Reducing sweat and humidity between an automotive seat and a driver's body in summer is very important for comfortable and safe driving and prevention of accidents. However, a method of evaluating sweat and humidity feeling has not yet been established from the viewpoint of physiology and human engineering.

We analyzed sweat and humidity feeling by carrying out sensory evaluation experiments in an automotive seat. From the analysis, the following results were obtained.

1. Sweat and humidity feeling is a complex sensation, consisting of thermal and humid sensation and sticky sensation between a seat and a driver's body.

2. Thermal and humid sensation can be explained by a discomfort index calculated using the data of temperature and humidity around a human body in an environment. Also, sticky sensation can be explained by a vapor pressure calculated using the data of temperature and humidity between a seat and a driver's body. Consequently, sweat and humidity feeling can be explained up to eighty percent by these two factors, the discomfort index and the vapor pressure. Based on this analysis, a system which automatically measures the value of sweat and humidity feeling was developed on a personal computer.