1)China

The standard filter material is divided into two categories (KN and KP) according to the filtering performance. The KN category is only suitable for filtering non-oil particles (NaCl), including KN90 ( ≥ 90%) , KN95 ( ≥ 95%) , KN100 ( ≥ 99.97%) Three levels. 

KP class is used for an oil filter (DOP , Dioctyl phthalate or paraffin oil) and non oil filter, comprising KP90 ( ≥ 90%) , KP95 ( ≥ 95%) , KP100 ( ≥ 99.97%) three levels.

According to the filtration efficiency, it is divided into : Ⅰ, Ⅱ, and Ⅲ. The corresponding filtration efficiency : Nacl medium is ≥ 99% , ≥ 95% , ≥ 90% ; Oil medium is ≥ 99% , ≥ 95% , ≥ 80% .

2) United States

According to the filter material of the middle layer of the mask, it is divided into three types : N , R , P series

N is used to protect non-oil aerosols, R, P are used to protect non-oil and oil aerosols .

Low protection (Level1) , medium protection (Level2) and high protection (Level3) .

 Level1 can block 95% of bacterial particles, even if it only reaches low protection standards, it is enough to protect general community users .

Level2 and Level3 ( medium to high protection standards ) require masks to block at least 98% of bacteria and particles, and the pressure difference is only lower than 49.0Pa/cm . 

Medical N95 masks need to not only meet the FDA Surgical Masks-Premarket Notification Submissions Guidance for Industry and FDA Staff standards, but also meet the NIOSH requirements for N95 masks. The synthetic blood penetration and surface moisture resistance have been tested. The FDA standard is basically Follow the ASTMF2100 standard. 

3) Europe

According to the tested particle penetration rate, it is divided into three grades : P1(FFP1) , P2(FFP2) , P3(FFP3) . Both Paraffin oil and Nacl are required.

FFP1 low filter effect ≥ 80% , FFP2 low filter effect ≥ 94% , FFP3 low filter effect ≥ 97% .

The filtration efficiency of FFP2 masks is very close to that of medical protective masks, KN95 masks and N95 masks mentioned above .

4) Japan

DS1: Low filter effect ≥ 80% ; DS2: Low filter effect ≥ 99% ; DS3: Low filter effect ≥ 99.9% . (Nacl and oil testing at the same time)

5) Korea

KF series are divided into KF80 , KF94 , KF99 .

F80: ≥ 80% ( only nacl medium ) ;    KF94: ≥ 94% (oil and nacl) ; KF99: ≥ 99%  (oil and nacl).