Ford, Toyota, General Motors and others have trained teams of sniffers who evaluate smells and then reject or reformulate any unpleasant materials. It's a daunting task: Car interiors are made of dozens of different odorous materials - plastics, foams, rubbers, carpet, fabric, leather.
— From Love the new-car smell? Automakers don't. at The Washington Post. The article includes some interesting details about cultural differences in smell preference. Many thanks to March for the link!