Open public activity areas, such as schools, hotels, high-speed railway stations, cinemas, supermarkets, restaurants, etc., are densely populated public spaces, which are easy to breed pathogens and cause the scenes of object-to-person and person-to-person transmission. It is difficult for infection prevention and control measures to fully cover the environments at all times and scenes, and it is very easy to have blind areas for prevention and control, which will cause the viruses to escape.