While paper and cloth masks may help controlling the spread of Covid-19 amongst the general public, they’re certainly not up to the mark for use in intensive care.
The simplest form of face covering is the surgical mask, generally made of three layers of paper or cloth. They’re resistant to droplets such as those caused by coughing or sneezing, but give little protection against viral particles themselves, which are only around 100 nanometres in size (a nanometre being a billionth of a metre).
“A mask, which goes over your nose and mouth, but doesn’t fit tightly to your face, is really there to be a barrier for any particles that you might expel,” explains Dr Nikki McCullough, head of safety for 3M, one of the world’s biggest suppliers of respiratory protection. “The mask isn’t going to prevent you from breathing in very small particles.”
“There you have a more comprehensive solution. There’s a hood face shield and a tube that would connect into a unit on the belt,” says Brian Hovey, chief marketing officer for major respirator manufacturer Honeywell Safety. “That has an engine or a motor that pumps air through a filter: it’s part of a white suit, so it’s a more comprehensive protective solution.”