Outside In | We’re choking on toxic tyre dust – we just didn’t realise it

Modern tyres are a chemical cocktail and scientists are realising that the microparticles they shed are actually quite harmful – to wildlife, the food chain and us

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A woman walks on an overpass in Beijing’s central business district on November 14. Tyres shed trillions of toxic microparticles, making up at least 10 per cent of the microplastics in the ocean, and small enough to interact with our cells, causing increasing concern to health scientists and environmentalists. Photo: AFP

Published: 4:30pm, 1 Dec 2023

Just when we thought we were getting on top of carbon dioxide and other exhaust emissions from our petrol-guzzling cars, along comes a newly noticed source of toxins from the world’s roughly 1.5 billion road vehicles.

And with exquisite perversity, it looks like battery-powered vehicles only make the problem worse. This time, the problem comes not from the fuel we burn but from our car tyres – and the way the rubber hits the road.

According to UK research group Emissions Analytics, an average car’s tyres emit over 1 trillion microparticles for every kilometre they travel. Over a car tyre’s average life, it sheds about 30 per cent of its tread – which amounts to about 1.5 million tonnes of tyre dust every year, according to a 2017 study.

We get more tyre dust with more cars, longer distances driven, more aggressive driving, underinflated tyres, faster acceleration power and heavier vehicles – and electric vehicle batteries add around half a tonne to the weight of the average EV.

As an Imperial College London report published in February this year put it, “by simply walking on the pavement we are exposed”.

This might not have been a problem back in 1888 when John Boyd Dunlop produced the first practical pneumatic tyre. His were made of natural rubber, and the tricycle he improved to protect his son from getting a sore bottom as he cycled to school along Belfast’s cobbled streets was hardly travelling at speeds likely to generate tyre dust.