Pam King Sams
University of Cambridge study shows many ventilation systems may increase risk of COVID-19 exposure.
A team from the University of Cambridge found that widely-used ‘mixing ventilation’ systems, which are designed to keep conditions uniform in all parts of the room, disperse airborne contaminants evenly throughout the space. These contaminants may include droplets and aerosols, potentially containing viruses.
The research has highlighted the importance of good ventilation and mask-wearing in keeping the contaminant concentration to a minimum level and mitigating the risk of transmission of SARS-CoV-2, the virus that causes COVID-19.
The evidence increasingly indicates that the virus is spread primarily through larger droplets and smaller aerosols, which are expelled when we cough, sneeze, laugh, talk or breathe. In addition, the data available so far indicates that indoor transmission is far more common than outdoor transmission, which is likely due to increased exposure times and decreased dispersion rates for droplets and aerosols.
“As winter approaches in the northern hemisphere and people start spending more time inside, understanding the role of ventilation is critical to estimating the risk of contracting the virus and helping slow its spread,” said Professor Paul Linden from Cambridge’s Department of Applied Mathematics and Theoretical Physics (DAMTP), who led the research. “While direct monitoring of droplets and aerosols in indoor spaces is difficult, we exhale carbon dioxide that can easily be measured and used as an indicator of the risk of infection.
Small respiratory aerosols containing the virus are transported along with the carbon dioxide produced by breathing, and are carried around a room by ventilation flows. Insufficient ventilation can lead to high carbon dioxide concentration, which in turn could increase the risk of exposure to the virus.”