Premature Mortality Associated with Exposure to Outdoor Black Carbon and Its Source Contributions in China

Abstract

Epidemiological studies have shown that outdoor black carbon (BC) has higher health risks than other constituents and the total fine particulate matter (PM2.5). In this study, we estimated premature mortality attributed to BC in China in 2013 using a health impact model combined with annual average BC concentrations predicted using the Community Multi-scale Air Quality model. Source contributions to BC from six different source sectors were estimated using the source-oriented method, including residential, industrial, transportation, open burning, power, and other sources. The sensitivity of BC-related premature mortality to emission reductions in different sources was quantified in different regions of China. The results showed that the total all-cause premature mortality related to BC was approximately 1,436,957 (95% CI: 998,746–2,029,210) in China in 2013. Residential, industrial, and transportations sources were the three main sources of BC-induced premature mortality. Central China, Yangtze River Delta, and Sichuan Basin had the highest BC-induced mortality due to a high level of emissions and a dense population. A sensitivity test by assuming the same exposure-response coefficient of BC as the total PM2.5 showed the number of deaths was 265,122 thousand (95% CI: 541,90, 445,943) which can be treated as the lower limit of the BC-related mortality in China. Despite the uncertainties in estimates, it is suggested that reducing BC emissions in China would lead to significant health benefits. Controlling BC from industrial and transportation sources would bring more relative mortality reductions, from a percentage point of view, in most provinces of China.