Of course. Wang Xinyu, deputy chief physician of the Department of Infectious Diseases, Huashan Hospital affiliated to Fudan University, said that if you are outdoors, the high-concentration aerosol emitted by infected people can be diluted by fresh air quickly due to the action of airflow, which can't reach the concentration of infected people.

Similarly, if the indoor aerosol containing high concentration of virus particles is blown to the outside through the window and diluted rapidly, it is unlikely to cause the phenomenon of "cross-building" transmission.

Air purifiers can replace ventilation.

Many experiments show that HEPA can effectively reduce the concentration of COVID-19 in the air of closed rooms, and it can be used as a beneficial measure and means to control infection.

According to GB/T 13554-2020 "High Efficiency Air Filter", the filtration efficiency of this kind of products without electrostatic treatment and after electrostatic treatment is not less than 99.95%, that is, the ratio of the aerosol quantity filtered by the filter element to the aerosol quantity before filtration.

Who also pointed out that although air purifiers can reduce the possibility of virus transmission, they do not provide ventilation and cannot replace other ventilation methods. Even if you use this kind of products, you should open the window for a few minutes every hour to introduce fresh air.