An emerging number of studies on the relationship between green space and health lead us to suggest that such a relationship is scale-dependent. For instance, there are generally no or poor relationships between green space and health in studies conducted at the city level; at smaller spatial scales, different strengths of the relationships have been reported. However, detailed understanding on the dependence of such relationships on scale of analysis is still scarce as very few studies explicitly examine such a dependence. We also suggest that scale dependence is influenced by urban morphology, e.g. between sprawling and compact cities. Few studies have been conducted in compact cities. To address this question, a cross-sectional study which examined green space and association with self-reported health in Singapore was performed. We conducted a population-based household survey with the sample of 1000. Eight different circular buffers with different radii (50 m, 100 m, 200 m, 400 m, 800 m, 1000 m, 1200 m, 1600 m) surrounding each respondent’s residential address were generated to calculate the green space quantity at different scales. Through spatial assessment and statistical analysis, we analyse the relationship between green space quantity and self-reported health at all these scales.
Results/Conclusions
Through the multi-scalar approach, we found that there is no significant correlation between green space and self-reported health at smaller scales with the radii of 50 to 100 m. Significant correlations were only found when the spatial scale is not less than 200 m. Despite the very weak correlations at larger scales, we observed the strongest statistically significant association between green space amount and health status at medium spatial scale. These results corroborate another recent study, indicating that there may be a threshold level for spatial scale to manifest health effects of green spaces. We also examined the effects of green spaces at nested buffers presented to distinguish the contribution of nearby greenery and distant greenery on self-reported health. This study contributes to understanding scale effects in spatial analyses and helps to inform policy making about the appropriate scale for greenery planning and provision.