Dominant Factors Affecting Temperature Elevation in Adult and Child Models Exposed to Solar Radiation in Hot Environment

Abstract—The number of children suffering from heat-related illness has been increasing in recent years. Children are more susceptible to heat-related illness than adults, which is considered to be caused by morphological and functional differences between adults and children. In the present study, the temperature change and perspiration in adult and child models during a simultaneous exposure to solar radiation and a hot environment are evaluated computationally. First, the power absorbed in the human body due to solar radiation is computed by the FDTD method for the Maxwell equations. Then, the temperature distribution inside the human body is modeled by the bioheat equation taking into account the thermophysiological response. Anatomicallybased Japanese adult male and 3-year-old child phantoms are used. An approximative analytical solution for the core temperature elevation is also derived to clarify the dominant factors affecting the temperature elevation. From our computational results, the core temperature elevation in the child phantom for both the solar and hot-environment exposures was larger than that in the adult phantom. The temperature elevation in the child was found to be mainly caused by the exposure