2.1.2. Mental health benefits
Blue-green spaces can provide good social benefits and greatly affect the livability of modern cities and the well-being of urban residents. The frequency of exposure to the natural environment and vegetation coverage may be important for improving human well-being, especially mental health (Wentworth, 2017). The exposure to the natural environment can increase social cohesion (Kaczynski and Henderson, 2007), reduce stress, improve attention, relieve fatigue (Grigsby-Toussaint et al. , 2015), improve mood, and decrease the symptoms of major depressive disorders (Hartig et al. , 2014). For example, a good park environment has the functions of attention recovery and stress relief effects (Tan and Li, 2009). Blue-green spaces are associated with children’s cognitive development, inhibition of impulsive behavior, prosociality enhancement, and stimulation of imagination and creativity (Dadvand et al. , 2015; McCormick, 2017). There is a significant correlation between urban blue-green space and depression in the elderly (Helbich et al. , 2019). In 2021, World Health Organization (WHO) released a survey report on blue-green spaces and mental health. The short-term and long-term effects of different types of green spaces and blue spaces on mental health (Table 2) demonstrated the overall positive relationship between blue-green spaces and mental health. Especially, under the background of COVID-19 pandemic, blue-green spaces can serve as a sanctuary for interactive leisure.