Anecdata I was living very close to a busy highway, and my young daughter was wheazing when she had a cold, we had to give her medicine via a nebulizer. When we moved out to the country more, far away from any major roads, these issues all disappeared within a couple months.
I'd like to imagine the stunned scientist is a scientist from another field, they show some medical findings to a guy who looks at snail butts all day and he's the one "stunned" by the findings
Tyre, no, but regen braking almost eliminates brake particles at the speeds I drive in London. But mostly I take the train. Unfortunately the highest I measured on my particulate sensor is not near the roads, but in the tube.
Visiting London used to mean blowing your nose to black snot for a week afterwards, these days living in London it's pretty good.