A review of methods to reduce the probability of the airborne spread of COVID-19 in ventilation systems and enclosed spaces

Abstract

COVID-19 forced the human population to rethink its way of living. The threat posed by the potential spread of the virus via an airborne transmission mode through ventilation systems in buildings and enclosed spaces has been recognized as a major concern. To mitigate this threat, researchers have explored different technologies and methods that can remove or decrease the concentration of the virus in ventilation systems and enclosed spaces. Although many technologies and methods have already been researched, some are currently available on the market, but their effectiveness and safety concerns have not been fully investigated. To acquire a broader view and collective perspective of the current research and development status, this paper discusses a comprehensive review of various workable technologies and methods to combat airborne viruses, e.g., COVID-19, in ventilation systems and enclosed spaces. These technologies and methods include an increase in ventilation, high-efficiency air filtration, ionization of the air, environmental condition control, ultraviolet germicidal irradiation, non-thermal plasma and reactive oxygen species, filter coatings, chemical disinfectants, and heat inactivation. Research gaps have been identified and discussed, and recommendations for applying such technologies and methods have also been provided in this article.

Keywords: Airborne virus ventilation; Buildings; COVID-19; Enclosed space.

Fig. 1

Filter efficiency without ionizer, illustrating theoretical and experimental results of low-efficiency fibrous HVAC filter media (Agranovski et al., 2006).

Fig. 2

Filter efficiency with ionizer, illustrating the experimental efficiency of low-efficiency fibrous HVAC filters (Agranovski et al., 2006).

Fig. 3

The thermodynamic range for thermal comfort and suggested conditions for decreased viral survivability (Spena et al., 2020).

Fig. 4

Typical diagram of an HVAC system with UVGI integration (Menzies et al., 2003).

Fig. 5

Schematic of a DBD packed-bed reactor (Xia et al., 2019).

Fig. 6

Silicon dioxide and silver nanoparticle fiber coating (Joe et al., 2014).

Fig. 7

Carbon nanotube fiber coating (Park and Hwang, 2014).