The " Six Feet Away " Rule is Woefully Inadequate

“...the rapid international spread of COVID-19 suggests that using arbitrary droplet size cutoffs may not accurately reflect what actually occurs with respiratory emissions,possibly contributing to the ineffectiveness of some procedures used to limit the spread of respiratory disease ” (Bourouiba, 2020).Dr. Lydia Bourouiba has published an important paper that updates 1930s-era models of respiratory infectious disease transmission based on the size of droplets emitted when a person breathes or talks or coughs or sneezes. Large droplets were thought to contaminate the area immediately surrounding an infected individual, because they settle before evaporating. In contrast, small droplets evaporate quickly and form residual particulates, or aerosols. However, the classification of droplet size (and therefore the mode of transmission) is not based on modern science. Yet this scheme still informs public health policy to this day.The figure above shows a Multiphase Turbulent Gas Cloud From a Human Sneeze (Bourouiba, 2020). The puff trapped droplets of many sizes and carried them quite a long distance (23-26 feet!) while evading evaporation. Droplets that settle can contaminate surfaces. Aerosols may persist in the air for hours, depending on ambient temperature and humidity, as well as prevailing winds orairflow of indoor ventilation systems.1Watch the educational video showing Respiratory Pathogen Emission Dynamics and you will be truly horrified!!“This newer understanding o...
Source: The Neurocritic - Category: Neuroscience Authors: Source Type: blogs