Elevated PM2.5 Nickel and Vanadium Increases Cardiovascular Mortality in Hong Kong

Abstract

O-31C3-4 Background/Aims: Depending on the chemical composition, some PM2.5 may be more dangerous than others. There is evidence that the toxicity and composition of airborne PM2.5 vary from one city to another. In Hong Kong, the recently available PM2.5 component time series data allow us to examine the heterogeneity in toxicity of PM2.5 components and its effects on cardiovascular disease mortality at a population level. To examine the association between the levels of PM2.5 chemical components and cardiovascular disease (CVD) mortalities in Hong Kong. Methods: Generalized additive model with log link and Poisson error was used to analyze the cardiovascular mortality, PM2.5 components, and covariate factors of the 2 years 2001 and 2005 in Hong Kong. As the PM2.5 components data were available only once every sixth day, we used the moving total mortality count as the health outcome for the time-series analysis. The results were provided as the percentage excess risk (ER) in CVD mortality per interquartile range difference in the concentration of each PM2.5 component. Results: We found statistically significant evidence that CVD mortalities were higher in days with higher concentrations of vanadium (ER = 4.7%; 95% CI: 1.5%–8.0%), nickel (ER = 4.1%; 95% CI: 1.1%–7.1%), and organic carbon (ER = 0.8%; 95% CI: 0.2%–1.4%). On average, the health effects of PM2.5 on day 0 became apparent in the subsequent days: day 2, day 3, and day 4. The nickel/vanadium and CVD mortality association echoes the earlier Hong Kong experience of the CVD mortality decrease linked to the airborne nickel/vanadium reduction in the 1990s. Conclusion: The nickel/vanadium and CVD mortality association warrants attention to the health effects due to marine bunker oil emissions in Hong Kong.