How do HEPA air filters work?
Most HEPA filters consist of interlaced glass fibers that are twisted and turned in myriad directions to create a fibrous maze. As particles traverse this web, they’re taken out of circulation in the following ways:
Direct Impaction: Large contaminants, such as certain types of dust, mold, and pollen, travel in a straight path, collide with a fiber, and stick to it.
Sieving: The air stream carries a particle between two fibers, but the particle is larger than the gap, so it becomes ensnared.
Interception: Airflow is nimble enough to reroute around fibers, but, thanks to inertia, particles continue on their path and stick to the sides of fibers.
Diffusion: Small, ultrafine particles move more erratically than larger ones, so they’re more likely to hit and stick to fibers.
