Researchers at Mayo simulated both an individual with coronavirus and a non-infected individual, both wearing masks, to measure what level of aerosol particles were blocked by having a face covering on.

Dr. Matthew Callstrom, chair of the department of radiology at Mayo Clinic, said both disposable paper medical masks and two-layer cloth masks were effective in reducing droplet transmission. Neither mask version proved superior to the other in blocking aerosol particles emitted by the wearer.

"We found objectively that masks are critically important for protecting yourself and the people around you," says Callstrom. "If you're wearing a mask, you're protecting others. If they're wearing masks, they're protecting you."

COVID-19 is most commonly transmitted through respiratory droplets, which are both larger than aerosols and are more easily blocked with masks, Callstrom notes.

"I think we had some knowledge about the importance of masks and there's been a number of studies that have showed masks are effective in blocking viruses, but what's really important here is just how effective masking is when done by both parties," says Dr. Elie Berbari, chair of the department of infectious diseases at Mayo Clinic.

In addition, data found that physical distancing of three feet lessens exposure to droplets, and the benefit increased with each 12-inch increment, with a six foot separation from others reducing particle counts to near baseline levels. 

Additional measures to reduce the risk of COVID-19 transmission include frequent hand washing, use hand sanitizer before and after meals and after removing masks, and limiting exposure to non-household members.