Tiny cough droplets, possibly carrying viruses, can remain airborne in an enclosed space for several minutes, therefore good ventilation is “crucial” to slowing down the spread of COVID-19, a report said on Thursday. These results were published in the scientific journal, The Lancet Respiratory Medicine, news website Dutch News reported. Researchers at the University of Amsterdam asked healthy human test subjects to speak and to cough, and used laser light to analyse the droplets that they produced.
“The light picked up large amounts of small droplets (between roughly one and 10 micrometres in size) during both speech and coughing. Larger droplets (up to one millimeter in size) were also produced during coughing,” read the article.
“The larger droplets fall to the ground within one second and therefore have a much smaller probability of transmitting viruses, the researchers say. “However, the small droplets only move very slowly due to the large amount of air drag they experience.
“When the same experiments were repeated in a well-ventilated room, the results improved dramatically. “With only mechanical ventilation turned on, half of the droplets disappeared within 2.5 minutes, but in a room that also had a door and window open, the number of droplets was halved after 30 seconds – ten times faster than in the unventilated room, said the researchers.”