> For the study, published in Particle and Fibre Toxicology, researchers grew human lung cells in a lab and exposed them to dust from car brakes and from diesel tailpipes, finding that brake dust caused greater injury to the cells.
That seems like an overly narrow way of defining harm.
E.g. what if brake dust is bad for your lungs but your lungs can repair the damage, but diesel fumes are harmful to your brain and the damage is permanent?
I'm not saying that's the case (I have no idea), just that studying lung cells in a lab doesn't tell you anything about the full-body harmful effects.
That seems like an overly narrow way of defining harm.
E.g. what if brake dust is bad for your lungs but your lungs can repair the damage, but diesel fumes are harmful to your brain and the damage is permanent?
I'm not saying that's the case (I have no idea), just that studying lung cells in a lab doesn't tell you anything about the full-body harmful effects.