Scientists from the United States filmed a clip of a person mid-sneeze and reduced it down to slow motion from 25 seconds to a minute and a half. The video shows an amazing course of a sneeze up to 27 feet away. Experts imagine the horrific scenario if the sneeze were to come from a person infected with the coronavirus.
They found that viral droplets coming from coughs and sneezes can travel in a moist, warm atmosphere at speeds between 33 to 100 feet per second. This forms an infectious gas cloud that is capable of reaching somewhere between 23 to 27 feet away.
Studies have found that a moist and warm environment within the turbulent gas cloud allows the enclosed droplets to avoid evaporation for much longer than usual.
Meanwhile, the United Kingdom public is advised to keep a distance of atleast six and a half feet from each other. The video alone proves that it might not be enough.
Social Distancing Done Wrong
The study suggests the UK government's coronavirus social distancing limit of 6.5 feet is at least four times too short if sneezing is taken into account.
Professor Bourouiba claims that the social distancing measures of today are based on old-fashioned models that need to be updated. She says that implementing public health instructions based on the older models may restrict the effectiveness of the proposed interventions.
She adds that the outdated standard does not account for the feasibility of a hot and moist gas cloud. This type of gas cloud can sustain viral droplets for longer distances. Her study on gas clouds can be found published in The Journal of the American Medical Association.
The Science Behind Sneeze Droplets
Although sneezing isn't a symptom of COVID-19, it is believed to be a means that allows droplets to spread. Droplets that remain along the pathway of a sneeze can contaminate surfaces, while the rest remain trapped and bundled in the moving cloud.
Eventually, the 'turbulent gas cloud' loses its force, and the remaining droplets within the cloud evaporate. The rate at which these droplets evaporate depends on their size, the speed of the gas cloud, and encompassing environmental conditions such as temperature and humidity.
However, even after evaporation, 'droplet nuclei' may stay suspended in the air for many hours. It could end up getting caught in airflows from ventilation or air conditioning systems, particularly in supermarkets or hospitals.
According to a report from China earlier this year, viral particles were found in the ventilation systems in hospital rooms of patients with COVID-19. For reasons such as this, experts stress the importance of having proper ventilation, humidity, and filtration in institutions to reduce the spread of pathogens like the new coronavirus.
Professor Bourouiba said that her new study of how infectious gas clouds travel could justify how virus particles can reach such long distances from one person to another.
She further stresses the importance of wearing appropriate personal protection for health care workers caring for patients who may be infected. Bourouiba mentions that health care providers shouldn't let their guard down even if they are farther than six feet away from a patient.
