March 5, 2020 - The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHARE) has published resources on how building HVAC systems can properly combat airborne infectious diseases, including a dedicated webpage that provides proactive guidelines for building industry professionals concerned about COVID-19.
Keeping indoor air quality high and having proper air circulation and ventilation are extremely important in reducing a person’s risk of contracting viruses like COVID-19, especially in high-risk areas like healthcare facilities. ASHARE recommends a two-step approach: exhausting air out of the building, and cleaning air within the building with filters and by circulating clean air from outside.
Filtering air, however, is not by itself an effective in reducing the transmission of COVID-19. Many commonly used air filters, such as many types of HEPA filters, are only rated to capture particles 0.3 microns or larger. Coronaviruses, on average, are 0.1 microns in size and may not be captured by an air filtration system. To be effective, any system that incorporates filtration fine enough to capture such small particles will still require additional power to overcome the pressure drop involved in pushing air through smaller pore sizes and to be designed so that air does not leak past the filter.
Furthermore, the virus will continue to live on the surface of the filter for a time, so extra care must be taken by those changing the filters. Which all comes back to the core recommendation: wash your hands often, and do not touch your face!
For further information, see Freedonia’s reports HVAC Equipment, Global HVAC Equipment, Global Filters, and Consumer Air Treatment Systems in the US.