The Effects of Green Space Scale and Structure on Mental Health from the Perspective of Neighborhood Differentiation

Urban green spaces can purify the environment, beautify the landscape, enhance the diversity of the ecosystem, improve the quality of space, and effectively promote public health. Green spaces can also improve residents' mental health by reducing pressure, promoting outdoor exercise, and increasing social capital. The spatial difference in green space distribution aggravates the differences between different social and economic groups and has different effects on their mental health. Many studies have focused on the relationship between the green space scale and mental health; however, only a few have explored the impact of green space structure. It is necessary to study the impact of the quantity and structure of green spaces in different neighborhoods on mental health from the perspective of green space equality. Taking the suburbs of Shanghai as a case area, this study focuses on the impact of neighborhood green space on mental health by integrating a questionnaire survey and multi-source green space data. It measures the quantity and quality of neighborhood green spaces and compares them among different neighborhoods. The quantity of green space is measured by the green space rate in neighborhoods and the NDVI around 1 km distance from neighborhoods. The structure of green space consists of the vegetation community structure, foliar habits, vegetation coverage, and accessibility of parks. Then, we constructed five ordered logit models to analyze the impact of green space scale and structure in high-end, low-end, inner suburban, and outer suburban neighborhoods on the mental health of residents. As this study mainly focuses on residents' green space and mental health, the research also controls for individual socio-economic attributes, activity variables, and neighborhood-built environment variables. The results show that: 1) The scale and structure of green spaces in different neighborhoods were significantly different. The difference in green space in high- and low-end neighborhoods was more significant than that in the inner and outer suburban neighborhoods. For inner suburban neighborhoods, the quantity of green space was better, but the accessibility of parks was lower than that in outer suburban neighborhoods. 2) Increasing the proportion of trees and shrubs in the neighborhood and increasing the accessibility of parks around the neighborhood was beneficial for the residents' mental health. 3) The mental health of residents in low-end neighborhoods was significantly affected by the vegetation coverage in the neighborhood and accessibility of parks. In contrast, residents in high-end neighborhoods were not sensitive to green spaces. 4) Residents in the inner suburban neighborhood were affected by the scale of surrounding green space and vegetation coverage in the neighborhood. In contrast, the green space rate and park accessibility in outer suburban neighborhoods had significant effects on the mental health of residents. Through research on low-end and inner suburban neighborhoods, attention should be paid to greenspace planning in the neighborhood. In contrast, for high-end and outer suburban neighborhoods, attention should be paid to the balance of green space inside and outside the neighborhood. This study considers both quantity and structural indicators of neighborhood green spaces, analyzes the impact of green space on mental health from the perspective of neighborhood differentiation, and enriches previous green space and mental health research that only focused on the measurement indicators of the quantity of green space.