A new study was published in the Physics of Fluids, a peer-reviewed scientific journal, that measured just how far saliva droplets could travel through the most common types of face masks that Americans are wearing during the COVID-19 pandemic. The study simulated human coughing using an artificial mannequin-and-pump system that sprayed a mixture of gelatin and water.
Of the different types of “face masks” tested, bandanas ranked the worst at containing the spread of coronavirus, allowing small droplets to travel almost 4 feet.