Face mask construction, materials matter for containing coughing, sneezing droplets
Currently, there are no specific guidelines on the most effective materials and designs for facemasks to minimize the spread of droplets from coughs or sneezes to mitigate the transmission of COVID-19. While there have been prior studies on how medical-grade masks perform, data on cloth-based coverings used by the vast majority of the general public are sparse.
Research from Florida Atlantic University’s College of Engineering and Computer Science, just published in the journal Physics of Fluids, demonstrates through visualization of emulated coughs and sneezes, a method to assess the effectiveness of facemasks in obstructing droplets. The rationale behind the recommendation for using masks or other face coverings is to reduce the risk of cross-infection via the transmission of respiratory droplets from infected to healthy individuals.
Researchers employed flow visualization in a laboratory setting using a laser light sheet and a mixture of distilled water and glycerin to generate the synthetic fog that made up the content of a cough-jet. They visualized droplets expelled from a mannequin’s mouth while simulating coughing and sneezing. They tested masks that are readily available to the general public, which do not draw away from the supply of medical-grade masks and respirators for healthcare workers. They tested a single-layer bandana-style covering, a homemade mask that was stitched using two-layers of cotton quilting fabric consisting of 70 threads per inch, and a non-sterile cone-style mask that is available in most pharmacies. By…