Particulate air pollution and mortality in 38 of China's largest cities: time series analysis

Objectives To estimate the short term effect of particulate air pollution (particle diameter <10 μm, or PM₁₀) on mortality and explore the heterogeneity of particulate air pollution effects in major cities in China.Design Generalised linear models with different lag structures using time series data.Setting 38 of the largest cities in 27 provinces of China (combined population >200 million).Participants 350 638 deaths (200 912 in males, 149 726 in females) recorded in 38 city districts by the Disease Surveillance Point System of the Chinese Center for Disease Control and Prevention from 1 January 2010 to 29 June 2013.Main outcome measure Daily numbers of deaths from all causes, cardiorespiratory diseases, and non-cardiorespiratory diseases and among different demographic groups were used to estimate the associations between particulate air pollution and mortality.Results A 10 µg/m³ change in concurrent day PM₁₀ concentrations was associated with a 0.44% (95% confidence interval 0.30% to 0.58%) increase in daily number of deaths. Previous day and two day lagged PM₁₀ levels decreased in magnitude by one third and two thirds but remained statistically significantly associated with increased mortality. The estimate for the effect of PM₁₀ on deaths from cardiorespiratory diseases was 0.62% (0.43% to 0.81%) per 10 µg/m³ compared with 0.26% (0.09% to 0.42%) for other cause mortality. Exposure to PM₁₀ had a greater impact on females than on males. Adults aged 60 and over were more vulnerable to particulate air pollution at high levels than those aged less than 60. The PM₁₀ effect varied across different cities and marginally decreased in cities with higher PM₁₀ concentrations.Conclusion Particulate air pollution has a greater impact on deaths from cardiorespiratory diseases than it does on other cause mortality. People aged 60 or more have a higher risk of death from particulate air pollution than people aged less than 60. The estimates of the effect varied across cities and covered a wide range of domain.