Quality reveals what quantity conceals: Deceptive equity patterns in urban green space distribution

Source abstract

Equitable provision of urban green space depends on how green space exposure is measured, yet aggregate, quantity-focused metrics can mask disparities in quality. We introduce the concept of deceptive equity, in which apparent distributional fairness conceals substantive inequality, and test it across 344 postcode areas in Sendai, Japan. For three dimensions — ecological (NDVI), perceptual (Green View Index) and service provision (Accessible park count) — we paired a quantity indicator with a quality indicator. A quantity–quality divergence emerged in every dimension: wherever a quality indicator showed a significant socioeconomic gradient it favoured affluent areas, whereas the corresponding quantity indicators were neutral or favoured deprived areas. Deprived areas could reach more parks overall (Spearman's ρ = 0.43, p < 0.001), yet access to large parks favoured affluent areas (ρ = −0.36, p < 0.001), as did tree-dominated street greenery (ρ = −0.32, p < 0.001). Several vegetation and street-greenery indicators also followed U-shaped relationships invisible to linear analysis; for dense vegetation, moderately deprived neighbourhoods reached only 39–52% of the levels at both socioeconomic extremes. Quality deficits further aligned spatially with deprivation, forming contiguous dual-burden zones. Aggregate metrics can therefore misrepresent environmental justice; equity assessment requires within-indicator disaggregation and nonlinear analysis, with policy tailored to both deprived peripheries and land-constrained mid-deprivation areas.