The environmental Kuznets curve (EKC) expresses the relationship between environmental quality and economic growth. Based on the defects of previous studies on EKC using only environmental pollution indicators, this study holds that environmental quality is the result of pollutants after treatment, absorption, and self-purification, including two dimensions of pollution and absorption. Therefore, the environmental pollution and absorption data of 74 key environmental monitoring cities in China from 2005 to 2017 were selected, and a comprehensive index of environmental quality was constructed using the vertical and horizontal grading method. Then, based on the relevant economic growth indicators of these cities, they were divided into first-tier and new first-tier, second-tier, third-tier, and below. It was found that the EKC of the total sample, the first-tier and new first-tier cities, and the second-tier cities presented an inverted N-shape and had passed the second inflection point, where environmental quality continues to improve with the deepening of economic growth. There was no EKC in the third-tier and below cities. The findings have important implications. China can cross the second inflection point of the EKC and improve environmental quality at a low income level. Therefore, by vigorously developing cleaner production technologies and raising residents’ awareness of environmental protection, it is possible to improve environmental quality at a lower income level than expected, which provides a useful reference for other developing countries.

Older adults’ family networks and social networks are important factors that influence life satisfaction, but their transmission mechanisms have not been adequately discussed. The objective of this study was to examine the mechanisms through which family networks and social networks influence the life satisfaction of older adults. We empirically examined the effects and mechanisms of older adults’ family networks and social networks on their life satisfaction using the 2018 China Longitudinal Aging Social Survey with a sample size of 11,418 older adults aged 60 years and older. In the research sample, 6.47% of older adults were subjected to at least one form of mistreatment. The research results indicate that family networks (β = 0.0060, p < 0.05) and social networks (β = 0.0122, p < 0.01) have a significant positive effect on older adults’ life satisfaction. The mechanism-of-action test found that family networks and social networks enhance older adults’ life satisfaction, mainly by reducing the level of physical mistreatment they experience, but these networks cannot improve the life satisfaction of the elderly by reducing their emotional mistreatment. Further research found that community-provided medical escorts, home chores, and meal delivery services can all alleviate the decline in life satisfaction among older adults due to emotional mistreatment. This study deepens our understanding of how older adults’ family and social networks affect their life satisfaction as we examine the mediating role of the physical and emotional mistreatment of older adults and discuss the effects of potential policy interventions.