High spatial resolution estimates of major PM components and their associated health risks in Hong Kong using a coupled land use regression and health risk assessment approach.

Few studies have focused on the spatial distribution of the typical components and source tracers of PM and their associated health risks, despite the fact that the chemical components of PM pose potentially significant and independent risks to human health. The main objective of this study was to evaluate the spatial distribution of major PM components and their associated health risks in Hong Kong using a coupled land use regression and health risk assessment modeling approach. The established land use regression models of the major PM components and source tracers achieved a relatively high statistical performance, with training and leave-one-out cross-validation R values of 0.85-0.96 and 0.62-0.88, respectively. The high spatial resolution (500 m × 500 m) distribution patterns of the chemical components of PM showed the heterogeneity of population exposure to different components and the related potential health risks, as evidenced by the weak spatial correlations between the mass of PM and some components. Elemental carbon, nickel, arsenic, and chromium from PM made major contributions to the total health risk and should therefore be reduced further. Our results will enable researchers to determine independent associations between exposure to the various components of PM and health endpoints in epidemiological studies.