A petrol car's exhaust can make more fine particles than its tyres

Tyre wear is a problem for every car. Using it to justify petrol means keeping the exhaust too.

A common argument against electric cars is that EVs are heavier; heavier cars wear their tyres faster; and tyre wear creates particulates, which are a serious pollutant — so EVs are worse for the environment than the petrol cars they replace.

The concern is reasonable. Tyre wear is a real source of pollution, and extra weight can make it worse. But the argument is an own goal rather than a gotcha. Some exhaust pollution that leaves the car as gases subsequently forms particles in the atmosphere, so a petrol car's exhaust can account for more fine-particle pollution than its tyres. In one 2022 study, the petrol car's exhaust-related fine-particle pollution was estimated to exceed that from its tyres by more than ten to one.

Using tyre dust as a reason to stick with petrol means keeping the engine that creates those additional particles — while doing nothing to eliminate tyre pollution. And that's before counting the climate damage from burning the petrol.

What the tyre argument leaves out

All else being equal, a heavier car wears its tyres faster, and batteries usually make an EV heavier than the petrol version of the same car. That's worth taking seriously. An electric badge doesn't let an oversized car off the hook.

But petrol cars shed tyre particles too. The fair comparison is how much extra an EV makes against the pollution it doesn't make, and that's where the tyre-dust argument usually stops counting.

Brakes are the first thing it leaves out. A conventional car stops by squeezing pads against discs, grinding a little of both into dust every time. An EV can do much of its slowing by using its motor as a generator, turning the car's kinetic energy back into charge while the friction brakes mostly sit it out. In research for the UK Department for Transport, Ricardo found that even when an EV was 200 kg heavier, regenerative braking significantly reduced its fine-particle brake emissions. Heavier, in this case, doesn't mean dustier.

The exhaust is the second, and an EV doesn't have one. The particles that form from exhaust gases weren't particles when they left the car. They're still particles when you breathe them.

The same 2022 study also compared the whole car — tyres, brakes, road wear, road dust, and exhaust. Counting secondary particles, it found the petrol and diesel versions producing roughly twice the fine-particle pollution of the electric one. That's a result for those cars under those conditions, not a universal ratio. It still shows how far the answer moves once the comparison looks beyond the tyres.

On climate, the gap is wide

"Worse for the environment" has to include the climate, which means counting the emissions from building the battery, generating the electricity, and producing the petrol. The International Council on Clean Transportation did that accounting in 2025 for cars sold in the European Union. Battery manufacture included, it estimated that a battery electric car produces 73% less greenhouse gas over its life than a petrol car, on the electricity mix Europe is expected to have over the car's working life. The margin shifts with the vehicle and the grid, but it's a big number, and a tyre-only comparison leaves it out.

The supporting calculation below tests an assumed increase in fine-particle pollution against the climate benefit. Under those assumptions, the carbon saving outweighs the additional particulate damage.

Tyre pollution is every car's problem

None of this makes tyre pollution OK. The damage doesn't stop at what people breathe. Rubber worn off tyres washes into rivers and streams, taking its chemistry with it. Researchers have identified 6PPD-quinone — formed from a chemical added to protect tyres — as a cause of coho salmon deaths in urban streams in Washington State, USA. Swapping the engine doesn't change what's in the tyres.

That calls for action on tyre chemistry, on runoff, and on vehicle weight, and it's one more reason to drive less where there's a choice. None of that competes with electrification. It belongs alongside it.

So if weight is the worry, scrutinise heavy cars, whatever's under the bonnet. If toxic tyre chemicals are the worry, deal with them across the whole fleet.

Tyre dust is a reason to build lighter cars and better tyres. It isn't a reason to keep burning petrol.

Supporting note: pricing both sides

Particulates and carbon do different kinds of harm, but both can be priced. The UK's Defra publishes a damage cost for each tonne of pollutant; for road-transport particulates, it varies by location (source). The US EPA's 2023 assessment estimated the social cost of carbon at $190 per tonne of CO₂ for emissions in 2020, using a 2% discount rate (source).

The comparison below is deliberately pessimistic. It uses an assumed lifecycle saving of only 100–160 g CO₂/km (the ICCT's EU estimate is about 170 g CO₂-equivalent/km). It assumes the EV adds 5 mg/km of PM2.5, with no credit for brakes, exhaust, or secondary particles. That is about two and a half times the roughly 2 mg/km of extra PM2.5 that a Paul Scherrer Institute study attributes to an extra 280 kg, counting tyre, brake, and road wear together (source).

Where the car is driven	Carbon benefit (p/km)	Particulate penalty (p/km)	Benefit per £1 of penalty
UK average	1.5–2.3	0.06	£24–38
Inner London	1.5–2.3	0.31	£5–7
Inner London, upper-bound harm	1.5–2.3	1.0	£1.50–2.30

Area type. Inner London is a Defra area type distinct from central London, which Defra values separately (road-transport PM2.5 £648,110/t against £628,530/t).
Price bases differ. Defra's values are in 2025 prices. EPA's $190/t is in 2020 dollars for emissions in 2020, converted here at about £0.76 per dollar. Adjusting it to 2025 prices, and to the later years in which a car bought today emits, would raise it, so the carbon column is understated. The social cost of carbon is also contested, and EPA announced in 2025 that it would overhaul its estimate.
Boundary. The calculation covers airborne fine particles and carbon only. It excludes tyre-related ecological damage, such as 6PPD-quinone in waterways.
Worked example. 5 mg = 0.000000005 t; × £628,530/t ≈ £0.0031, or 0.31p per km.