Smoke from Australia's bushfires killed far more people than the fires did, study says

https://www.theguardian.com/australia-news/2020/mar/21/smoke-from-australias-bushfires-killed-far-more-people-than-the-fires-did-study-says

John Pickrell
Fri 20 Mar 2020 15.00 EDT
Last modified on Fri 20 Mar 2020 15.02 EDT


Smoke pollution that blanketed Australia’s south-east for many months during the bushfire crisis may have killed more than 400 people, according to the first published estimate of the scale of health impacts – more than 10 times the number killed by the fires themselves.

The figures, published in the Medical Journal of Australia, are “definitely alarming”, according to Chris Migliaccio, who studies the long-term effects of wildfire smoke at the University of Montana in Missoula and was not involved in the research.

Lead author Fay Johnston, an epidemiologist at the University of Tasmania in Hobart, estimates 80% of Australia’s population of about 25 million was blanketed by smoke this summer.

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“When you’re affecting millions of people in a small way, there are going to be enough people at high enough risk that you’re going to see really measurable rises in these health effects,” Johnston said.

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Many of the deaths and hospitalisations are likely to have been older patients with heart disease or lung problems, such as chronic bronchitis or emphysema – but severe asthma attacks will likely have resulted in deaths in younger people too, Johnston said.

In patients with pre-existing cardiorespiratory issues, smoke exposure promotes inflammation, stresses the body and makes blood more likely to clot, increasing the risk of a heart attack. “In someone at high risk, subtle changes due to stress … can be the precipitating factor for a very serious or terminal event,” she said.

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