Big and Small (2)

Just as a follow-on from my earlier post, where I got as far as having discovered that virus particles are about 0.02 microns in size.

A bit more time today, and a bit more digging.

I didn’t bother with Denier, overnight I decided that was probably a red herring.

I did, however, find a UK company called Filtrex. I had in my mind something like DIY masks for sanding etc. but these guys seem far more upmarket – clean rooms etc. On their site, I found a useful page which talked about standards. Apparently there is one, ISO 16890. It only came about in 2016 so I suspect it isn’t ubiquitous yet. Bottom line, it splits filters into four levels, and even the highest quality of these only filters particles of 0.3-1 micron. That’s still an order of magnitude bigger than COVID-19. Imagine trying to get a yardstick through a 10-yard gap…. Conclusion – I’m looking in the wrong ballpark.

I then started looking at other standards. I came across FFP1, 2 and 3, which I think are EU standards. FFP = filtering facepiece. The masks gradually restrict smaller particles. with FFP3 offering the highest level of protection.

FFP3 masks are what is used by our NHS to care for COVID patients, with a big caveat that if you’re working in the NHS, these masks are supposed to be fitted to your face, so there’s no gap. With all the hoo-ha here about PPE, I have no idea whether that is actually happening, but it is what is supposed to happen.

FFP3 is also the type of mask recommended by the WHO to treat COVID patients – reassuring that in this case at least, we are fitting in with international standards. On some sites I have seen that it is the equivalent of N99. Funny, Jim Adams mentioned an N-rating after my original post, yesterday, but I couldn’t dig up any info. I’m guessing it is the corresponding US standard.

FFP3 masks seem to be retailing on eBay at around GBP20 minimum. That’s not far different in USD or EUR, and that’s each. Pretty blatant profiteering, most likely.

Nevertheless I might get one with a view to washing it between trips out, although that is bloody expensive just for a mask. And before I buy anything I’ll need to be clear whether it is washable or not.

Even after that, I’m not sure that they will be a barrier, but I’m guessing that since the NHS use this standard of mask, it’ll be the best I can get hold of. I might have to settle for that. Given this appears to be a European standard, and we have been in the EU for forty-odd years, I wouldn’t expect to have to look for any other standards.

Mister Bump

In the UK people have been talking about lifting lockdown, with the mandatory wearing of masks in public places. My gut feel is that our government is libertarian in nature, so won’t go near that. They might advise, but I doubt they’ll mandate. “Experts” seem split on whether they are effective or not (the masks, not the government. Everybody is pretty unanimous about the government!) I think it is a case of choose an expert who fits in with what you already think. So one of the questions I have had on my list of things I really need to do, (and sooner rather than later) has been to evaluate the question of just how much use a facemask would be.

I started off, I must admit, thinking: particles small, gaps in the mesh of facemask fibres big, so really did not see the point in wearing one. But I…

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  1. The 2.5 in PM2.5 refers to the size of the pollutant in micrometers. Micrometers are equivalent to 0.001 millimetres. The smallest thing that the average human eye can perceive is about 0.1 millimetres, which is around the same width as a human hair. So this is incredibly small and can only be seen using a powerful microscope.

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  2. I have concluded that there is value in wearing a mask, as a kinda “just in case”, but I have also concluded that my wife and I must act in unison, there is no point in acting unilaterally. And she is not convinced that a mask will help her. She does wear something at work, where she is in close proximity to other people, but does not see the value of wearing one “privately”, where she is much more distanced from everybody except me. She is a practising nurse so probably understands this subject better than I do.


  3. We are obliged to wear a mouth mask on public transportation and every where when you cannot keep social distancing. So in stores, hospital etc. That were the rules when isolation became less strict, only the government did loosen up the rules and promised the masks but ’till this day they are not delivered. First we were told to make them ourselves (I mean!). I have a disposable one and a washable one that I air dry for three days at least. I still try to be at home as much as possible, that seems the easiest solution for me.

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    • That was it, as far as our media is concerned, a mask is a mask is a mask, but actually there are a million different types out there. So I set out to find out whether a mask was a good idea, and if so, what type. I think I heard something yesterday that our government was going to mandate masks on public transport from mid-June. My immediate thought was, if you take any action, it should be straight away. There is an overall feeling here that we are fed up with lockdown, and things are being reinstated with no real evidence from the numbers.
      Incidentally, we had a tv news article about Be here last night. They said that you had the worst per-capita numbers in the world (I didn’t check this) but that was because of your honest reporting. That’s what they said.

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      • The honest reporting goes a little bit far, as I’ve been told they just counted all the deaths, covid and suspicion of death related to covid.
        It is all a bit confusing here as we are allowed more things but the rules aren’t clear at all!

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