occurs when the random (Brownian) motion of a particle
causes that particle to contact a fiber. As a particle vacates an area
within the media, by attraction and capture, it creates an area of lower
concentration within the media to which another particle diffuses, only
to be captured itself. To enhance the possibility of this attraction, filters
employing this principle operate at low media velocities and/or high
concentrations of microfine fibers, glass or otherwise.
The more time a particle has in the “capture zone”, the greater the
surface area of the collection media (fibers), the greater the chances of
capture. Filter manufacturers have two distinct methods of addressing
this principle — employ more square footage of fine glass-mat type
media or employ less square footage of high lofted glass media