Even a simple mask is very effective at trapping droplets from your coughs and sneezes.
A recent study published in Nature
from the University of Hong Kong and the University of Maryland asked 111 people, infected with various viral illnesses (influenza, rhinovirus and a more-mild coronavirus), to exhale into a giant funnel. Sometimes their noses and mouths aren't covered; other times they used a simple, not-particularly-well-fitted mask.
Without the masks, the infected people exhaled contagious droplets and aerosols, tiny particles that linger in the air, about 30 percent of the time they were tested.
When the infected patients wore a mask, it blocked nearly 100 percent of viral droplets and some of the aerosol particles.
"If we look at all the results together, we found that masks were able to stop most virus-laden respiratory droplets and some of the virus-laden said Ben Cowling, at the School of Public Health of the University of Hong Kong, and the s senior author.