There are also many studies demonstrating the negative health effects of living within a similar radius to a highway or any other major road, which encompasses

There are also many studies demonstrating the negative health effects of living within a similar radius to a highway or any other major road, which encompasses most land in every major city. It's not like car emissions are perfectly clean because of unleaded gas and catalytic converters. They're cleaner than before the introduction of those things, but any emissions still carry health impacts so why are we demonizing the comparatively tiny GA fleet here? The only escape from any form of human pollution is to live far out in a rural area, but I'm willing to bet you've made a tradeoff of the convenience and economical benefits of being near a city/some town in exchange for exposure to some degree of pollution.