The University of Cambridge has designed a website for detecting the risks of infection with the Coronavirus in indoor spaces.
The app has many customizable settings, which include ventilation level, passenger count, activity level, and mask wear.
And anyone can use it to know the level of risk they are taking while in a room of nearly any size or type. For each set of parameters, the site produces a graph showing the chance of infection over a specified period of time, with the default setting from 9 AM to 5 PM.
The graph it creates calculates and shows an individual’s risk of infection through a series of scientific equations illustrated in a new study published in Proceedings of the Royal Society A.
Users can specify room occupancy, mask type, and activity level. Mask settings do not include any mask, surgical masks, N95 masks, or cloth caps.
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The activity level can also be changed, from sitting / breathing to strenuous exercise. Ventilation can also be changed, with six options ranging from poor ventilation to artificial ventilation in hospitals.
Academics also built room dimensions and time period taken into account in the equation.
As part of their research, the scientists found that two people who talk freely in a poorly ventilated place while not wearing a mask pose a higher risk of infection than if one of them was coughing.
This, they say, is because speaking leads to the exhalation of tiny droplets called aerosols that float around a confined space. Without adequate ventilation, it can remain in the air, which increases the risk of inhalation and consequently infection.
However, coughing produces large droplets that are much heavier and more likely to land to the nearest surface and not remain suspended in the air.
Dr Pedro de Oliveira, first author of the paper said: “Our knowledge of SARS-CoV-2 airborne transmission has evolved at an amazing pace, when you consider that it has only been a year since the virus was discovered. There are different ways to deal with this problem. Consider the wide range of respiratory droplets that humans exhale to show different scenarios of virus transmission through the air – the first being the rapid spread of small infectious droplets over several meters within a few seconds, which can occur indoors and outdoors, and outdoors. Then we explain how these can accumulate. “Small drops in indoor areas in the long term, and how this can be mitigated through proper ventilation.”
The free online tool shows that in an office of 30 people of 100 square meters (1,076 square feet) with high ceilings of three meters (9.8 feet), the risk of a person contracting the virus is from 9 a.m. to 5 p.m. if one person is infected and not One wears masks, 6.06%.
And if everyone in the office wore a surgical face mask all day and took an hour’s lunch break outside, that drops to just 2.13%. But if three people work in a medium-sized dining room (18 square meters / 193 square feet) with poor ventilation, and one person becomes infected, the risk of contracting the virus over an 8-hour period is 48.73%.
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The calculations are based on the assumption that “hands are washed and individuals are far from each other – that is, there is no risk of short-term transmission via droplets / aerosols”.
Now, the tool is actively used by the University of Cambridge, making it a prerequisite for high-risk spaces in the organization that will allow employees to place mitigating factors, such as reduced capacity or increased ventilation.
“The tool can help people use fluid mechanics to make better choices, and adapt their daily activities and surroundings in order to suppress risks, both for themselves and others,” said co-author Savas Gakantonas, who led the development.
A similar tool was previously created by researchers across the Atlantic at the Massachusetts Institute of Technology.
The tool reveals that the size or type of room does not matter much – but the types of masks that the people occupying it wear and the ventilation system equipped with them can greatly increase or decrease the risk.
And in a standard room with 8-foot-high ceilings and each wall about 15 feet long, 10 young men wearing surgical face masks could sit safely there and talk normally for two hours if the windows were closed due to the cold temperatures outside.
But for a family of ten, some of them elderly, in a regular dining room for dinner where no one wears a mask because they eat with the windows closed due to the cold weather outside – and there are some heated discussions with voices – the tool reveals that the safe limit is reduced to just three minutes. .
Its developers say the website allows people to calculate risks with more nuance than simple and often vague directions to form “bubbles” or social distance.
The accounts that reported the site were published by the authors, John Bush and Martin Bazant, on the medRxiv print server.
Source: Daily Mail
