When used correctly, air and HVAC filters can help reduce airborne contaminants, including viruses, in a small building or space. However, it is important to note that cleaning or filtering the air is not enough to protect people from COVID-19. Most public health guidelines suggest that transmission of COVID-19 is predominantly associated with large droplets. This is why air filtration is only a small part of a solution, since it generally does not address transmission by contact with the surface or by close contact between people. The distinction between droplets and airborne droplets is particle size.
We know that droplets can remain in the air for long periods of time. In addition, DNA and RNA from other viruses that are usually associated with droplets have been found in used filters. Therefore, it is important to take precautions when changing filters, as particles inside the filter may contain live viruses. Filtration in building heating, ventilation and air conditioning (HVAC) systems may be part of a general risk mitigation approach, but it is generally not considered a solution on its own.
Ventilation is the process of bringing fresh air from the outside to the inside and letting the indoor air out to maintain or improve air quality. You can purchase approved air purification systems that are specifically designed to remove dust, mold, bacteria, and viruses from the air. For many years, homeowners have had the option of installing ultraviolet lights in their HVAC system, where the air that is distributed through the home is first treated inside sealed air ducts. One of the ways you can improve the air quality in your home is to improve the filter in your HVAC unit.
In fact, research shows that changing the air in a room several times an hour with clean or filtered outdoor air (using a window fan, using higher MERV filters in a heating, ventilation and air conditioning (HVAC) system, using portable air cleaning devices, and even opening a window) can reduce the risk of transmission of COVID-19. Studies show that five air changes per hour reduce the risk of transmission by 50 percent. The only way to effectively remove particles from the air is with a system that circulates air continuously. If it's not possible to create a cross breeze, you can place a fan in front of an open window to increase airflow and blow indoor air out. Before making any changes to the air filter of an HVAC system, users should consult their HVAC manual or an HVAC professional. Air filters that remove small particles, such as high-efficiency particulate air (HEPA) filters, are effective in removing contaminants from the air.
Using ceiling fans can improve air circulation from the outside and prevent stagnant air pockets from forming inside. Experts agree that the most practical method for now is high-efficiency HEPA filtration of particulate air most commonly found in portable air purifiers. One of the ways many people are trying to protect themselves from COVID-19 is by upgrading their HVAC filters and purchasing air filtration systems. Researchers suspect that an air conditioner spread particles containing the virus among three families and suggested that restaurants improve their filtration systems and separate their seats.