Social factors influencing the household solid waste generation and recycling rate in urban areas of Japan

Abstract As population density and economic activities continue to grow in urban areas, household solid waste (HSW), especially household plastic waste (HPW), has become a pressing issue in Japan. This study aims to investigate the social factors influencing the generation and recycling rate of HSW and HPW in urban Japan. Using panel data from 105 cities across the years 2000, 2005, 2010, 2015, and 2020, we conducted an actual situation analysis and stepwise multiple regression analysis. Social factors were categorized into demographic (age, gender, income) and non-demographic factors, including economic, infrastructure-related, and HPW-related policy indicators. The actual situation analysis revealed a rise in HPW and stagnant recycling rates in Japan. Regression results confirmed several previous findings, such as older people generating less HSW and recycling more, and positive correlations between economic indicators and recycling rates. Novel findings include: (1) people aged 20–29 and those with higher incomes generate less HSW but more HPW; (2) females are negatively linked to recycling, possibly due to shifting gender roles; (3) higher power generation efficiency of incinerator facilities is statistically associated with higher HPW generation and lower HPW recycling, suggesting a structural trade-off in cities that focus on energy recovery rather than recycling HPW; (4) HPW-related policy indicators significantly improved both HSW and HPW performance. These findings highlight the complexity of urban waste management. By integrating both HSW and HPW dimensions and incorporating underexplored indicators, this study deepens understanding of localized HSW dynamics and offers targeted recommendations for enhancing municipal recycling systems in Japan.