droplet spread were N95 masks without valves, they found, while fleece coverings and bandanas were shown to be "counterproductive."The main route of coronavirus spread is said to occur from person to person through respiratory droplets containing the virus when an infected person coughs, sneezes or talks.
These droplets can land in the mouths or noses of people nearby, according to the Centers for Disease Control and Prevention (CDC).BANDANA IS LEAST EFFECTIVE FACE MASK MATERIAL, STUDY FINDSIt is also estimated that up to 40% of those infected have no symptoms, emphasizing the need for widespread use of face masks to curb virus spread.Researchers used a simple optical measurement method of a cellphone camera and laser pointer to illuminate.