Australian study links planned savanna burns to Darwin's worsening air pollution

Savanna burning aims to reduce emissions caused by intense fires later in the season. (ABC News: Che Chorley)

Savanna burning projects across the Top End are causing air pollution in Darwin, say a group of Australian researchers, raising concerns for people with asthma or lung disease. 

As part of their study, researchers from the University of Tasmania analysed the health risks of fire management in northern Australia, where land managers are offered carbon credits in exchange for burning savanna before the end of July each year.

Between 2004 and 2019 — when the carbon abatement program was introduced and expanded — the researchers found smoke pollution in Darwin was worse in the early dry season, particularly in June and July.

That's when "large areas of tropical savanna to the south-east of Darwin [were] intentionally burned in the early dry season", they wrote.

In northern Australia, fire is standard land-management maintenance. (ABC News: Jane Bardon)

The study's co-author, Fay Johnston, said the group found a "worrying trend of worsening air quality, particularly in the last five or six years". 

"The overwhelming source of air pollution for Darwin is the surrounding fires in the savannas," she said.

Another contributing factor could be the spread of highly flammable grasses, such as gamba grass, around the Darwin region, the researchers wrote.

Almost all of Darwin's smoke pollution is caused by landscape fires, say researchers from the University of Tasmania. (ABC News: Che Chorley)

Andrew Edwards — a bushfire researcher at Charles Darwin University — said those invasive weeds were likely the main culprit behind worsening air pollution, rather than prescribed burns.

"I would find it difficult to believe that [savanna burning] is the problem," Dr Edwards said. 

"The problem is the Darwin region, where we have to reduce weeds and reduce the amount of smoke that's coming from weeds."

Andrew Edwards says he isn't convinced that prescribed burns are behind Darwin's air pollution. (ABC News: Myles Houlbrook-Wallk)

Asthma a cause for concern

In an article about the study, published in The Conversation, the researchers wrote:

"In Darwin, smoky days bring more hospital admissions for lung and heart disease, and more emergency department presentations for asthma."

It's a trend that Asthma Foundation NT chief executive Leanne Elliott-Holmes has seen firsthand. 

"We get a lot of calls at this time of the year, particularly with our controlled burns and the poor air quality," she said. 

"And this is when a lot of people notice the effects and the increase in their asthma symptoms."

Leanne Elliott-Holmes says it's common for asthmatics to have some difficulty breathing in the dry season. (ABC News: Myles Houlbrook-Walk)