“Enhancing urban heat island mitigation in region 12 Tehran: Integrating greenery and high albedo materials for improved thermal Comfort”

Abstract

The Urban Heat Island (UHI) phenomenon leads to increased temperatures in urban environments compared to rural areas due to human activities and development. Mitigating UHI is essential for reducing health risks, improving urban livability, and decreasing energy consumption, thereby fostering sustainable and climate-resilient cities. This research focuses on UHI reduction through the use of vegetation and high-albedo materials, with a case study conducted in Tehran’s 12th district, a worn urban fabric facing significant UHI challenges. The study explores the effects of various strategies, including planting native street trees at different heights and densities, as well as incorporating green roofs and cool materials, using Envi-met for simulation. Climatic data collected on August 12, 2023, was used to validate the simulation results. The results indicate that these strategies can decrease air temperatures by 1 °C during peak summer hours (11 am to 3 pm). Notably, vegetation proved to be 15 % more effective than material changes in lowering mean radiant temperature, while high-albedo materials were found to be about 50 % more effective in reducing surface temperature than greenery. However, the correlation between UHI reduction and thermal comfort improvement was minimal, resulting in only a 9 % enhancement. The study suggests that while lowering surface temperatures may connect to improved thermal comfort, the overall impact remains limited.