Each smell is graded on a scale from one (“odorless”) to six (“unbearable”). Only materials such as glass, ceramics, and metals are rated odorless since they are classed as core components, but other materials need to be rated below four (“irritating”) to pass Audi’s strict smell test. Audi even tests production cars to make sure they still smell factory fresh after they leave the showroom.
“It can be the case that a supplier after a certain time employs a slightly different material composition or uses another manufacturing process, and suddenly we have odors in the vehicle that are undesirable,” explained Lussmann-Geiger. So there you have it. Now you know why your Audi A8 interior smells so good.