Buffering effects of green space on residents' mental wellbeing: A regression discontinuity analysis during COVID containment policy shift

During the COVID-19 pandemic, access to green space was crucial for mental wellbeing, particularly in urban areas under lockdown. However, studies on the transition from strict containment measures to reopening are limited. This transition, while relaxing mobility and enabling free access to green spaces, also increases infection risks. Our study used a regression discontinuity design (RDD) with a unique dataset (N = 2545) from two major Chinese cities, Beijing and Shanghai, to examine the effects of the COVID containment policy shift on mental wellbeing and green space exposure. We compared participants by different green exposure categories to investigate variations in mental wellbeing during this transitional phase. The findings confirm that the policy does not promote short-term mental wellbeing, as measured by CES-D scores, self-rated health, happiness, and frequency of negative feelings. Residing 400–1200 m from a park, but not extremely close (within 400 m), confers mental health benefits. Visual exposure to greenery from windows bolsters mental wellbeing compared to limited greenery views, although the magnitude of this effect is modest. This study underscores the importance of urban green spaces in buffering mental wellbeing impacts of major policy changes during pandemic, highlighting their importance in urban planning and public health strategies.