Since the outbreak of novel coronavirus pneumonia in early 2020, public health control measures such as wearing masks, washing hands frequently and maintaining social distance have played an important role. Recently, a video about "there are carcinogens in the disinfection residues of masks. Shake before using masks" has aroused discussion on the Internet. According to the video, when wearing the mask, shake or shake the unpacked mask in the air for 10 to 20 times, otherwise directly wearing the mask disinfected with ethylene oxide will have the risk of cancer. So, is this view correct? As an important petrochemical product and disinfectant, ethylene oxide is widely used in washing, pharmaceutical, printing and dyeing industries. For example, it is used in the disinfection of medical supplies such as bandages, sutures and surgical instruments. However, exposure to high concentration ethylene oxide will cause damage to human body and cause cancer risk. Experts in relevant fields pointed out that medical articles in China have relevant technical standards, and can be used normally as long as the relevant values of residues are under the national mandatory standards. For example, in novel coronavirus pneumonia outbreak in the early 2020, there were a shortage of anti epidemic materials such as masks and protective clothing. Many factories produced protective clothing that needed to be removed for 7 to 14 days before being released. Some medical masks produced by factories will have chemical residues after processing, which will take about 14 days to resolve and release. After reaching the relevant standards, it is already in a safe state and can be used by the crowd immediately. Experts stressed that it is unscientific to "talk about toxicity regardless of dose" for mask disinfection residues. On May 6, 2020, the General Administration of market supervision (Standards Committee) officially issued the recommended national standard of technical specifications for children's masks, which stipulates the basic requirements, appearance quality and test methods of masks for children aged 6 to 14. Among them, the ethylene oxide sterilization residue in the harmful substance residue of children's masks shall not be higher than 2 μ g/g。 The network video also pointed out that the five masks tested were below the national specified value. In addition, some mask industry practitioners pointed out that not all masks need to be sterilized with ethylene oxide. For example, Shanghai Dasheng sanitary products manufacturing Co., Ltd. uses ultrasound for disinfection in the manufacturing process of masks. The bacterial residue after disinfection is far lower than the national standard, which can meet the protection use of public daily life. Its products are not only supplied to the domestic market, but also exported to the United States, Canada and other countries and regions. Experts suggest that when consumers choose masks, the key is to choose products produced by formal enterprises. The products produced by some small workshops and companies with incomplete qualifications may have defects in raw materials and processes, resulting in unqualified products or excessive bacteria. The State Drug Administration has also been stepping up efforts to crack down on illegal vendors. Consumers can rest assured to use masks produced by formal enterprises. So, how to use masks scientifically in daily life? Li Taisheng, director of Infectious Medicine at Peking Union Medical College Hospital, pointed out that wearing masks, washing hands frequently and keeping social distance are the most important measures to prevent respiratory infectious diseases. Among them, wash your hands before wearing the mask. Be sure to touch only the outside of the mask and not the inside of the mask. "Theoretically, disposable medical surgical masks should be replaced after 3 to 4 hours of use. When removing masks, we should also pay attention to the scientific storage of masks and place waste masks in the medical waste bin." Li Taisheng said, "if we master the basic specifications for the use of these masks, we should be able to use masks scientifically and safely." (outlook new era)