In almost every older car (about 10-20 years) there is always a certain smell. By this I mean now not the classics like dog or cigarette, but simply the car smell, which even cars have never been smoked in and in which a dog has never been driven. In summer in heat the smell comes most intensely when you enter fresh. Are these any material evaporations that become active only after years? The interior filter can actually auc h not be when the smell is the most intense in the car. I am not concerned with the elimination of the smell, I want to understand where it comes from. Can someone explain the smell technically?