Nguyen and colleagues make quality the central problem of green-space research. Reviewing 68 articles from 59 studies, they show that health relationships cannot be adequately represented by generic greenness measures alone. Environment type, vegetation type, size, connectivity and both objectively and subjectively assessed qualities appear relevant, with tree canopy showing more consistent benefits than grassland for several outcomes. The review’s theoretical contribution is to shift environmental analysis from presence to differentiation: what kind of green space, configured how, experienced by whom and for what forms of use? Its methodological importance lies equally in identifying the heterogeneity and weakness of existing measures, particularly around culturally appropriate amenities, soundscape and networked spatial qualities. This opens a direct bridge to design research because quality is where epidemiological exposure begins to meet architectural and landscape specificity. Green space becomes an assemblage of form, access, perception, ecology and programme rather than a uniform land-cover category.
