Nothing like the cars from the '70s or earlier. Every once in a while driving, I'll pass a restored car from the 60s or 70s going the other way, and can smell the exhaust for about a mile. And that's one car.

Nothing like a two-stroke moped. Those are the worst by far.

That reminds me of the Wartburg [1]. Our neighbor had one where I grew up, and us kids used to call it the "Atom bomb" due to the mushroom cloud of blue smoke it generated when it started up or pulled in.

[1] https://en.wikipedia.org/wiki/Wartburg_353

Between those, the Trabants and the Serenas a morning in the former Eastblock would always look like fog. Heavy, worn out diesel engines of trucks and buses didn't help either.

The situation is now much better than when I lived there but even so Poland still has a huge smog problem.

Yep. That was the reason I chose a four-stroke myself. Also easier maintenance and less problems starting in bad weather.

The worst people are those who drive two-stroke mopeds over the bridge bike paths in NYC.

My car (gasoline Euro-5) smells only when the engine is cold. Once it warms up, I can't smell anything. I guess it probably means that the catalytic converter is working as expected (it needs to be hot enough to work properly).

One funny thing I've realized is that I like the smell of coal fires. It must have been horrible back when cities were choking on it, but coal is so completely phased out now that when I occasionally do smell coal smoke from a domestic fire or say a steam engine I really like it.

s/bad/good/g