When used correctly, air and HVAC filters can help reduce airborne contaminants, including viruses, in a small building or space. However, air cleaning or filtration alone is not enough to protect people from COVID-19. MERV-13 or higher filters can trap particles capable of carrying the COVID-19 virus. However, because the filter only works when the system moves air through the filter and because particles are trapped, they are not removed, the virus can continue to live inside the filter. To reduce this risk, the Centers for Disease Control and Prevention (CDC) recommends allowing air to flow for longer periods of time.
When changing the filter, it is important to use protection as particles inside the filter may contain live viruses. To help direct air to a desired location, such as an HVAC return air grille or a portable air cleaner inlet, a barrier can be aligned with the intended airflow. The virus is trapped in mucus or saliva particles, which enter the filter and are removed from the air. This can be done passively, by intentionally placing heating, ventilation and air conditioning (HVAC) supply and exhaust grilles, or by intentionally creating pressure differentials between adjacent spaces through the specification of compensated exhaust and supply air flow rates.
When considering air cleaning technologies that potentially or intentionally expose building occupants, safety data should apply to all occupants, including those with health conditions that could be aggravated by air treatment. It is important to consult professionals with experience in heating, ventilation and air conditioning (HVAC) when considering changes to HVAC systems and equipment. Scientific advances in filter design and manufacture have reduced the amount of increased pressure drop and its resulting impact on HVAC operations, but not all filters have adopted the latest technology. That's why it's important to open windows and doors whenever a fan is used to replace indoor air without outside air.
These accessories disinfect air as it circulates through mechanical ventilation, ceiling fans, or natural air movement. If you can't get below 800 ppm, you'll need to rely more on improved air filtration (including portable HEPA air filters). Viral RNA has reportedly been found in return air grilles, return air ducts, and heating, ventilation and air conditioning (HVAC) filters, but detection of viral RNA alone does not imply that the virus is capable of transmitting the disease. Before making any changes to the air filter of an HVAC system, users should consult their HVAC manual or an HVAC professional.
The Building Clean Air Challengeexternal icon helps building owners and operators improve indoor air quality and protect health. UVGI coil treatment devices are not designed to disinfect air and should not be installed for air disinfection purposes. The only way to effectively remove particles from the air is with a system that circulates air continuously. 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.