Benefits of Various Urban Green Spaces for Public Health Based on Landscape Elements: A Study of Public Visual Perception

Urbanization has amplified the critical role of urban green spaces in enhancing public health and well-being. While natural landscape elements are known to influence physiological and psychological states through visual perception, their mechanistic pathways remain underexplored, and existing studies often focus on singular environments. This study examines how specific landscape elements affect public health and proposes optimization strategies for urban green space planning. Focusing on five green space types in Kunming (forests, wetlands, urban parks, street green spaces, and residential green spaces), this study employed PSPNet-based semantic segmentation to quantify landscape elements and conducted human-subject experiments using paired visual stimuli. Physiological metrics and psychological questionnaires were analysed to assess health outcomes. Key findings reveal that forests and urban parks, rich in natural elements (Plant and Earth and Mountain Elements), outperformed artificial-dominated spaces (residential/street green spaces) in physiological and psychological restoration. Artificially designed green spaces achieved benefits comparable to natural counterparts when mimicking natural element composition. Notably, aggregated indices (naturalness, artificiality, and enclosure) showed negligible correlations with health outcomes, underscoring the primacy of specific elements. The Plant and Earth and Mountain Elements mediated physiological recovery, while minimizing the Building and Artificial Element and enhancing the Sky Element exposure improved attention coherence. Excessive Water Element perception impaired heart rate stabilization, while psychological restoration mechanisms were multifaceted but were consistently linked to higher natural element proportions. These results provide actionable guidelines for optimizing visual proportions of natural elements in urban green space planning and management.