Greenspace equity across variation in residential densities: Insights for urban sustainability

The enhancement of eco-social services provided by greenspace enhances human well-being and supports sustainable urban development. The United Nations has explicitly emphasized the need to “ensure the availability of greenspaces for urban residents” in SDG11. Nonetheless, with the current trends of urban sprawl and residential densification, greenspace shrinkage and degradation are accelerating, thereby diminishing its multifaceted benefits. These trends have also exacerbated inequalities and environmental justice issues. The disparity in greenspace exposure and its inequality across residential areas with varying densities has also been further exacerbated during this process. However, the specific magnitude and trend of change in this disparity were still poorly understood. To address this gap, we incorporated a random forest algorithm-based 30-m time-series greenspace mapping and an RSEI-based population-weighted exposure framework to quantify spatiotemporal variations in human exposure to greenspace across residential areas of varying densities in 154 cities at the patch scale. Finally, the Gini coefficient and MGWR were combined to assess the spatiotemporal heterogeneity of inequality in greenspace exposure and its influencing factors. Results indicated that greenspace exposure was greater in low-density residential areas than in high-density areas (0.72 vs 0.16), while equality was weaker (Gini coefficient:0.83 vs 0.61), both gaps have shown a tendency to narrow over time. Greenspace exposure equality was primarily driven by greenspace quality rather than its coverage ratio (Beta: −0.434 vs 0.40, P < 0.05). These findings contribute to our understanding of greenspace inequality in residential areas of different densities, suggesting directions for optimizing greenspace layout and offering new insights for sustainable urban development.