Aligning green spaces with human activity: uncovering opportunity-realization mismatches in urban green exposure

Urban green exposure provides multiple benefits, but its effectiveness depends not only on the presence of green spaces but also on whether such opportunities are realized through residents’ daily activities. However, existing assessments largely emphasize exposure opportunities and provide limited diagnosis of opportunity–realization mismatches at life-circle scale. This study developed a 15-min life-circle based opportunity–realization framework in which passive green exposure (PGE) represents exposure opportunities and human activity green exposure (HAGE), constructed by integrating location-based service (LBS) data into PGE assessment, represents realized exposure. Using 2966 life-circle service areas in Shanghai, this study quantified HAGE and PGE across visibility, availability, and accessibility pathways, identified mismatch clusters using local bivariate Moran's I, and applied an XGBoost–GeoShapley model to assess landscape configuration associations. Results showed that 911 service areas (30.7%) exhibited significant mismatches, revealing substantial local decoupling between green exposure opportunities and realization. These mismatches comprised two distinct regimes: high-realization/low-opportunity (HL), reflecting concentrated realization under limited or weakly embedded opportunities, and low-realization/high-opportunity (LH), reflecting inefficient conversion of existing opportunities into realized exposure. GeoShapley results further suggest differentiated planning implications: HL mitigation should expand and embed effective exposure opportunities by improving green space boundary and interface conditions and green contact along residents’ mobility routes. LH mitigation should activate existing green spaces by enhancing entrances, route integration, and attractiveness. Overall, this study provides a quantitative diagnostic framework to support more targeted planning for urban green exposure opportunity–realization mismatches.