As car engines are getting cleaner and tyres wider and softer, pollution from tyres is already as high as pollution from engines. But:

Levels of nitrogen oxides, byproducts of burning gasoline and diesel that cause smog, asthma and other ailments, have fallen sharply as electric vehicle ownership has risen.

But there is still a problem where the rubber meets the road. Oslo’s air has unhealthy levels of microscopic particles generated partly by the abrasion of tires and asphalt. Electric vehicles, which account for about one-third of the registered vehicles in the city but a higher proportion of traffic, may even aggravate that problem.

“They’re really a lot heavier than internal combustion engine cars, and that means that they are causing more abrasion,” said Mr. Wolf, who, like many Oslo residents, prefers to get around by bicycle.