Day 160 – (even) More on Masks

It takes quite a lot for me to read a Physics paper. Of the the three, traditional “main” branches of science, Physics was my least favourite. And that’s saying something, given that one of the others is Chemistry.

However, this paper by Verma et al. in the journal Physics of Fluids (please try to restrain your excitement, readers) is actually rather interesting and offers further evidence that masks with exhalation valves are frankly useless in the fight against Covid-19. It also adds that those plastic face shields people are starting to use are equally kak. (In addition, they are not “cloth covering the nose and mouth”, so technically not legal either. Not that that will bother anyone in SA.)

Thus:

…there is an increasing trend of people substituting regular cloth or surgical masks with clear plastic face shields and with masks equipped with exhalation valves. One of the factors driving this increased adoption is improved comfort compared to regular masks. However, there is a possibility that widespread public use of these alternatives to regular masks could have an adverse effect on mitigation efforts.

Just for the record: “improved comfort compared to regular masks” just means “people being overly dramatic about having to wear a mask”. Having “an adverse effect on mitigation efforts” is merely fancy language for “won’t work at stopping the transmission of Covid-19”.

It’s been said before.

And there are some more of those lovely visualisations of coughs and sneezes, which I screenshotted.
For the clear plastic face shield:

And for the mask with exhalation valves:

Full descriptions and even some delightful (and educational) videos on that link through to the paper, but basically (as you may have already guessed), green cloud is not good. And there’s a lot of green cloud in those images.

So. If you are one of those people who wears one of these masks or face shields or you know someone who does, please (politely) let them know that they’re not helping the situation at all.

Day 123 – More on masks

I’ve made my thoughts on wearing masks in public places completely clear, I think.
Not least here:

…and it used to be so easy in that you either wore one or you didn’t.

The fact is that while a mask is always better than no mask, equally some masks are better than others. Here’s a video from the University of New South Wales demonstrating this with a sneeze.

Prepare yourself.

(Incidentally, earlier in that video, there are demonstrations of talking and coughing as well – just click on the YouTube icon bottom right to have a look).

So yes, surgical mask > two layers of cloth > one layer of cloth.
And all of them are MUCH better than no mask at all.

It’s pretty clear how the differing masks have differing efficacy, and it’s pretty clear how no mask means that you spread respiratory droplets and aerosols – potentially laden with virus – everywhere when you sneeze.

A reminder here that we are asked to wear masks exactly for that reason: to stop us breathing out respiratory particles which might spread the virus to other people.

Which brings me to my next point.

I’m seeing a lot of masks on sale that look like this:

Or this:

Check out how stylish they can like to be!

They’re often advertised with catchy phrases like “low resistance” or “easy breathing” or some such. And that’s because, as demonstrated by the photoshopped whoosh of air in the top image, these are one-way masks. That circular plastic “respirator valve” thing clicks shut when you inhale, meaning that what you breath in is filtered through the mask fabric, but it pops open when you exhale, meaning that there is no barrier for what you breathe out. Magic.

A quick quote, if I may?

A reminder here that we are asked to wear masks exactly for that reason: to stop us breathing out respiratory particles which might spread the virus to other people.

Oh.

Yes, I’m sorry, but these masks are completely useless in the context of coronavirus and Covid-19. There is literally no barrier at all to prevent you breathing out aerosolised virus all over everyone around you. And that’s exactly why you’re wearing it in the first place.

Sure. They’re probably great for sanding or mowing grass or working in dusty environments like woodworking shops and grassmowing sheds(?), because in those instances, we’re trying to stop ourselves from breathing nasty stuff in.

That’s not why we are wearing masks at the moment.

But let’s be honest about this: getting people just to wear masks is proving difficult enough. If we’re now going to try to give them more detailed rules and regulations, we’re not going to get very far.

So all I am asking of you is that if you are planning to get a mask like this, just don’t. It doesn’t help. And when the inevitable mask debate comes up with friends and/or family, send them here so that they don’t buy one either.

Don’t buy these sorts of masks. 

A little bit of information goes a long way.
(Nowhere near as far as a little bit of misinformation, but that’s a whole other story.)