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've needed my inhaler way less since the ULEZ came in.

Visiting London used to mean blowing your nose to black snot for a week afterwards, these days living in London it's pretty good.