As an expert in the field of air purification, I can confidently say that HEPA filters can help reduce inhalation of SARS-CoV-2 and other airborne viruses. Indoor ventilation improvements, HEPA purifiers, and respirators can all reduce the inhalation of these viruses, as well as aerosolized bacteria, particulate pollution, and allergens such as pollen, dust, bacteria, fungi, etc. Research studies have demonstrated that HEPA filters can remove viruses from the air, but their effectiveness depends on the size of the virus particles. Contagious viruses that cause respiratory illnesses can be transmitted directly through the air or be enclosed in respiratory droplets that are released when an infected person coughs or sneezes.
When viruses are inside the droplets, the size of the droplets suspended in the air is larger and it is easier to remove them with HEPA filters. It may seem logical that a medical air purifier is needed to filter viruses. As it turns out, standard HEPA air purifiers can filter viruses. The MK3 filter samples come from Pullman AC and NitroPep Ltd pre-treated them with a 0.002% chlorhexidine digluconate solution (Azelias) using an automated treatment system at room temperature to produce coated filters. Once the filters were aged, there was no significant increase in cell infection compared to unaged filters.
Cleaning or replacing HEPA filters should be done more frequently during allergy seasons, when there is a high content of pollen and particulate matter in the air. This causes the coronavirus, and most other viruses, to have a much smaller particle size than a HEPA filter may intend to trap. While an air purifier with a HEPA filter can help remove these small particles from the air, the viruses are also likely to be found on a person's skin or on a hard surface touched by an infected person. HEPA filters are ideal for respiratory allergies, such as mold, pollen, dust, and pet dander, because these allergens are airborne. However, studies show that a HEPA filter can still trap such tiny particles, and in fact, the filter is very likely to trap most of those tiny particles it finds.
To optimize the efficiency of HEPA filters, mechanical filters require periodic cleaning or replacement to work at their best. However, extensive studies still need to be done before the use of a HEPA filter can be recommended to protect against airborne viruses. The MK3 filters and filters treated with CHDG were installed in an industrial condensing air unit and operated for 6 hours. Air purifiers and HVAC filters are designed to filter contaminants or contaminants from the air that passes through them. According to the EPA, these HEPA filters can remove airborne particles as small as 0.3 microns in size. In conclusion, HEPA filters can help reduce inhalation of SARS-CoV-2 and other airborne viruses by trapping larger particles suspended in the air.
However, they may not be effective against smaller particles such as those found on surfaces or skin. Cleaning or replacing HEPA filters should be done more frequently during allergy seasons when there is a high content of pollen and particulate matter in the air. Extensive studies still need to be done before recommending their use for protection against airborne viruses.