Do you know car tyres produce more particle pollution than exhausts?

In a study by Emission Analytics, a leading independent global testing company it was 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 tire wear mass emissions, Emissions Analytics used high-precision scales to weigh all four wheels – tires and rims together, without detaching – over at least 1,000 miles on real roads.  

This is coupled with a proprietary sampling system that collects particles at a fixed point immediately behind each tire, which is, via a sample line, drawn into a real-time detector measuring the size of distribution of particles by mass and number. 

Typically, this measures particles from 10 microns down to 6 nanometres.  This combination allows the real-time signal to be calibrated to the mass loss, and, by using the size distribution, the proportion of the particles likely to be suspended in the air can be estimated. 

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 for pollutants that, if you were starting out afresh, you wouldn’t even bother regulating them.”

“We came to a bewildering amount of material being released into the environment – 300,000 tonnes 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 harder to measure repeatably they become.  Growing scientific evidence suggests that these ultrafine particles more easily enter the human bloodstream and lungs, and cross into the brain.