Key points:
- Ventilation systems may increase Covid-19 exposure risk in the winter season.
- According to the scientists, a three-layered mask decreases the amount of those contaminants that are recirculated through the room by ventilation.
Ventilation systems in many buildings, which are designed to keep temperatures comfortable, may increase the risk of exposure to the novel coronavirus which causes Covid-19, particularly during the winter season when people prefer to stay indoors, says a new study.
Scientists, including those from the University of Cambridge in the UK, 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. According to the study, published in the Journal of Fluid Mechanics, these contaminants may include droplets and aerosols, potentially containing viruses such as the novel coronavirus SARS-CoV-2.
With evidence increasingly indicating that the coronavirus is spread primarily via droplets and aerosols expelled as people cough, sneeze, talk, or breath, the findings underscore the need for good ventilation and mask-wearing to mitigate SARS-CoV-2 transmission risk. Based on studies conducted so far, the researchers said indoor transmission is far more common than outdoor transmission – 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 study co-author Paul Linden from the University of Cambridge. 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, Linden said.
“One thing we could clearly see is that one of the ways that masks work is by stopping the breath’s momentum,” said Linden. “While pretty much all masks will have a certain amount of leakage through the top and sides, it doesn’t matter that much, because slowing the momentum of any exhaled contaminants reduces the chance of any direct exchange of aerosols and droplets as the breath remains in the body’s thermal plume and is carried upwards towards the ceiling,” he said.
Source: PTI
