Risk assessment of mortality from acute exposure to ambient fine particles based on the different toxicities of chemical compositions in China

ABSTRACT Health risks, including mortalities and morbidities, attributed to chronic or acute exposure to ambient fine particulate matter (PM2.5), have been assessed based on the increments in ambient concentrations. Different toxicities of the various chemical compositions in PM2.5 mixtures have been confirmed by epidemiological evidence but have rarely been considered. We proposed an approach to calculate the disease burden of both the chemical components and concentrations of PM2.5 by combining their pre-established dose–response relationships with a multivariate Gaussian model. We estimated that PM2.5 mixtures account for 0.43 (95% CI: 0.29 ~ 0.56) million premature deaths in China in 2013, consistent with estimates based on single-pollutant models in quantifying the total risk but with differing risk distributions. The residential, an elemental carbon-rich emission sector, accounted for approximately a quarter of PM2.5 emissions, but for half of the premature deaths attributable to air pollution, due to the stronger toxicity of carbonaceous particles than other PM2.5 compositions. Conventional risk assessments based on PM2.5 mass assume equality in the toxicity of PM2.5 compositions and may therefore fundamentally underestimate the skewness of the risk distribution and the adverse health effects of particles from the residential emissions. The different toxicities of the of PM2.5 compositions modify the risk estimates and thus should be included in emission reduction plans.