How does the virus infect the human body and how can N95 masks protect us?

The receptor of the new coronavirus is Angiotensin Converting 2 (ACE2). The exposed cells containing ACE2 are mucous membranes, which are mainly distributed in the oral cavity, nasal cavity, and eyes. The virus can pass through the human mouth, nose and eyes, and combine with ACE2 cells in the mucosa to infect the human body. When a person carrying the virus talks, coughs, or sneezes, the virus can be emitted through droplets or droplet nuclei, and it can come into contact with the mouth, nose, and eyes of others, and achieve human-to-human transmission. There are mainly the following two propagation methods:

Contact transmission: The virus can stay in various places with droplets. According to the latest statement from domestic medical experts, in a dry environment, the virus can survive on glass, plastic, and metal for at least 2 days, and in a suitable environment, it can survive for 5 days. Viruses are sensitive to ultraviolet rays and heat. At 56°C for 30 minutes, 75% alcohol and chlorine-containing disinfectants can effectively inactivate the virus. The best way to avoid contact and infection is to wash your hands frequently and disinfect items.

Respiratory tract transmission: Large droplets quickly fall to the ground, and small droplets stay in the air for a short time and are confined around the source of infection. After the droplet loses moisture in the air, the remaining proteins and pathogens become droplet nuclei, which drift to a distance in the form of aerosols and stay in the air for a long time, but the droplet nuclei (aerosol) is still spreading. To be clear. The best way to avoid droplets and droplet nuclear infection is to wear a mask.