IIT Bombay Study on Cough and Masks
 First 5 to 8 seconds after coughing are critical:
During this time the exhaled droplets remain suspended in the air and can spread of the disease. After that time, the cough cloud typically starts to disperse.
 Masks work:
Surgical mask reduces the cloud volume 7 times.N95 mask reduces the cloud volume by 23 times.
 Every measure matters:
Anything that reduces the distance traveled by the cloud, such as a mask, handkerchief, or coughing into an elbow, should greatly reduce the region over which the droplets disperse upon coughing.
Link: Physics of Fluids, Oct 2020