From Washington Post newspaper. Direct link blow.

DOUBLE MASKING: some public health experts to recommend doubling up face coverings or donning medical-grade masks.Officials initially discouraged most people from buying medical masks such as N95s and KN95s, to try to protect the supply for health-care workers. If you’re going to buy KN95s, choose a type that has received emergency use authorization from the Food and Drug Administration, said Anne Miller, executive director of Project N95, a nonprofit organization that helps health-care and other essential workers access protective gear. The FDA keeps a list of approved products, which the agency refers to as “respirator models manufactured in China.”

The Centers for Disease Control and Prevention’s National Institute for Occupational Safety and Health also maintains a website focused on counterfeit N95s for reference.

Whatever face covering you choose, it should be snug and without gaps. Here is a link on masks from NYTIMES and a very nice 3D graphic demonstrating how the viral “particle” aerolization lingers in the air, drifting beyond the 6’ perimeter where larger droplets tend to fall. 3D GRAPHIC SIMULATION. See the September 2020 post below for more helpful links specifically on masks, and which ones to avoid.

Currently, it is felt that placing a cloth mask over a blue paper mask with metal prongs to shape over the nose provides filtration approaching that of an N95, if placed correctly. See the video at the link for the correct way to put on 2 masks.

Washington Post Link To Original Article Feb 2, 2021
Washington Post Video On The “Variant” Covid-19 Strains, Feb. 2, 2021