These sorts of pollution are largely caused by building massive amounts of car infrastructure and not building transit instead. The health effects extend beyond the direct pollution exposure to lifestyle things such as inactivity social isolation, and more.

And yet the US largely bans healthier, denser living by law. Density grows out of less dense areas, and those less dense areas nearly all have strict density caps preventing density, as well as road infrastructure designed to never allow density. And the dense areas of the country, which already show healthier lives for people and longer lifespans, have similarly tight caps on building more density

All this is to say that we have made a political choice as a society and are now reaping what we have sown. However we can choose something better for the future.