Every time a vehicle brakes, accelerates or turns a corner, the tyres wear down through friction and tiny particles become airborne. This produces 500,000 tonnes of tyre particles annually in Europe alone. Globally, it is estimated tyre wear accounts for nearly half of road transport particulate emissions. It is also the second-largest microplastic pollutant in the oceans after single-use plastic.
https://www.theguardian.com/environment/2020/sep/17/device-to-curb-microplastic-emissions-wins-james-dyson-award