The Urban Heat Island Effect its Causes and Mitigation with Reference to the Thermal Properties of Roof Coverings

Abstract

The Urban Heat Island (UHI) is a phenomenon that affects millions of people worldwide. The higher temperatures are experienced in urban areas compared to the surrounding countryside and have enormous impacts on the health and well being of people living in cities. The increased use of man made building materials and increased anthropogenic heat production are the main causes of the UHI. This has led to the perceptive that increased urbanisation is the most important cause of the urban heat island. The UHI impact additionally results in expanded energy demands that further add to the heating of our urban landscape, and the related environmental and public health issues. Pavements and roofs dominate the urban surface exposed to solar irradiation. This article summarizes the contribution that roofs make to the UHI effect and analyses localized mitigation strategies against the UHI. In this study, the thermal properties of the widely used roofs are investigated to estimate the potential for mitigating the UHI effect. The ability of roofs to regulate indoor thermal comfort was also analysed.