The Pros and Cons of HEPA Filters

HEPA filters, short for High-Efficiency Particulate Air, have been around since the 1950s and are commonly used in applications where contamination control is needed. This includes medical devices, food, and pharmaceuticals. HEPA filters are generally comprised of a fiberglass mat that traps contaminants and particles as they pass through. The standard for HEPA filters differs between the U.

S. and other countries, but generally the filter must capture at least 99.97 percent of the particles at 0.3 microns. To put this into perspective, particles smaller than 10 microns cannot be seen by the human eye. HEPA filters are highly efficient at removing dust, allergens, bacteria, mold and more from the air. However, they do not capture all particles, such as bacteria, allergens, and viruses which vary in size and may be smaller than 0.3 microns.

This means that some harmful contaminants may still remain in the air even after a HEPA filter has been used. Replacing HEPA filters can be costly depending on the number of times the filter is changed. It is recommended to replace them every 12 to 18 months or when needed to ensure that mold does not grow inside the fibers. The shape and compactness of the unit depends on the type of air purifier you have. It is important to understand that a HEPA filter is only part of the solution to improve indoor air quality. If you are concerned about other sources of indoor air pollution such as VOCs, viruses, and bacteria, then a HEPA filter may not be right for you.

Unfortunately, mold, VOCs, viruses, bacteria, and small particles smaller than 0.3 microns cannot be safely removed from the air with a HEPA-based air purifier. When looking for an appliance that contains a HEPA filter and is labeled “absolute HEPA” or “true HEPA” it is important to understand that these terms do not indicate that the filters actually comply with the HEPA standard. With higher humidity levels and elevated temperatures, bacteria and mold growth can even be populated in particulate filter media such as HEPA. In conclusion, while HEPA filters are highly efficient at removing large particles from the air such as animal dander, dust, pollen and more; other common particles from the air such as viruses, bacteria, and VOCs remain in the air. Therefore it is important to understand what a HEPA filter can and cannot do before investing in one.