What is the old car exhaust smell?

The dose is what makes a poison. Making laws banning things is kind of a dick move. There are tons of people who'd be absolutely fucked if the state made their beater car out right illegal. The richest country in the world where something like 60% of people have less than like $500 in savings. Things like cash for clunkers helped a lot. There are fewer and fewer old cars on the road each year. You hardly see anything with a carburetor and pre-cats anymore. The comparatively small amount of "poison" they exhaust is miniscule compared to oh so many other things. I suggest you redirect your anger to something like single use plastic, fake recycling programs, and illegal dumping. Any one of those effects you magnitudes more than <1% of cars on the road being pre-cat carbureted engines.