Air pollution kills 1 million a year – hundreds of whom are Australians

Short-term exposure to air pollution has been found to kill more than 1 million people globally every year, even when people are exposed to bushfire smoke, dust and other pollutants for only a few hours or days.

In Australia, the Black Summer bushfires of 2019-20 were estimated to have caused 429 smoke-related premature deaths and 3230 hospital admissions from acute and persistent exposure to bushfire smoke and pollution.

Bushfire smoke pollution over Sydney in December 2019, during Black Summer.Credit: Wolter Peeters

The fires were estimated to have scorched about 12 million hectares across Australia, and the fires in NSW and Victoria alone were the largest recorded since European settlement, cloaking large areas in smoke for long periods.

But the Australian team’s findings, published in The Lancet Planetary Health on Wednesday, show that even short-term exposure to bushfire smoke and other fine particle matter can be deadly.

A team of Monash University researchers conducted an extensive study of mortality rates and levels dangerous fine particulate pollution known as PM2.5 in more than 13,000 cities and towns across the globe between 2000 and 2019.

In a world first, the team examined the impacts of short-lived episodes of air pollution on people’s health rather than the impacts of living in urban areas with long-term and persistently high levels of pollution.

They found that across Australia and New Zealand, an average of 614 people lost their lives prematurely every year between 2000-2019, due to their short-term exposure to fine-particle air pollution.

By the time bushfire smoke reaches densely populated areas, the main factor that can cause harm is the presence of minuscule solid particles within it.

These particles are classed as PM2.5, which means particulate matter less than 2.5 micrometres in diameter – so small they can travel deep into the lungs and enter the bloodstream.

These tiny particles are treated like a foreign object by the body, which will trigger a defensive response with inflammation.

As well as irritations including sore eyes and itchy throats, short-term exposure to PM2.5 can trigger underlying conditions like atrial fibrillation, spark heart attacks and worsen conditions including asthma and chronic obstructive pulmonary disease.

Head of Monash’s Air Quality Research Unit and lead researcher Yuming Guo said the health effects of exposure to air pollution had been well documented, but this was the first study to show the global impacts of exposure to short bursts of pollution.

He said air-pollution warning systems and community action plans on high-risk days, as well as individual protective actions including face masks and limiting outdoor exposure, could help protect people.

Monash University professor Yuming Guo urged people to heed health warnings when air pollution levels were high.

“People should pay attention to protecting their health on these days, and wear a face mask and other measures.”

Australia and New Zealand had among the lowest level of deaths attributable to short-term PM2.5 exposure globally, with an average of 614 deaths across both countries attributable to fine-particulate air pollution each year between 2000-19.

In contrast, Asia accounted for 65 per cent of global deaths due to short-term exposure to air pollution, with an annual average of 663,889 people losing their lives to PM2.5 exposure across the region.

Within Asia, the worst region was East Asia, including China and Hong Kong, where an average of 316,290 annual deaths were recorded.

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