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
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Resistance to Oil
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Letter Designation
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not resistant
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N
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resistant
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R
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oil proof (strongly resistant)
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P
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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.
