空气污染会对人体健康造成一定程度危害，目前已经成为世界各国最为重要的环境问题之一。过去几十年尽管发达国家已经在治理空气污染问题上取得了长足进步，但随着发展中国家的迅速崛起，包括中国在内的广大发展中国家仍然面临着自身发展与环境污染的双重压力。准确定量国家或地区因空气污染引起的人群或个体的潜在健康风险，对于促进公众积极参与空气污染治理行动，早日实现清洁空气目标具有重要的推动意义。本研究通过耦合环境科学、流行病学等多领域模型方法，系统评估1995-2019全球不同国家或区域空气污染对的人口过早死亡和人均预期寿命减少的影响。

首先，本研究结合网格化的人口数据以及PM_2.5浓度数据计算全球各区域PM_2.5的人均暴露浓度，并利用污染暴露响应模型和生命表方法，计算全球及13个区域由于PM_2.5暴露所导致的过早死亡人数和预期寿命减少情况。研究发现，在1995-2019这24年里，全球空气污染导致的过早死亡人数持续增加，从1995年的325万，增加到了456万人；而人均减寿程度呈先增后减趋势，从1995年的0.91年增加到2010年的1.03年，而后降低到2019的0.95年。基于指数分解分析的结果表明，人口年龄结构与升高的PM_2.5暴露浓度是促使死亡数增加的关键因素，而医疗卫生水平的提高以及PM_2.5浓度的降低则是减少死亡数的决定因素。基于区域结果分析显示，由于发展阶段及污染控制实施阶段和控制水平的差异，不同国家PM_2.5污染影响趋势及主要驱动因素呈现出一定差异。其中发达国家的死亡数在逐年下降，人均预期寿命损失也最小，大部分区域小于0.6年，而广大发展中国家的死亡数却居高不下甚至仍在升高，以中国和印度两个人口大国的情况最为严重，两区域合计占全球总量的55%，PM_2.5污染引起的人均预期寿命损失也最高（2019年两国相关减寿分别为1.16年和1.50年）。针对中国研究结果显示，2013年以来，中国政府实施了史上最为严格的污染控制行动，污染浓度和人群健康影响显著降低，2013-2020 年7年间PM_2.5暴露过早死亡人数减少了30万人， PM_2.5污染引起的全国平均预期寿命损失从2013年的1.57年降低到2020年的1.07年；由于发展程度和污染控制水平的差异，中国不同省份也呈现出不同的污染影响及减排的环境收益。

空气污染是当前人类面临的重要健康风险之一。尽管像中国一样的一些发展中国家已经认识到空气污染问题的严重性并开展了积极的治理行动，但全球总体范围内空气污染对人体健康的影响仍在恶化，尤其是落后的印度及非洲地区。为了各国人民的身心健康，各国政府应当更为主动采取有效行动并展开紧密合作，公众也应该自觉参与到治理行动中来，一起努力降低全球大气污染水平，降低大气污染带给人类的危害。

Air pollution can bring great harm to human health, making it one of the most serious environmental concerns of all the countries around the world. Although developed countries have made great progress in controlling air pollution in the past few decades, with the rapid rise of developing countries, the vast number of developing countries, including China, are still facing the dual pressures of their own development and environmental pollution. Accurately quantifying the potential health risks caused by air pollution in a country or region is of great significance. It will help a lot in promoting the active participation of the public in air pollution control actions and achieving clean air goals as soon as possible. In this study, we evaluated the effects of air pollution on premature death and the reduction of life expectancy during the 1995-2019 time series by coupling environmental science, epidemiology and other multi-domain models.

Firstly, we combined gridded population data with PM_2.5 concentration data to calculate the per capita exposure concentration of PM_2.5 in various regions of the world. The global and 13 regional number of premature deaths due to PM_2.5 exposure and the loss of life expectancy were then calculated respectively by using the pollution exposure response model and the life table method. The study found that in these 24 years, the number of premature deaths in the world rose from 3.25 million in 1995 to 4.56 million in 2019; while the average loss of life expectancy showed a trend of first increase and then decrease, it rose from 0.91 years in 1995 to 1.03 years in 2010, and then decreased to 0.95 years in 2019. The results based on the index decomposition analysis show that the age structure of the population and elevated PM_2.5 exposure are the key factors to the increase of deaths, while the improvement of medical health standards and the reduction of PM_2.5 concentration are the determinants of reducing the number of deaths. The analysis based on regional results shows that due to the differences in the development as well as the level and stage of air pollution control, the impact trend and main driving factors of PM_2.5 pollution in different countries show certain differences. The number of deaths in developed countries is decreasing year by year, and the loss of life expectancy per capita is also slight, which is less than 0.6 years in most regions. While the number of deaths in the vast developing countries is still high or even rising. The two worst countries are China and India. They together account for 55% of the global deaths in 2019 and their average loss of life expectancy caused by PM_2.5 is also the highest (1.16 years and 1.50 years respectively in 2019). According to the research results of China, the PM_2.5 concentration and its impact on human health have been significantly reduced since the Chinese government has implemented the most stringent pollution control actions in history in 2013. The number of premature deaths due to PM_2.5 exposure has reduced 300,000 while the national average loss of life expectancy decreased from 1.57 years in 2013 to 1.07 years in 2020. Due to the differences in development and control levels, different provinces also showed different results in the environmental benefits of abatement.

Air pollution is one of the most important health risks of human beings. Although some developing countries like China have recognized the seriousness of air pollution and carried out active governance actions, the impact of air pollution on human health is still worsening globally, especially in the backward regions like India and Africa. For the physical and mental health of people in all countries, governments all over the world should take more active actions and cooperate closely. The public should also consciously participate in governance actions, and work together to reduce the level of air pollution as well as the harm it brings human beings.