Background Evidence from cohort studies in North America and Europe indicates that long-term exposure to fine particulate matter (PM₂ • ₅) is associated with an increased mortality risk. However, this association has rarely been quantified at higher ambient concentrations. We estimated the hazard ratio (HR) for all-cause mortality from longterm exposure to PM₂ • ₅ in a well established Chinese cohort of older adults. Methods The Chinese Longitudinal Healthy Longevity Survey (CLHLS) is a prospective cohort study of men and women aged 65 years and older enrolled in 2008 and followed up through 2014 for mortality events. We studied individuals for whom residential locations were available in 2008 for linkage to 1 km grids of PM₂ • ₅ concentrations, derived from satellite remote sensing. Cox proportional hazards models were used to estimate the effect of long-term exposure to PM₂ • ₅ on all-cause mortality, controlling for age, sex, smoking status, drinking status, physical activity, body-mass index, household income, marital status, and education. We then used our results to estimate premature mortality related to PM₂ • ₅ exposure in the population aged 65 years and older in China in 2010. Findings 13 344 individuals in the CLHLS cohort had data for all timepoints, yielding follow-up data for 49 440 person-years. In a 3-year window, these individuals were exposed to a median PM₂ • ₅ concentration of 50•7 μg/m³ (range 6•7-113•3). The overall HR for a 10 μg/m³ increase in this value was 1•08 (95% CI 1•06-1•09). In stratified analyses, HRs were higher in rural than in urban locations, in southern versus northern regions, and with exposure to lower versus higher PM₂ • ₅ concentrations. Based on the overall HR, we estimated that 1 765 820 people aged 65 years and older in China in 2010 had premature mortality related to PM₂ • ₅ exposure. Interpretation Long-term exposure to PM₂ • ₅ is associated with an increased risk of all-cause mortality among adults aged 65 years and older in China, but the magnitude of the risk declines as the concentration of PM₂ • ₅ increases.

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Background Ambient fine particulate matter (PM2.5) pollution is currently a serious environmental problem in China, but evidence of health effects with higher resolution and spatial coverage is insufficient. Objective This study aims to provide a better overall understanding of long-term mortality effects of PM2.5 pollution in China and a county-level spatial map for estimating PM2.5 related premature deaths of the entire country. Method Using four sets of satellite-derived PM2.5 concentration data and the integrated exposure-response model which has been employed by the Global Burden of Disease (GBD) to estimate global mortality of ambient and household air pollution in 2010, we estimated PM2.5 related premature mortality for five endpoints across China in 2010. Result Premature deaths attributed to PM2.5 nationwide amounted to 1.27 million in total, and 119,167, 83,976, 390,266, 670,906 for adult chronic obstructive pulmonary disease, lung cancer, ischemic heart disease, and stroke, respectively; 3995 deaths for acute lower respiratory infections were estimated in children under the age of 5. About half of the premature deaths were from counties with annual average PM2.5 concentrations above 63.61 μg/m3, which cover 16.97% of the Chinese territory. These counties were largely located in the Beijing-Tianjin-Hebei region and the North China Plain. High population density and high pollution areas exhibited the highest health risks attributed to air pollution. On a per capita basis, the highest values were mostly located in heavily polluted industrial regions. Conclusion PM2.5-attributable health risk is closely associated with high population density and high levels of pollution in China. Further estimates using long-term historical exposure data and concentration-response (C-R) relationships should be completed in the future to investigate longer-term trends in the effects of PM2.5.

Background Air pollution and its adverse effects on public health remain a considerable problem in China, where policies have been implemented to improve the situation. We aimed to estimate the disease burden associated with particulate matter (PM) 2·5 across China for 2020 and 2030 to identify the populations and regions most at risk, quantify the health benefits of air quality improvement targets, and determine the effect of population growth and ageing on this disease burden. Methods In this modelling study, we investigated premature deaths associated with PM 2·5 across China on the basis of air quality scenarios proposed by the expert group involved in the formulation of the 13th Five-Year Plan for Eco-Environmental Protection and population scenarios based on the Shared Socioeconomic Pathways of theIntergovernmental Panel on Climate Change. We used the integrated exposure-response model used for the Global Burden of Disease Study to estimate the number of PM 2·5 -related premature deaths under each scenario. Findings The projected health benefits of the air-quality-improving targets are substantial, and could reduce the number of PM 2.5 -related premature deaths in China by approximately 129 278 by 2020 and 217 988 by 2030, compared with 2010. However, since China's population is increasing and ageing, the number of PM 2.5 -related premature deaths was estimated to increase by 84 102 by 2020 and by 244 191 by 2030, indicating that the health benefits induced by air quality improvements could be offset by the effect of the population increasing in size and ageing.Interpretation To reduce the future disease burden in China, targets that are stricter than the interim target and stringent policies to improve air quality and protect public health are needed, especially for at-risk population groups, such as older individuals (aged >55 years) and patients with cardiovascular diseases, particularly in regions with a high disease burden.

Studies worldwide have estimated the number of deaths attributable to long-term exposure to fine airborne particles (PM 2.5 ), but limited information is available on short-term exposure, particularly in China. In addition, most existing studies have assumed that short-term PM 2.5 -mortality associations were linear. For this reason, the use of linear exposure-response functions for calculating disease burden of short-term exposure to PM 2.5 in China may not be appropriate. There is an urgent need for a comprehensive, evidence-based assessment of the disease burden related to short-term PM 2.5 exposure in China. Here, we explored the non-linear association between short-term PM 2.5 exposure and all-cause mortality in 104 counties in China; estimated county-specific mortality burdens attributable to short-term PM 2.5 exposure for all counties in the country and analyzed spatial characteristics of the mortality burden due to short-term PM 2.5 exposure in China. The pooled PM 2.5 -mortality association was non-linear, with a reversed J-shape. We found an approximately linear increased risk of mortality from 0 to 62 μg/m 3 and decreased risk from 62 to 250 μg/m 3 . We estimated a total of 169,862 additional deaths from short-term PM 2.5 exposure throughout China in 2015. Models using linear exposure-response functions for the PM 2.5 -mortality association estimated 32,186 deaths attributable to PM 2.5 exposure, which is 5.3 times lower than estimates from the non-linear effect model. Short-term PM 2.5 exposure contributed greatly to the death burden in China, approximately one seventh of the estimates from the chronic effect. It is essential and crucial to incorporate short-term PM 2.5 -related mortality estimations when considering the disease burden attributable to PM 2.5 in developing countries such as China. Traditional linear effect models likely underestimated the mortality burden due to short-term exposure to PM 2.5 .