Tyre pollution might be the next major cleanup for automobiles – because of significant amounts of particulate matter (PM) emitted into the environment 

United Kingdom 

While much progress has been made on the obvious source of pollution from cars – tailpipe emissions – there could be another major factor that has been overlooked: Tyres. 

UK-based scientific analysis firm Emissions Analytics released a study in 2020 that is now gaining lots of traction, and revised findings show that pollution from tyre wear could be as much as 1,850 times worse than that of exhaust emissions. 

The company’s research showed that a car driven over 340km at high road speeds could see as much as 1.8kg of material loss from its tyres. Given that this material is abraded and becomes superfine particulate matter (PM), this is particularly concerning. 

As mentioned in our previous story about air pollution, superfine particulate matter is measured in the nanometres, and at this size it can enter the human bloodstream via the lungs, and affect overall health severely.

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PM pollution is something Singaporeans are familiar with: The haze is considered a form of fine particulate air pollution. PMs is essentially smog, when it is airborne, and when it pollutes the earth or water, can also become a source of microplastics. The study also shows that tyre wear can be even more when driving aggressively, or when driving heavier vehicles such as electric vehicles (EVs). 

Emissions Analytics tested a variety of cars and tyres. It used extremely sensitive weighing equipment, as well as pollution measurement devices trailing the test cars, to find out what sort of pollution was being emitted. Used tyres produced 36mg/km, compared to 0.02mg/km from the exhaust pipes, while aggressive driving on new tyres saw a huge amount of pollution – 5,760mg/km. 

Emissions Analytics also has released information on tyre pollution itself, and it says that as much as 300,000 tonnes of rubber pollution is released in the USA and Europe each year. 

Tyre composition is ‘opaque’, that is, what exactly goes into making tyres is known only to the tyre manufacturers themselves, a result of performance and price demands of a very competitive market. Besides latex rubber, there’s also carbon black, organic compounds, esters, and many other additives. 

Emissions Analytics representative Nick Molden told the Guardian newspaper: “There are hundreds and hundreds of chemicals, many of which are carcinogenic. When you multiply it by the total wear rates, you get to some very staggering figures as to what’s being released.”

Earlier this year, tyre pollution was firmly linked to mass deaths of salmon in the USA and Australia, hinting at the fact that tyre pollution can not only enter the soil and earth, but also groundwater and bodies of water. 

Another source of concern is brake dust, the byproduct of the wearing down of brake discs and pads, and it is known to be toxic. Luckily, with more hybrids and EVs on the roads, the amount of brake dust is less of a concern than tyre particulates/pollution. 

What can you do to reduce tyre pollution? Emissions Analytics give the obvious steps: Drive less, drive more efficiently and gently, drive at lower speeds, and do not corner aggressively. Other steps beyond consumers are improving the road conditions, and reducing vehicle weight.