Tire Wear Pollution 1,000 Times Worse Than Tailpipes

Pollution from tire wear can be up to 1,000 worse than tail-pipe emissions and EV powertrains is adding to the problem.

That’s the claim by independent vehicle testing specialist Emissions Analytics which says harmful particle matter from tires brake pads and linings is a very serious and growing environmental problem. The issue is also being exacerbated by the increasing popularity of large, heavy vehicles, such as SUVs, and growing demand for EVs which are heavier than standard cars because of their batteries.

It points out that only tail-pipe emissions are subject to regulation, emissions that have been rapidly reduced by carmakers thanks to the pressure placed on them by European emissions standards. However, these efficiencies now see the bulk of a modern vehicle’s emissions coming from tire and brake wear.

Non-exhaust emissions (NEE) are particles released into the air from brake wear, tire wear, road surface wear and re-suspension of road dust during on-road vehicle use. The outfit says no legislation is in place to limit or reduce NEE yet 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 NEE are immediately recognized 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 says it performed some initial tire wear testing. Using a popular family hatchback running on brand new, correctly inflated tires, we found that the car emitted 5.8 g/km of particles. 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. The organization notes that this could be even higher if the vehicle had tires which were under-inflated 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.

Richard Lofthouse, senior Researcher at Emissions Analytics said: “What is even more frightening is that while exhaust emissions have been tightly regulated for many years, tire wear is totally unregulated – and with the increasing growth in sales of heavier SUVs and battery-powered electric cars, non-exhaust emissions (NEE) are a very serious problem.”

Nick Molden, CEO of Emissions Analytics added: “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.”

— Paul Myles is a seasoned automotive journalist based in London. Follow him on Twitter @Paulmyles_


7 comments

  1. Avatar Jussi Sauna-aho 9th March 2020 @ 8:25 pm

    Tire wear and breaking are important and are becoming more important, because the population and traffic are concentrating more and more into cities from countryside. In countryside the traffic flow is staple, speed variation and breaking are rare but in cities braking is continuous. The “stop and go phenomenon” causes a lot of tire, brake wear and road wear and small NEEs.

    The following study data could be valuable and interesting – the amount of tire wear particles as a function of the following factors: vehicle type, vehicle mass, deceleration distance to speed 0 (or to speed 10, 20, etc, km/h from target speed (80, 60 40 k m/h). With this kind of data we could determine the amount of tire wear particles (brake wear particles and road wear particles, too) for different kind of vehicles in different kind of traffic conditions.
    My question is: Is it possible to get your study report(s). I understand that this is an area we may work more and perhaps together.

      • TU-Editor TU-Editor 10th March 2020 @ 10:10 am

        I take your point although it’s worth pointing out that, while it’s only an anecdotal observation, roadside debris in busy cities is clearly evident on the edges and gutters of roads. It also gets washed away by frequent rain showers in Northern Europe and the risk is that these micro plastics enter the water system and, consequently, the sea food chain with unknown health issues to ourselves.

  2. Avatar Si Won Hwang 10th March 2020 @ 1:25 am

    It is very important research report to me as a professor at the Dept. of Mechanical Engineering, SUNY KOREA, In Cheon, Korea. I would want to make a course for my students this coming semester. I would want to translate in Korean language the ‘Tire Wear Pollution 1,000 Times Worse Than Tailpipes’.

  3. Avatar Frank Kroon 10th March 2020 @ 9:54 am

    A typical tire weight is around 4 – 6 kilo. According to this statement, a car would lose 5.8 kilo of weight per 1,000 kilometer. I could run some more maths on this but this claim doesn’t make any sense. I would have no tires left at all on my car in a few weeks. In reality they last some 60K kilometers. And then I have lost just a few millimeters of the outside material, with most of the tire still there.

    But taking this a little further: in the Netherlands cars in total drive 100 Billion kilometers a year. With an emission of 5.8 g/km – the dutch fleet would emit 580 Million kilo or 580,000 tonnes of material. Where are they hiding all this material?

  4. Avatar Eric Verhulst 10th March 2020 @ 7:21 pm

    Unbelievable. The writer of this article makes an error of a factor 1,000 and only the 5th comment from Frank Kroon notices it. In the meantime, the false rumor is spread. In the meantime, I agree cars (like SUVs and many BEVs) are way too heavy and take up too much space. Energy consumption is proportional to the weight. Friction as well.

    • TU-Editor TU-Editor 11th March 2020 @ 6:50 am

      The writer is only accurately reporting the study’s findings in specific testing scenarios which, I am sure you will agree, does not include all situations.

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