Indeed. I understand my parent to be saying that since we allow this other thing that's more harmful, we shouldn't be so concerned, that there's an inconsistenc

Indeed. I understand my parent to be saying that since we allow this other thing that's more harmful, we shouldn't be so concerned, that there's an inconsistency. My point is that we do make the attempt to reduce the harm of vehicle exhaust, that we do attempt to limit harm (and nuisances, for that matter). We certainly can discuss whether those protections are adequate. And we very well may disagree on the level of protection necessary. That doesn't mean we should dismiss protections on one because we think protections on another aren't sufficient.