The material and textile method of the mask make the gap of the mask smaller than the diameter of the virus. The cotton gauze mask that filters out the virus is mainly based on this principle and plays a protective role." Therefore, its protective effect is relatively low. The general gauze mask has a resistance The principle of dust is mechanical filtration, that is, when dust hits the gauze, it passes through layers of barriers, blocking some large particles of dust in the sand cloth.
