Study on the Prediction of VOC Concentration in Vehicle Cabins (1) Investigation of Relationship between Toluene Concentrations and Evaluation Conditions using Interior Parts 2013-01-0490

The Japan Automobile Manufacturers Association (JAMA) has recommended the voluntary regulation of the levels of volatile organic compound (VOC) emissions from vehicles. However, initiatives to reduce these emissions further are being implemented in Japan to create a healthier and more comfortable environment within vehicles. In this study, it was attempted to estimate the observable amounts of VOC emitted from products used in vehicles based on the actual emission of VOC from the products components. The VOC we focused on was toluene. The amounts of toluene volatilizing from the components of a disassembled vehicular product were measured and tested whether a simple sum of these values could be used to predict the amount of toluene emitted from the whole product. However, it was found this predicted value deviated significantly from the actual amount of toluene emitted from the product.

The reason for this deviation was assumed that the measurements were made under different conditions for different components. Therefore, the amount of toluene volatilizing (amount of toluene observed) from a test piece was measured under various conditions using the sampling bag method. Consequently, the predicted amount deviated from that observed because of the number of samples tested, the amount of gas filled in the test bag, and the heating temperatures, i.e., the measurement conditions. This was because the measured amount of toluene volatilized varied even for the same sample depending on these conditions.