Dynamic differences in urban park accessibility across age groups: A case study of Shanghai, China

As an important component of urban green spaces, urban parks play an important role in building sustainable cities and offer numerous benefits to residents. Among these residents, the older population, as a vulnerable group, is more likely to suffer equity and environmental justice issues when accessing urban park services. Therefore, there is a need to examine how urban park accessibility has changed over time and whether the older population has gained more equal services during this process. Using the SD2SFCA method, this study analyses the dynamic changes in urban park walking accessibility for both the older population and the general population in Shanghai from 2016 to 2020, and quantifies the relative role of population, urban parks, and the transport network on accessibility changes. Moreover, the study examines the accessibility gap between these two groups and how that gap changes over time. Results show that during the study period, the spatial accessibility, absolute population shares of accessible residents, and horizontal equity of both groups continuously improved. However, in the suburbs, the accessibility gap between them is continuously widening. Over time, the older population in the suburbs faces increasing inequity in accessing urban park services. This accessibility gap forms a "circular effect", which becomes more obvious as the threshold increases. The study enriches existing research on urban park accessibility, provides empirical support for urban park planning in the context of population ageing, and contributes to the sustainable development of cities and the age-friendly city construction.