Rubber tyres, that soft interface between a bumpy road and our tired bodies, are significant polluters. It’s hard to imagine their production to be environmentally friendly or their disposal to be under control. But worse, while in use, tyres produce microplastic particles that jeopardise all animal life, including our own.
In its 4 December 2020 issue, Science Magazine reports that a chemical substance used to protect tyres from ozone swiftly kills coho salmon when rain water trickles from roads into their spawning grounds.
In September 2019, the San Francisco Chronicle reported that 7 trillion tiny pieces of plastic wash from city streets into San Francisco Bay each year. Nearly half of this pollution consists of black rubbery fragments that the study’s authors believe are from worn out tyres. In fact, tyre wear is the most important single source of microplastics in the natural environment, with an estimated 6 million tonnes, or 0.81kg per person, being produced each year and worldwide.
Tyre wear— together with brake and road wear— contribute to air pollution as well by producing microparticles, just as diesel motors do. In fact, they produce between 50 and 75% of the infamous PM10 microparticles we usually associate with diesel motor exhaust.
Among other factors, and just like fuel consumption, tyre wear depends on the weight of a vehicle. Research from the Dutch Institute of Public Health has shown that the amount of microplastics produced by tyres is about 10 times higher for passenger cars as that for mopeds. There is no data for bicycles, but no doubt that the amount must be even lower.
While governments around the world have taken measures to reduce particle emissions from engines, tyre wear has remained totally overlooked despite constituting a much greater threat to biodiversity and our own health. Atop of road transport being responsible for 21% of the EU’s CO2-emissions, tyre wear makes for yet another crucial reason we urgently need to phase out of cars and towards greener modes of transportation!