> It really looks different from what you see from cars. It's like a haze.. sorta like fog, but more gray. But it's very uniform and everywhere.

Cars can cause it too. Long time Los Angeles residents can attest to that. The fuel efficiency and smog requirements in recent decades have made it much less likely though[1].

1: https://www.google.com/search?q=la+smog&tbm=isch#tbm=isch&q=...