Urban Heat Island: Causes, Consequences, and Mitigation Measures with Emphasis on Reflective and Permeable Pavements

Abstract

Economic and social development of urban and rural areas continues in parallel with the increase of the human population, especially in developing countries, which leads to sustained expansion of impervious surface areas, particularly paved surfaces. The conversion of pervious surfaces to impervious surfaces significantly modifies local energy balance in urban areas and contributes to urban heat island (UHI) formation, mainly in densely developed cities. This paper represents a literature review on the causes and consequences of the UHI and potential measures that could be adopted to improve the urban microclimate. The primary focus is to discuss and summarise significant findings on the UHI phenomenon and its consequences, such as the impact on human thermal comfort and health, energy consumption, air pollution, and surface water quality deterioration. Regarding the measures to mitigate UHI, particular emphasis is given to the reflective and permeable pavements.

Raman Spectroscopic Investigation and Electronic State Calculation for Ca2(Mn,Ti)O4 Black Pigments with High Near-Infrared (NIR) Reflectivity

“…In recent years, functional inorganic pigments, which exhibit color properties as well as near-infrared (NIR) reflective ability, have attracted attention as materials used to prevent heat storage due to NIR light absorption. The application of NIR-reflective pigments on outer walls and building roofs is effective in mitigating the urban heat island effect due to which the ambient temperature in an urban area is higher than that in the surrounding areas. , Natural sunlight is composed of ultraviolet (UV: 300–400 nm, 5%), visible (vis: 400–700 nm, 43%), and NIR (700–2500 nm, 52%) radiations . In particular, sunlight in the wavelength range of 700–1300 nm plays the most significant role in heat generation because this constitutes 80% of the total energy in the NIR region .…”

Effect of Thermal Variances on Flexible Pavements

“…In addition, a rise in the temperature ranges as a consequence of weather and climatic changes increases the thermal stress of asphalt layers and thus might worsen thermal assumptions [37]. Moreover, greater temperatures may lead to a quicker (accelerated) aging of the asphalt layers and because of increased fracture, pavements may become more prone to cracking [37,38]. Furthermore, low temperatures may lead to asphalt concrete hardening and result in thermal cracking on the road surface; low temperatures promote cracking processes, whereas high temperatures distort plastic deformation processes such as rutting [39].…”

Enhanced Thermoelectric Performances of CNTs-Reinforced Cement Composites with Bi0.5Sb1.5Te3 for Pavement Energy Harvesting

“…Due to the low heat dissipation rate of cement, the cement-related infrastructures store large-scale thermal energy after exposure to a large quantity of sun irradiation [ 4 , 5 ]. This results in structural damage in the cement-related infrastructures [ 6 ], the growing intensity of urban heat island effect and increasing energy consumption of the air conditioning system in summer [ 7 , 8 ].…”