COVID-19 becomes 90% less contagious within 20 minutes of its flight and loses most of its potential for infection within the first five minutes, according to a pioneering new study that examines how the deadly infection survives in the world. exhaled air. Researchers said the results of a study published by the Aerosol Research Center at the University of Bristol underscore the need to use face masks and maintain social distancing to prevent transmission of COVID-19.
The study, which has yet to be peer reviewed, is the first of its kind to replicate how the coronavirus moves through the air after being exhaled. The researchers created equipment to generate particles containing viruses and allowed them to float between two electrical rings for five seconds to 20 minutes in a tightly regulated environment to mimic what happens to the virus when suspended in the air. air.
The Guardian reported, citing the director of the Aerosol Research Center at the University of Bristol and lead author of the study, Professor Jonathan Reid, as saying: “People have focused on poorly ventilated spaces and have thought of airborne transmission over meters or across a room. I’m not saying it doesn’t happen, but I think the greatest risk of exposure is when you’re around someone anyway. “
He added that the further away one goes, not only the aerosol is diluted, but there is also less infectious virus since the virus has lost its infectivity. [due to time]. According to research, when viral particles leave the lungs, they lose a lot of water, and the reduced levels of carbon dioxide in the air cause the pH to rise rapidly. According to the research paper, this impacts the ability of the virus to infect human cells.
Air temperature has no effect on the infectivity of the virus
In a typical office, where the surrounding humidity is usually less than 50%, the virus became half the infectious in less than five seconds, after which the loss of infectivity became slower and more constant, with further loss. by 19% over the next five minutes. On the other hand, the fall is noticeably slower in a more humid environment, such as a hammam or a shower. However, the researchers found that air temperature had no effect on viral infectivity, contrary to popular belief that viral transmission is reduced at high temperatures.
The results underscore the importance of short-range transmission of COVID-19, with physical separation and mask use being possibly the most effective methods of preventing infection. While ventilation is always beneficial, it is likely to have a reduced benefit. Researchers at the University of Bristol devised a device that allowed them to create an unlimited number of microscopic particles containing viruses and pass them gently between two electric rings for five seconds to twenty minutes. It also allowed the researchers to have complete control over the temperature, humidity and intensity of UV light in their environment.