When used correctly, air and HVAC filters can help reduce airborne contaminants, including viruses, such as the novel coronavirus, in a small building or space. People expel droplets of respiratory fluid, saliva, and possibly virus into the air when breathing, coughing, and talking. Even if the water in the droplet evaporates, the droplets contain salts, proteins, and other material in addition to any viruses, which means that the remaining particles are usually a few microns in size, making them quite easy to catch with a HEPA filter. Air filters that remove small particles, such as high-efficiency particulate air (HEPA) filters, are effective in removing contaminants from the air.
The most common appliances that use HEPA filters are portable air purifiers, vacuum cleaners, and heating, ventilation, and air conditioning systems. In that sense, a HEPA air filter can protect against COVID-19 from spreading to someone from an infected person. However, as noted by the EPA, it takes a multi-pronged approach to combating COVID and other viruses. This type of filter is normally found in the best air purifiers (opens in a new tab), but not in all of them.
Some air purifiers have built-in HEPA filters and have additional filtering capacity to improve the quality of the air distributed in a room. The team chose high-efficiency particulate air (HEPA) filters, which expel air through a fine mesh that traps extremely small particles. Therefore, say the authors, filtering the virus from the air could be more important in general wards than in ICUs. Appliances that use HEPA filters only work when turned on, so you may need to run your oven fan continuously or for longer periods of time. Due to their particulate trapping qualities, HEPA air filters are an effective line of defense to combat the spread of COVID-19 indoors. You can also get high-quality HEPA air filters from large home improvement stores, but the selection is likely to be limited.
Researchers have conducted experiments to evaluate the ability of air filters to remove inactive particles in carefully controlled environments. HEPA stands for “high-efficiency particulate air” and these filters come in a variety of sizes and capacities. It's essential to purchase a filter that has the ability to filter air in a particular room size. Honeywell True HEPA Allergen Eliminating Air Purifier is a popular choice that comes in five sizes for spaces between 75 and 465 square feet. Some studies revealed that HEPA filters are capable of eliminating some viruses enclosed in droplets and those with a larger diameter than the mesh pores in HEPA filters.
A research study conducted to determine the effectiveness of air purifiers with HEPA filters (opens in a new tab) showed significant improvement in allergic rhinitis symptoms among participants. Surprisingly, the team didn't find many viral particles in the ICU room air, even when the filter was turned off. To sum up, when used correctly and combined with other measures such as social distancing and wearing masks, HEPA filters can help reduce airborne contaminants including viruses like COVID-19.