Microplastic tyre pollution found in Brisbane balcony dust

Tyre particles and potentially toxic tyre chemical additives have been found in dust collected from Brisbane residential balconies.

University of Queensland researchers examined balcony dust from homes across inner-city, suburban, and near-road settings, to see how traffic-related pollution travelled from streets to residential environments.

PhD candidate Simran Kaur, who conducted the research with UQ’s Queensland Alliance for Environmental Health Sciences, said the study provided the first quantitative evidence of tyre pollutants on Australian balconies, including a chemical called 6PPD-quinone.

“6PPD-quinone is a chemical used in tyre production that has caused mass salmon mortality events in the United States,’’ Ms Kaur said.

“These findings indicate outdoor residential dust may be an important ‘sink’ for 6PPD-quinone, with implications for human exposure.’’

Balcony dust samples were collected between June 2024 and March 2025.

Researchers detected tyre additive chemicals in 29 of 30 samples, with 6PPD-quinone detected on 23 balconies. 

Other chemicals used in tyre production including Hexa(methoxymethyl)melamine (HMMM), 2-(4-Morpholinyl)benzothiazole (24MoBT), and 5-methylbenzotriazole (5-MBTR) were also detected.

Balconies that were closer to Brisbane's CBD and closer to ground level had higher concentrations of tyre-related pollution.

“Wind speed played a major role in how much tyre wear was deposited on the balconies,’’ Ms Kaur said.

“This suggests that tyre pollution does not stay on busy roads but can be carried through the air to be deposited further into the urban environment.

“To our knowledge, this study reports the first quantitative measurements of tyre wear particles or their chemicals 6PPD-quinone, HMMM, 24MoBT, and 5-MBTR in urban dust collected from outdoor areas of residential dwellings.’’

Tyre wear particles are a mixture of synthetic rubbers, fillers and tyre additive chemicals that resist degradation and can persist in the environment.

These particles accumulate on road surfaces and can be transported by wind or water runoff.

It is estimated about 6 million tonnes of tyre wear particles are released globally each year and this is recognised as one of the world's largest sources of microplastic pollution.

Dr Cassandra Rauert of UQ’s Queensland Alliance for Environmental Health Sciences said tyres were an often-overlooked source of microplastics.

“People see tyre wear as a normal part of driving, but the material does not simply disappear, the particles and chemicals are released into our environment and can travel beyond the road,’’ Dr Rauert said.

“Previous research has focused on roads, water and sediments, so we wanted to understand whether tyre pollution could also be transported through the air and reach residential spaces.

“These findings could help inform environmental monitoring programs of tyre pollution and guide research into ways of reducing tyre wear through better tyre design and formulation, as well as improved stormwater and urban pollution management.’’

Ms Kaur said while an increased use of electric vehicles was expected to reduce exhaust emissions, their heavier weight could increase tyre and road wear and see tyre wear particles remain a source of urban pollution. 

“These trends are particularly relevant in Australia’s rapidly expanding urban centres, where dense traffic, high vehicle dependence, and extensive road networks generate substantial and continuous tyre wear,’’ she said.

Read the research in ACS ES&T Air.