Numerical expression of odor intensity of volatile compounds from automotive polypropylene

Abstract Polypropylene (PP), as a common automotive plastic, enhances the performance of parts, but emits odorous volatile compounds and increases the risk of exposure to air pollutants. The organic compounds and carbonyl compounds emitted can induce respiratory diseases and even cancers. However, the measurement of odor intensity is regarded as a challenge for the vehicle market in order to meet the increasingly strict environment regulations. This study aimed to numerically express the odor intensity of volatile compounds from automotive polypropylene. The samples with different odor intensities were prepared by the thermostatic heater, and the electronic nose composed of ten various sensors was employed to acquire the odor information. The factor analysis was implemented to analyze the odor data of different intensities. The results showed that the odor intensity values of four materials were around 1.3 at 50℃, which increased to 1.8, 2.0, 2.3, and 1.9 respectively at 80℃. Besides, grey relation analysis was introduced to verify the results of numerical expression, and the corresponding relation degree in accord with the odor intensity value. This study shows the numerical expression could be used as an effective alternative to rapidly and objectively describe the odor intensity in vehicles.