Research progress of air pollutant emissions of Chinese coal⁃fired power plants

China is the largest coal producer and consumer in the world，and the coal⁃fired power sector is one of the major sources of air pollutants. In order to improve ambient air quality continuously，China has issued and im⁃ plemented some staged⁃stringent emission standards and control measures to reduce air pollutant emissions from the sector. Accurate quantification of emission characteristics and long⁃term trend of coal⁃fired power plants is essential for deeply understanding the environmental effect of the coal⁃fired power sector. This paper reviews the control stages， standards and the research progress of coal⁃fired power sector emissions over the past two decades. It aims to improve the knowledge on air pollution control process and evolution of emissions for the coal⁃fired power sector and to provide a scientific basis for environmental pollution prevention in the sector. The coal⁃fired power sector in China has experienced four stages，namely emission growth，emission restraining，policy tightening，and ultra⁃low emission retrofit for 2000—2020. Based on the gradually improved “bottom⁃up” methodology，the emissions of three typical pollutants， PM2.5，SO2 and NOx，were estimated to reach the peak around 2004—2005，2005—2006，and 2011，respectively，fol⁃ lowed by continuous declines. The annual emissions of PM2.5 decreased from million tonnes to hundred thousand tonnes，and those of SO2 and NOx from ten million tonnes to million tonnes. Attributed to insufficient informa⁃ tion on the emission control measures， some global and Asian emission inventories overestimated the level of China coal⁃fired power sector’s emissions. Influenced partly by the West⁃to⁃East Power Transmission Project，the frac⁃ tion of power sector emissions declined in the eastern provinces with a large demand of electricity，and increased in the western provinces with a large abundance of energy. Besides， the “ top⁃down ” method based on satellite observation has been also applied to evaluate the effectiveness of emission control for the coal⁃fired power sector. For the past two decades， the shares of installed capacity and electricity generation for the coal⁃fired power have dropped clearly，but they are still at a relatively high level compared to that in European and North Ameri⁃ can countries. Along with the increase of non⁃fossil energy in the future，the clean use of coal should be further strengthened to continuously play a basic role in power security and supply and to achieve the target of synergetic con⁃ trol of pollution and carbon emissions.