ST Paper, 15 Nov 2020
Picking a reusable mask: Breathability v filtration efficiency
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Working with lab experts from local testing and inspection company Setsco Services, a particle filtration efficiency (PFE) test was conducted to measure how well the mask prevents tiny respiratory droplets – at 0.1 microns or one millionth of a metre – from escaping.
A good mask should have a PFE rate of at least 95 per cent.
The surgical masks had a PFE range of more than 98 per cent, while most reusable masks had a PFE range of 0 to 20 per cent, with the exception of sample four – the triple-layered mask in black – which had a PFE of 88.51 per cent.
This means that most of the reusable masks were not very efficient at filtering 0.1 micron particles but they may filter particles that are larger in size.