Mitigating urban heat island effects on building interiors in metropolitan areas in Nigeria: Case study of Yola

Abstract

The urban heat island (UHI) effect, caused by human activities and rapid urbanization, leads to significantly higher temperatures in urban areas compared to surrounding rural zones. In Nigeria's tropical climate with unreliable power supply, excessive urban heat necessitates both mechanical and passive cooling techniques for building interiors, making it crucial to mitigate the UHI impact on building performance. This study aims to develop a framework using micro-climate simulations. Data were collected through field measurements on 27 October, 2024 for validation of simulation results and subsequent simulations. Four different strategies to mitigate the UHI effect, including the current situation, changing the low-albedo materials with high-albedo ones, nature based solutions, and changing building façade materials, were employed with a micro-climatic simulation tool. Then, the output of the strategies, which is potential air temperatures are compared. Results showed potential air reduction of 1.5 ⁰C, 3.01 ⁰C and 2.45 ⁰C for Case B, Case C and Case D respectively. The results showed that applying nature based solutions (NBSs) such as green roofs and changing existing trees with high leaf area density ones, have the highest ranking among all mitigation strategies. Although applying only one strategy may not give the desired temperature reduction, applying two to three different strategies should give a greater temperature reduction. The output of this study can inform urban planning policies, promoting sustainable urban development in rapidly growing Nigerian cities and bridges architecture, urban planning, climatology, and socio-economic considerations, promoting a holistic approach to urban development.