Application of corona discharge-generated air ions for filtration of aerosolized virus and inactivation of filtered virus

Abstract

A B S T R A C TThe effect of corona discharge-generated air ions on the filtration of aerosolized bacteriophage MS2 was studied. A carbon-fiber ionizer was installed upstream of a medium-efficiency air filter to generate air ions, which were used to charge the virus aerosols and increase their filtration efficiency. After the virus aerosols were captured by the filter for a certain time interval, they were exposed to a newly incoming air ion flow. Captured virus particles were detached from the filter by sonication, and their antiviral efficiency due to air ions was calculated by counting the plaque-forming units. The antiviral efficiency increased with ion exposure time and ion concentration. When the concentration of positive air ions was 10 7 ions/cm 3 , the antiviral efficiencies were 46.1, 78.8, and 83.7% with exposure times of 15, 30, and 45 min, respectively. When the ionizer was operated in a bipolar mode, the number concentrations of positive and negative ions were 6.6×10 6 and 3.4×10 6 ions/cm 3 , respectively, and the antiviral efficiencies were 64.3, 89.1, and 97.4% with exposure times of 15, 30, and 45 min, respectively. As a quantitative parameter for the performance evaluation of air ions, the susceptibility constant of bacteriophage MS2 to positive, negative, bipolar air ions was calculated as 5.5×10 −3 , 5.4×10 −3 and 9.5×10 −3 , respectively. These susceptibility constants showed bipolar ion treatment was more effective about 1.7 times than unipolar ion treatment.

Numerical and experimental study on airborne disinfection by negative ions in air duct flow

“…C 0 is the initial concentration of airborne bacteria, which is equal to the upstream concentration, CFU/m 3 , Z is the microorganism susceptibility constant under negative ions, CFU/ions, and N ion is the number of negative ions that reached a single bacteria, ions/ CFU, which can be expressed by Eq. (10) [29].…”

“…The key issue becomes how to obtain the constant Z. It can be determined by considering the surviving fraction of airborne microorganisms exposed to negative ions in a ventilated room [29]:…”

Recent advances in antimicrobial air filter

“…However, a less effective disinfection was observed on B. subtilis endospores. Bioaerosol inactivation may also be performed by using air ions, as reported by Hyun et al [52]. They used air ions during the filtration of bacteriophage MS2 bioaerosols.…”

COVID 19: challenges for virologists in the food industry

“…Another study investigated the inactivation of MS2 Coliphage through air ions generated by electrical discharge. Bipolar and unipolar treatment reduced MS2 Coliphage by < 2 log 10 and < 1 log 10 respectively (Hyun et al ., 2017). Therefore, currently there is little evidence that ionization can reduce the probability of transmission of SARS‐CoV‐2 via circulating aerosols in rooms.…”