At a time when public health is of great concern, high hopes are placed in the decontamination of public places. However, a misunderstanding prevails: “sterilisation measures in public places can completely eliminate the spread of infection”. This idea is really wrong, and today we are going to go into the reasons.
First, there are limitations to the sterilisation measures themselves. In public places, various forms of disinfection are used, such as spraying of disinfectants, UV exposure, etc. In the case of chemical disinfectant spraying, its effects are constrained by a number of factors. Concentrations of disinfectants, time of operation, coverage, etc. must be carefully controlled. Some pathogens are likely to survive if concentrations are too low, they do not have sufficient working time, or if there is a detoxification angle. For example, in the corners of large malls, warehouses, etc., some viruses or bacteria can be hidden and spread when the cleaners are not working very well. Moreover, the resistance of different pathogens to disinfectants, such as sprouts of Bacillus, with limited use of certain common disinfectants, may remain active even in the post-sterilization environment.
Ultraviolet sterilisation is equally not without loss. The strength of UV will decline as distance increases, and in some large and complex public places, such as airport terminal halls, UV light exposures may not be available in areas far from the source of UV lamps of sufficient intensity, thus significantly reducing the disinfection effect. In addition, UV can only disinfect the surface of the object within its irradiation, and the pathogens remain viable for the part of the shadow or the area covered.
Moreover, the high mobility of people and goods in public places is a major challenge. Even in the immediate post-sterilisation environment, which is almost sterile, frequent movement of people can rapidly change the situation. For example, at railway stations, tens of thousands of passengers travel on a daily basis and may carry various pathogens. An influenza passenger can spread the virus to the surrounding environment instantaneously by coughing, sneezing and so on, while he/she is in the sterilised waiting room, while the latter may be exposed to the virus in a short time. At the same time, objects carried by people, such as luggage, parcels, etc., may also become carriers of pathogens. Contaminated luggage, when exposed to facilities such as seating, arming, etc. in public places, spread pathogens to the surface of these objects, further increasing the risk of transmission.
In addition, the emergence of new pathogens tested the effectiveness of traditional sterilization measures. As science and technology develop and the environment change, new viruses and bacteria are being created. For example, new canopy strains, which may differ from the original strains in terms of transmission properties, environmental adaptability, some of which may be more viable in the environment and have changed resistance to disinfectants. Existing sterilization programmes in public places may not be able to respond in a timely and complete manner to the threat posed by these new pathogens.
In practice, there are cases of concentrated infections in public places such as schools, writing buildings, etc., despite regular sterilization, during the high incidence of infectious diseases. This fully demonstrates the difficulty of completely disrupting the spread of infection by means of disinfection measures alone.
How, then, is it right to view public disinfection? Sterilization in public places is an important part of public health control, which can significantly reduce the number of pathogens and the risk of transmission and create a critical line of defence for public health. In hospitals, for example, strict sterilization procedures have been effective in reducing the incidence of medical-sourced infections, and in restaurants, the sterilisation of meals and the environment has ensured the food security of the eaters. But we cannot rely too much on disinfection, but we also need to integrate a variety of means of control. Public health awareness, hand washing and masking; public-sector managers to improve ventilation and reasonable control of human density; and, in the case of patients with infectious diseases or suspected patients, to prevent them from entering public places to spread pathogens.
In short, disinfection measures in public places play an indispensable role in preventing the spread of infection, but they must not be considered as a complete eradication. We need to be rational about its role and its limitations and to work together to create a healthy and safe public environment.
