Mortality burden of ambient fine particulate air pollution in six Chinese cities: Results from the Pearl River Delta study
Introduction
Epidemiological time series studies have provided evidence of an association between daily levels of airborne particulate matter smaller than 2.5 μm (PM2.5) and daily numbers of deaths, particularly from cardiovascular and respiratory diseases (Dai et al., 2014, Pope et al., 2015, Shi et al., 2015). However, studies from Asian countries are still sparse though higher levels of particulate air pollution are often observed in Asia, making region-specific results difficult to interpret and compare with those from developed countries (Li et al., 2013, Lin et al., 2016a).
Along with the rapid socioeconomic development in recent years, some Chinese megacities are experiencing some of the worst air pollution in the world (Jahn et al., 2011). Concerns have been growing about air pollution associated health impacts and disease burden in some serious polluted regions, such as the Pearl River Delta (PRD) in the coastal part of southern China (Liu et al., 2014). This region covers 0.5% of the Chinese geographic area, but holds 4% of the Chinese population and produces about one-fifth of the total gross domestic product. Remarkable problems of traffic and particulate air pollution have emerged in this region, mainly due to vehicle and industrial emissions (Jahn et al., 2011).
Ambient PM2.5 was only included in the China's Air Quality Standard since 2013, there is thus only a limited number of studies to examine the health effects of ambient PM2.5 in China. Air monitoring data collected across cities in the PRD region have made it possible to assess the health effects and disease burden of ambient air pollution at a regional scale and in a multicity setting. In this study, we estimated the short-term associations between ambient PM2.5 and mortality, and mortality burden in the PRD, using a time-series approach.
Section snippets
Study settings
Six cities were included in this study, including Dongguan, Foshan, Guangzhou, Jiangmen, Shenzhen, and Zhuhai in the PRD region (Fig. 1). These cities are typical of the PRD cities with respect to geographical, meteorological, and cultural conditions, although they vary in population and industrial structure. Guangzhou, the capital city of Guangdong Province, is a megacity that had 12.8 million in 2013; Shenzhen, Zhuhai, Dongguan, Foshan, and Jiangmen had 10.6, 1.6, 8.2, 7.2 and 4.1 million
Results
During the study period, a total of 316,305 deaths were recorded in the six cities. Table 1 summarizes the distribution of daily mortality, air pollution, and meteorological variables in the six cities in PRD region. The daily mean numbers of total, cardiovascular, and respiratory mortality varied among the cities and ranged from 13 to 130, from 6 to 52, and from 1 to 21, respectively. On average, cardiovascular and respiratory diseases accounted for 44.55% and 13.33% of the total
Discussion
To our knowledge, this is the first multicity study on the association between PM2.5 and mortality in China. Using six cities in the Pearl River Delta region, this study illustrated that short-term exposure to ambient PM2.5 was associated with increased mortality from all causes and cardiopulmonary diseases. The observed associations were generally not sensitive to the model specifications, such as df for time trend and meteorological factors. Our analysis also provided evidence that older
Conclusions
In summary, our study suggests that ambient PM2.5 might be an important trigger of mortality risk, and is associated with remarkable mortality burden in the Pearl River Delta region of China. We also suggest that age and location of death may modify the association of PM2.5 with mortality.
The following are the supplementary data related to this article.
Acknowledgments
This study is funded by Guangdong Provincial Science and Technology Program (2016A020223008) and The National Key Research and Development Program of China (2016YFC0207000).
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