Tyres, and brakes, bigger pollution villains than tailpipes: Scientists

We have all witnessed smoky exhausts emanating from cars and wondered about the potential impact on our lungs, but tires have often evaded suspicion. Recent studies show that pollution from tires is 2,000 times worse than car exhaust emissions. But, the common assumption is that tires and brakes do not cause harm.

“Traditionally, it’s been assumed that it’s been big chunks of rubber breaking off tires and it’s just captured in the drains and it’s not a big problem,” said Nick Molden, the founder and CEO of Emissions Analytics told The Washington Post. “What we’ve shown from our testing is that it’s a mixture of bigger particles, but also ultrafine particles."

Particulate matter

As cars travel, small particles separate from tyres, become airborne and can be inhaled deep into the lungs, entering organs via the bloodstream. Larger particles of tyre wear are most likely to be washed into rivers and oceans and are a significant component of plastic pollution.

A 2023 study led by Imperial College London also revealed that 6m tonnes of tyre wear particles are released globally each year. These particles often contain toxic chemicals including polyaromatic hydrocarbons and benzothiazoles, and heavy metals such as zinc and lead.  Some of these substances are carcinogenic and can have devastating impacts on human and animal health.

The wear and tear on tires and brakes have been shown to produce increasingly more particle (both fine and ultra-fine)  pollution, by mass, than car exhaust. The tests also revealed that tyres produce more than 1tn ultrafine particles for each kilometre driven. These particles are smaller than 23 nanometres. However, they are hard to measure and are not regulated by governments at present. Scientists remark that research on tyre wear and its effects continues neglected compared with work on fuel emissions.

The studies also point to increased tyre pollution with battery electric vehicles (BEVs), which are heavier than conventional cars. This increasing weight of cars means more particles are being thrown off by tyres as they wear on the road.

Concerns

The Lancet Commission on Pollution and Health reported in 2019 that pollution remains responsible for approximately 9 million deaths per year, corresponding to one in six deaths worldwide. Additionally, air pollution caused 75% of the total deaths due to pollution.

The need to conduct further research on potential alternatives to synthetic tyres is strongly emphasized by the findings. The issue of tyre pollution is highlighted as a pressing need to address. Furthermore, the proposal suggests implementing regulations aimed at minimizing adverse effects on public health and the environment.

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