Talking indoors, especially when he is not well ventilated, with someone who has the coronavirus, can be just as dangerous to get stuck as it is for the other person to cough. This is due to the tiny droplets that are exhaled during speech and which are suspended in the air for longer than the larger cough particles, according to a new study in Britain led by Greek researchers in the diaspora.
There is a scientific consensus that the vast majority of Covid-19 cases occur through indoor transmission, especially in winter. Researchers' new mathematical model estimates that if two people – one of whom is infected with the virus – speak in a poorly ventilated area and no one wears a mask, their speech is more likely to transmit the coronavirus than the coughing of one.
While heavier droplets, such as those secreted by coughing, fall to the ground a short distance from the cougher, the smaller particles emitted by speech travel more than two meters and remain longer in the air, resulting in a A simple conversation with a coronavirus carrier poses similar – if not greater – risks to being in the same area as a cough virus carrier.
Researchers from Cambridge and Imperial Universities in London, led by Professor of Applied Thermodynamics Epamineondas Mastorako, published in the Proceedings of the Royal Society A the journal of speech two meters. Therefore, according to scientists, they need masks, keeping distance and good ventilation indoors, so that potentially contaminated particles do not accumulate in the trapped air.
The study estimates that it is unsafe to stand without a mask at a distance of two meters from a man with a talking coronavirus. According to research, one hour after an infected person has spoken for half a minute, the remaining aerosol contains much more particles than after a cough. In a narrow and closed space this amount of suspended coronavirus is considered enough to transmit it. Whether this will actually happen will depend on how many particles one inhales, so it is vital to wear a mask.
The researchers also created a free online computer (Airborne.cam) that helps calculate the risk of being infected indoors only by airborne particles. The computer (https://airborne.cam/), developed by the Greek researcher Savva Gandona, can be used by shopkeepers, hoteliers, employers, etc. to calculate whether there is sufficient ventilation in their premises.
According to this tool, an hour's stay in a store of 250 square meters with a maximum capacity of 50 people and ventilation proportional to the offices, results in an 8% chance of someone getting a coronavirus, assuming that there are five people carrying the coronavirus and no one wears a mask. If ventilation is improved, the risk can fall below 2%, while the same, according to model estimates, can happen if everyone wears a mask permanently indoors.