Assessing Pedestrian Exposure to Heat via the Wet-Bulb Globe Temperature Using Mobile Phone Location Data and Urban Thermal Simulations

The recent rise in temperatures in urban areas has raised concerns about various health problems, such as heat-related illnesses. This study quantified the number of individuals exposed to outdoor heat during the daytime in the summertime waterfront area of Tokyo. Conventional meteorological observa...

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Main Authors: Yasunobu Ashie, Eiko Kumakura, Takahiro Ueno
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Buildings
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Online Access:https://www.mdpi.com/2075-5309/15/5/676
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author Yasunobu Ashie
Eiko Kumakura
Takahiro Ueno
author_facet Yasunobu Ashie
Eiko Kumakura
Takahiro Ueno
author_sort Yasunobu Ashie
collection DOAJ
description The recent rise in temperatures in urban areas has raised concerns about various health problems, such as heat-related illnesses. This study quantified the number of individuals exposed to outdoor heat during the daytime in the summertime waterfront area of Tokyo. Conventional meteorological observation and administrative data are insufficient for high-resolution analyses of people flow and heat conditions in urban environments. Therefore, this study introduced a new methodology combining urban computational fluid dynamics (CFD) and mobile phone global positioning system (GPS) data. A numerical simulation was performed to estimate the wet-bulb globe temperature (WBGT) by analyzing fluid dynamics and radiation models. The WBGT in parks was determined to be approximately 27 °C, while the on-road temperature exceeded 29 °C. Simultaneously, pedestrian density was assessed by collecting high-resolution mobile phone GPS data, revealing that pedestrians concentrated near stations, office areas, and shopping districts within a 5 km × 5 km area. Furthermore, a review of heat stroke cases (2010–2020) indicated that combining heat and people flow yielded stronger correlations with the number of heat stroke cases than considering heat alone. Finally, a new heat risk index was established, integrating heat, people flow, and aging rate, which more accurately predicted the heat stroke cases.
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spelling doaj-art-d92d077631c94eb08bc33fe4d169059f2025-08-20T02:05:24ZengMDPI AGBuildings2075-53092025-02-0115567610.3390/buildings15050676Assessing Pedestrian Exposure to Heat via the Wet-Bulb Globe Temperature Using Mobile Phone Location Data and Urban Thermal SimulationsYasunobu Ashie0Eiko Kumakura1Takahiro Ueno2Building Research Institute, Tsukuba 305-0802, JapanBuilding Research Institute, Tsukuba 305-0802, JapanFaculty of Environmental Engineering, The University of Kitakyushu, Kitakyushu 808-0135, JapanThe recent rise in temperatures in urban areas has raised concerns about various health problems, such as heat-related illnesses. This study quantified the number of individuals exposed to outdoor heat during the daytime in the summertime waterfront area of Tokyo. Conventional meteorological observation and administrative data are insufficient for high-resolution analyses of people flow and heat conditions in urban environments. Therefore, this study introduced a new methodology combining urban computational fluid dynamics (CFD) and mobile phone global positioning system (GPS) data. A numerical simulation was performed to estimate the wet-bulb globe temperature (WBGT) by analyzing fluid dynamics and radiation models. The WBGT in parks was determined to be approximately 27 °C, while the on-road temperature exceeded 29 °C. Simultaneously, pedestrian density was assessed by collecting high-resolution mobile phone GPS data, revealing that pedestrians concentrated near stations, office areas, and shopping districts within a 5 km × 5 km area. Furthermore, a review of heat stroke cases (2010–2020) indicated that combining heat and people flow yielded stronger correlations with the number of heat stroke cases than considering heat alone. Finally, a new heat risk index was established, integrating heat, people flow, and aging rate, which more accurately predicted the heat stroke cases.https://www.mdpi.com/2075-5309/15/5/676urban CFDmobile phone GPS datawet-bulb globe temperatureheat-related illness
spellingShingle Yasunobu Ashie
Eiko Kumakura
Takahiro Ueno
Assessing Pedestrian Exposure to Heat via the Wet-Bulb Globe Temperature Using Mobile Phone Location Data and Urban Thermal Simulations
Buildings
urban CFD
mobile phone GPS data
wet-bulb globe temperature
heat-related illness
title Assessing Pedestrian Exposure to Heat via the Wet-Bulb Globe Temperature Using Mobile Phone Location Data and Urban Thermal Simulations
title_full Assessing Pedestrian Exposure to Heat via the Wet-Bulb Globe Temperature Using Mobile Phone Location Data and Urban Thermal Simulations
title_fullStr Assessing Pedestrian Exposure to Heat via the Wet-Bulb Globe Temperature Using Mobile Phone Location Data and Urban Thermal Simulations
title_full_unstemmed Assessing Pedestrian Exposure to Heat via the Wet-Bulb Globe Temperature Using Mobile Phone Location Data and Urban Thermal Simulations
title_short Assessing Pedestrian Exposure to Heat via the Wet-Bulb Globe Temperature Using Mobile Phone Location Data and Urban Thermal Simulations
title_sort assessing pedestrian exposure to heat via the wet bulb globe temperature using mobile phone location data and urban thermal simulations
topic urban CFD
mobile phone GPS data
wet-bulb globe temperature
heat-related illness
url https://www.mdpi.com/2075-5309/15/5/676
work_keys_str_mv AT yasunobuashie assessingpedestrianexposuretoheatviathewetbulbglobetemperatureusingmobilephonelocationdataandurbanthermalsimulations
AT eikokumakura assessingpedestrianexposuretoheatviathewetbulbglobetemperatureusingmobilephonelocationdataandurbanthermalsimulations
AT takahiroueno assessingpedestrianexposuretoheatviathewetbulbglobetemperatureusingmobilephonelocationdataandurbanthermalsimulations