Megacity urban green space equity evaluation and its driving factors from supply and demand perspective: A case study of Tianjin

Urban green space (UGS) equity is crucial for sustainable urban development, social harmony, and stability. Given the escalating environmental justice crisis in megacity UGS, ensuring spatial justice and social equity in these areas is vital for sustainable development. This study analyzes the equity of UGS in megacity by assessing both spatial equity from the supply perspective and social equity from the demand perspective while exploring key factors driving this equity. This study found that: 1) The green Gini coefficient in Tianjin's central city, stands at 0.7787, indicating significant spatial inequity, with small UGS exhibiting the highest, followed by medium and large spaces. 2) There is a varying perception of UGS equity across different socioeconomic groups, most pronounced in the center urban area, then in the encircling urban area and remote urban area, indicating a gradual diffusion of green equity from the city center outward. 3) Key external factors influencing UGS equity include economic development, population density, traffic patterns, and local environmental quality, while internal factors like accessibility and size also play a role in spatial equity. Thus, enhancing UGS equity in megacities requires not only top-down supply interventions but also bottom-up demand feedback mechanisms.