Principles for the selection of a sensory panel for the evaluation of car interior materials

Vehicle interior air quality has gained importance since the 1990s. One of the most widely accepted methods to measure emissions in this respect is the VDA 270—Determination of the odor characteristics of trim materials in motor vehicles. So far, it describes the odor evaluation procedure, but not the selection of the sensory panel. Therefore, the aim of this study was to investigate principles that might be applicable for the selection of a VDA 270 panel. Based on this work, a dedicated three-step approach is detailed to aid in selecting a panel. It comprises of an odor threshold determination, a hedonic tone evaluation and a reproducibility test. In addition, a “Screening 12” test was performed to verify the assessors' olfactory function. The selection was not specific to gender and the age of the candidates ranged from 19 to 55 years. Out of 26 volunteers, only 10 were able to meet all of the self-developed criteria for the panel. With this approach, the individual ratings of the selected panelists did not deviate by more than two odor grades for the selected polyolefin samples considering the VDA 270 scale. Practical Applications: A meaningful comparison and interpretation of VDA 270 data requires objective test results. This is challenging as the VDA 270 scale is, at least partly, subjective and only a small minimum number of panelists is defined. The terminology used in the 6-point scale itself was investigated in order to deduce potential tests for the panel selection procedure. Relevant international standards that are linked to the topic of interior air quality were screened to compare related guidelines for the panel selection. The implementation of a selection procedure needs to consider practical aspects in an industrial environment, too. Therefore, feasibility and quality issues are discussed to overcome some of those problems. As fundamental questions of sensory testing are involved this work might be relevant for other olfactory screening applications in an industrial setup. However, where hedonic tone measurements are required only consumer panels can provide reliable information.