Face mask utilizes filtration mechanisms and aims at optimizing between two competing necessities. The size of the mask filters pores should be small enough to trap particles and should also not be too small in order to allow the individual to breathe conveniently. Hence, masks filters are not allowed to go beyond a certain pore diameter.
To meet these optimized filtration requirements, mask should operate based on three principles. These principles are:
1.      Inertial Impaction- Dust or aerosol particles that are 1 micron or larger in size possess enough inertia to prevent them from flowing around the fibers into the filtration layers slate into the mask material and they get filtered.
2.      Diffusion- Smaller particles of 0.1 micron and smaller are not subject to inertia. They undergo diffusion and get stuck to the fibers of the filter as they undergo Brownian motion around the tortuous porous matrix of the filter fiber.
3.      Electrostatic attraction- Electro charged polymer and resin fibers attract both small and large oppositely charged particles and traps them.

The physical properties of the mask include a foldable outer part which can transform into a W shape when folded. When the mask is unfolded, a three-dimensional convex surface is formed over the nose.
The outer surface faces inwards when the mask is folded while the outer surface face outwards to minimize the chances of contacting the outer part of the mask hence minimizing contamination.