Masks

Just a footnote on masks. New requirements to wear them on public transport and in other social situations in which it is not possible to maintain a 2m distance will be a new experience for many Britons. And the columns in the papers make quite clear that our journos know bugger all about them. I offer a few notes not as an expert but certainly better informed than the press. Masks are not homogeneous and do different things -

Home made mouth and nose coverings
These range from the pointless (home knitted) to the improvised (scarves, shemaghs, bandanas and balaclavas) to self-sewn pleated masks make of paper or fabric. These are intended to protect other people from you in case you are infectious but not showing symptoms. They need to lower the level of the vapour in your breath and droplets from speaking, coughing or sneezing that reaches other people. It’s this vapour and tiny droplets that carry the virus particles. If they work, they will get damp and soggy from use as they trap vapour. Will need frequent washing at 60deg or more if not disposable (detergents like soap and washing powder ‘melt’ the outer coating of the virus, but the conditions may also encourage moulds and bacterial growth in unwashed coverings)

‘Surgical’ masks
These will be by far the most commonly available. Disposable and made of pleated layers of paper with a polymer outer coating to give limited protection from inhaling direct droplets. Intended to protect others rather than you. Again, if these are working properly they will get damp and soggy and need frequent changing if worn for prolonged periods. Can be cheap – bundles of 50 sell for about €37 here.

Filtering Face Piece masks – disposable
The most common masks worn by health and care workers in aerosol-generating environments. They have an airtight fit over mouth and nose and are valved – you breath in air filtered through the fabric and exhale through a one-way valve. Primarily to protect you rather than others. FFP2 and FFP3 masks filter respectively a minimum of 94% and 99% of particles including vapour down to 0.3 microns. They will not filter out airborne virus particles (which are between about 0.05 to 0.2 microns), but SARS CoV 2 is not an airborne virus – it is carried in vapour and droplets. I’ve got a box of FFP2 masks in the workshop bought from Screwfix a year ago for about £1.50 each

Filtering face Piece masks – rechargeable
These are the ones that look like WW2 gasmasks without the eye protection. I’ve got three or four in the workshop with replaceable FFP3 cartridges – great for cutting masonry with a diamond blade, which creates huge clouds of fine dust indoors. Also excellent protection from SARS CoV 2.

Facial recognition cameras
There’s one upside – facemasks, particularly when work with eye protection or reflective visors, completely bugger the new facial recognition cameras installed everywhere in London, as ZDnet reports.

Note – I neither recommend, endorse or condemn the use of facemasks. These are just a few notes on the differences for anyone interested.