Why do we need a face mask
Coronavirus is transmitted between people, usually when someone is exposed to the secretions of the infected person. The transmission of the virus directly affects the transmission route. The current route of transmission of the new coronavirus is unclear, but past experience has shown that exposure to the body fluid that the infected person coughs or sprays, or shaking hands with the infected person lead to infection. If your hand touches something that the infected person has touched and then touches your own mouth, nose or eyes, it may also infect the virus.
Normally, people have about a liter of fluid in their lungs, which, each time they sneeze, spray like a squeezed water bottle. In vitro, they are divided into more than 40,000 droplets, each containing a large number of viruses and bacteria. Because of the huge thrust in the body, the velocity of these liquids can be as high as 35 m / s, and the propagation distance can reach 3~8 m. Come on, this picture is more intuitive.
In 2003, SARS was so horrifying because the speed at which it was transmitted through droplets was beyond control, with the south-east asian flu on monday, south-south china next monday and the whole country next monday.
So be sure to wear a mask! Even if you are exposed to an infected person, wearing a mask can prevent you from inhaling the virus directly from the droplets.
Wash your hands! Even if the virus is left in hand, hand washing can block the virus through the hand into the body.
What's the difference between KN95 and N95?
N95 mask actually is a kind of respirator, a kind of respiratory protection equipment, which is designed to fit the face more tightly than the ordinary mask, and can filter the particles in the air very effectively. The character "N" indicates that it can be used to protect non-oil suspended particles; 95 means that the filtration efficiency is greater than or equal to 95%, indicating that after careful testing, this respirator can block at least 95% of very small (0.3 micron level) test particles.
By design, if ranked according to the priority of the wearer`s own protective ability (from high to low): N95 masks > surgical masks > ordinary medical masks, ordinary cotton masks.