Most Penetrating Particle Size (MPPS) is a key metric used to determine a Filter’s efficiency, it defines the worst case size of a particle for that filter design. As filters make use of four main mechanisms:
- Impaction
- Interception
- Diffusion
- Electrostatic attraction - Only for charged particles
they vary in effectiveness based on the mechanism in play, typically in the Interception range where a particle is too large for Impaction and too small for Diffusion.