Emissions Analytics are an outfit that, as their name implies, analyses emissions. They were in the news six years ago when they showed that emissions from diesels were worse than we thought. They also measured real-world fuel economies and found that they were worse than advertised.

Searching Google News shows that the Guardian picked up the diesel emissions story. It has not yet picked up Emissions Analytics’ latest “worse than we thought” emissions story, or if it has, Google is not aware of that fact.

If that omission surprised a jaundiced climate cynic, his raised eyebrows probably settled back to their accustomed lodgement when they read the new headline from Emissions Analytics:

Gaining traction, losing tread

Pollution from tire wear now 1,850 times worse than exhaust emissions

Emissions Analytics, wisely diversifying into non-exhaust emissions from surface vehicles, found in 2020 that particulate emissions from tyre wear now dwarfs that from (new) engines.

On the one hand, we have the improved filtration unit on diesel cars:

Filters are so good that we have measured that in certain circumstances, when the ambient air is already polluted, a diesel car will tend to extract more particles from the air than it emits.

Not something that I would have predicted.

On a polluted day where ambient concentrations of particles are already high at 50,000 #/cm3, the vehicles remove on average 27,984 particles per second of operation.

[They still pollute on clean-air days.]

At the moment it sounds as if new diesels could be described as mobile air filtration units. As particulates concern me far more than CO2 emissions (which don’t concern me at all in fact), this sounds like a big tick for diesels.

On the other hand, tyre wear is surprisingly high:

Driving a 2011 VW Golf 320kms at high road speeds on the track resulted in a mass loss of 1,844g which equates 5.8g per km. This was 29 times worse than our hypothesis, and partly explained by our deliberate quest for a ‘worst case scenario’. It should be noted that the driving and vehicle payload would be aggressive but legal if conducted on the public highway.

The mass loss from tyres was >1000 times higher than permitted particulate emissions from exhausts:

Nevertheless, it is a very high figure: 5,760mg/km of completely unregulated tyre wear emission versus regulated exhaust emission limits of 4.5mg/km – a factor of over 1,000.

Yea, I hear you cry, but these are big lumps and are not remotely comparable to the smoke coming out of a diesel. You probably have in mind the tracksides after an F1 race. And yes, most of the mass lost falls straight to the ground. But:

…the tyre wear emissions also included a high number of particles down to 10nm, as a result of volatilisation of the tyre material due to heat in the tyres. Therefore, tyres shed material that both leads to microplastics in the watercourse, and ultrafines that compromise air quality.

That was 2020. In 2022, Emissions Analytics have revisited tyre wear.

They note that their previous work had made electric vehicle drivers a little twitchy:

Particularly vocal were the battery electric vehicle (BEV) community, sensitive to any suggestion that the added weight of these vehicles might lead to tire wear emissions that might confound the ‘zero emissions’ tag.  Such was the reaction, the story was translated into over 40 languages worldwide.

Now, in the first study they loaded up a golf and threw it around a race track to measure tyre mass loss – that’s because they were worried that if they drove it normally at low weight they wouldn’t be able to measure the mass loss. But in 2022, they report wear under “normal” conditions:

The headline conclusion we draw now is that, comparing real-world tailpipe particulate mass emissions to tire wear emissions, both in ‘normal’ driving, the latter is actually around 1,850 times greater than the former.  Yes, in normal driving the ratio is almost double the previous figure for aggressive driving.

This seems counterintuitive, but:

Tailpipe emissions are falling over time, as exhaust filters become more efficient and with the prospect of extending the measurement of particulates under the potential future Euro 7 regulation, while tire wear emissions are rising as vehicles become heavier and added power and torque is placed at the driver’s disposal.  On current trends, the ratio may well continue to increase.

Heavier… torque… power…

An image is forming in my mind…

Are they by any chance talking about cars that are carrying a little extra around the middle because they run on battery power?

