As the largest developing country,China has been changing rapidly over the last three decades and its economic expansion is largely driven by the use of fossil fuels,which leads to a dramatic increase in emissions of air pollutants.China is now facing the worst air pollution problem in the world.A number of epidemiological studies on air pollution and population health have been conducted in China,using time-series,case-crossover,cross-sectional,cohort,panel or intervention designs.The increased health risks observed among Chinese population are somewhat lower in magnitude,per amount of pollution,than the risks found in developed countries.However,the importance of these increased health risks is greater than that in developed countries,because the levels of air pollution in China are very high in general and Chinese population accounts for more than one fourth of the worlds totals.Ambient air pollution alone contributes to over 1.2 million deaths and 24 million healthy years of life lost in China,ranking at number 4 among all risk factors contributing to the health burden.Future research in China will need to clarify the life-time course of these effects with full control of potential confounders(e.g.prospective cohort studies),to examine the relevance of cumulative exposure,to disentangle the effects of the various pollutants,to gain insights into the modification of individual socio-demographic characteristics and seasonal variation of air pollution health effects.