This paper explores the application of the Rapid Impact Assessment Matrix (RIAM) method in environmental impact assessment (EIA) during the COVID-19 pandemic, focusing on Tehran, Iran. The study aims to quantify the environmental impacts of COVID-19 using RIAM and to evaluate the effectiveness of the method in a real-world case study. The research highlights both positive and negative environmental consequences of the pandemic, such as reduced air pollution and increased medical waste. The RIAM method is praised for its objectivity, transparency, and ease of use, making it a valuable tool for decision-makers to understand and mitigate environmental impacts. The study concludes that RIAM is an effective tool for EIA, particularly during crises, and suggests further research to refine and expand its application.This paper explores the application of the Rapid Impact Assessment Matrix (RIAM) method in environmental impact assessment (EIA) during the COVID-19 pandemic, focusing on Tehran, Iran. The study aims to quantify the environmental impacts of COVID-19 using RIAM and to evaluate the effectiveness of the method in a real-world case study. The research highlights both positive and negative environmental consequences of the pandemic, such as reduced air pollution and increased medical waste. The RIAM method is praised for its objectivity, transparency, and ease of use, making it a valuable tool for decision-makers to understand and mitigate environmental impacts. The study concludes that RIAM is an effective tool for EIA, particularly during crises, and suggests further research to refine and expand its application.