Question of the week…
What is a HEPA filter?
Think about the long list of important terms, buzzwords, and acronyms in your life that you haven’t quite wrapped your brain around: FDIC-insured, Big Data, Organic, to name a few.
If you’ve ever bought an air purifier or vacuum, you can probably add “HEPA” to that list.
What does it mean for a filter to be called “HEPA”, and why does it matter? We’re happy to explain:
What does HEPA mean and where did it come from?
HEPA, which stands for High Efficiency Particulate Air, is a designation used to describe filters that are able to trap 99.97 percent of particles that are 0.3 microns. Though the HEPA standard and certification process wasn’t established until 1983, development of HEPA filters dates back to World War II, when American scientists with the Manhattan Project created the first HEPA filter to capture radioactive particles released during the creation of the atomic bomb.
What are HEPA filters made from and how do they work?
Most modern 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.