Anyway, what was it I was saying the other day? A picture paints a thousand words? Here is their provided figure:

Figure by Emissions Analytics at above link

The bar on the left is mass loss from the 2020 Golf study. The next two bars are tyre wear from new or used tyres. The next is airborne (fine particle) emissions from normal driving on new tyres. Then we have the additional wear from +500 kg on the vehicle, then the legal limit for tailpipe particulates, then tailpipe particulates of new diesels. Note the log scale.

Tailpipe emissions are now 1/250th of the legal maximum. Airborne tyre wear on new tyres with normal driving already exceeds the legal tailpipe limit. So it’s not just lumpy bits.

…11% of the mass of tire emissions is smaller than 2.5 microns in diameter (defining the common metric for fine particle dust, PM2.5, which can be airborne). Therefore, the airborne tire emissions are more likely to be around 8 mg/km as shown in the table above – this is still more than 400 times higher than tailpipe emissions.

Emissions Analytics are now working on finding out what lovely toxins are present in these ultrafine particles.

I don’t think electric vehicle drivers are going to want to know. Will the Guardian?

Final point: these guys are engineers, so they probably know what they’re doing. Nevertheless, we don’t want to seize on data that supports our worldview just because it supports our worldview. Other groups need to replicate or refute this study before we start up the Muttley laugh.

But on this data, EVs could be the next CFT.


  1. Sorry Mark. There is a finite chance that I meant CFL. In any case I was referring to those little twisted lightbulbs that were being handed out in vast numbers a few years ago as better than incandescents, only to prove worse.


  2. Well, that *was* an interesting post, Jit. Thanks for sharing the info.

    Perhaps Emissions Analytics could now be working on finding out what amount of particles there are from cars with ‘normal’ braking vs cars with an extra 500 kg mass and regenerative braking.


  3. The RAC seems to have commissioned a report to cast doubt on EVs being worse than diesel or petrol cars when it comes to particulates from tyres and brakes:

    “Do electric vehicles produce more tyre and brake pollution than their petrol and diesel equivalents?”


    “So, in conclusion, electric vehicles already vastly reduce particulate matter from brake wear, and claims of tyre wear contributing 1,000 times the particulate matter pollution of petrol and diesel exhausts are greatly overexaggerated. Real EV fleets are already seeing brake lifespans increased fourfold versus the diesel vehicles they have replaced, and tyre wear that is broadly on par with petrol and diesel cars (unless, as like with any vehicle, the drivers get a bit throttle happy!).

    One final thought on emissions to end with: the UK is set to close its last remaining coal-fired power plants, but even if EVs were 100% powered by coal, it is much easier to fit particulate filters to a small number of very large, static power plants located away from city centres, than it is to fit effective filters to millions of small, mobile petrol and diesel engines running in urban areas.

    The end result is that cities that have embraced EVs have already demonstrably benefitted from reduced pollution and improved air quality, and this trend shall only continue as more EVs switch to drum brakes, new tyres are developed that reduce nanoparticulate pollution even further, and the UK’s grid becomes ever increasingly powered by clean renewable energy.”

    It was written by Dr Euan McTurk, and I am in no position to contradict his findings. It does read to me, though, a little as though he doth protest too much, and a quick internet search reveals that he has skin in the game:

    “Dr Euan McTurk is an expert in electric vehicle charging technology. Based in Inverkeithing, he runs Plug Life Consulting.”


    Liked by 2 people

  4. Mark, I’m prepared to believe that Emissions Analytics’ claims are exaggerated. But McTurk’s commentary does appear to have a few holes in it. If EVs have comparable tyre wear to conventional vehicles, some magic has gone on with the extra 500 kg of mass. It is possible that having four-wheel drive reduces oversteer and consequently wear on front tyres as folk drive around roundabouts. But that should be balanced by reduced wear on free rolling wheels.

    If new materials are going to produce better tyres, then such tyres could also be used on the lighter vehicles.


  5. Hi JIT – Interesting read.

    TV ads – https://dieselemissionclaims.co.uk/ seem to be the latest “ambulance chasers” on diesel cars/vans/etc

    from the site “What is the Diesel Emission SCANDAL?
    Vehicle software cheated air pollution tests by adjusting the engine to emit less and make it look like a low-emissions vehicle, when in fact they were emitting dangerous levels of pollutants.”

