The impact of heating, ventilation, and air conditioning design features on the transmission of viruses, including the 2019 novel coronavirus: a systematic review of filtration

Abstract

Historically, viruses have demonstrated airborne transmission. Emerging evidence suggests the novel coronavirus (SARS-CoV-2) that causes COVID-19 may also spread by airborne transmission. This is more likely in indoor environments, particularly with poor ventilation. In the context of potential airborne transmission, a vital mitigation strategy for the built environment is heating, ventilation, and air conditioning (HVAC) systems. HVAC features could modify virus transmission potential. A systematic review following international standards was conducted to comprehensively identify and synthesize research examining the effectiveness of filters within HVAC systems in reducing virus transmission. Twenty-three relevant studies showed that: filtration was associated with decreased transmission; filters removed viruses from the air; increasing filter efficiency (efficiency of particle removal) was associated with decreased transmission, decreased infection risk, and increased viral filtration efficiency (efficiency of virus removal); increasing filter efficiency above MERV 13 was associated with limited benefit in further reduction of virus concentration and infection risk; and filters with the same efficiency rating from different companies showed variable performance. Increasing filter efficiency may mitigate virus transmission; however, improvement may be limited above MERV 13. Adapting HVAC systems to mitigate virus transmission requires a multi-factorial approach and filtration is one factor offering demonstrated potential for decreased transmission.

Filter evaluation and selection for heating, ventilation, and air conditioning systems during and beyond the COVID ‐19 pandemic

“…Recent studies provide incontrovertible evidence that SARS‐CoV‐2 spreads via airborne transmission, mainly through the long‐distance transport of fine particulate matter (PM) in indoor environments 1,2 . Therefore, there is an urgent need to find effective controls to limit indoor transmission of fine PM during and beyond the COVID‐19 pandemic.…”

“…Recent studies provide incontrovertible evidence that SARS‐CoV‐2 spreads via airborne transmission, mainly through the long‐distance transport of fine particulate matter (PM) in indoor environments. 1 , 2 Therefore, there is an urgent need to find effective controls to limit indoor transmission of fine PM during and beyond the COVID‐19 pandemic. High‐efficiency filtration systems in heating, ventilation, and air conditioning (HVAC) systems play a vital role in controlling indoor air quality by removing various indoor air pollutants, such as particulate matter (PM), microorganisms (e.g., bacteria and viruses), and gaseous pollutants.…”