Interrelationships between Land Use Land Cover (LULC) and Human Thermal Comfort (HTC): A Comparative Analysis of Different Spatial Settings

Lee Bak Yeo,Pau Chung Leng,Gabriel Hoh Teck Ling,Mou Leong Tan

doi:10.3390/su13010382

Abstract

A few studies on outdoor human thermal comfort (HTC) have been conducted in the tropical region in a hot and humid climate; however, there is a paucity of discussions on how exactly different spatial settings influence HTC. Thus, this paper aims to examine how land use land cover (LULC) affects HTC on the basis of the simulation of Predicted Mean Vote (PMV) and Physiologically Equivalent Temperature (PET) indices via ENVI-met and Rayman. The results reveal that people living in the urban area have a higher tendency to experience strong heat stress (25% of the areas with PMV ranging from 3.4 to 3.9 and 2% of the areas, where PMV reached 4.1), followed by the rural area (43% of the areas with PMV ranging from 2.1 to 2.4), and the suburban area (more than 50% of the areas with PMV values less than 2.4). Surprisingly, a concrete LULC in the suburb area exhibits a higher air temperature than an asphalt surface at 4 p.m., due to the large area of high albedo that increases the reflection of solar radiation, subsequently contributing to warming up the airmass. Similarly, sandy, and loamy LULC tend to emit more heat during nighttime, while the heat is absorbed slowly during daytime, and it is then slowly released during nighttime after 6 p.m. Spatial settings that promote heat stress in the urban area are mainly contributed by an LULC of asphalt, concrete, sandy, and loamy areas. Meanwhile, people in the suburban and rural areas are less likely to experience heat stress, due to agricultural plantations and lowland forest that provide shade, except for the barren lands-loamy areas. The result also indicates that tree-covered areas near the river in the suburban area afforded the best thermal experience with PMV of 2.1 and PET of 30.7. From the LULC comparison, it is pivotal to consider tree species (canopy density), surface material (albedo), sky-view factor, wind direction, and speed toward designing a more comfortable and sustainable environment.

Highlights

human thermal comfort (HTC) is an essential element in the built environment; improving HTC is challenging, considering its various aspects/determinants
Numerous studies have been conducted to investigate how physical planning factors (i.e., land use land cover (LULC)) influence urban heat island effect (UHI), very few were focused on a spectrum of urban-suburbrural effects on HTC
Considering the large number of man-made features in urban areas, a general assumption is that urban areas are always warmer than suburbs, and suburban areas are warmer than rural areas

Summary

Introduction

Rapid urbanization has induced changes in ecological function and processes, where it has significantly impacted ecosystem services [1]. One of the best-known effects that changes the atmospheric condition of an urban environment is known as the urban heat island effect (UHI), which makes a difference. Sustainability 2021, 13, 382 in temperatures between an urban and a rural environment [5]. Such effects are attributed to the rampant growth and expansion of built-up areas, contributing to heat stored and radiation by urban structures [6]. The capacity of an ecosystem to reduce the heat through biologically mediated processes is crucial [7]. Trees are vital, serving as a cooling agent mainly through evaporative cooling and shading of the ground; they reduce the sky-view factor that obstructs solar radiation received at the ground and human body [14]

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