    “Vehicle software cheated air pollution tests” !!!


  6. Here’s the thing:

    Tyre emissions are produced by wear on the tyre. Therefore to minimise the emissions wear has to be reduced. Hence the life of the tyre will increase, which suggests that the aim, therefore, would be a tyre which had, if not an infinite life, then one which matched the life expected of the vehicle.

    I can’t see the tyre manufacturers being too happy with this prospect. I suspect it ain’t gonna happen.

    Also, a tyre that minimises wear is likely to produce less grip, which would raise other safety concerns.


  7. Bill, I think you are right in that there will be a tradeoff between durability and grip.

    On the other hand, if you want to change the velocity of a car then the force acting where the rubber meets the road is proportional to the mass of said car, so presumably lighter cars have lower tyre wear, which is what Emissions Analytics is getting at. You could also reduce the scale of velocity changes. As an example, in our dystopian future where every car is tethered to the one in front by some automagical device, then those compression waves we see on motorways could be eliminated. Even replacing roundabouts with crossroads could help by reducing cornering speeds. And of course reducing speed limits would naturally decrease tyre wear. I’m not advocating any of these things because I’m still at the stage where I can’t quite believe the data as have been presented. But I would like it if drivers in our fine city actually stuck to the presently prescribed limit, just to make it easier to cross the road.


  8. “Electric cars should face ‘tyre tax’, says air quality adviser
    Particulates generated by tyre wear are more dangerous to public health than diesel exhaust fumes, a Government expert claims”


    “A ‘tyre tax’ will need to be imposed on electric cars to combat poor air quality in cities, the Government’s top clear air adviser has claimed.

    The chairman of the Government’s independent science advisory group on air pollution said charges for low-emission zones are likely to be replaced with alternative levies as drivers switch to electric vehicles.

    Particles from tyre wear are more dangerous to public health than diesel exhaust fumes, Professor Alastair Lewis said.

    Known as “particulate matter (PM) 2.5”, the amount of air pollution is growing because motorists are driving ever larger vehicles with more substantial tyres.

    Professor Lewis said: “If you compare a modern Mini now with an old Mini, they’re almost unrecognisable in their size.

    “[And] larger, heavier vehicles will generate more particles.”…

    …Professor Lewis, also chairman of the Department for Transport Science Advisory Council, said: “When everybody owns a low emissions vehicle, low emission zones become a toothless control lever to try to manage air pollution.

    “A world where we [have] jam-packed roads full of electric cars [also] isn’t a particularly attractive one… Even if they are electric, [they] will generate lots of particles.”

    “At some point in the future when most of those cars have disappeared, a different form of air pollution control” is likely to be needed, he added.

    “We do have to project forward about how we’re going to manage vehicles in large cities like London in the future when we have a largely electrified fleet of vehicles.”

    Luke Bosdet, an AA spokesman, said he was opposed to the idea of any tax on an electric vehicle which would act as a deterrent to them replacing traditional petrol or diesel vehicles….”


  9. Thanks Mark. I had seen that story but hadn’t got around to posting it here. Seems I was wrong before – someone with the ear of power, and at least a part of the media, have noticed Emissions Analytics’ stuff after all.


  10. “Car tyres produce vastly more particle pollution than exhausts, tests show
    Toxic particles from tyre wear almost 2,000 times worse than from exhausts as weight of cars increases”


    “Almost 2,000 times more particle pollution is produced by tyre wear than is pumped out of the exhausts of modern cars, tests have shown.

    The tyre particles pollute air, water and soil and contain a wide range of toxic organic compounds, including known carcinogens, the analysts say, suggesting tyre pollution could rapidly become a major issue for regulators.

    Air pollution causes millions of early deaths a year globally. The requirement for better filters has meant particle emissions from tailpipes in developed countries are now much lower in new cars, with those in Europe far below the legal limit. However, the increasing weight of cars means more particles are being thrown off by tyres as they wear on the road.”

