> Nobody studies this > Even playgrounds are filled with shredded tires, which borders on biohazard. They don't study it, but you're worried about it? I'm cur

> Nobody studies this > Even playgrounds are filled with shredded tires, which borders on biohazard. They don't study it, but you're worried about it? I'm curious to know why these things in particular (brake dust and rubber tires) are on the radar. (And a quick search shows that people do study this.)