What is the material and structure of the N95 mask?

Generally speaking, masks are made of non-woven materials, (non-woven fabrics are composed of oriented or random fibers, and the clothes we wear are woven fabrics, which are knitted or woven regularly)

Specifically, the raw material is polypropylene, while medical protective masks and n95 masks are generally multi-layered, also called SMS structure:

There are 3 layers of structure, SMS (2 S layers, 1 M layer), and some masks even have 5 layers of SMMMS (2 S layers, 3 M layers)

S stands for Spunbond, the diameter is about 20μm, the main function is to support the mask structure, and it has little effect on barriers

M stands for barrier layer or meltblown layer, which is the most important structure of a mask, with a diameter of about 2μm, which plays the most important role in blocking bacteria, viruses and blood penetration (Regarding the concept of μm, the diameter of human hair is generally 73μm, so the concept of 20μm and 2μm can be compared with your hair)

If there are too many layers of S, the mask will be harder, and too much meltblown layer, it may be difficult to breathe, of course, the protective effect is also the best, if the meltblown layer is too few, breathing is very smooth, but the protective effect is very poor , So it involves a balanced choice problem