Life cycle assessment in urban territories: a case study of Dalian city, China

摘要

PurposeA city comprises different subsystems, such as an industry subsystem, agriculture subsystem, building subsystem, and transport subsystem. With the rapid development of the economy and technology, the urbanization of China has accelerated during the last 10years, which has caused great pressure on the environmental carrying capacity, and the 5-Year Plans carried out by Chinese government have intensified environmental protection efforts. Therefore, it is important to quantify the environmental impacts and changing trends of all subsystems, such that money can be used effectively to solve targeted urban environmental problems. The purpose of this study was to adapt the existing life cycle assessment (LCA) method in urban territories and apply the improved method to a Chinese city, Dalian, to assess its environmental impacts, thereby validating the effectiveness of the method.MethodsOn the basis of the existing territory LCA framework, we revised the land use functions, including regional characteristics, inventory analysis, and impact assessment, and performed a supplementary results' interpretation of land use functions. Environmental analysis was performed based on the LCA with the ReCiPe method, which allowed us to analyze 12 different categories of environmental impact. LCA was performed based on the ISO14040 standard using the GaBi software. The adapted method was applied to a Dalian city, China, in 2000, 2005, 2010, and 2012.Results and discussionThe results showed that, over time, the environmental impacts on Dalian have increased, but at a decreasing rate. The environmental impacts of all subsystems have increased rapidly over time, except for the food subsystem. The industry subsystem was the main contributor of environmental impacts and accounted for 80% approximately of the total impact each year. At the same time, tourism and aquatic products also play a significant role in the environment, society, and economy of Dalian. The shortage of water has become a problem that requires attention.ConclusionsThe study adapted the existing territory LCA method to highlight regional characteristics in urban territories and applied the improved method to a Chinese city. According to the results, decision makers could identify the subsystem that is the main contributor to targeted environmental problems and improve them accordingly. The quantitative relationship among the environmental impacts of all subsystems and changing trends could benefit decision-making in the future.