Even before the emergence of coronavirus (SARS-COV-2) which took the world by storm, surgical masks were already being used in the healthcare and construction industries.
Now since the arrival of the coronavirus pandemic surgical mask use has multiplied several fold.
Medical masks form a barrier between a person's face and external environment.
They tend to cover the nose, chin and sides of the face of the wearer, protecting it from dust, pollen, nasal and respiratory secretions.
According to European standard EN 14683,surgical masks are divided into :
- Type I and IR - Bacterial Filtering efficiency (BFE) of 95%
- Type II and IIR- Bacterial Filtering efficiency (BFE) of 98%
(Note: R indicates Splash Resistance)
These type 1 and IR stops the transfer of infection from the wearer to the external environment.
It will stop the spread of respiratory & nasal secretions when the wearer exhales.
They do not work efficiently the other way around - i.e. protecting the wearer from immunological agents.
They can be worn by patients to limit the spread of infection to other people.
Layers in a Surgical Mask
They are 3 ply masks which denote that it is made up of 3 separate layers;
Outer and inner layer made up of non woven material, whilst the middle layer is made up of polypropylene.
The middle layer acts as a filtration barrier.
- Outer Layer acts as a water repellent layer - this will protect the wearer from inhaling large aerosolized liquid particles.
- Middle Filter Layer - acts as a barrier between the two layers (outer and inner)
- Inner Layer acts to absorb water - It will absorb secretions when the wearer exhales.
This absorbency can get used up early, that's why these masks are disposable. They should be discarded after using them once. (1)
Surgical masks do not form an efficient seal around the face, so air can easily leak out from the edges.
Because of this, they are not required to pass a face fit test, as compared with respirators.
They do have a nose clip so the mask can sit firmly on the nose. Elastic loop provides an adjustment leverage, so can be worn by people of all age and sizes.
Surgical masks are cost effective methods and widely used by people while out and about in public places in this Covid 19 era.
Choosing an appropriate mask should be done after a proper risk based analysis.
It should be based on an individual health status, their environment and nature of their job while comparing it with properties of that particular mask.
Respirators protect from small airborne particles, gases & vapour, whilst surgical masks protect the wearer from large airborne particles, dust and secretions