Neighborhood Effects of Blue Space in Historical Environments on the Mental Health of Older Adults: A Case Study of the Ancient City of Suzhou, China

With the rapid aging of the global population, China’s old urban areas, especially historical urban areas, are facing a more severe aging situation. In the context of heritage protection, the development and regeneration of historical urban areas are restricted. They usually face the aging and decay of housing, infrastructure, and public service facilities, which are harmful neighborhood environmental factors to the health development of older adults. Since the World Health Organization adopted “healthy aging” as a development strategy to deal with population aging, the mental health of older adults has become an increasingly important public health issue. A growing body of research demonstrates the positive impact of blue spaces (including oceans, rivers, lakes, wetlands, ponds, etc.) on older adults’ mental health, yet evidence on the potential of blue spaces in a historical environment to promote mental health among older adults remains limited. Therefore, exploring the neighborhood impact of blue space on the mental health of older adults has become a new entry point to provide an age-friendly environment for older adults in the ancient city. This study uses multi-source data such as community questionnaire data, remote sensing images, urban street view images, and environmental climate data of the ancient city of Suzhou, to extract a variety of blue space quantitative indicators, and uses the hierarchical linear model and mediation effect model to explore the neighborhood impact of blue space exposure in the historical environment on older adults, to try to explore the impact path and formation mechanism behind it. The result is that exposure to neighborhood blue space in Suzhou’s historic urban area is significantly related to the mental health of older adults. Additionally, neighborhood blue space exposure improves the mental health of older adults by relieving stress and promoting physical activities and social interaction. The health effects of neighborhood blue space exposure vary among elderly groups with different age and income stratifications, and have a greater impact on the healthy lifestyle and mental health of older adults in younger and lower-income aging groups. Based on a multidisciplinary theoretical perspective, this study enriches the empirical literature on the impact of blue space on the mental health of older adults in historical environments and provides a scientific basis for the regeneration planning of “healthy neighborhoods” and “healthy aging” in historical urban areas.