27 JAN 2026 (TUE) 17:05 - 17:35

Effects of Exposure to Urban Green Spaces, Heat Stress and Air Pollution on Mortality Risk: A Geo-Health Perspective    

Miss GAN Ziying 

( Supervisor: Prof Wendy Y Chen )

Abstract:

As an emerging field, Geo-Health integrates geospatial technologies, (spatial) epidemiology, and health services/resource allocations, with a focus to fight the burden of diseases. A key thread of existing studies attempts to theorize how the spatial structure of neighborhood built environment could influence the health outcomes of individuals living/working in these neighborhoods. Of particular importance are urban green spaces, whose salubrious effects have received increasing scholarly attention. Amongst several direct and indirect pathways, the linkages of green space exposure-urban heat mitigation/air pollution reduction-reduced mortality have been documented in the literature. Recent work suggests that increasing vegetation cover could regulate urban microclimate via evapotranspiration and shading, thus preventing high ambient temperatures on heat-related cardiovascular morbidity and mortality. Additionally, urban vegetation could remove air pollutants (such as PM2.5) through dry deposition, which could significantly reduce the mortality burden of residents. Systematic examination of the relationships between green space exposure, multiple environmental stress exposure and mortality risk is therefore of great significance. 

While mounting empirical evidence has been generated, knowledge gaps remain. On the one hand, an integrated framework is needed to simultaneously incorporate urban green space exposure, heat stress and air pollution to systematically assess the individual and interactive, direct and indirect effects of multiple environmental exposures on residents’ health. On the other hand, existing studies mainly focus on differences in green space exposure between social groups, define it as green equity, and often use green equity directly as a proxy of health equity, assuming that a more equitable distribution of green spaces will automatically lead to more equitable health outcomes. In fact, even when the spatial distribution of green spaces becomes relatively equitable, substantial differences in health vulnerability and various pathways can lead to highly uneven health benefits across different groups, so that inequalities in mortality risks and health outcomes may persist. In other words, green equity cannot be simply translated into health equity, and the distinctions and linkages between these two concepts have not yet been clearly elucidated. 

To fill these two knowledge gaps, this study takes Guangzhou and Zhuhai as the study areas and constructs a comprehensive analysis framework of multiple environmental exposures and mortality risk, centred on the links between green space exposure, heat stress, air pollution and mortality risk. The research objectives include: (1) to reveal the spatial patterns and inequality characteristics of green space exposure, heat stress and air pollution exposure in Guangzhou and Zhuhai and associated green/environmental inequality; (2) to analyse the direct and indirect, individual and interactive pathways through which multiple environmental exposures affect all-cause and cause-specific mortality risks; (3) to assess the spatial heterogeneity of effects of green spaces on mortality risks; and (4) to examine the links and differences between green equity and health equity, and to identify patterns of health inequalities across different exposure combinations and vulnerable groups. 

This study will use individual-level death registration data from 2017-2021 to construct cohorts of all-cause, CVD and CRD mortality, and will combine these data with green space exposure, heat exposure, air pollution exposure and SES indicators to build a multiple environmental exposure database. It will then employ spatial models, SEM, Cox survival analysis and DLNM to conduct analyses at both long-term and short-term time scales and at both area and individual levels. The findings of this study will advance theoretical understanding of the health effects of urban green spaces and environmental justice, and provide scientific evidence for optimising urban green space layouts, and promoting health equity.