WHEN THE WORLD fully transitions from cars that run on dinosaur juice to cars that run on electricity, humanity will have eliminated a major source of planet-warming carbon dioxide and a major threat to human health—air pollution kills nearly 550,000 children under age 5 each year.
But a hidden environmental threat from cars will persist, and perhaps get worse as more of the world enters the middle class, putting more vehicles on the road: the microplastics that shear off cars’ tires and brakes.