This problem gets worse as cars get bigger and heavier, no matter what they are powered by.
Three years ago I got in serious trouble with reader for a post asking Do electric cars generate as much particulate pollution as gas and diesel powered cars? It was based on a study with a simple thesis: tire, brake and road wear is proportional to the weight of vehicles, and electric cars are generally heavier than ICE powered cars. The EV community went insane and called me a shill for the oil companies, but even the study authors came to the same conclusion I did:
Here we are, three years later, and we know even more about how dangerous PM2.5 particulate pollution is. And now, in North America, 69 percent of vehicles sold are heavier "light trucks" or SUVs and pickups. Also now, Robinson Meyer writes in The Atlantic about how if you melt enough Arctic snow to get a gallon of water, "it might contain as many as 53,000 shreds of microplastic."
“Future policy should consequently focus on setting standards for non-exhaust emissions and encouraging weight reduction of all vehicles to significantly reduce PM emissions from traffic.”
Weirdly, the most prevalent form of plastic was from varnish. "And the second-most-common type of microplastic in their samples was rubber, like the kind used to make car tires. Bergmann, with admirable understatement, called these results 'kind of problematic.'"
An article from New Zealand by Michelle Dickenson makes the same point with a different spelling:
When measured by volume of emission, tyre, brake and road wear from vehicles is the second largest contributor to microplastic pollution worldwide. The tyres on your car are made from a complex blend of different materials and chemicals including several types of plastic in addition to their rubber base. As vehicles are driven, the friction, pressure and heat caused from the tyres rubbing against the road and the brakes rubbing against the wheels results in tiny pieces of plastic material known as microplastics to be shed on to the road surface and accumulate as a dust.
She goes on to note "a UK study showed that brake, tyre and road surface wear made up 60 percent of air pollution emissions for particles 2.5 micrometres in diameter, and 73 per cent of the particles that were 10 micrometres in diameter."
Of course, the study is already being used by writers at the Telegraph to conclude that "electric cars share the blame." And I will be attacked again for agreeing that they do. There are light little electric cars and there are big heavy ICE powered cars but they all put out tonnes of this stuff because ultimately a car is a car is a car when it comes to tire wear and road wear. It is purely a function of weight, speed, and the way one drives.
Jonathan Manning of Fleet Management Europe notes that this may become a problem for managing those fleets. The British government is on the case now:
Thérèse Coffey, UK Environment Minister, said: “It is not just fumes from car exhaust pipes that have a detrimental impact on human health but also the tiny particles that are released from their brakes and tyres... Emissions from car exhausts have been decreasing through development of cleaner technologies and there is now a need for the car industry to find innovative ways to address the challenges of air pollution from other sources.”
As more cars become electric, this will be an even bigger issue. Manning suggests that "further ideas to combat non-exhaust emissions include a reduction in the number of vehicle journeys, a shift to other modes of transport, and road charging to cut congestion (stop start traffic creates more brake and tyre PMs)."
Riding my current e-bike hobby horse, I agree with Manning about shifts to other modes. However, he misses another option: promoting smaller, lighter vehicles. Bigger, heavier cars cause all kinds of problems. They consume more fuel, they cause more wear and tear on infrastructure, they take more room to park, they kill more pedestrians both by hitting them and by poisoning the air with exhaust from ICE powered cars, plus particulates from every kind of car, no matter what is pushing it.
Perhaps the CAFE rules regulating fuel economy were too narrow a target; maybe we should be regulating weight instead.