id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-298227-av1ev8ta	Kähler, Christian J.	Fundamental protective mechanisms of face masks against droplet infections	2020-06-28		.txt	text/plain	7149	376	58	Many governments have instructed the population to wear simple mouth-and-nose covers or surgical face masks to protect themselves from droplet infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in public. First of all, we show that the masks protect people in the surrounding area quite well, since the flow resistance of the face masks effectively prevents the spread of exhaled air, e.g. when breathing, speaking, singing, coughing and sneezing. Thirdly, we show that even simple mouth-and-nose covers made of good filter material cannot reliably protect against droplet infection in contaminated ambient air, since most of the air flows through gaps at the edge of the masks. However, if the distance rules cannot be observed and the risk of inhalation-based infection becomes high because many people in the vicinity are infectious and the air exchange rate is small, improved filtration efficiency masks are needed, to take full advantage of the three fundamental protective mechanisms these masks provide.	./cache/cord-298227-av1ev8ta.txt	./txt/cord-298227-av1ev8ta.txt