Human BIometeorology along Human Pathway using Wearable Measurement System

An outdoor summer experiment on thermal physiology along the subjects' pathways was conducted in a Japanese city using a unique wearable measurement system that measures all the relevant thermal variables: ambient temperature (Ta), humidity (q), wind speed (U), short/long wave radiation (S and L), and some physio–psychological parameters: pulse rate (PR), skin temperature (Tskin), subjective thermal sensation (Tsv), and state of body motion (BM). U, S, and L were measured using a globe anemo-radiometer, which is a suitable sensor for mobile observations. The accuracy of the meteorological instrument in wearable use was carefully validated. The subjects were 26 healthy Japanese adults (14 males, 12 females) ranging from 23 to 74 years in age. Every subject wore a set of instruments that recorded individual microclimate and physiological responses along the observed route, which covered various urban textures. The subjects experienced widely varying thermal environments that could not be assessed from fixed-point routine observational data. S fluctuated highly, reflecting the mixture of sunlit/shade distributions within the complicated urban districts. Ta was generally higher in urban districts than in typical data, except for urban green spots and biotopes. U was generally low within urban canyons due to drag by urban obstacles such as buildings, and the subjects' movements enhanced the convective heat exchange from the body to the atmosphere, leading to a drop in Tskin. The amount of sweating increased as SET* increased. Moreover, a clear dependence of sweating on gender and body size was found. Males sweated more than females, and overweight subjects sweated more than standard and underweight subjects. Tskin had a linear relationship with SET* and a similarly clear dependence on gender and body-size differences. The Tskin of the higher-sweating groups was lower than that of the lower-sweating groups, reflecting differences in evaporative cooling by perspiration.