Assessing the restorative benefits of open rooftop green spaces characteristics using virtual reality and EEG...

Open rooftop greening spaces (ORGS) offer a critical yet underexplored pathway to health restoration in high-density cities. While the general benefits of urban greenery are established, the specific environmental mechanisms and user responses within elevated, built-form-constrained spaces like rooftops remain poorly understood.

This study systematically investigates how three key design variables-Green View Index, Sky View Factor, and functional type-independently and interactively influence multidimensional health outcomes. We employed a controlled virtual reality experiment integrated with electroencephalography and subjective scales to measure psychological, physiological, and social health responses among participants (N = 97).

Our results revealed a pattern of functional and environmental specificity in health benefits. Psychological relaxation and social well-being consistently peaked in environments combining high GVI with high SVF. In contrast, physiological activity willingness showed precise calibration: low-intensity activities (e.g., walking) were favored in high visual quality settings, while high-intensity exercise was uniquely promoted in fitness-oriented spaces with high GVI but lower SVF. Analyses delineated distinct roles for each variable. GVI emerged as the broadest predictor, particularly associated with social health and relaxation. SVF specifically facilitated psychological decompression. Functional type emerged as a key driver of activity intention but had minimal direct effect on social perception. Crucially, interaction models demonstrated that synergistic combinations are superior to maximizing single elements. The pairing of medium (not high) GVI with high SVF yielded the strongest psychological restoration, and high GVI was found to enhance the mental health benefits of dining/entertainment spaces.

This study provides new quantitative evidence for the health-promoting potential of ORGS. The findings move beyond generic prescriptions, offering nuanced, evidence-based insights for salutogenic design. By leveraging specific visual-environmental synergies aligned with intended use, this work supports the design of rooftops that can contribute to urban mental resilience, social cohesion, and physical vitality.