Sure, but your personal experience could very easily be on the higher end of the distribution. You simply CANT confirm something like that based on personal experience. Either your personal experience lines up with some statistical fact or it doesn’t, either way, without the proper statistical context it’s borderline useless.

Sure, but if the napkin math spits out results orders of magnitude higher than reasonable personal variance then you're still on the way to a decent answer.

FWIW I think the qualitative difference between tire and brake dust is going to mean a lot more than individual variance.