Odor emissions from key vehicle interior components using combinatorial experimental design

This study used a combinatorial approach with vehicle interior components to bridge perceived odors and volatile organic compound (VOC) emissions, capturing real-world interactions like odor masking. A dynamic source-tracing experimental design sequentially introduced five key interior components (seats, carpets, headliners, door panels, and weatherstrips) into controlled chambers according to their odor intensity. Odor profiles and VOC emissions were characterized via panel evaluations, odor activity value (OAV) analysis, and chemical mass balance (CMB) modeling. Results showed that seats and door panels were the dominant contributors shaping the overall odor type. Adding a seat increased the average odor intensity (OI) by 0.6 to 1.1 and odor similarity by 28 % to 40 %. The addition of a door panel increased the similarity from 12 % to 48 %. In contrast, weatherstrips did not significantly influence the odor character, their distinct smell was masked by the other components, even though their presence boosted overall odor intensity. OAV screening identified 11 key odor-related substances, including butanal, nonanal, and decanal. The CMB analysis revealed that door panels, seats, and weatherstrips contributed 58 %, 26 %, and 16 % of the odor-related substances, respectively. The carpet and headliner did not result in noticeable odor changes, and the carpet occasionally exhibited a negative source effect. These findings contribute to the understanding of in-vehicle odor sources and provide insights into the reduction of unpleasant odors through targeted materials and manufacturing adjustments.