ABSTRACT

Health risks, including mortalities and morbidities, attributed to chronic or acute exposure to ambient fine particulate matter (PM_2.5), have been assessed based on the increments in ambient concentrations. Different toxicities of the various chemical compositions in PM_2.5 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 PM_2.5 by combining their pre-established dose–response relationships with a multivariate Gaussian model. We estimated that PM_2.5 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 PM_2.5 emissions, but for half of the premature deaths attributable to air pollution, due to the stronger toxicity of carbonaceous particles than other PM_2.5 compositions. Conventional risk assessments based on PM_2.5 mass assume equality in the toxicity of PM_2.5 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 PM_2.5 compositions modify the risk estimates and thus should be included in emission reduction plans.