A framework for green space equity in central business districts: Exposure assessment and comparative analysis for office workers across global cities

Urban green spaces (UGS) are vital for well-being, yet equitable access within high-density Central Business Districts (CBDs) remains critically understudied, despite acute health needs of office workers facing spatiotemporal constraints. This study addresses this gap by developing a novel, CBD-specific framework to assess UGS exposure and equity across five global CBDs (Shenzhen, Singapore, Melbourne, Tokyo, New York). This framework integrates: (1) An improved Gaussian Two-Step Floating Catchment Area (GA2SFCA) model quantifying daytime green exposure potential through NDVI-weighted supply and CBD-specific demand (derived from floor-area ratios), (2) A regional per capita exposure metric combining accessibility, quantity, and quality, and (3) Equity diagnostics using Gini coefficients, Lorenz curves, and bivariate local Moran's I. We apply this framework to five global CBDs (Shenzhen, Singapore, Melbourne, Tokyo, New York), revealing: (1) Significant exposure disparities: Shenzhen (highest) > Singapore > Melbourne > Tokyo > New York (lowest); (2) Equity variations: Lower inequality in Shenzhen (Gini = 0.33), Singapore (0.32), and Melbourne (0.29) vs. Tokyo (0.38) and New York (0.41); (3) Universal supply-demand mismatches via spatial clustering. This comparative analysis demonstrates how divergent urban policies yield distinct equity outcomes, with Shenzhen and Singapore offering models for effective CBD greening. Our framework provides planners with a transferable tool to advance environmental justice for high-density workplace populations. It advances beyond residential-focused models by capturing workplace-specific exposure dynamics. • CBD-specific equity framework: GA2SFCA model adapted for office workers' constraints. • Policy-driven exposure disparities: Shenzhen > Singapore > Melbourne > Tokyo > Manhattan. • Gini 0.29–0.41: Shenzhen & Singapore lead via micro-greening strategies. • 30–40 % of CBD office workers face green deficits, requiring interventions. • Transferable tool advances SDG 11 by diagnosing green injustice in CBDs.