Utilizing multi-objective optimization in improved green infrastructure for enhanced pollution reduction and carbon mitigation in sponge cities

Improved green infrastructure offers a practical approach to enhancing the environmental performance of urban green spaces. This study evaluated the benefits of transforming green spaces into improved green infrastructure in Shenzhen, a rapidly developing sponge city. Using a combination of field experiments, life cycle assessments, and optimization modeling, we investigated improvements in soil organic carbon (SOC), pollutant removal, and runoff control. Results indicate that SOC content increased by up to 11 %, while the net annual benefit reached 4.6 CNY/m2, accounting for the difference in cost and benefit between improved and baseline green spaces. Measures such as biochar addition, earthworm activity, and litter application demonstrated complementary effects, enhancing both soil health and pollution mitigation. To maximize outcomes, urban planners are encouraged to maintain a high proportion of green infrastructure and integrate targeted improvement measures to address local conditions. These findings provide actionable recommendations for balancing ecological benefits and economic feasibility in urban green space development.