Arne.

Thank you very much for such a clear, logical and

practical exposition of the use and need for face masks  

To help reduce the spread, and SAVE LIVES  

Brilliant  

Anonymous wrote:

 Let me point out the obvious..... The comment about cloth masks becoming "dangerous" is absurd in this context.   Viruses do not reproduce except by injecting their DNA into human cells..... or whatever organism they are programmed to infect.  They will NOT breed and reproduce in the warm moist environment of a cloth mask.  This applies ONLY to bacterial pathogens, and not all of them.  

    In another bit of ignorance,  it was suggested that surgical masks were somehow superior to an N95.......... which is utter nonsense.    Surgical masks are only to prevent things from the doctor or nurse's mouth or nose... water droplets, etc from contaminating the operation.  They do not fit even remotely tightly.  They cup out at the cheeks, and allow air to enter and exit through those cups.

     The N95 designation means that the mask will filter out 95% of small particles.   These are the masks you buy at the hardware store or auto parts store as dust masks.  That box of masks you bought when sanding fiberglass on your boat is probably N95 designation.... I know the box of 50 3M masks I have on a back shelf I bought at the local hardware store has that designation.   The press picked up on N95, and has repeated it and blown  it up out of proportion, as if it were some special medical grade mask...... it's not.  It's a dust mask!

     I encountered a friend at the grocery store the other day who was wearing a mask, and commented on it........ he proudly proclaimed that it was an N95.  I pointed out that it had a valve, and thus was useless in protecting people around him if he should be infected.  If you have one with a valve, you should tape over the valve for the protection of others.  

Just a bit of humor......... It appears that we are about to receive help from a higher power.  I've seldom laughed so hard!     Judgment is Executed by  Kenneth Copeland

This was March 30th, and as you have no doubt observed the number of infections and deaths in the US has been in steep decline ever since   ;-)

                                                                H.W.

Howard, I think you misread the article.

The categories of masks were N95, surgical, and cloth, listed in order of effectiveness.

Yes, viruses don't breed on wet masks, however as you stated other things do.  The last thing you need in a Covid outbreak is another form of respiratory infection.  This problem becomes worse as you reuse a mask if it is not adequately sterilized.

I think there is also another issue with the wet mask, which your earlier suggestion of a salt layer applies to.  As the cloth mask becomes wet the layer of water retains virus, also a wet mask begins to clog the pores of the mask and you effectively begin to increase the vaccuum inside as you breath.  As the mask becomes progressively wet you can begin to draw that water saturated with the virus through the mask.  The coarser pore size of a home-made cloth mask an the fact that cloth masks are not hydrophobic causes the problem.

For something that looks so simple from the outset, masks are surprisingly complex, especially if you look at using them in a heterogeneous group of users.

Anonymous wrote:

I'm getting tired or reading and writing about masks, and I'm sure most who have been patient enough to read what I've written have felt the same.  Before I step away from it, I thought I would share this paper, which is probably the single best one I found on the effectiveness of home-made masks.  I know some of you are in areas where masks are becoming mandatory so it is worth being aware of the limits, especially home-made masks.  I couldn't find a scientific article to confirm it, but this article in TIME also suggests that cloth masks may become more dangerous as they get moist, so if you use cloth masks change them to keep them dry and store the used ones safely until they can be sterilised again.

For those that don't have to wear masks, this paper is a good example of why every single N95 mask available should be heading to a hospital in need.  The demand for them is global and even if your local hospitals have enough, this chart shows a good reason not to use N95's yourself.

 Let me point out the obvious..... The comment about cloth masks becoming "dangerous" is absurd in this context.   Viruses do not reproduce except by injecting their DNA into human cells..... or whatever organism they are programmed to infect.  They will NOT breed and reproduce in the warm moist environment of a cloth mask.  This applies ONLY to bacterial pathogens, and not all of them.  

    In another bit of ignorance,  it was suggested that surgical masks were somehow superior to an N95.......... which is utter nonsense.    Surgical masks are only to prevent things from the doctor or nurse's mouth or nose... water droplets, etc from contaminating the operation.  They do not fit even remotely tightly.  They cup out at the cheeks, and allow air to enter and exit through those cups.

