A website has been created by the University of Cambridge to disclose the risk of coronavirus infection in indoor areas.
The app has several customizable settings, including ventilation level, number of occupants and activity level, and wearing a mask.
Anyone can use it to find out how much risk they are in a room of almost any size or type.
For each set of parameters, the site creates a graph of the probability of infection over a period of time, with the default setting of 9:00 AM to 5:00 PM.
The site is called Airborne.cam and can be accessed here.
A website built by the University of Cambridge is programmed to reveal the risk of infection from indoor coronavirus, and is used by the university to research sites and make them Covid-safe (stock)
The online tool shows that in an office of 30 people measuring 100 square meters with three-meter ceilings, the risk of a person contracting the virus from 9 a.m. to 5 p.m. if one person is infected and no one is wearing a mask, 6.06 percent is (photo)
The graph it creates and shows a person’s risk of infection is calculated by a series of scientific equations described in a new study published in Proceedings of the Royal Society A.
Users can determine the room’s occupancy, mask type and activity level. The mask settings do not include a mask, surgical masks, N95 masks, or cloth covers.
The activity level can also be changed from sitting / breathing to strenuous exercise.
Ventilation can also be adjusted, with six options ranging from poorly ventilated to industrial hospital ventilation.
The academics also built in room sizes and a time period that are factored into the equation.
As part of their research, the scientists found that two people chatting freely in a poorly ventilated area without wearing a mask poses a greater risk of infection than if one of them were coughing.
If everyone in the same office and with consistent settings wears a surgical face mask all day and takes an hour for lunch outside, this drops to just 2.13 percent (photo)
Pictured, the various settings that can be changed by users to calculate a specific level of individual risk for a room via the Airborne.cam website
This, they say, is because speaking leads to the exhaling of tiny droplets called aerosols that float around a confined space.
Without adequate ventilation, they can linger in the air, increasing the risk of someone breathing them in and subsequently becoming infected.
However, a cough produces large droplets that are much heavier and are likely to descend to the nearest surface and not linger in the air.
“Our knowledge of airborne transmission of SARS-CoV-2 has evolved at an incredible rate, considering that it was only a year since the virus was identified,” said Dr. Pedro de Oliveira, lead author of the study. article.
‘There are several ways to tackle this problem. In our work, we look at the wide range of respiratory droplets that humans exhale to demonstrate different scenarios of airborne viral transmission – the first being the rapid spread of tiny infectious droplets over several meters in a matter of seconds, both indoors and outdoors. can happen. outdoors.
‘We then show how these small droplets can accumulate in indoor spaces in the long term and how this can be collected with adequate ventilation.’
The free online tool shows that in an office of 30 people, which is 100 square meters (1076 square feet) with three-meter ceilings, the risk of a person contracting the virus from 9 a.m. to 5 p.m. if one person is infected and no one wears masks is 6.06 percent.
If everyone in the office wears a surgical face mask all day and takes an hour for lunch outside, this drops to just 2.13 percent.
But if three people work in an average-sized (18 square meters / 193 square feet) dining room with poor ventilation, and one person is infected, the risk of contracting the virus within eight hours is 48.73 percent.
The calculations are based on the assumption that “hands are washed and that individuals are far from each other – that is, there is no risk of short-range transmission by droplets / aerosol”.
The tool is now actively used by the University of Cambridge, making it a prerequisite for high-risk areas at the institution, allowing staff to apply mitigating factors such as reduced capacity or increased ventilation.
“The tool can help people use fluid mechanics to make better choices and adjust their daily activities and environment to suppress risk, both for themselves and others,” said study co-author Savvas Gkantonas, who led the development. of the app with Dr. de Oliveira.
A similar tool has previously been created by researchers across the Atlantic at MIT.
The tool shows that the size or type of the room doesn’t matter all that much, but what types of masks the people wear on it and the ventilation system it is equipped with can dramatically increase or decrease the risks.
In a standard room with 2-meter ceilings and each wall about 4.5 meters long, 10 fit young people, all diligently wearing surgical face masks, could sit there and talk safely for two hours with the windows closed due to the cold temperatures outside.
But for a family of ten, some of whom are elderly, in a standard dining room for dinner where no one wears a mask because they are eating and the windows are closed because it is cold outside – and there are some heated arguments with raised voices – the tool reveals that the safe limit has been reduced to just three minutes.
The developers say the online site allows people to calculate risk with more nuance than the simple and often vague guidelines for forming ‘bubbles’ or social distance.
Calculations informing the site have been published by authors John Bush and Martin Bazant on the pe print server medRxiv.
The MIT tool’s settings for homes, schools, and restaurants suggest that a few people are likely to be safe in a house with more space for days, or hours in a restaurant – but more densely occupied rooms increase the risk.