Abstract:This article describes a comprehensive survey of the “Haze Observation Project Especially for Jing-Jin-Ji (Beijing,Tianjin,Hebei) Area (HOPE J³A) ” based on the project of “Formation Mechanism and Control Strategies of Haze in China” carried out by the research groups of the Chinese Academy of Sciences. Various measures are taken to understand the formation processes of several haze pollution incidents before and during APEC, such as surface measurement, radar remote sensing, vehicle navigation, satellite observation and numerical model forecasting. In addition, the environmental capacity for atmospheric pollutants, regional transportation changes, and proportions of secondary aerosols are analyzed. Finally, the emergency control measures in place during APEC are evaluated, and some suggestions for keeping “APEC Blue” are proposed.