It doesn't matter. What matters:
(0) Being happy is good
(1) Pollution makes people unhappy
(2) Personal mobility makes people happy
(3) Freedom to choose makes people happy
What matters is whether and at what point the unhappiness caused by a free choice outweigh the happiness caused by free choice.
The obvious extreme hypothetical example would be vehicle A and vehicle B that differ only in that A produces more pollution than B. Should A be allowed to be sold?
If not, what difference must there be between A and B to allow A to be sold?
Just out of curiousity, did you ever have days where it hurt to breathe due to smog? Do you remember hearing the death counts on the news? No PE classes at school, some airports would close, 'temperature inversion' was like a tornado warning?
People who think air pollution is the critical issue of our times in the USA should have been alive back then. GHG are the issue today, not air quality. Air quality continues to improve. Seriously. With virtually no EVs on the road.