FAQs

How long can you use a KN95 mask for?

For regular usage you CAN reuse KN95 masks, for up to a total of 40 hours. For high risk environments (hospitals, bars) you dispose of it after a 8hr shift. This here tweet explains why 40hrs usage is reasonable.

With UK regs changing to mandatory #masks, here's a short 🧵to answer the question: can you wear a disposable #facemask more than once? The answer is YES. Many manufacturers state that masks should be disposed of after 8 hours but this is not true. Read on to find out why ... 1/ pic.twitter.com/f9jXCKq3LT

— Prof Claire J. Horwell 😷 (@claire_horwell) December 2, 2021

A good but long video explainer:

What about cloth and surgical masks?

Sadly, they don't cut the mustard in the age of omicron, as this great graphic from the Wall Street Journal illustrates:

Difference between N95, P2, KF94, KN95 mask standards

These standards can essentially considered to be the same for practical purposes. 3M has a straightforward summary table in this pdf comparing the different standards, and concludes that Australia's P2, China's KN95 and EU's FFP2 is essentially equivalent to N95. 

Whats more important than which of the three standards you buy, is that the mask actually meets that filtration standard. There is a difference in filtration quality b/w mask manufacturers and there is also the issue of substandard and outright counterfeit masks.

This is a good short video explainer:

Confused about N95, KF94, KN95, double-masking? You're not alone. Here is my 90-second explainer. Thanks to @GreaterBoston and @jimbraude for having me on. pic.twitter.com/xKbp2LdjIT

— Joseph Allen (@j_g_allen) January 28, 2021