Assessing the inequities in access to peri-urban parks at the regional level: A case study in China's largest urban agglomeration

Access to peri-urban parks (PUPs) has recently gained considerable attention because of the limited green space in urban areas that cannot meet residents' increasing demands for engaging with nature. Here, we aim to assess the accessibility to PUPs and monitor the underserved areas in the context of urban agglomeration, and to examine the inequities across districts with heterogeneous social groups. A Huff-2SFCA (Huff-two step floating catchment area) model was developed to evaluate the PUP accessibility. In addition, we adopted 30, 60, 90, 120, and 150 min as the threshold of travel time to identify the areas that are underserved by PUPs. Welch's ANOVA test (one-way ANOVA with unequal variances) was used to monitor the disparities in PUP accessibility among different cities, and a bivariate correlation was used to explore the associations between PUP accessibility and socioeconomic variables. Factor analysis (using varimax rotation) was then applied to cluster socioeconomic indicators into three factors, which were further divided into four quartiles. Lastly, the average value of PUP accessibility in each quartile group was calculated and compared to measure inequities. The Yangtze River Delta urban agglomeration (YRDUA), China's largest urban agglomeration, was selected as the case study. The results suggested the following: 1) PUP accessibility increases while the number of underserved subdistricts decreases as the threshold value of travel time increases from 30 to 150 min, and 90 min is a 'turning point', after which an increasingly small difference is suggested both in PUP accessibility and underserved subdistricts; 2) there are statistically significant disparities in PUP accessibility across different cities in YRDUA; and 3) the socioeconomically disadvantaged districts have fewer opportunities to enjoy PUP services, while districts with lower social status groups or higher ethnic minority populations were not treated unequally. Our findings contribute to the environmental justice paradigm by assessing the inequities in access to PUPs over an extensive geographical scope, which could help decision-makers formulate effective policies and strategies for improving nature exposure from a regional planning perspective.