Oh I think most of that is hoopla complaining from the peanut gallery. If there weren't federal mandates, there probably wouldn't be any effort to clean up emissions by the manufacturers because there is no profit or glitter associated with it. We would still have crankcase blow down tubes dropping oil on the ground.
If you ever want to remember what it used to be like, watch an old 60s movie and see the smoke coming out of the tailpipe as well as the drivers nostrils. I would never wish us to go back to that. I have a 1952 Cushman Eagle at home the puts out more pollution through that 1 cylinder aspirated engine than my Cummins, and that was normal.