Life Wellbeing Air pollution, bushfire smoke linked to increase in cardiac arrest risk

Air pollution, bushfire smoke linked to increase in cardiac arrest risk

Research has found short-term exposure to hazardous levels of bushfire smoke can dramatically increase the risk of cardiac arrest. Photo: ABC
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Not only are bushfires making it harder for us to breathe, they could be leading to an increase in deadly cardiac arrests, an Australian-led study has revealed this week.

While the world has been donning face masks as millions of hectares burn – from Australia to California and the Amazon – car emissions and coal mining practices contribute heavily to pollution levels.

What’s even more concerning is that while there’s a “safe” standard for fine particulate matter pollution (measured by the marker PM2.5) – an overwhelming 90 per cent of cardiac arrests occurred in periods with ratings below that “safe” level.

What does that mean?

It means there’s truly no “safe” level of this type of pollution, said co-author Professor Kazuaki Negishi, from the University of Sydney School of Medicine.

The report was published in The Lancet Planetary Health on Tuesday.

resident-puts-out-fire-garden hose
A resident holds a leaking hose on his burning property at Sunland, California.

Only one out of 10 people survive out-of-hospital cardiac arrests, and this adds to the mounting evidence that links them with acute air pollution, Professor Negishi said.

The research, led by the University of Sydney, concludes there needs to be urgent action to transition to cleaner energy resources.

“We analysed almost a quarter of a million cases of out-of-hospital cardiac arrests and found a clear link with acute air pollution levels,” Professor Negishi said.

“Our study supports recent evidence that there is no safe level of air pollution – finding an increased risk of cardiac arrest despite air quality generally meeting the standards.

“Given the fact that there is a tendency towards worsening air pollution – from increasing numbers of cars as well as disasters such as bushfires – the impacts on cardiovascular events, in addition to respiratory diseases and lung cancer – must be taken into account in health care responses.”

While it all seems very alarmist – and in some cases it is – it’s important to note that the biggest risk increase was for people aged over 65.

Smoke effects linger

What the research found, which was based off study undertaken nationwide in Japan, was the effects of being exposed to elevated PM2.5 levels sometimes didn’t cause cardiac problems between three and up to seven days after exposure.

The researchers presented Sydney’s recent bushfire pollution as an example.

On its worst day, the New South Wales capital’s PM2.5 peaked at more than 500 µg/m3 in the suburb of Richmond – well past the standard of 25 µg/m3.

That’s a level of pollution equivalent to chain smoking cigarette after cigarette.

Using the existing data of how many cardiac arrests there are annually in Australia, applying a hypothetical 10-unit increase in the daily PM2.5, it could lead to another 600 cardiac arrests a year, therefore 540 more deaths.

Every time there’s for every increase of 10 µg/m3, the cardiac arrest risk gets bumped up as much as 4 per cent.

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