Wearing two masks are better than one against COVID-19 CDC finds in a limited study

When both the exhaling and inhaling heads were double-masked, more than 95 percent of the particles were blocked.

from http://www.firstpost.com/tech/science/wearing-two-masks-are-better-than-one-against-covid-19-cdc-finds-in-a-limited-study-9291951.html