On Dec 5, Gan Zhang attended the 2nd International Symposium on Environmental Health (ISEH) at Shanghai. He gave a key note speech introducing the newly identified up-PCBs in the atmosphere of Ningbo regional atmospheric background station which was done by  Shuduan. It was very cold in Shanghai that day! He also chaired a session on ‘Toxicity characterization of emission sources’ with some ‘old’ friends and excellent young scientists, especially Wang Rong of Fudan-U who published his first paper, while he was a undergraduate student in Peking University, coauthored with Gan, who he haven’t met before!