What are the common masks?
Now we often mention masks, including kn95, N95, medical surgical masks, etc.
The first is kn95 mask. According to the classification of national standard gb2626-2006 respiratory protective equipment self-priming filter type particle respirator, masks are divided into kn and KP according to the efficiency level of filter elements. KP is suitable for filtration of oily particles and kn is suitable for filtration of non oily particles. When kn95 respirator is tested with sodium chloride particles, its filtration efficiency shall be greater than or equal to 95%, that is to say, the filtration efficiency shall be greater than or equal to 95% for non oil particles above 0.075 μ M.
N95 respirator is one of nine kinds of particle respirators certified by NIOSH (National Institute of occupational safety and health). "N" means not resistant to oil. "95" means that the particle concentration in the mask is more than 95% lower than that outside the mask when exposed to a specified number of special test particles.
Then there is the medical surgical mask. According to the definition of YY 0469-2004 "technical requirements for medical surgical masks", medical surgical masks are "masks worn by clinical medical personnel in the invasive operation environment, which provide protection for the patients who are treated and the medical personnel who perform the invasive operation and prevent the spread of blood, body fluids and splashes". This kind of mask is used in medical environment such as clinic, laboratory and operating room. It is divided into waterproof layer, filter layer and comfortable layer from outside to inside.