We have travelled past coal fired power plants in Zimbabwe and South Africa that are belching massive clouds of brown smoke. The smoke hangs low and is visible for dozens of miles as we pass by.
It must have been like that in the US during the 1950’s. I can recall that when the first news stories in the 60’s about power plants damaging the trees downwind that the power generating industry responded by building taller smoke stacks to better disperse the smoke. As we know now that was not the answer.
I do not believe that Americans of any political persuasion would currently accept living in the brown haze I have seen. Say all you want to about coal plant regulations. It is easy to criticize when you are breathing clean air to talk about it.