Outdoor thermal physiology along human pathways: a study using a wearable measurement system

Abstract

An outdoor summer study on thermal physiology along subjects' pathways was conducted in a Japanese city using a unique wearable measurement system that measures all the relevant thermal variables: ambient temperature, humidity, wind speed (U) and short/long-wave radiation (S and L), along with some physio-psychological parameters: skin temperature (T skin), pulse rate, subjective thermal sensation and state of body motion. U, S and L were measured using a globe anemo-radiometer adapted use with pedestrian subjects. The subjects were 26 healthy Japanese adults (14 males, 12 females) ranging from 23 to 74 years in age. Each subject wore a set of instruments that recorded individual microclimate and physiological responses along a designated pedestrian route that traversed various urban textures. The subjects experienced varying thermal environments that could not be represented by fixed-point routine observational data. S fluctuated significantly reflecting the mixture of sunlit/shade distributions within complex urban morphology. U was generally low within urban canyons due to drag by urban obstacles such as buildings but the subjects' movements enhanced convective heat exchanges with the atmosphere, leading to a drop in T skin. The amount of sweating increased as standard effective temperature (SET*) increased. A clear dependence of sweating on gender and body size was found; males sweated more than females; overweight subjects sweated more than standard/underweight subjects. T skin had a linear relationship with SET* and a similarly clear dependence on gender and body size differences. T skin of the higher-sweating groups was lower than that of the lower-sweating groups, reflecting differences in evaporative cooling by perspiration.

A review of human thermal comfort in the built environment

“…Field studies were conducted at outdoor sites in Gothenburg (Sweden) and Matsudo (Japan) [441,442], in Lisbon (Portugal) [443], in Matsudo [444], Tajimi [445] and 14 forests and urban areas in Japan [446], in Taichung [447][448][449][450] and Chiayi [451] (Taiwan), in Marrakech (Morocco) and Phoenix (US) [452], in the Hague, Eindhoven and Groningen (Netherlands) [453][454][455] and in Beirut (Lebanon) [456]. Additional field studies were also conducted in Xi'na [457], Guangzhou [458], Nanjing [459], Chengdu [460], Tianjin [461], Wuhan [462] and others [463] (China), in Cairo (Egypt) [464], in Curitiba (Brazil) [465][466][467], in Hong Kong [468,469], in Szeged (Hungary) [470,471], in Malaysia [472,473], in Athens [474][475][476][477] and Crete [478] (Greece), in Damascus (Syria) [479], in Glasgow (UK) [480], in Singapore [481,482], in Mendoza (Argentina) [483], i...…”

Progress in Urban Greenery Mitigation Science – Assessment Methodologies Advanced Technologies and Impact on Cities

“…Although these measurements may be of some help for such specific conditions (city marathon run circuits), they are not representative of the most common conditions of people walking over dedicated sidewalks, much closer to buildings and affected, at the same time, by street traffic and impervious surfaces' radiation. Therefore, dedicated wearable systems were developed with the purpose to monitor the pedestrian level microclimate parameters directly interacting with the human body and suitable for more reliable energy budget calculation (Nakayoshi et al 2014;Pigliautile, Pisello 2018). In fact, deep personal heat stress analysis at individual scale has been demonstrated to be driven by measurable and nonmeasurable parameters and indexes coming from multidisciplinary fields of investigation such as behavioural sciences, people's susceptibility, medical conditions and environmental comfort outcomes.…”

Outdoor Wellbeing and Quality of Life: A Scientific Literature Review on Thermal Comfort

“…In arid climates, ITS results show high correlation with field studies [196,200], while SET [52,142,191] and OUT SET* [133,148] appear to be more applied in and reliable for temperate climates. Being more scientifically updated, UTCI is instead the only index that was applied to all climates [59,84,99], ensuring a good matching between onsite measures and simulations [70,133,157].…”