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.

Uncertainty around the Long-Term Implications of COVID-19

“…It is essential to reduce long-term risks from this novel virus until we understand them better, as well as reduce the risk of new variants emerging by suppressing transmission. There is now extensive evidence that transmission can be reduced through widespread use of face masks [ 78 , 79 , 80 , 81 ], better ventilation [ 82 ] and air filtration [ 83 ]. Contact tracing and isolation are established and effective methods of reducing transmission.…”

Smart Thermostats for a Campus Microgrid: Demand Control and Improving Air Quality

“…Several works and research projects have already shown that enclosed spaces are infection grounds for COVID-19 [27][28][29][30][31][32]. The Department of Education of England will spend 25 million pounds installing 300,000 CO 2 monitors in classrooms in state schools and colleges.…”

Comparison of Indoor Environment and Energy Consumption before and after Spread of COVID-19 in Schools in Japanese Cold-Climate Region

“…The society of Heating, Air-Conditioning and Sanitary Engineers of Japan (SHASE) [5], as well as American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) [6] and Federation of European Heating, Ventilation and Air Conditioning Associations (REHVA) [7] published several documents on the use of buildings under the spread of COVID-19 infection, in which the importance of improving ventilation systems and increasing the ventilation rate is mentioned. Zehng et al [8], Pan et al [9], Elsaid et al [10], and Berry et al [11] refer to the above reports by ASHRAE, RHEVA, SHASE, etc., and clarify the problems of the current air conditioning systems and suggest possible countermeasures and future design methods. In cold-climate regions with severely cold winters, increasing the ventilation rate by opening windows in winter increases the heating load for ventilation.…”