The principle of using slow-release gaseous disinfection factor to disinfect air has been proved to be feasible, but the problem is that a disinfection stick has very limited space to disinfect. While considering the killing effect of chlorine dioxide on viruses, we must also consider the harm to human health. A few days ago, the first financial reporter saw on some e-commerce platforms that an air disinfection stick product with a killing effect of 99.9% on coronavirus is being sold. This is a long thin tube with a shape similar to that of a pen.
According to the manufacturer, this product has reached the medical level and can be directly worn on the body or placed in the indoor space requiring disinfection. The anti-virus effect can be maintained for about two weeks.
The first financial reporter carefully reviewed the working principle of this air disinfection stick. In the thin tube, the sodium chlorite liquid reacts directly with the solid acid to generate chlorine dioxide gas. As chlorine dioxide can produce strong oxidation after contacting with pathogens, which can destroy the components of pathogens, chlorine dioxide gas can be continuously released through slow-release agents and slow-release membranes, which can play a role in air disinfection.
At least onethousand times the difference from the disinfection and sterilization concentration
Previously, people used chlorine dioxide as a disinfectant mainly for liquid disinfection. The special feature of this product is that it uses gaseous disinfection, which can greatly save costs. And theoretically, compared with liquid disinfection, when the gas reaches a certain concentration in the air, it can cover any surface of the whole space without leaving a dead corner, and can also disinfection and sterilization the virus in the form of aerosols.
Based on the above principle, the key question is, how much concentration of chlorine dioxide in the air can kill the virus? In the early stage of the epidemic, a research team in Taiwan hoped to develop an intelligent and robust chlorine dioxide gas release system and assess the impact of chlorine dioxide emissions on the indoor environment. To this end, they reviewed some cases of chlorine dioxide use in hospitals.
Based on a number of studies from 2006 to 2016, it is found that high concentration chlorine dioxide has an effective disinfection effect on confined spaces. For example, in a 2007 study, researchers used 200-1000ppm (parts per million) of chlorine dioxide gas to evaluate the germicidal efficacy of indoor air in laboratories, hospitals and conference rooms. The results showed that when the concentration reached 625ppm, the disinfection effect reached 90% within 30 minutes.
Dr. luobeiping, a researcher in the Department of environmental science of Zurich Federal University of technology, explained to the first finance and economics reporter: "the concentration of 625ppm chlorine dioxide has been particularly high. People can't stay in such a concentration environment. Generally, they can enter only after closed disinfection. Generally, in the environment with people working, the maximum concentration of chlorine dioxide in the air can't exceed 0.1ppm."
This also means that while considering the killing effect of chlorine dioxide on viruses, we must also consider the harm to human health.
Luobeiping said that it is absolutely impossible for the concentration of chlorine dioxide slowly released through a thin tube to reach hundreds of ppm. "This kind of air disinfection rod may be several orders of magnitude different from the concentration required for disinfection, at least a thousand times different." He told China business news, "through ventilation and adsorption on walls and furniture surfaces, the concentration will be further reduced. If the concentration is not enough, it will not play an anti-virus role."
The enterprise has not yet issued a strict review report
The first financial reporter noted that this air disinfection stick product was produced by an enterprise in Shanghai. According to the public sales records, the company originally sold a product called "sterilization and disinfection stick", which can be used for deodorization and sterilization, such as putting it in a refrigerator for deodorization. At the end of October last year, the company changed its business scope, added a new item of "production of disinfection products for infectious disease prevention" and "upgraded" the product to a new anti coronavirus disinfectant.
According to the person in charge of the company, the product has the disinfection and sterilization effect of coronavirus, and has passed the inspection in terms of safety. However, the first financial reporter found that the current public test reports are only about the bactericidal effect of the stock solution against bacteria, and the company has not issued detailed effectiveness data for killing novel coronavirus.
In this regard, Professor shenhanming of the University of Macao put forward: "since the manufacturer claims that the product is effective in killing novel coronavirus, it must disclose the detailed effectiveness data before being allowed to go on sale. If it is a laboratory simulation environment, then all laboratory parameters should be listed. This is a product involving the public interest and cannot mislead the public. The relevant regulatory authorities should also bear the responsibility of market supervision."
An insider told the first finance and economics reporter: "the primary gaseous chlorine dioxide is used by the World Health Organization (who) The identified new generation of safe disinfectant is a kind of cheap, safe and efficient product. The principle of using slow-release gaseous disinfection factor to disinfect air has been proved feasible by many authoritative experiments at home and abroad. However, the problem is that a disinfection stick can disinfect very limited space, which depends on whether you put it in a closed wardrobe for disinfection or use it for disinfection in a larger public space. "
The above-mentioned people proposed that the key to chlorine dioxide disinfection is to make chlorine dioxide molecules "evenly dispersed in the air", so as to achieve continuous disinfection effect. "We are designing an intelligent system that can ensure the continuous and uniform release of chlorine dioxide gas concentration, and can adjust the air supply system and concentration dose." He told China business news. He added that the matrix layout pipeline designed by the intelligent disinfection system transmits the gasification disinfection factor, which can ensure the continuous and stable concentration of disinfection and sterilization in a large space, and has no harm to the human body.
He also said that at present, there are very few products with such slow-release disinfection effect in the market, and the relevant standards have not been established. The industry still needs to make joint efforts to further develop disinfection standards.
An expert from the Institute of Atmospheric Sciences of the Chinese Academy of Sciences told the first finance and economics reporter: "it is also very difficult to accurately detect the content of chlorine dioxide in the air. To judge whether a product has disinfection effect, we must see the complete scientific evaluation report issued by the testing institution before reaching a conclusion."