A novel approach for assessing the spatiotemporal trend of health risk from ambient particulate matter components: Case of Hong Kong.

Abstract The spatiotemporal assessment of health risk due to exposure to particulate matter (PM) components should be well studied because of the different toxicity among PM components. However, this research topic has long been overlooked. This study aimed to examine the spatiotemporal variability in ambient respirable PM (PM10) components associated inhalation carcinogenic and non-carcinogenic risk (ICR and INCR) in Hong Kong over 2015–2019. The land-use regression (LUR) approach was adopted to predict the spatial distribution of PM10 component concentrations for the period of 2015–2019, whereas the ICR and INCR values of PM10 components were also estimated using the classic health risk assessment method. Both concentration of PM10 and INCR of PM10 components showed a general decreasing trend, while ICR of PM10 components increased slightly over the study period. LUR-model-based spatial maps at 500 m × 500 m resolution revealed the important spatial variability in PM10 and its eleven components, and their associated ICR and INCR values. High pollution levels and high ICR and INCR of studied PM10 components were generally found in developed urban areas and along the road network. Despite the fact that the PM10 concentrations met the Hong Kong annual PM10 air quality objective of 50 μg/m3, but there was still significant potential health risk from the studied PM10 components. This study highlights the importance of taking PM component concentrations and associated inhalation health risk as well as PM mass concentrations into account for the perspective of air quality management and protecting public health.