Green disparities, happiness elusive: Decoding the spatial mismatch between green equity and the happiness from vulnerable perspectives

The equity of urban green spaces (UGS) plays a crucial role in social well-being. While previous studies have examined UGS disparities among various social groups, few have addressed the spatial heterogeneity of UGS inequality affecting vulnerable populations and its impact on their well-being. This study explores how streetscape greenness (SG), neighborhood greenery (NG), and public green spaces (PGS) influence the happiness of vulnerable groups, and it provides regional priorities for green policy through spatial mismatch analysis. The results reveal a strong and stable inequity in the center of Nanjing, which decreases toward the suburbs. Analysis of four vulnerable groups shows that the low-educated population is impacted by activity isolation; therefore, increasing activity facilities and reducing barriers to participation in PGS can alleviate this issue. Elderly groups favor expansive PGS or vibrant SG but are sensitive to the distance and accessibility of these green areas. Low-income groups, acting as “gardeners” to develop NG. This spontaneous behavior needs to be regulated differently for formal and informal neighborhoods. Additionally, PGS has the most potential to enhance the sense of belonging among expatriate household groups. The differentiated UGS planning recommendations we proposed offer new insights into strengthening spatial equity and social integration. • Nonlinear relationships were revealed between green space and residents' happiness. • Significant and stable inequality was identified in central Nanjing. • Nonlinear effects differ by green space types among vulnerable groups. • Differentiated green space planning can reduce green segregation based on mismatch results. • The research provides insights for creating equitable and healthy urban environments.