     The N95 designation means that the mask will filter out 95% of small particles.   These are the masks you buy at the hardware store or auto parts store as dust masks.  That box of masks you bought when sanding fiberglass on your boat is probably N95 designation.... I know the box of 50 3M masks I have on a back shelf I bought at the local hardware store has that designation.   The press picked up on N95, and has repeated it and blown  it up out of proportion, as if it were some special medical grade mask...... it's not.  It's a dust mask!

     I encountered a friend at the grocery store the other day who was wearing a mask, and commented on it........ he proudly proclaimed that it was an N95.  I pointed out that it had a valve, and thus was useless in protecting people around him if he should be infected.  If you have one with a valve, you should tape over the valve for the protection of others.  

Just a bit of humor......... It appears that we are about to receive help from a higher power.  I've seldom laughed so hard!     Judgment is Executed by  Kenneth Copeland

This was March 30th, and as you have no doubt observed the number of infections and deaths in the US has been in steep decline ever since   ;-)

                                                                H.W.

Anonymous wrote:

Re-using a non-reusable mask.

I leave it to you to decide if you will use a facemask or not.

An armchair idea:
This idea struck me: How can one sterilise and then reuse a ‘non-reusable’ mask?
My guess is that they will not survive a flat-iron treatment, but I see two other options:

·         Soak it in alcohol for a while and then let it dry.

·         Put it in the oven which has been set to 100°C, and keep it there for, say fifteen minutes.

If the mask has not disintegrated because of one of these treatments, it should now be virus-free and ready for another use.
Just a thought....

Arne

A bit of research over coffee this morning suggests that the short answer is no, here is a link to an entire book on the subject if you want the long answer, the amount of info available in the free preview should satisfy most of us.  Most of the scientific articles I could find were geared to hospital settings where there is a need to reuse masks at a pretty short interval.  If you are only going shopping once a week and you can carefully quarantine your mask in a breathable paper bag in the interim.  Then, there should not be infectious Coronavirus on the mask after six days.  I'm not sure if there might be long-term risk from other pathogens by doing this (some other things such as molds, fungus have long-lasting spores etc, that the mask would eventually accumulate).  There are also other pathogens that have prolonged environmental survival (e.g., methicillin-resistant Staphylococcus aureas, vancomycin-resistant enterococci, Clostridium difficile, norovirus, etc.).   

If you were to try this it would be very important to wash you hands, then remove and quarantine the mask, then wash your hands.  The first handwash stops you from contaminating the mask, the second prevents the mask from contaminating you.  Here is a more extensive guidance on extended mask use.

I'm still in favour of not wearing masks by anyone who doesn't have to work in very close conditions with other people.

Wearing masks by the general public has real negative side effects.  After introducing the idea for the public to wear face-masks, then getting the CDC involved (to really get the public attention) and then switching from face-masks to scarves (because there aren't enough face-masks), the Trump administration now wants to ban the export of N95 masks to Canada.  Although 3M has protested, it will be interesting to see what happens.  3M has operations on both sides of the border, and things are normally shipped back and forth seamlessly, however all the mask manufacturing is in the US......  Hospitals and care centres in Canada have already been carefully rationing personal protective gear because of a very limited supply....

China has "generously donated" 30 000 masks to Canada.  However, there are questions regarding quality.  When you consider that Canada sent 16 tons of protective gear to China at the start of the outbreak, I'm not sure this feels like a very even trade.

I can't help but think about what Annie said at the beginning of this thread: "And as so many people are pointing out: our parents and grandparents were told to kill an be killed".  If we had only been more effective at getting out the message about the ineffectiveness of masks used broadly in the public and instead asked people to step-up, be brave and physical distance with a bare face.  Imagine the number of lives of doctors and nurses that could have been saved.  I really feel we will look back at this in several years time and see where the irrationality of panic and politics trumped science and reason.

Even if you sew a cloth mask, wearing it ratchets up the anxiety of those around you.  They want masks too now, then they buy them from where-ever they can.  Then you get Chinese officials saying wearing masks makes a difference and by the way we can sell them to you for a premium.  

This outbreak really does seem to have brought out the best, but also the worst in people.