poop
The belt is burning up and wind is pushing the smell through the air conditioning.
burning rubber
That smell is probably your clutch burning out.
The clutch is slipping and needs replaced.
Because of the rubber. The rubber can smell a little weird.
Mothballs could create some of the odor.
Bad electrical fixtures.
Acetone.
most likely the rubber or plastic wiring insulation.
Most air conditioning systems on the market today do not get rid of unwanted odors, instead many absorb the smell. However, if this becomes an issue there are many inexpensive ways to fix this problem. Regular cleaning of the air conditioning unit is one way to prevent odors from happening.
when changing the oil sometimes oil can be spilled on the engine block. as your engine heats up it causes this smell. it is completely normal
a burnt rubber ball in the cardorater