What is Air Change?
The act of rolling down all the windows in a car simultaneously so that the wind replaces all the old air with new.
Air changes are, like oil changes, a routine part of car maintenance especially during long car rides or if the car has a bad smell in it.
"awww duuude... JESUS, that is awful. Shit, man. We need an air change, pronto."
"Dude it's getting mad stuffy in this vehicle, let's get an air change."