I'm not sure, but I suspect that modeds do pollute a lot. Two cycle engines are vry dirty and ineficient.
Here is the deal.
Mopeds go farther on a gallon of gas so they use less non-renewable recources.
The polution from a moped is mostly unburned hydrocarbons from incomplete combustion.
Mopeds take up less space so they ease congestion.
Mopeds are dangerous to the rider. You can mitigate this with defensive driving.
Mopeds are not good in bad weather.
Mopeds are more fun to ride than a fat girl!
Cars use a lot of gas, except for the new hybrids.
Cars produce large quantities of carbon dioxide, (greenhouse gas).
Cars take up a lot of space.
Cars are dangerous to others, depending on the driver.
I'd rather ride a fat girl.
Everyone has thier opinions and "hot buttons" and you will have a real hard time changing thier minds.
The best you can hope for is that it will start some people thinking about getting a ped.