Particle

A single piece of solid material which is small in relation to its environment. Normally characterized by its size and shape.

FAQ
A particle is a single piece of solid material which is small in relation to its environment. Normally characterized by its size and shape.
Retention mechanisms for removing particulates from air or gas enable much higher efficiencies to be realized than those applicable to liquids. Efficiencies for air filtration are normally expressed as percent penetration or retention for a stated airborne particle size. The dioctyl phthalate (DOP) test is commonly used, wherein the filter is tested with an aerosol containing 0.3 μm particles.
In a filtration process, the particle retention efficiency of a depth-type filter is often expressed in terms of the particle size (in μm) at which a set level of the total number of particles initially testing the filter is obtained. It is customary to quote the retention levels at 98% efficiency to allow for secondary filtration effects.