Using the innovative technology, the researchers concluded that the conditions the virus needs are ideal in the lungs, but are lost when the particles expire. In the best case scenario, as with offices, a lot of infection is lost within the first five seconds.
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The COVID-19 virus loses 90% of its infection in the first 20 minutes it is in the air, and most of this loss occurs in the first five minutes. This is the conclusion The first study about how the virus survives after its expiration date and reinforces the theory that transmission can occur with greater probability in the first minutes of contact.
For the authors of the study, which was conducted by the University of Bristol Aerosol Research Center, this finding underscores the need to implement preventive measures such as social distancing, mask wearing (You know what’s best) and ventilation. For example, let’s look at applying the three measures together: social distancing and masking will reduce spread among people sharing a space. Then, ventilation plays a major role, because air circulation regenerates the environment, providing greater safety for the environment in question.
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“People focus on poorly ventilated spaces and think that transmission through air occurs within meters or in a room. I wouldn’t say it doesn’t, but I still think the biggest exposure risk is when you are close to someone,” said the study’s lead author, Jonathan Reed, in statements to Watchman.
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Thus, the specialist defines social distancing as the most effective measure, in which “not only is the aerosol diluted, but the virus loses its infectivity”, dissipating over time.
And the only studies conducted so far have not accurately reflected the behavior of the virus when it exits the human body through coughing or breathing. To date, studies have been carried out on spraying SARS-cov-2 in closed containers. The most reliable data showed that the virus can live for up to three hours. These studies were done using an instrument called the Goldberg drum, a machine widely used in studying aerosols, which simulates the circulation of air that has virus particles inside.
Researchers at the University of Bristol decided to develop their own device, which allowed them to generate small particles of viruses, which were then analyzed for between five seconds and 20 minutes, while temperature, humidity or ultraviolet rays were strictly controlled.
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The process was so innovative that Jonathan Reed had no doubt: “This is the first time anyone has been able to simulate what happens to an aerosol during exhalation.”
The secret of the rapid loss of infection is associated with moisture and carbon dioxide. If there is more moisture and carbon dioxide in the lungs, going out into the air does the opposite, as the particles find drier environments with a greater volume of oxygen.
Thus, the relative humidity of the air also gains some predominance. According to the study, when this value was less than 50% — similar to what would be found in a typical office — the virus lost half the infection in just five seconds, and lost another 19 percent in the next five minutes. On the other hand, at a relative humidity of 90% – present in conditions such as a sauna or bath – it takes longer for infection to decrease. About 52% of the particles remain in the air for five minutes, which drops to only 10% after 20 minutes. Basically, even in the most favorable scenario for covid-19 transmission, after 20 minutes the virus loses nearly all of its ability to spread.
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“This means that if I’m at a bar with my friends, the greater risk is that they will pass the virus on to me, or I will pass it on to them, rather than everyone else in the room,” explains Jonathan Reed, who highlights the importance of wearing Mask in places where physical distancing is not possible.
The study developed at the University of Bristol has yet to be reviewed, but it appears to mark a crucial finding in the fight against Covid-19. It should also be noted that although it did include some variants, such as alpha, the study was not able to analyze microns, which is clearly more transmissible than its predecessors.
