In theory, this type of air filter can remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particulate matter with a size of 0.3 microns (µm). You'll notice that while HEPA filters perform incredibly well compared to many of the air filters you can find, there are a few important things missing from this list. HEPA filters don't get rid of most viruses, simply because they're too small. HEPA filters also do not remove VOCs or volatile organic compounds, since they are also too small.
Even so, HEPA filter technology can be combined with other technologies that will also remove these substances from the air. But what makes an old filter a HEPA filter? It turns out that using the term “HEPA” has a strict set of requirements. In Europe, HEPA filters must remove 99.95% (ISO) of particulate matter. In the U.
S., they must eliminate 99.97% of the particles. A research study conducted to determine the efficacy of air purifiers with HEPA filters showed a significant improvement in allergic rhinitis symptoms among participants. HEPA filters, short for high-efficiency particulate air filters, are mechanical filters designed to remove airborne particulates, such as microorganisms, dust, pollen, and pet dander, from a room. To optimize the efficiency of HEPA filters, mechanical filters require periodic cleaning or replacement to perform at their best.
HEPA filters reduce the frequency of allergens and alleviate symptoms by eliminating indoor air particles that cause allergies in susceptible people. The HEPA filters in air purifiers effectively reduced the concentration of house dust mites and particulate allergens, which are one of the main causative agents of allergic rhinitis. HEPA filters help remove these respiratory allergens from the air and improve indoor air quality. Few research studies have shown that HEPA filters can completely remove viruses from the air, but there are cases where they can help.
Cleaning or replacing HEPA filters should be done more frequently during allergy seasons, when there are high levels of pollen and suspended particulates in the air. Since HEPA filters are so good at capturing nanoparticles, it's reasonable to think that they could also capture volatile organic compounds and gases. However, this is not the case as these substances are too small for the filter to capture them effectively. Nevertheless, HEPA filters are ideal for respiratory allergies, such as mold, pollen, dust, and pet dander, as these allergens are airborne.
The important thing about HEPA air filters is that they are incredibly effective at capturing particles of almost any size. To see what the layer of randomly aligned fibers looks like, here is a close-up of the HEPA filter that Smart Air makes for The Sqair air purifier and, next to it, a view at the nanometer level with the help of a microscope. A study by the University of Castilla-La Mancha revealed the effectiveness of HEPA filters in eliminating aerosols containing the COVID-19 virus.
