Brisbane's 'safe' levels of pollution still raise death risk, research finds
Jul 02, 2020
By Stuart Layt
A study of more than 240,000 deaths in Queensland over more than a decade has found even low levels of air pollution raises the risk of dying.
The Monash University study looked at Queensland’s causes of death for a 15-year period to 2013, to examine whether even cities with relatively clean air, such as Brisbane, were adversely affected by air pollution.
The study found that for every rise of one microgram per cubic metre (ug/m3) of particles 2.5 microns or smaller, there was a corresponding 2 per cent increase in the risk of dying.
Professor Yuming Guo from Monash University's school of public health and preventive medicine said the link between high levels of air pollution and an increased risk of dying had already been established, but the study confirmed that very low levels were also a risk.
“What we found is that even very low levels of air pollution can have a serious effect on health and hasten death,” Professor Guo said.
“The results suggest there is a potential threshold around 4.5 ug/m3 above which there is increased risk of death.”
The researchers matched the mortality data to postcodes and then cross-referenced that with the air-quality data for that area leading up to a person’s death.
They found that, in particular, cardiovascular and respiratory diseases were exacerbated by rises in air pollution.
Particles smaller than 10 microns can become lodged in the lung tissues and cause breathing difficulties, however health authorities are primarily concerned with particles 2.5 microns in size (PM2.5), which can pass through the lungs and into the bloodstream.
They are caused by a range of sources, from heavy industry to cars and also in large bushfires such as those which scorched much of Australia over the recent summer.
For comparison, a human hair is about 50 microns thick, while a grain of beach sand is 90 microns on average.
The air quality in Queensland by postcode varied between one and nine ug/m3 over the study period, with the highest levels recorded in Brisbane postcodes.
The World Health Organisation has set its safety threshold for PM2.5 in the air at 10 ug/m3, with federal, state and local governments in Australia using that as a guideline.
Professor Guo said the study findings showed that the WHO’s advice and the practical measures put in place by governments needed to be changed.
“If, as we’ve found, there is an increased risk of mortality associated with levels of air pollution below this quality standard, that is a new risk for human health,” he said.
“So the standard should be changed.
“We think that our air in Australia is good quality, but this research says it’s not good enough."