U.S. scientists filmed a horrifying slow-motion video that shows the trajectory of a sneeze that may be carrying the coronavirus, and it shows that it can travel up to 27 feet, which is more than the social distancing measure that is mandated by the World Health Organization (WHO).
The said video was slowed down from 25 seconds to a minute and a half, and the scientists found that viral droplets expelled in coughs and sneezes can travel in a moist and warm atmosphere at speeds of between 33 and 100 feet per second.
A warm and moist atmosphere can create an infectious and turbulent gas cloud that is capable of reaching somewhere between 23 feet to 27 feet or 7 meters to 8 meters away. The study suggests the UK government's coronavirus social distancing limit, which s 6 feet or 2 meters, is at least four times too short if sneezing is taken into account.
Video shows coronavirus infected sneeze in slow motion
Professor Bourouiba wrote in the Journal of the American Medical Association or JAMA and stated that the social distancing measures are based on outdated models. The measures do not account for the possibility of a hot and moist gas cloud, which is very capable of sustaining the viral droplets for more than 6 feet.
The social distancing measure that is practiced today was developed in the 1930s, and implementing the measure based on older models could limit the effectiveness of the interventions proposed by the scientists. The distance of 6 feet was based on estimates of a range that have not considered the possible presence of high-momentum cloud carrying the droplets in long distances.
According to Professor Bourouiba, the droplets settle along the trajectory of a sneeze and can contaminate surfaces, while the rest remain trapped and clustered in the moving cloud. The turbulent gas cloud loses momentum and the remaining droplets within the could evaporate.
The rate at which the droplets evaporate depends on their sizes, the speed of the gas cloud and ambient environmental conditions such as humidity and temperature. Under high temperatures, the lifetime of droplet could be extended by up to 1,000, or from a fraction of a second to several minutes.
However, even after evaporation, the droplets may stay suspended in the air for hours, it could get caught in airflows from air conditioning systems or ventilation from hospitals and supermarkets. The viral particles could be found in the ventilation systems in hospital rooms of patients with coronavirus, which is why the rooms need to be properly disinfected before it can be used by another patient.
Professor Bourouiba stated in her study how infectious gas clouds can travel and she explained how virus particles can reach long distances from person to person. She said that with the turbulent cloud, recommendations for separations of three to six feet may underestimate the distance, timescale and the persistence over which the cloud and its pathogenic payload travels. This means that it can generate an exposure range for a healthcare worker.
Social distancing measures
In the United Kingdom, people are finding themselves in crowded places like supermarkets and sidewalks, thus making it impossible to follow social distancing requirements. The UK government says that coronavirus spreads through close sustained contact with someone who is COVID-19 positive, such as being 2 meters from someone for more than 15 minutes.
In the U.S., some states are still not practicing the health guidelines mandated by the WHO. The state of Michigan even held a rally to oppose the stay-at-home order of Governor Gretchen Whitmer.
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