The 3rd Technical and Management Meeting of Sino-Swiss Clean Air China Project (Phase 1) was held virtually on April 9, 2021. Overall 21 participants attended the meeting. The purpose of this workshop is to enable all participants to actively discuss knowledge, results, experiences, and potential publications about this research. Topics to be discussed at this workshop include: data analysis for each site, perform source apportionment, health impacts. ROS on offline filters, testing models, et al. Dr. Qi Lu introduced the current processing progress of the data obtained from the field campaigns conducted in Beijing and Langfang in 2021. Prof. Wang Qiyuan said that part of the online instruments is still continuing to observe. In addition, the meteorology and gas data will be uploaded to switchdrive in monthly chunks after quality-checked. Dr. Cui Tianqu provided the work progress related to filter analysis. He showed the basic information of the current collection of filters and the plan of subsequent analysis work. In addition, participants summarized the scientific results of this research, including literature, conference reports, and other publications. Finally, the discussion topics and conference agenda of the online meeting to be held in May were clarified.