Short people may face a greater risk of catching coronavirus, a new study of Singapore’s Science, Technology and Research Agency has claimed.It is because of the way droplets fall slowly to the ground after a cough or sneeze.
Researchers, having recreated the trajectory of droplets on a computer model, found that a shorter person may be in the path of the droplets.
The new study was published in early November in the journal Physics of Fluids. The researchers said the downwards trajectory put shorter people at greater risk of inhaling the droplets compared to taller people. Academics have suggested teenager and anyone under 165 cm keep more than two metres away from others.
The research also indicates that children should be at a greater risk but a wealth of studies have shown primary school-aged children are less likely to catch the disease than adults. Experts believe this is a genetic benefit that may be linked to fewer receptors that Covid-19 uses to enter human cells.
A typical cough emits thousands of droplets across a wide size range. The larger ones drop quicker than the small ones. The study looked at how droplets disperse in the air under different outdoor environments.
The study was done using animations on a computer model. A model simulated what would happen when two people were standing two metres apart. The “cougher” was 170 cm in height, while the “listener” was 160 cm. The researchers ran the simulation with different droplet sizes, air temperatures, relative humidity and wind speed.
Around 15 per cent of all droplets fall in the “wake”, which is an area between the two people and in close proximity around. However, some deposit land on “the lower part” of the “listener”.
Contamination of person’s clothes or exposed skins may lead to the secondary transmission through face, mouth, or nose touching. This result highlights potential risk for shorter persons, including children, who are less than one metre away from a cougher.
Overall the study suggested coronavirus-infected cough droplets can travel more than two metres. Large droplets settled on the ground quickly but could be projected one metre even without wind.
Medium-sized droplets could evaporate into smaller droplets, which can travel further by the wind. These extremely small particles can linger in the air for long periods and are more susceptible to be inhaled deep into the lung.
New data show that maintaining a social distance of two metres alone is not enough to keep people from being infected. All protective measures should be followed, especially the wearing of facemasks.
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