OICC Press Anthropogenic Pollution 2588-4646 8 1 2024 06 25 Environmental risk assessment of urban underground public space development in Tehran using EFMEA and TOPSIS techniques 10.57647/j.jap.2024.0801.12 EN Mohammad Mahdi Safaee Ph.D. Student in Architecture, Islamic Azad University Campus, Kish International Branch, Iran Mohammad Saeid Izadi Member of Academic board, School of Art and Architecture, Buali Sina University Ali Afshar Assistant professor, Eqbal Lahoori Institute of Higher Education, Mashhad, Iran Hamid Reza Ameri Siyahouei Associate Professor, Department of Art and Architecture, Payame Noor University, Journal Article 2024 06 25 The purpose of this study was the environmental pollution risk assessment of urban underground public space development in Tehran (Iran). This applied research was conducted by survey and mixed methods in two phases: estimating risk potentials using Environmental Failure Mode and Effect Analysis (EFMEA), and Delphi Technique. The results identified 12 different environmental risks for the underground public space development. Among these, three risks showed high level, including sewage discharge (Risk Priority Number (RPN=504), inappropriate ventilation (RPN=567) and seismic hazard (RPN=640). Moreover, five cases were classified as medium level risks, including Construction waste accumulation of (RPN = 294), Land subsidence (RPN = 250), Municipal waste accumulation (RPN = 441), Non-renewable energy consumption (RPN = 256) and Thermal pollution (RPN = 210). In addition, three items were among high-level risks, including Sewage discharge (RPN = 504), Inappropriate ventilation (RPN = 567) and Seismic hazard (RPN = 640). The development of urban underground public space in Tehran can be a solution to improve the level of services and urban per capita, which is a great help in the urban management of a metropolis like Tehran. Meanwhile, it is important to pay attention to the environmental, health and safety polices.