Smells like new car or rather like an old carriage? - Resolution of the decay behavior of odorants in vehicle cabins during usage.

The typical new car smell is not only perceived directly after vehicle delivery. Vehicle interiors maintain their characteristic odors for a period of time during use even though the gas composition of the vehicle interior changes due to external influences. To obtain deeper insights into the odorant composition of a passenger cabin, this study aimed at characterizing the gas phase of two vehicle interiors at defined time intervals after vehicle delivery, and use by a customer in a controlled environment using a targeted odorant analysis. Thereby, the decrease in the general emissions in the cars did not coincide with the decay behavior of the odorants due to the chemical characteristics such as polarity of the odorants. Identification of the odorants in the vehicle interior during use revealed three groups of odor contributors exhibiting different decay behaviors: (i) odorants vaporizing rapidly via elevated temperature; (ii) odorants released by continued diffusion from materials; and (iii) fragrance chemicals of the customer. After 23 weeks of vehicle use, octanal, p-chloro-m-cresol, nonanal, p-tert-butylphenol, γ-nonalactone, and unsaturated aldehydes and ketones represented the most important odorants in the vehicle interior constituting the investigated car odor. The results of a descriptive sensory analysis corresponded with the identified odorants.