Several different types of face masks may be used in medicine. In most cases they are intended to protect the mouth and nose.

A mask may need to protect the user against:

(1) dust and debris

(2) body fluids

(3) infectious aerosols


Surgical masks:

(1) protect against splashes, spray and splatter but not aerosols

(2) do not seal tightly to the wearer's face

(3) are not considered respiratory protection against infectious aerosolized particles


Air-purifying respirators:

(1) half mask with or without face shield

(2) Powered Air-Purifying Respirator (PAPR) with face mask or hood


An air-purifying half mask respirator must fit the user's face tightly to be effective, and so fit testing is required.


Designation for air-purifying half masks:

(1) percent of airborne particles filtered out: 95, 99 or 100

(2) resistance to oil


Resistance to Oil

Letter Designation

not resistant




oil proof (strongly resistant)



The filter for a PAPR is termed high efficiency (HE) is >= 99.97% of airborne particles are filtered out.


For some infectious diseases more extensive protection is required to include eyes and exposed skin. This may require multiple separate types of protection or a full body suit.

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