John Swinney has said that people might soon be required to wear 'medical grade face masks' to help halt the spread of mutated strains of coronavirus around Scotland.
While the wearing of cloth masks has become routine, the idea of upgrading to a specialised version has caught many people by surprise.
Last week, Germany became the first major European country to require the medical grade protection for people in shops and on public transport - but there is no such requirement in the UK.
Mr Swinney said officials in Scotland were mulling over introducing the tougher action as mutated strains of Covid-19 piles pressure on hospitals and NHS services.
Deputy First Minister John Swinney
What is a medical face mask?
The World Health Organisation (WHO) defines medical masks as: ‘surgical or procedure masks that are flat or pleated; they are affixed to the head with straps that go around the ears or head or both.’
Crucially, a medical-grade mask must have at least a 95% droplet filtration system, breathability and consist of multiple layers of manufactured, non-woven materials such as polypropylene, polyethylene or cellulose. This level of protection ensures that all but 5% of droplets from the mouth are caught by the mask - cutting of one of the major sources of trabnsmission of Covid 19.
Cloth masks, while effective, are thought to catch between around 70-90% of droplets, although this varies depending on the make.
The WHO advice continues: "Medical masks are rectangular in shape and comprise three or four layers. Each layer consists of fine to very fine fibres. These masks are tested for their ability to block droplets and particles.
"The masks must block droplets and particles while at the same time they must also be breathable by allowing air to pass."
A medical-grade mask
Where can I buy a medical face mask?
While stocks of masks - along with all other types of medical protective equipment - became scarce almost overnight at the beginning of the pandemic, supplies have now rebounded and boxes of masks are available online at Amazon, online chemists and other retailers.
However, a sudden surge in buyers could result in stocks dwindling again so people are being asked to wait until official advice changes.
Should I stop wearing my cloth mask?
In no circumstances should people stop wearing cloth masks. While not as good as a medical grade mask, they are still an important tool in the fight against the spread of the disease.
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