Air Filtration and COVID-19

01.Can building air filtration protect me from getting COVID-19?

Filtration in building heating, ventilation, and air conditioning (HVAC) systems can be a part of an overall risk mitigation approach but is not generally regarded as a solution by itself.  There is no direct scientific evidence of benefit, but some reduced exposure can reasonably be inferred based on the ability of some filters to remove particles that contain a SARS-CoV-2 virus.  In order for filters to have any impact on infectious disease transmission, transmission has to occur through the airborne route, filters have to be properly installed and maintained in appropriate systems to treat recirculated air, and filters have to be appropriately designed for the building in which they are used.  More importantly, in most buildings and in most situations, filters may be considerably less effective than other infection control measures including social distancing, isolation of known cases, and hand-washing.

02.What filter should I use to protect those in my building from COVID-19?

There is no obvious answer to this question given unknowns about the nature of SARS-CoV-2 containing particles and droplets, as well as the broader issues raised above.  We do know that low-efficiency filters (e.g., less than MERV 8 according to ASHRAE Standard 52.2 or less than ePM2.5 20% according to ISO 16890-1:2016) are very unlikely to make a difference.  Properly installed higher efficiency filters can remove particles of a relevant size depending on their installed capture efficiency, but current information does not allow for specific recommendations.