The second plenary meeting of the expert panel of the working coordination group of the national implementation of the Stockholm Convention and the working coordination group of the national implementation of the Mercury Convention was held virtually on May 11th with all panel members included. Zhang Peichao, vice president of CCAIA and Zhang Xin, vice president participated in the webinar as expert members. The meeting was chaired by Professor Yu Gang, Director of the expert panel. First, Xiao Xuezhi, Deputy Director of the Foreign Environmental Cooperation Center, Ministry of Ecology and Environment, briefed the participants on the details of the 12th coordinator meeting of the national coordination group for the implementation of the Stockholm Convention and the third coordinator meeting of the national coordination group for the implementation of the Mercury Convention. The 2022 work arrangement was reviewed at the conference. The attendees were also informed about the progress of the preparation of the national mercury emission and release list and the national implementation plan of the Stockholm Convention on Persistent Organic Pollutants (2022 Supplement Edition). The meeting focused on the Research Report on the Emission Factors of Dioxin Like Substances. In its speech, CCAIA stressed that as China's caustic soda was basically membrane process, It is suggested that the dioxin emission factors of chlor-alkali production in the toolkit of UNEP 2013 version should be clearly defined as whether it is the diaphragm or membrane method. At the same time, it is suggested that the differences of raw material routes should be considered in the calculation of combustion tail gas emission factors and output of PVC production by ethylene oxychlorination-based method.