Quantity or quality? Exploring the association between public open space and mental health in urban China

•Association between Quantity or Quality of public open space and mental health was studied.•Four specific attributes were audited: activity, environment, amenities, and safety.•Analyses suggest that POS quality is crucial for residents’ mental wellbeing.•Activity and environment attributes were associated with better mental health.•Findings may help urban planners develop evidence-based approach to healthy cities. Public open space (POS) is a component of the urban built environment that is considered crucial for people’s mental health. Most studies, however, have focused on the quantity of POS, and those investigating the association between POS quality and mental health are limited. Through a 2018 survey of 590 residents and 160 POSs in Zhuhai, this study explored the association between both the quantity and quality attributes of POS and residents’ mental health in urban China. We employed an audit tool (POST) to measure POS quality and decomposed it into four attributes: activity, environmental quality, amenities, and safety. The statistical analyses suggest that POS quality is important for positive mental wellbeing, while, among the four attributes, activity and environment attributes are significantly associated with better mental health. The findings not only shed light on the potential mechanism of POS’ impact on mental health, but also help urban planners and policymakers develop an evidence-based approach to healthy cities.