Format Pollutant Emission Measurement And Environmental Performance Assessment Of Freight Station In Ecological Zone

With the rapid economic development and increasingly frequent circulation of commodities,many environmental problems such as water pollution,soil pollution and air pollution have arisen,seriously affecting and restricting the local ecological environment and sustainable development.The Qilian Mountain National Nature Reserve,as a national key ecological public welfare forest,is listed as one of the 50 important ecological service areas in China,and the requirements and importance attached to the natural environment are selfevident.The various freight yards located in them have become the key units for pollution emission monitoring.In this paper,two aspects of system dynamics modelling analysis and environmental performance assessment are investigated,taking Zhangye freight yard station as an example.The system dynamics literature and modelling methods at home and abroad are summarised and analysed,and the causal feedback relationships of pollutant emissions from freight yards are sorted out based on the operation of the yards and the interaction with the surrounding environment.A system simulation model of pollutant emissions from Zhangye railway yard is constructed using Vensim software.The simulation results show that the main pollutant emissions from the yard are NOx,CO,PM10 and HC in descending order,and the emission of all four pollutants from the yard decreases with the reduction of coal operation,indicating that the impact of coal operation on the surrounding environment is worth exploring.Further literature on environmental performance evaluation and assessment frameworks were collected and collated.Twelve evaluation indicators were identified through field research to construct an environmental performance assessment indicator system.The data of the indicators were standardised and the entropy weighting method was used to calculate the environmental performance index of Zhangye freight yard station under different contexts.Combined with the established pollutant emission system simulation model,it can be seen that the current environmental performance of the yard station is at a high level,but has a tendency to decline year by year,and will soon be downgraded to an average level if strong environmental management and improvement measures are not taken.The implementation of environmental performance improvement strategy one: change the internal combustion forklifts and other loading and handling equipment to electric power,the average emissions of four pollutants,NOx,CO,PM10 and HC,will be reduced by 20.23%,19.44%,7.29% and26.81% in 2021～2025.Implementation of Environmental Performance Improvement Strategy II: Reduce the amount of coal operations at the site,comparing the two scenarios with a 20%and 50% reduction,it was found that the improvement in the Environmental Performance Index was somewhat helpful,but the improvement was not significant.Implementing environmental performance improvement strategy three: loading both strategy one and strategy two into the system simulation model,the environmental performance index of the yard station will reach and remain stable at a high level rating after 2021.It can be seen that the main directions for environmental management and improvement at Zhangye railway freight yard station are: replacing loading and unloading handling equipment such as internal combustion forklifts at the freight yard station with electric power drives,encouraging the widespread use of clean energy in the ecozone;and actively adopting dust and dust suppression techniques to tightly control environmental pollution from coal operations,and appropriately limiting the amount of coal operations at the yard station rather than simply cutting the normal coal circulation demand by a large percentage.The research process and conclusions of this paper can also be useful for other similar sites located in the Qilianshan National Nature Reserve.