According to the FDA explanation and CDC’s recommendations, N95 respirators and surgical masks (face masks) are examples of personal protective equipment that are used to protect the wearer from airborne particles and from liquid contaminating the face (https://www.fda.gov/). N95 respirators meet the U.S. National Institute for Occupational Safety and Health (NIOSH) requirement for air filtration by filtering at least 95% of airborne particles. The NIOSH respirator selection logic defines respirators with filters in the N, R, and P series. N series respirators, including the N95 mask, are only effective in the absence of oil particles, such as lubricants, cutting fluids, or glycerin( https://en.wikipedia.org/). In healthcare, the N95 mask needs to have NIOSH and FDA approval. In the USA, OSHA requires all healthy workers who are expected to perform patient activities with those suspected or confirmed to be infected with COVID-19 to wear respiratory protection such as N95 respirator medical masks.

Medical N95 mask material usually has 5 layers. The first layer, also called the outer layer, is made with non-woven fabric. The outer layer is treated hydrophobically. The second layer is made with filter sponge. The third layer is made with melt blown cloth. The fourth layer is made with melt blown cloth. The fifth layer also called the inner layer is made with ultra-soft non-woven fabric. Non-woven fabric is also known as synthetic polymer fibers produced through a process called melt blowing that forms the inner filtration layer that filters out hazardous particles including the COVID-19 virus.

KN95 is also called a mechanical filter respirator that meets the standard originating in the People’s Republic of China ( https://en.wikipedia.org/). It has the ability to filter 95% of air particulates 0.3 microns and larger. The Chinese government has permitted KN95 respirator masks to be used for the covid-19 pandemic (https://www.extmedical.com). The FDA authorized KN95 respirators to be used in accordance with CDC’s recommendations in their appendix A, updated April 24, 2020 (https://www.cnn.com).

Medical KN95 mask material usually has 4 layers. The first layer, also called the outer layer, is made with Non-woven fabric, and is treated hydrophobically. The second and third layers are made with melt blown cloth. The fourth layer, also called the inner layer, is made with ultra-soft non-woven fabric. Non-woven fabric is also known as synthetic polymer fibers produced through a process called melt blowing that forms the inner filtration layer that filters out hazardous particles including the COVID-19 virus(https://www.extmedical.com).

N95 and KN95 medical masks are tested for fluid resistance (hydrophobically), filtration efficiency including particulate and bacterial filtration efficiency, flammability and biocompatibility (https://www.tri-cpromo.com). For example, the mask filters specific amounts of viruses or bacteria, reduce the amount of and/or kill viruses, bacteria, or fungi, or affecting allergens, or the respirator contains coating technologies unrelated to filtration (i.e. to reduce and or kill microorganisms). As a result, it also needs to have NIOSH and FDA approval and be regulated under product code MSH(https://www.fda.gov/).

Reference:

1.U.S. Food and Drug Administration. 2020. N95 Respirators And Surgical Masks (Face Masks). [online] Available at: <https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respirators-and-surgical-masks-face-masks> [Accessed 1 May 2020].

2.En.wikipedia.org. 2020. N95 Mask. [online] Available at: <https://en.wikipedia.org/wiki/N95_mask> [Accessed 1 May 2020].

3.En.wikipedia.org. 2020. Mechanical Filter Respirator. [online] Available at: <https://en.wikipedia.org/wiki/Mechanical_filter_respirator#Other_standards_(KN95_and_others)> [Accessed 1 May 2020].

4.Geneva Sands and Cristina Alesci, C., 2020. FDA Changes Course And Allows China's KN95 Mask To Be Used In US. [online] CNN. Available at: <https://www.cnn.com/2020/04/03/politics/fda-china-kn95-us-certain-criteria/index.html> [Accessed 1 May 2020].

5.PCS), W., 2020. White 4-Ply KN95 Face Masks N95 Respirators Alternatives & Equivalents(10 PCS). [online] Extmedical.com. Available at: <https://www.extmedical.com/p/4-ply-kn95-face-masks-n95-respirators-alternatives-and-equivalents-10-pcs-99038/white.html> [Accessed 2 May 2020].

6.Reanod International Network Technology Co., L., 2020. What Is The Difference Between Kn95 And N95 Masks?. [online] Tri-cpromo.com. Available at: <https://www.tri-cpromo.com/news/difference-between-kn95-and-n95-masks.html> [Accessed 2 May 2020].