Disc Brakes: air pollution
Air Pollution by Disc Brakes causes 20% of the total emissions by a standard car and the pollution (ultra-fine dust) is more toxic for humans than exhaust fumes.
"Vehicle tailpipe emissions are going down, but the emissions from disc brakes will remain to some extent, even if you drive an electric car," Weber said. "Therefore, this kind of process will continue to play out in the future and will be an important consideration when we look at the health effects of particulate matter." (Phys.org)