The US Surgeon General tweeted that face masks were ineffective but at the same time insisted that healthcare providers should have them, so do they work or don't they?
Obviously any protection is better than none but the level of protection varies dramatically depending on what mask you have
Surgical masks
These are designed to capture what people breathe out so they will limit the chance of the wearer from infecting others with what they expel but as they're so loose fitting and don't impede droplets they are next to useless as a means of personal protection
A scarf or bandanna would be similar the main benefit is these simple cloth face coverings keep your hands away from your face
Particulate respirators
These have several grades in Europe P1, P2 and P3 that corresponds to their ability to filter particles and liquids out of the air
America uses a slightly different system of 95, 99, and 100 prefaced with a letter to signify its resistance to oil N for not resistant, R for partially resistant and P for proof for strongly resistant
Some have one way exhale valves for easier breathing and the lettering isn't really important for the transmission of viruses but I will use P for comparison between the two systems as that is the highest rating
P1 are standard dust masks able to block 80% of airborne particles only suitable for short term exposure in non hazardous environments such as doing some DIY at home
P2 are occupational standard filters that block 94% of particles, the US P95 offers slightly more protection blocking 95% and the P99 is a further step up at respectively 99%
P3 is the highest level of filter you can purchase blocking 99.95% and is equivalent to the US P100 with its ability to filter 99.97%
Both are considered to be effectively 100% for particles and droplets down to 0.3 of a micron
Mostly made as single use disposable masks that surround the nose and mouth but there are reusable versions where you simply replace the filters but retain the mask although this will require you to sterilise them safely
An N95 / P2 rated respirator is the recommended PPE (personal protective equipment) for blocking the SARS-CoV-2 virus but the higher the number the better it is obviously
There are some that include eye protection known as full face that prevent the virus being absorbed through contact with the eyes
So read the specification and know what you're buying, they do work so long as they're correctly fitted but your best defence is to isolate yourself as much as possible
Take care
Roo
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