How do landscape elements affect public health through the physical neighborhood environmental factors? A cross-sectional study of a subtropical high-density city, Guangzhou

BACKGROUND: Neighborhood landscapes and environments influence public health through multiple pathways, but few studies have assessed their effects in high-density cities in subtropical monsoon regions, especially mediating pathways of the physical environmental factors.Purpose: Objectives of this study are to explore associations between neighborhood landscape elements and public health in a subtropical high-density urban context, elucidate mediating effects of physical environmental factors, and propose corresponding neighborhood renewal strategies.METHODS: Nine sampling sites were selected in Guangzhou, China, and cross-sectional health data were collected from 438 participating residents using the SF-36 scale. Landscape elements of the neighborhoods, including greenness, blue spaces, walking trail systems, hard open spaces, landscape architecture, and dedicated sports spaces were mapped by unmanned aerial vehicle surveys. Six physical environmental factors were also measured in the surveys: the heat stress index (HSI), relative humidity (RH), average wind speed (AWS), negative oxygen ions (NOI), <2.5 µM particulate matter (PM2.5), illumination (I), and noise (N). Analysis of variance (ANOVA) and general linear models were used to explore differences between neighborhoods in landscape elements. Relationships between public health and both landscape elements and physical environmental factors, as well as the mediating pathways involved, were explored by correlation analysis and Mediation analyses.Results: I, RH, HSI, NOI, and PM2.5 were significantly correlated with public health in the neighborhoods, as were greenness, blue spaces, walking trail systems, and hard open spaces. No significant correlations were found between public health and either landscape architecture or dedicated sports spaces. Multiple mediation analysis showed that greenness, blue spaces and hard open spaces significantly affected public health, with mediation by I, HSI and NOI, while walking trail systems had significant effects on public health mediated by I, HSI and NOI, but the total mediation effect was not significant.Conclusion: In subtropical high-density neighborhood, landscape elements have close associations with public health, especially greenness, blue spaces, walking trail systems, and hard open spaces, mainly mediated by effects on light, thermal, and atmospheric environments. Low-quality landscape architecture and space areas do not promote public health. These closely related landscape elements and physical environments need careful attention in community renewal efforts.