No Child Left on the Sidelines: Fostering Equality in Outdoor Activity Environments in Beijing Metropolitan Area

In rapidly urbanizing metropolitan areas, children increasingly face risks to their physical and mental health, largely due to constrained access to suitable outdoor spaces that support regular physical activity. The uneven distribution and varying quality of these urban outdoor environments further intensify such risks by limiting children’s opportunities for safe, stimulating, and health-promoting activities. However, the existing research often lacks a systematic framework to quantify these spatial inequities across multiple dimensions. This study aims to fill this gap by constructing a robust analytical framework for evaluating outdoor environmental quality. It quantifies spatial distribution and determinants of these inequalities. The framework is structured around four core dimensions: Safety, Facility Variety, Fun, and Greenness. Taking Beijing as a case study, data from 1598 primary and secondary schools were analyzed. The Gini coefficient and Moran’s I were used to evaluate the equality and spatial clustering of environmental indicators, while the Geographically Weighted Regression model explored how Spatial Construction, Social Development, and Economic Level shape environmental quality. The results reveal the following findings: (1) the quality of children’s outdoor physical activity environments in Beijing is notably unequal, especially regarding Greenness and Fun; (2) these disparities correspond closely to the city’s “core–periphery” metropolitan structure; and (3) the relationships between metropolitan-level factors and environmental quality exhibit strong spatial heterogeneity. This study provides a comprehensive framework for evaluating and visualizing inequalities in children’s outdoor environments, offering empirical support for inclusive and health-oriented urban governance.