    Being the Guardian it seeks to downplay the possibility that EVs might be worse than ICE vehicles:

    “…The average weight of all cars has been increasing. But there has been particular debate over whether battery electric vehicles (BEVs), which are heavier than conventional cars and can have greater wheel torque, may lead to more tyre particles being produced. Molden said it would depend on driving style, with gentle EV drivers producing fewer particles than fossil-fuelled cars driven badly, though on average he expected slightly higher tyre particles from BEVs.

    Dr James Tate, at the University of Leeds’ Institute for Transport Studies in the UK, said the tyre test results were credible. “But it is very important to note that BEVs are becoming lighter very fast,” he said. “By 2024-25 we expect BEVs and [fossil-fuelled] city cars will have comparable weights. Only high-end, large BEVs with high capacity batteries will weigh more.”…”.


  11. Mark, it is interesting that the Guardian has noticed this story. I must say I find Dr. Tate’s optimism very hard to believe. The mass differential between the Volvo XC40 ICE/EV as mentioned in “Slips the Green Halo” was given as: ICE 1690 kg and EV 2170 kg. That’s a difference of 480 kg, close to the Emissions Analytics’ used value of 500 kg.

    Of that 480 kg difference, the battery accounts for 350 kg. I would expect that, exempting the battery, the EV would be lighter, but seemingly not.


  12. “Tyre dust: the ‘stealth pollutant’ that’s becoming a huge threat to ocean life”


    “…Tyre-wear particles – a mixture of tyre fragments, including synthetic rubbers, fillers and softeners and road surface particles – are considered by environmental scientists to be one of the most significant sources of microplastics in the ocean.

    Created during acceleration and braking, they are dispersed from road surfaces by rainfall and wind. The main environmental pathway is from road run-off into storm drains, where they empty into rivers and the sea. They are also released from sewage effluent and from the atmosphere, where they can circulate into the ocean and back again. A 2020 study suggested windblown microplastics are an even bigger source of ocean pollution than rivers.

    While it is fiendishly difficult to pin down the exact composition of microplastics, there is plenty of research which points to tyre dust making up a significant portion.

    In 2017, a global model by the International Union for the Conservation of Nature estimated tyre wear to be the second largest source of primary microplastics in the ocean, at 28%, after synthetic textile fibres, at 35%.

    And, in 2019, a report by scientists across Europe concluded abrasion from car tyres was a large source of microplastics and possibly nanoplastics. While there remains a lack of data on risks to the environment and human health, the scientists concluded that if future emissions remain constant or increase “the ecological risks could be widespread within a century”.

    One thing is certain. Tyre-wear particles are ubiquitous. The average tyre loses 4kg over its lifetime. About 6m tonnes of tyre particles are emitted annually and have been found everywhere from the deep sea, to the atmosphere, even in the Arctic and the Antarctic.

    And it is only going to get worse. Electric cars will lower tailpipe emissions, but tyre wear is projected to rise, due to heavier vehicles and torque (the rotational force of a car engine). The UK’s air quality group warned in 2019 that dust from tyres and car brakes would continue to pollute the air, rivers and ultimately the sea, even when the fleet has gone electric….”.

    All potentially true. However, I fear I know where this is going – ICE cars bad because of CO2 emissions. EV cars bad because of tyre emissions. Answer – we all have to give up our cars.


  13. Only slightly O/T, I think:

    “Building works responsible for 18% of UK large particle pollution
    Experts call for tighter regulation as construction accounts for more than 30% of PM10 pollution in London”


    For a long time, construction was overlooked as an air pollution problem by both government and scientists. And then in July 1999 the signal from new equipment at London’s Marylebone Road field laboratory suddenly leapt to more than 10 times its normal value. My team went out to investigate. Larger polluting particles, called PM10, were the main problem and a nearby building refurbishment was the culprit.

    Since then, scientists at Imperial College London have tracked pollution from a whole range of building works, including demolition, construction and street repairs. We also made a three-year study of a road-widening scheme in south-east London and found that residents suffered increased air pollution as the new road was built. This was followed by yet more traffic pollution when the road opened.

    A new report and survey highlights the air pollution from construction, and the lack of policies and action to address it. The latest estimates show that construction is responsible for about 18% of the large particle pollution in the UK and this share is growing. In London it is more than 30%.

