You still haven't offered one shred of actual evidence from a 70's or 80's era 2 stroke moped engine's actual output of pollution vs the output of a typical car found on the road.
In ppm... or anything else.
Or versus its gas mileage.
Or versus its miles traveled.
Or on a per person basis.. (considering 2 people or more per car)
Or considered that very few people own ONLY a moped (most own cars/trucks also)
And you still haven't named the 3 or 4 categories of pollutants put out by the 2 types of engines.
By the way... I have not disagreed with you yet.
But I will now.
You said a cars can carry 8 times as many people as a moped.
What car carries 8 people ?
And I want to start my real disagreement with this fact.
Most mopeds get no better than 80mpg.
Any economy car gets 40 mpg.
So... 2 people in an economy car are effectively getting IDENTICAL gas mileage to a moped.
Understand that?... they are both using gasoline at the same rate per person.
Annnnnnd... the cars higher average speed pays off with the benefit of half the time spent in transit.
The whole "efficiency" situation is not as simple as you seem to think.