Assessment of spatial and socioeconomic disparities in urban green space accessibility based on a Physical Activity Diversity Index (PADI)

Urban green spaces (UGS) contribute to residents' health by promoting physical activity. However, there are significant spatial and socioeconomic disparities in UGS accessibility, leading to unequal access to UGS benefits among residents. Current assessments of UGS accessibility often overlook the role of UGS in promoting physical activity. Additionally, the consideration of UGS components typically focuses on their quantity rather than diversity. In light of this, our study proposes an evaluation method for the Physical Activity Diversity Index (PADI) of UGS and revises the supply scale parameter in the Gaussian two-step floating catchment area (Ga2SFCA) model based on this index. Taking Harbin, China as an example, we measure UGS accessibility and explore its association with residents' income levels using the bivariate Moran's I and multiple linear regression models. Our findings indicate that a higher PADI can partially compensate for insufficient UGS area, thereby increasing accessibility in certain areas and alleviating the relative disadvantage of low-income groups in accessing UGS. Considering PADI can more accurately identify underserved areas, providing more precise guidance for urban planning. This study highlights the importance of considering the diversity of UGS components in accessibility assessments and offers feasible solutions to mitigate spatial and socioeconomic disparities in UGS accessibility.