The Society of Motor Manufacturers and Traders (SMMT) has hit back at new research from Emissions Analytics that shows pollution from tyre wear can be up to 1,000 times worse than vehicle tailpipe emissions.
Exhaust emissions have been rapidly reduced by car makers as a result of the pressure placed on them by European emissions standards. New cars now emit very little in the way of particulate matter but there is growing concern around ‘non-exhaust emissions’.
Richard Lofthouse, senior researcher at Emissions Analytics, said the company’s initial tests reveal particle pollution from tyres that was 1,000 times worse than emissions from a car’s exhaust.
Lofthouse said that while exhaust emissions have been regulated for years, tyre wear is totally unregulated, but the increased growth of heavier SUVs and battery-powered electric cars will make non-exhaust emissions “a very serious problem”.
Mike Hawes, SMMT chief executive, said: “Making sensationalist claims based on testing of a single vehicle is not credible and, quite frankly, irresponsible.
“Emissions from safety-critical brakes, tyres and road surfaces are very difficult to measure, and a challenge already taken seriously by the sector, governments and a UN global group, which are working together to better understand, and agree, how to test them in a scientific way.
“Further, there is no evidence to suggest that electric vehicles have a propensity to emit more non-exhaust particulates than any other – in fact, their regenerative braking systems mean wear is significantly reduced.”
NEEs are currently believed to constitute the majority of primary particulate matter from road transport, 60% percent of PM2.5 and 73% percent of PM10 – and in its 2019 report ‘Non-Exhaust Emissions from Road Traffic’ by the UK Government’s Air Quality Expert Group (AQEG), it recommended that NEE are immediately recognised as a source of ambient concentrations of airborne particulate matter, even for vehicles with zero exhaust emissions of particles – such as EVs.
To understand the scale of the problem, Emissions Analytics performed some initial tyre wear testing. Using a popular family hatchback running on brand new, correctly inflated tyres, it found that the car emitted 5.8g/km of particles.
Compared with regulated exhaust emission limits of 4.5mg/km, the tyre wear emission is higher by a factor of more than 1,000.
Emissions Analytics notes that this could be even higher if the vehicle had tyres which were underinflated, or the road surfaces used for the test were rougher, or the tyres used were from a budget range – all very recognisable scenarios in ‘real world’ motoring.
Nick Molden, Emissions Analytics chief executive, said: “The challenge to the industry and regulators is an almost complete black hole of consumer information, undone by frankly out of date regulations still preoccupied with exhaust emissions. In the short term, fitting higher quality tyres is one way to reduce these NEEs and to always have tyres inflated to the correct level.
“Ultimately, though, the car industry may have to find ways to reduce vehicle weight too. What is without doubt on the horizon is much-needed regulation to combat this problem. Whether that leads to specific types of low emission, harder wearing tyres is not for us to say – but change has to come.”