Dust from car brakes and tyres will still pollute city air even when the vehicle fleet has gone all-electric, a report has warned.
Fragments of microplastics from tyres, road surfaces and brakes will also flow into rivers, and ultimately into the sea, government advisers say.
Ministers say they want to pass standards to improve tyres and brakes.
But critics say they need to go further by developing policies to lure people out of private cars.
The government’s Air Quality Expert Group said particles from brake wear, tyre wear and road surface wear currently constitute well over half of particle pollution from road transport.
They warn: “No legislation is currently in place specifically to limit or reduce [these] particles.
“So while legislation has driven down emissions of particles from exhausts, the non-exhaust proportion of road traffic emissions has increased.”
They say the percentage of pollutants will get proportionally higher as vehicle exhausts are cleaned up more.
Environment Minister Thérèse Coffey said : “The documents published today make clear that 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”.
Mike Hawes, chief executive of the Society of Motor Manufacturers and Traders, said: “The industry is committed to improving air quality and has already all but eliminated particulate matter from tailpipe emissions.
“Brake, tyre and road wear is a recognised challenge as emissions from these sources are not easy to measure.”
The document chimes with a recent report warning that electric cars won’t offer a complete solution to mobility.
It said even self-driving electric cars would produce pollution and congest the roads.
The key was to reduce the use of cars by getting people on to less-polluting forms of transport, said Prof Jillian Anable, one of the authors of the report.
She said: “For many years ministers have adopted the principle of trying to meet demand by increasing road space. They need to reduce demand instead.”
The UK transport department said it was spending £6bn on buses, walking and cycling – and £50bn on roads.