Tire wear can be 1,000 times worse polluter than car exhaust

EMISSIONS ANALYTICS, the leading independent global testing and data specialist for the scientific measurement of real-world emissions and fuel efficiency for passenger and commercial vehicles and non-road mobile machinery, said that “pollution from tire wear can be 1,000 times worse than what comes out of a car’s exhaust.”

The United Kingdom-headquartered company said that harmful particle matter from tires — and also brakes — should be regarded as a very serious and growing environmental problem. It is made worse by the “increasing popularity of large, heavy vehicles such as SUVs, and growing demand for electric vehicles, which are heavier than standard cars because of their batteries.”

Emissions Analytics further contends that vehicle tire wear pollution is completely unregulated, unlike exhaust emissions which have been rapidly reduced by car makers, thanks to the pressure placed on them by emissions standards around the world.

The concern thus is on non-exhaust emissions (NEEs) — particles released into the air from brake wear, tire wear, road surface wear and resuspension of road dust during on-road vehicle usage. The company observed that no legislation is in place to limit or reduce NEEs, but they cause a great deal of concern for air quality.

NEEs are currently believed to constitute the majority of primary particulate matter from road transport, 60% of PM2.5 and 73% 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 NEEs should immediately be recognized as a source of ambient concentrations of airborne particulate matter, even for vehicles with zero exhaust emissions of particles such as EVs.

Emissions Analytics performed some initial tire-wear testing. Using a popular family hatchback running on brand-new, correctly inflated tires, the company discovered that the car emitted 5.8 grams of particles per kilometer.

Compared with regulated exhaust emission limits of 4.5 milligrams per kilometer, the completely unregulated tire wear emission is higher by a factor of over 1,000. Emissions Analytics notes that this could be even higher if the vehicle had tires which were underinflated, or the road surfaces used for the test were rougher, or the tires used were from a budget range — all very recognizable scenarios in real world motoring.

Senior researcher at Emissions Analytics Richard Lofthouse said: “It’s time to consider not just what comes out of a car’s exhaust pipe but particle pollution from tire and brake wear. Our initial tests reveal that there can be a shocking amount of particle pollution from tires — 1,000 times worse than emissions from a car’s exhaust.”

Added company CEO Nick Molden: “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 tires is one way to reduce these NEEs and to always have tires 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 tires is not for us to say — but change has to come.”