Air Filter Significantly Reduces Airborne Viral (SARS-CoV-2) Bioaerosol in COVID-19 Ward: Study

A group at Addenbrooke’s hospital, including the researchers, wellbeing experts, and specialists, introduced an air filtration machine in Coronavirus wards and found that it obliterated a few hints of airborne SARS-Cov-2.

covid-19 virus aerosol

They wanted to know if SARS-COV-2 could be spread via air in tiny droplets throughout the pandemic. However, PPE kits in covid wards have significantly reduced the probability of covid-19 virus transmission through the air. However, there have been a few transmission cases between healthcare workers and patients.

According to ICU consultant Vilas Navapurkar, reducing the virus’s airborne transmission is crucial for patient and staff safety. Using personal protective equipment (PPE) kit significantly reduces the risk of transmission. However, they intend to do something to minimize the danger even further. Because of the increase in covid-19 cases, many patients were admitted, forcing them to use wards that were not designed for them.

They enlisted the assistance of a group of researchers from the University of Cambridge and the Cambridge University Hospitals NHS Foundation to see whether air filtration or UV sterilization devices could reduce the risk of transmission through the air in general wards that were not structured for respiratory infections. 

The research was held at Addenbrooke’s Hospital in two recreated COVID-19 units. The first was a surge ward for patients who only required simple oxygen treatment or no respiratory support. The second was an intensive care unit for patients who only needed ventilation.

HEPA (High-Frequency Particulate Air) air filter/ UV sterilizer was installed. The machines were introduced and left running for seven days, filtering the whole air volume in each room five to ten times each hour. 

During the initial week before the air, the channel was actuated, and they were able to detect SARS-COV-2 on all the testing days in the surge wards. Whereas, when the device was turned on and ran continuously, they could not detect the virus. Later, they turned off the machine and continued the detection, sampling of the SARS-CoV-2 on three of the five examining days.

When the machine was turned off in the ICU, the team found limited evidence of covid-19. When the machine was activated, still traces of the virus was found on one of the sampling days.

It was later determined that the air filter could lower bacterial, fungal, and other viral bioaerosols in both the surge ward and the ICU.

According to the first author, Dr. Andrew Conway Morris from the Department of Medicine at the University of Cambridge, they were quite surprised how well the air filter could remove traces of the airborne SARS-COV-2 in both wards. Although it was a small study, they were able to improve the safety of the ward, which was not designed for such viruses. 

“Cleaner air will reduce the risk of airborne disease transmission, but simply installing an air filter will not suffice.” Every room and situation will be unique. “Developing a robust method of measuring air quality has been a key part of our work,” says Professor Stephen Baker of the University of Cambridge’s Cambridge Institute of Therapeutic Immunology and Infection Disease.


Andrew Conway Morris et al. The Removal of Airborne Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Other Microbial Bioaerosols by Air Filtration on Coronavirus Disease 2019 (COVID-19) Surge Units, Clinical Infectious Diseases, 2021; ciab933,

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