Study On Optimal Design Of Urban Residential Green Space Based On Green Space Measurement Method

With the rapid development of global urbanization and the rapid expansion of cities,more and more natural surfaces are replaced by artificial environments,and urban ecosystems are destroyed,which seriously harms the physical and mental health and well-being of residents.The mental health of the elderly is not optimistic because of the decline of physical function and the change of living conditions.As an important place for residents to carry out physical activities and social exchanges in their daily lives,reasonable and effective planning and design can promote the physical and mental health of the elderly and stimulate social vitality.The research on the relationship between urban green space and mental health has increased significantly in the past ten years,but these studies often only focus on the influence of a single green space index or potential variable on mental health,and there are few proofs on the causal relationship and correlation mechanism between them.In this study,the main urban area of Nanjing(six districts in the city)was taken as the research area.Based on the urban satellite,street view images and residents’ samples of 17 residential quarters in the main urban area,the relationship between street vegetation and people’s subjective feelings was established through Arc GIS,SPSS and Amos.Calculate various green space measurement indicators(subjective and objective green space indicators),intermediary variables(physical activity,neighborhood satisfaction,sense of belonging and environmental perception)and mental health scores,establish structural equation models(single,parallel and serial intermediary models),and analyze the mechanism of green space in residential areas on residents’ mental health;According to the effective way of green space index to mental health,this paper puts forward the green space design strategy of residential area to regulate residents’ mental health and applies it to Crossstreet community.The conclusions are as follows:(1)Residents’ perception of the environment in the city center is more positive than that in the surrounding areas.Residents’ sense of monotony is the highest and sense of vitality is the lowest in the border areas of Gulou District,Xuanwu District and Qixia District,so the urban landscape in this area needs to be optimized.People’s perception is related to the actual functional areas and road types of the city.The negative perception of industrial land,commercial land and old blocks is higher,and the environmental perception of living streets is the most positive.Therefore,it is of key significance to improve the positive environmental perception of living streets around old residential areas,and street view vegetation can reduce the negative environmental perception and improve the positive environmental perception,which is the key factor affecting environmental perception.(2)As for the mechanism model of green space and residents’ mental health in residential areas,the single intermediary model shows that when the green space index is extended from two-dimensional normalized difference vegetation index(NDVI)to three-dimensional green visibility and green visual exposure,the effect on mental health increases;Green vision rate can directly affect mental health and significantly promote positive environmental perception.When green vision exposure is an independent variable,environmental perception has the highest effect on mental health.When the subjective green space measurement index is the independent variable,there are intermediary signs of neighborhood satisfaction,sense of belonging and subjective built environment,and the effect of subjective green space quality is higher than quantity.(3)The parallel mediation model shows that NDVI has a positive effect on mental health when mediation variables work together.The effect of subjective green space index on neighborhood satisfaction and subjective built environment is higher than that of single intermediary model.The higher the amount of green received by residents in their daily activities,the more positive they feel about the environment.High-quality green space can promote more physical activities and perceive more mental health benefits.The serial intermediary model shows that NDVI has a direct effect on mental health when the subjective green space function-neighborhood satisfaction is used as a continuous intermediary;Higher NDVI can enhance the perception of the quantity and quality of green space,promote neighborhood satisfaction and positive perception of the built environment,thus promoting mental health.(4)The design strategy of green space in residential areas to regulate residents’ mental health: improve the greening degree and green space quality of street scenes in urban residential environment,and increase small green spaces around each intersection or T-junction;Provide plant devices of various sizes and heights in residential green space for people with different physical conditions to use,and provide facilities to shelter from sunlight,rain and wind to enhance people’s comfort;Avoid overly complicated garden road design,provide formal facilities for different levels of physical activities,and provide informal green space for exploration and adventure;Edible plants are added to the plant design of residential green space to provide residents with opportunities to participate in gardening activities.This study analyzes the mechanism of the influence of green space in residential areas on the mental health of the elderly,and puts forward and applies strategies,which enriches the research content of the relationship between urban green space and mental health,provides empirical basis for the planning and design of green space in residential areas in an aging society,and is conducive to the construction of healthy cities.