Findings from a recently published study have shown that our car tyres produce more particle pollution than exhaust fumes.
The study, conducted by Emissions Analytics, a leading independent global testing company, revealed that almost 2 000 times more particle pollution is produced by tyre wear than is pumped out of the exhausts of modern cars.
To measure tyre wear emissions, the company used high-precision scales to weigh all four wheels, both tyres and rims together, over a minimum distance of a thousand miles (1 600km) on real roads.
Nick Molden, a researcher at Emissions Analytics, said: “Tyres are rapidly eclipsing the tailpipe as a major source of emissions from vehicles. Tailpipes are now so clean that, if you were starting afresh, you would not even bother regulating them.”
“We came to a bewildering amount of material being released into the environment, over 300 000 tons of tyre rubber in the UK and US, just from cars and vans every year,” he added.
The smaller the particles get, the more volatile and difficult to measure they become. Growing scientific evidence suggests that these ultra-fine particles enter the human bloodstream and lungs, and cross into the brain more easily than larger particles.
“The Guardian” reported last year that air pollution causes millions of early deaths a year globally.
The regulations for better filters have meant that particle emissions from exhausts in developed countries are now much lower in new cars, with those in Europe far below the legal limit. The increasing weight of cars means more particles are being thrown off by tyres as they wear on the road.
Internationally, there are currently no regulations on the wear rate of tyres and extraordinarily little regulation on the chemicals they contain. Emissions Analytics has determined the chemicals present in 250 distinct types of tyres, which are usually made from synthetic rubber, are derived primarily from crude oil.
“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 is being released,” said Molden.
The wear rate of different tyre brands varied substantially, and the toxic chemical content varied, even more, he said, showing low-cost changes were feasible to cut their environmental impact.
“You could do a lot by eliminating the most toxic tyres,” he said. “It is not about stopping people driving or having to invent completely different new tyres. If you could eliminate the worst half and bring them in line with the best in class, you can make a massive difference. But now, there is no regulatory tool, there is no surveillance.”