Is it good for kn95 masks to have valves or not?

When you buy masks recently, you will find that KN95 masks/N95 masks are divided into two types: with or without breathing valve and without breathing valve. Why do masks have breathing valves? If mask wearers, people with chronic respiratory diseases, heart diseases or other diseases accompanied by breathing difficulties, use KN95 masks/N95 masks, it may make it more difficult for the wearers to breathe. Why? We know that KN95 or N95 masks have a relatively high level of protection. It can be understood that this type of mask with good protection effect is thicker, so the breathing force needs to be stronger than ordinary masks. Therefore, the use of KN95 or N95 masks equipped with breathing valves can make them breathe easier and help reduce heat accumulation.

　　
1. The difference between breathing valve
We often see some more expensive masks like KN95 and N95. As for the difference between KN95 and N95, we will not discuss it here. This article mainly introduces the breathing valve, such as anti-smog masks, which have a breathing valve switch like a button to breathe. The design of the valve is one-way air outlet, with several layers of flaps on it.
When inhaling, the mouth cover will close tightly. At this time, the air inhaled by the wearer enters through the mask, that is, the air is filtered through the mask before entering the human body. At this time, the mouth cover is closed to ensure that no particles enter.
When exhaling, the mouth cover will open. At this time, the air exhaled by the wearer passes through the exhaust port to let the hot and humid air radiate. At this time, the exhausted air is not filtered by the mask. In the figure below, the function of the breathing valve can also be clearly seen.
　　
Some people may think that the effect of breathing valve is better and the protection effect is better. The fact is, the same, whether a mask has a breathing valve or not can protect the wearer. The difference is that the N95 with an exhalation valve can protect the wearer, but because the breathing valve mentioned above is a one-way design, the gas exhaled by the wearer is not filtered, and the droplets or germs and viruses exhaled by the wearer will be transmitted through the breathing valve. To the surroundings, so the mask with breathing valve only protects the wearer but not the people around. Mainly used in industrial dust masks and anti-smog (PM2.5) masks, not suitable for medical institutions. If you are a virus carrier, please use N95 without an exhalation valve and do not spread the virus.
　　
You can watch the news program, you will find that the front-line doctors and nurses wear masks without breathing valves, so in medical use, they do not have breathing valves, and only civilian ones have breathing valves.
　　
2. Summary
1. Whether the mask has a breathing valve or not has the same protective effect on the wearer, but if there is a breathing valve, it only protects the wearer and does not protect the surrounding people;
2. If you have been diagnosed with pneumonia, please use a mask without breathing valve;