    The London mayor has produced guidelines for large construction sites and has set minimum standards for the diesel-powered diggers, generators and machinery, but elsewhere action is patchy.

    Kate Langford, from the charity Impact on Urban Health, said: “We also know that the solutions to improve air quality are out there. It’s time for national government and local authorities to work with the construction industry to implement significant and practical measures to reduce its impact on the air we breathe.”

    The survey, by Impact on Urban Health and the Centre for Low Emission Construction, reveals that more than 90% of people working in the industry recognise the sector’s impact on air pollution. When asked for a way forward, people pointed to better information and clearer, stronger regulation. They felt that widespread adoption of new practices and use of less polluting equipment would only come about through regulation that produced a level playing field between contractors.

    Tighter standards and regulation can be a spur for innovation. Examples include new types of generators to power temporary site buildings but the survey also revealed the impacts from a lack of future government policy. This means no incentive for the industry to adapt and for manufactures to implement new technologies.

    Daniel Marsh from Imperial College London, who led the industry survey said: “The construction industry currently lacks any clear regulatory pathway to reduce machine emissions as there are no standards or dates for new engine limits or signalling from the UK government of future policy direction.”

    I dislike pollution as much as the next person, but I do worry that at this rate we’re not going to be allowed to carry out any useful activities at all, unless we do so in a completely impractical and expensive way.


  14. I would like to see some pollution surveys taken on fine summer days when the wind is southerly and all the cars parked along the roadsides become covered with fine red dust.


  15. The Sahara & Angle & other Grinders should be banned ASAP.

    PS – “he London mayor has produced guidelines for large construction sites and has set minimum standards for the diesel-powered diggers, generators and machinery…..Daniel Marsh from Imperial College London…. clear regulatory pathway to reduce machine emissions as there are no standards or dates for new engine limits”

    The madness just goes on. and what about wood burners this winter in London?


  16. bill – “Wood burners have been banned in most London boroughs for a couple of years”

    ok – never new that, so it’s gas or lecy heating in London?
    thought Wood burners were the in thing a few year ago?


  17. “Delaying MOTs could spark a rise in the number of electric cars on the road with dangerously worn and damaged tyres, report says”

    EVs have a higher MOT failure rate linked to poor tyres than petrols and diesels

    Its primary concern around EVs is their higher proportion of MOT failures than petrols, and the main cause for flunking the test being defective tyres.

    The institute says this is due to electric cars being heavier and having more torque and faster acceleration, which wears rubber quicker.

    The combined impact is faster tyre wear than for comparable petrol or diesel models, it says.

    It = The Institute of the Motor Industry

    The reply?

    However, tyre manufacturers dispute this suggestion, claiming they often last longer than tyres fitted to combustion engine cars. This is due to their different compounds and structures, which are specifically designed around the increased weight of the vehicles.

    Not trying to spot a logical fallacy here, but presumably one could fit these better tyres to ICE vehicles, and then the tyres on the EVs would still wear out faster?


    Liked by 2 people

  18. Jit; fitting tyres designed for heavy EVs to normal cars would probably make the ride very harsh – although they might last well longer!

    Robin; you make a good point – one which is under-appreciated in discussions of ending fossil fuels. One example is sulphur, a key chemical for a myriad of processes and applications. A very large part of the world’s supply comes, very cheaply, from processing crude oil and gas. If that supply is curtailed, we will have to revert to mining with obvious cost and environmental implications.
    Aiui, 10 – 15% of oil and gas production is used as feedstock for a multitude of processes.
    Those seeking to shutdown oil and gas should be challenged as to how all of the products derived from them would be replaced – affordably and at scale.

    Liked by 1 person

  19. Yes, Mike, they should be so challenged. The list is formidable: it includes concrete, steel, plastics, fertiliser, pharmaceuticals, anaesthetics, lubricants, paints, adhesives, tyres and asphalt – all essential to our lives and wellbeing and all of which either require the combustion of fossil fuels or are made from oil derivatives.

    Liked by 1 person

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