Which particles can a HEPA filter remove from the airstream?
The HEPA standard traps very small particles, including those that are
invisible to the human eye, but harmful to our health, such as viruses and
bacteria. Since the web of fibers in a medical-grade HEPA filter are extremely
dense, they can trap the smallest particles at the highest rate, and are more
efficient at removing harmful toxins from the environment.
For perspective, a human hair is between 80 and 100 microns in diameter. Pollen is 100-300 microns. Viruses vary between >0.1 and 0.5 microns. However, it is important to remember that, even though the H13 HEPA is considered 99.95% effective at removing particles in the air measuring 0.2 microns, this is the worst case efficiency. It can still remove particles that are smaller and larger. In fact, the process of diffusion is very effective for removing particles under 0.2 microns, such as the coronavirus.
