Spatio-temporal Evolution And Driving Factors Of Plastic Wastes In Passenger Vehicles Based On Material Flow Analysis

China is the largest plastic producer and consumer in the world,contributing to nearly a third of global plastic production.As a polymer material,plastics are widely used in passenger vehicles for their lightness and low cost.With the rapid development of the automobile industry,society has accumulated a large amount of discarded automotive plastic,which has greatly pressured the environment and the recycling industry.It is necessary to quantify the discarded quantity of passenger-vehicle plastics,explore its evolution rule and predict its future development trend.In this study,31 provinces and cities in mainland China were taken as the research area,and passenger-vehicle plastics were taken as the research object.Combined with passenger vehicle data,the stock and waste of different kinds of passenger-vehicle plastics at the provincial level were quantified.Plastic waste’s temporal and spatial evolution characteristics in the passenger vehicle were explored.The influence degree of different factors on the spatial distribution of plastic waste was revealed.The development trend of plastic waste from all passenger vehicles under different scenarios is forecasted.Based on a variety of model studies,this paper draws the following four conclusions:(1)The method of material flow analysis combined with normal life distribution function was used to estimate the stock and waste of passenger-vehicle plastic.The study found that from 1985 to 2020,the plastic stock of passenger vehicles showed a high growth trend of first slow and then fast,with a growth rate of 15.4%.From 1998 to 2020,plastic waste increased from 50,600 tons to 1.75 million tons,showing a growing trend of "slow first and then fast",with a growth rate of 17.5%.In terms of space,the plastic stock and waste in passenger vehicles presented the spatial distribution characteristics of "more in the east and less in the west".Due to the rapid economic development and high population density,the eastern region,represented by Guangdong and Jiangsu,has nearly 50% of the plastic stock and waste.The western region,represented by Xizang,has a low population,a small proportion of passenger vehicles,and a low quantity of plastic waste.(2)The study used spatial autocorrelation,hot spot analysis and other spatial metrology methods to explore the accumulation of passenger-vehicle plastic waste in different provinces and draws the migration trajectory of passenger vehicle plastic gravity center by using the gravity center migration model.The results show an obvious positive spatial correlation between the plastic waste of passenger vehicles and an obvious aggregation area.The low-value area is mainly concentrated in the western region mainly in Tibet,and the overall range remains unchanged.The high-value area is mainly concentrated in the eastern province,Jiangsu Province,which is transferred from north to south,from "strip" to "round".The center of gravity of plastic waste from passenger vehicles was concentrated in the eastern region of Henan province from 2000 to 2020.The spatial center of gravity shifted from Zhoukou City to Zhumadian City,and the overall migration from north to south,the migration distance presented a cyclical trend of first increasing and then decreasing.(3)The influence of different factors on the amount of plastic discarded in passenger vehicles was studied by using the geographical detector model.The results showed that socioeconomic factors were the determinants of the spatial distribution of plastic waste,and GDP,total population at the end of the year and urban passenger transport turnover were the main driving factors.From 2000 to 2020,the explanatory power of five factors,including GDP and total population at the end of the year,on the spatial distribution of plastic waste of passenger vehicles gradually increased,while the other factors gradually decreased.The interaction between any two factors was more significant than the influence of a single factor,which was mainly manifested by double-factor enhancement.Under the synergistic action of other factors,GDP has the strongest explanatory power and the most significant influence on the spatial characteristics of plastic wastes in passenger vehicles.This indicates that the spatial distribution of plastic waste was not explained by a single factor but by multiple factors.(4)Based on the results of the drive analysis,different scenarios were set according to the future population and passenger vehicle ownership rate,and the development trend of various types of passenger vehicle plastic waste in different scenarios was predicted.The results show that in most scenarios,the future plastic waste of passenger vehicles presents a trend of continuous growth.In the early period of 2021-2030,the waste shows a rapid growth trend,and in the later period,they show different development trends according to different parameter Settings.In 2030,in the baseline scenario,the plastic waste of passenger vehicles reaches 2.78 million tons,and the high ownership scenario has the largest amount of waste,which is 3.12 million tons.Compared with the baseline scenario,the waste volume increases by 12.25%.The low-possession scenario had the least amount of waste,which was 2.22 million tons,and the amount of waste was reduced by 19.89% compared with the baseline scenario.