Under the COVID-19, air purifiers have become popular products, especially in places with more people and closed spaces. However, some experts said that if the air purifier is used improperly, it will not only fail to achieve the preventive effect, but also may increase the risk of virus transmission!

For example, the location of air inlets and outlets in confined spaces such as elevators has a great impact on airborne viruses. Researchers from the University of Nicosia in Cyprus have published a research result in the journal fluid physics of fluid mechanics, which shows that although air purifiers in confined spaces can accelerate the flow of air, they may actually increase the risk of virus transmission. Without ventilation, the air quality in small spaces will decline rapidly. However, increasing ventilation will increase the speed of air circulation in small spaces, and the air may carry viruses. Some elevator manufacturers have added air purifiers to solve this problem, but the design of these systems does not take into account their impact on the overall air circulation.

Previous studies have shown that when an unmasked person coughs, saliva droplets can move 18 feet in five seconds. Researchers calculated a three-dimensional space equivalent to an elevator that can accommodate five people. Simulate mild cough at one location in space, and add air inlets and outlets at different locations to study their effects on circulation. An air purifier is also included in the simulation.

The researchers found that when the ventilation rate is low, the risk of airborne virus is the lowest. The observed risk of virus transmission increases with the increase in the number of infected people in the elevator. Limiting the number of passengers in the elevator will minimize the spread of the virus. The researchers also suggested that "the regulatory authority should determine the minimum ventilation required according to the type of building."

This study focuses on the role of the air purifier, only considering the air intake and exhaust related to the purifier, without considering the mechanism of virus killing inside the purifier. But even if air purifiers are installed, the spread of viruses in the air is still very serious.

At present, the air disinfection technology on the market is difficult to achieve full-time and full scene coverage of the space environment, and it is very easy to have a prevention and control blind area, resulting in the escape of the virus. For example, although the air disinfection technology used in unmanned environment such as ultraviolet ray and ozone has remarkable disinfection effect, it can not solve the problem of sustainability of disinfection effect; Although UV circulating wind, plasma and other technologies have solved the problem of man-machine coexistence during disinfection, due to the basic principle they adopt, artificial air circulation needs to be applied in the space environment, which still cannot effectively deal with the possible virus aerosol pollution at any time, but is easy to accelerate the air transmission of the virus.

Therefore, it is very important to choose the right air purification products. The air purifier only plays a role in reducing and inhibiting bacteria and viruses, while the disinfection machine plays a role in disinfection and sterilization viruses and other pollutants, and it is of medical grade, which is more safe and reliable to use.