Illustration showing the layers of an N95 face mask. An N95 mask is tight-fitting and has layers that filter out 95% of airborne particles. The fine mesh is made of nonwoven polypropylene, manufactured by melt blowing. The mask is worn tight to the face, forming a seal with the skin. The masks were designed for use in industries including painting and mining, but have been recommended to help prevent the spread of pathogens in exhaled aerosols, such as the SARS-CoV-2 virus that causes Covid-19. Their tight fit and mesh layers make them much more effective than a simple surgical mask.