One of my neighbours has kids who love to play on a go-kart and wake me up at 6am on a Saturday morning
As long as it’s not ... extremely obnoxious (playing extremely loud music and refusing to turn it down)
I'm not sure I see a meaningful difference here. And why is it you don't see polluting the air to be a direct health risk? If you wanted to ride a bike or walk instead of drive everywhere, I'm sure you'd see how car exhaust doesn't just disappear immediately.