KN95 is divided into two types with or without exhalation valve. People with chronic respiratory disease, heart disease or other diseases accompanied by symptoms of dyspnea may use the KN95 mask to make it harder for the wearer to breathe, so using an KN95 mask with an exhalation valve will make it easier for them to breathe and help reduce heat accumulation.
The design of the exhalation valve is very delicate, with several layers of flaps. During inhalation, the flap will close tightly to ensure that no particles enter. As you exhale, the flap will open, allowing the hot and humid air to escape. At the same time, there is a soft flap inside to ensure that no small particles enter.
In the past two days, there have been many misunderstandings about KN95 with exhalation valve. Some people think that there is no protective effect if there is an exhalation valve. A study published in 2008 specifically investigated whether the exhalation valve would affect the protection of the wearer. The conclusion is: whether there is an exhalation valve does not affect the respiratory protection of the wearer. Simply put, the KN95 mask with an exhalation valve can protect the wearer, but not the people around it. If you are a virus carrier, please choose KN95 mask without exhalation valve, do not spread the virus.
Masks are not a panacea, but wearing masks correctly and frequently washing and disinfecting can greatly reduce the chance of infection! Note: Wear a surgical mask, wash your hands frequently, reduce going out and don't go to crowded places!