At One Place

What is a Surgical mask made of?

What is a Surgical mask made of?
Three layers of polypropylene, of which only the electrostatically charged middle one does the filtering.

Everything effective about a mask is the charge on the meltblown layer, and the charge is fragile. Washing, alcohol spraying, steaming and, in most tests, prolonged heating strip it, leaving a mechanical filter that is far worse than the original — which is why decontamination protocols for respirators had to be validated carefully rather than improvised. The other half of the story is fit: a filter is only as good as the seal around it, which is the entire difference between a loose surgical mask and a fitted FFP2 or N95 respirator, and why facial hair at the seal line matters. Valved respirators protect the wearer but vent unfiltered exhaled air, which is why they were excluded from many source-control requirements.

Component by component

Every material is a choice, and the third column is the constraint that drove it.
Part Material Why that material
outer layer spunbond polypropylene nonwoven It resists splashes and gives the mask its shape and strength; it filters almost nothing.
filter layer meltblown polypropylene, fibres roughly 1-5 µm across, electrostatically charged The charge attracts and holds particles far smaller than the gaps between fibres, which is why the mask breathes and still filters.
inner layer a softer spunbond nonwoven It absorbs moisture from breath and is comfortable against skin, which is the only reason anyone keeps it on.
nose wire aluminium or a plastic-coated wire Air takes the easiest path; without a nose seal a large share of every breath goes past the filter rather than through it.
ear loops spandex-nylon braid, welded or stapled to the edge The attachment method is a common failure point, and welded loops hold far better than stapled ones.

Other medical and personal care objects

Common questions

What is a Surgical mask made of?
Three layers of polypropylene, of which only the electrostatically charged middle one does the filtering.
What is the outer layer of a Surgical mask made of?
Spunbond polypropylene nonwoven. It resists splashes and gives the mask its shape and strength; it filters almost nothing.
What is the filter layer of a Surgical mask made of?
Meltblown polypropylene, fibres roughly 1-5 µm across, electrostatically charged. The charge attracts and holds particles far smaller than the gaps between fibres, which is why the mask breathes and still filters.

Related pages

Sources

  1. Official vendor product documentation — At One Place

How these figures are compiled and checked