[CyberWasp]

Have a close look at your headlights and windscreen and you will see the evidence of the extremely hot microscopic brake dust that hits your car.

All you can do is keep a larger distance to the car in front, especially the ones that ride their brakes down the slightest of hills. What are those things called to avoid this, yes gears.

Can't tell you if it finds its way into your lungs or is bad for you, but it does get on your car and if vain like me, I will try to minimise it.