Qingdao Daily/Guan Hai reported on April 30th that today, @ Qingdao Metro issued an operation announcement: From now on, Qingdao Metro will check the nucleic acid detection record within 7 days and the boarding code in the middle and high risk area within 14 days. For the passengers whose first line sign of nucleic acid detection under the electronic health code in Shandong Province changed from blue to yellow, that is, "bright yellow card", and those who have lived in the city where the middle and high risk area is located for 14 days.