Study on long-term impacts of bushfire smoke

Canberra had the worst air quality in the world at the height of last summer's bushfire crisis, with fires burning in NSW and within the Territory.

Research published in the Medical Journal of Australia estimated in the ACT there had been 31 excess deaths, 82 cardiovascular hospital admissions, 147 respiratory admissions and 89 asthma related emergency department attendances from last summer's smoke haze.

The bushfire smoke study, funded by the Medical Research Future Fund's Bushfire Impact Research grants program will seek to better understand the physiological impacts of prolonged bushfire smoke exposure, to improve health outcomes for Australians.

Professor Phil Hansbro, deputy director at the Centenary Institute as well as director of the Centenary UTS Centre for Inflammation was the successful recipient of the grant and will be leading a team of specialist respiratory disease researchers and clinicians on the project.

"The true extent of bushfire smoke on people is still largely unknown," Professor Hansbro said.

"We just don't know the full impact on people resulting from prolonged smoke inhalation or if short-term effects resolve after the exposure ends.

"There is a real knowledge gap as to what level of smoke exposure is likely okay and what level may lead to adverse health effects, particularly for the more vulnerable in our society."

Professor Hansbro said he was not surprised 31 deaths could have been attributed to Canberra's bushfire smoke. He likened it to the severe thunderstorm event in Melbourne in 2016 when there were 10 asthma-related deaths.

"What you're doing is creating air pollution, essentially, and you breathe it in and that causes inflammation in your airways. And then people with diseases such as asthma, CIPD, older people, a lot of them already have inflamed airways, so if you get an additional hit on top of that, then that can become quite serious, acutely, but also in the longer-term as well."

For this study, the research team will explore the short and prolonged physiological effects of bushfire smoke using mouse models and primary human cells and tissues. Assessed will be how bushfire smoke affects the airways, lungs and other organs and what the long-term consequences of this exposure could be.

Potential smoke impact on healthy individuals and those with common pre-existing respiratory disease such as asthma, emphysema and lung cancer will also be explored. "Ideally from our study, we'll be able to help define safe levels of bushfire smoke exposure across all of these population groups," Professor Hansbro said.

The study will look at bushfire ash from combusted major vegetation types from the different states (the ACT will be included with NSW).

"We don't know as a scientific community what level of particulates are damaging," he said.

"Are bigger particles more damaging? Are smaller particles more damaging? That could well determine safe guidelines and also what sort of masks do you need to wear."

The study will take scrapes of airway cells from volunteer's throats and grow them into airways in a petrie dish. The airways would be exposed to bushfire ash that undergoes a process to return it to smoke. Major tree types and vegetation had been collected and combusted in a furnace to make the ash.

"Then you've got an airway in a dish and you're exposing it to actual bushfire smoke," he said.

"We can make [the smoke] as severe as we want and we're going to look at acute affects and chronic effects, longer-term effects."

Professor Hansbro said his team would be releasing their results as they went, with some likely to be made public as soon as within three months.