A report published in the US journal Physics of Fluids, on Tuesday, suggested that masks with a valve outspread invisible droplets when a person coughs or sneezes, making them ineffective against the novel coronavirus.
The researchers from the Florida Atlantic University carried the study by using vertical and horizontal laser sheets to create a simulation model to track tiny droplets of distilled water and glycerin.
The researchers put the mask around a mannequin’s head and released the droplets to track their trajectory.
The researchers noted that the mask initially blocked the droplets. But the expelled droplets were later spread over a large area by moving around.
“A large number of droplets pass through the exhale valve unfiltered, which makes it ineffective in stopping the spread of the virus if the person wearing the mask is infected,” the authors noted in their study.
The researchers further recommended high-quality cloth or medical masks of plain design that can help in preventing the spread of the virus.