Peng Zhan, Zhong Zheng
Urban park crowding has emerged as a pressing challenge worldwide, potentially undermining their mental health benefits and exacerbating environmental inequities. This study investigated the associations among urban park characteristics, perceived crowding, and mental health, with attention to differences across sociodemographic groups. We conducted on-site surveys at 10 parks in Hangzhou, China, and combined Mann–Whitney U tests, partial least squares–structural equation modeling (PLS-SEM), and eXtreme gradient boosting (XGBoost) with SHapley additive explanation (SHAP) analysis. Results showed that younger visitors, lower-income groups, and local residents reported higher post-visit mental health scores, whereas women and older visitors perceived higher crowding levels. Perceived crowding was consistently associated with poorer mental health across the overall sample [ β = −0.603, 95% confidence interval (CI)]. Greater public transportation access, higher nearby house prices, denser vegetation configuration, greater water coverage, and greater distance from residence were positively associated with perceived crowding. More frequent park visits were associated with lower perceived crowding ( β = −0.130, 95% CI) and better mental health ( β = 0.156, 95% CI). These findings underscore the need for equity-driven park planning that optimizes accessibility, encourages revisits, and implements effective crowd management strategies to ensure inclusive and sustainable urban green spaces.