Hundreds of students at the University of Michigan are taking part in a landmark study examining whether surgical masks can reduce the risk of catching the influenza. For participating, they can receive $100. [1]
The pore size for common surgical masks is about 16-51 um while the size of virus is about 22 nm. Now, you should know if a surgical mask can stop the spread.
By the way, a N95 mask is 95% efficient at filtering out particles of a size of approximately 0.3 microns and above.
Flu Infection
[1] Students wear masks to try to stop flu AP Feb 8 2007.
