adults affected by the bushfires close to Canberra.

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Virtually all of them – 97% – said they had experienced at least one physical symptom attributed to the smoke. Half of respondents reported symptoms of anxiety and depression, as well as sleep loss.

Only one in five people sought medical attention for their symptoms, suggesting the breadth of health impacts was far greater than the number of cases officially recognised by the health system, Walker said. “A much wider segment of the population was exposed to bushfire smoke than bushfires directly.”

“People with any previous experience of bushfires reported more symptoms [both physical and mental] than those who hadn’t,” he added.

In addition to the stress of nearby fires, bushfire smoke disrupted routine activities such as the ability to exercise or travel outside, Walker said. “All of those have secondary effects on health and wellbeing.”

The most commonly reported physical symptoms were eye or throat irritation, and cough.

Between 15 December and 15 February, roughly a quarter of days in Canberra had “extremely poor” air quality levels as a result of bushfire smoke, while the other three-quarters had air quality classified as “poor” or worse. On the worst days, hourly levels of PM2.5 particulate matter peaked at almost 50 times the threshold for “poor” air quality.

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A royal commission last year estimated that the 2019-20 fires caused an estimated 445 deaths and hospitalised at least 4,000 people across the country.

“Then there’s the long-term impacts,” said Jo Dodds, the president of advocacy group Bushfire Survivors for Climate Action. “I have friends who have not been able to breathe comfortably since the fires hit.”

Dodds formed the group after a 2018 bushfire tore through her town of Tathra, on the New South Wales south coast. For hours, she watched as a fire on her street destroyed the homes of her neighbours. “The loss of the sense of safety in your home or in your community is huge,” she said.

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With Australia predicted to experience more frequent and severe fires as a result of the climate crisis, Walker said the country needed “to seriously address the capacity of the health system generally in order to be able to meet … peak surges in demand”.

“That might mean – as has happened with Covid – that the health system finds ways to create surge workforces or other surge capacities.”

Dodds said: “If you haven’t been affected by bushfire yet, then you will be, one way or the other: whether it’s the smoke, or knowing someone who was impacted, or losing something yourself.

“That should lend urgency to everybody who wishes it to be otherwise,” she said. “It’s still important that we all call for urgent action on reducing emissions, because without that, we’re going to see even worse fires and even worse impacts on communities.”