[vhfpmr]

This is interesting:

[Petrochemicals]

A

This is interesting:

And  yet on that grapg italy and south Korea are closer than japan and singapore. 85 percent of statistics are made up !

[vhfpmr]

A

This is interesting:

And  yet on that grapg italy and south Korea are closer than japan and singapore. 85 percent of statistics are made up !

They aren't made up, they're the stats from the Johns Hopkins University database that seems to be everyone's go to reference. That was a tweet from a virologist at Columbia University.

Here's a review published in Nature this morning, drawing attention to a study published a few years ago finding that surgical masks do reduce transmission of coronaviruses. To quote Dr Beale, in charge of the Cell Biology of Infection lab at the Crick Institute, "As far as I am concerned the mask 'debate' is over. They work.".
https://www.nature.com/articles/s41591-020-0843-2

[Petrochemicals]

A

This is interesting:

And  yet on that grapg italy and south Korea are closer than japan and singapore. 85 percent of statistics are made up !

They aren't made up, they're the stats from the Johns Hopkins University database that seems to be everyone's go to reference. That was a tweet from a virologist at Columbia University.

Here's a review published in Nature this morning, drawing attention to a study published a few years ago finding that surgical masks do reduce transmission of coronaviruses. To quote Dr Beale, in charge of the Cell Biology of Infection lab at the Crick Institute, "As far as I am concerned the mask 'debate' is over. They work.".
https://www.nature.com/articles/s41591-020-0843-2

But i didnt say to mug grannies and club puppies to death

[set fair]

Important note on masks. If yours has a valve, then you need to wear a bandana or scarf over it. The valve points down (usually) but you don't want to breath virus out if your infected but have no symptoms.

ps or glue it shut even better

[Petrochemicals]

I do not think the humidity the person is breathing will alter, if you have ever used a propper sealed respitator from the atmosphere, not gas tank, you will notice the difference in effort to draw breath.  Face masks with the elastic draw of breath  just goes up the sides !

Whenever I’ve used them in cold air I’ve noticed condensation on the outlets and sometimes on inside.
I decided to try testing humidity yesterday. I used a 3M disposable dust mask P2. Relative humidity was 48%, after 2min I put the probe inside the mask and recorded 95%. Not surprising as we breath out a lot of moisture.

This may help
https://www.hse.gov.uk/research/rrpdf/rr619.pdf

Also, this one might, backs up much of what you are saying:

 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5058571/

Ive just held a surcical mask tight on my face and breathed through it, it it very much hard work even at that low protection factor,  how easy is this with a p2 mask ?

[Colin2B]

Ive just held a surcical mask tight on my face and breathed through it, it it very much hard work even at that low protection factor,  how easy is this with a p2 mask ?

I use P2 and P3 and find them very easy, but then I don’t find a surgical mask offers any real resistance.
When working with irritating dusts eg hardwoods I use a forced air headset, just because the dust clogs the mask filters, so if you are in an area of high particle/droplet concentration it’s worth changing regularly.

[RD]

When working with irritating dusts eg hardwoods ...

Wood-dust can do more than irritate ...

An increased risk of adenocarcinoma of the sinonasal cavity is an important and serious problem associated with occupational exposure to wood dust. Adenocarcinoma constitutes about half of the total number of cancers induced by wood dust. An increased incidence of the squamous cell cancers can also be observed.

https://www.ncbi.nlm.nih.gov/pubmed/8231799

[Colin2B]

Wood-dust can do more than irritate ...

An increased risk of adenocarcinoma of the sinonasal cavity is an important and serious problem associated with occupational exposure to wood dust. Adenocarcinoma constitutes about half of the total number of cancers induced by wood dust. An increased incidence of the squamous cell cancers can also be observed.

https://www.ncbi.nlm.nih.gov/pubmed/8231799

I know, yet another reason I take precautions, not to mention the effects on the lungs.

[set fair]

Early to be certain but it looks like the Czechs have reduced R0 below 1... by wearing masks. Time one of the experts to break ranks and tell the truth. Homemade masks will work to slow the spread, if we all wear them. Be brave Chris, you don't want to be remembered for saying no to masks.

OK pretty please then 

[alancalverd]

ve just held a surcical mask tight on my face and breathed through it, it it very much hard work even at that low protection factor,  how easy is this with a p2 mask ?

A surgical mask is not designed for inhaling - you inhale through the lack of fitting at the edges. A builder's dust mask is a lot more effective at trapping incoming aerosol (because it is a full fit) whilst providing enough total area  to allow relatively easy inhalation. If you use a HEPA-quality full-fit mask, you are doing as well as possible short of a Noddy suit. A one-way valve will stop your goggles steaming up.

[alancalverd]

As far as statistics are concerned, most people will accept a 1 in 10,000 risk for a substantial reward, but would avoid anything above 1 in 100,000 if the reward is purely pleasure. My bands all cancelled gigs as soon as the probability of anyone present being infectious exceeded about 1 in 50,000.   

[Petrochemicals]

ve just held a surcical mask tight on my face and breathed through it, it it very much hard work even at that low protection factor,  how easy is this with a p2 mask ?

A surgical mask is not designed for inhaling - you inhale through the lack of fitting at the edges. A builder's dust mask is a lot more effective at trapping incoming aerosol (because it is a full fit) whilst providing enough total area  to allow relatively easy inhalation. If you use a HEPA-quality full-fit mask, you are doing as well as possible short of a Noddy suit. A one-way valve will stop your goggles steaming up.

I agree whole heartedly.Point is that the air takes the least resistance, which is round the leaky edges. I think you would be surprised at the difference between a propper face fit mask, with its extravagent gussets and the pressure that has to be applied, and the paper single use dust mask that you describe, which are only good for stuff that falls to the ground fairly quickly. Amazon search for aerosol filter mask, they do not make them for nothing.

https://www.amazon.co.uk/spray-paint-masks/s?k=spray+paint+masks

[Petrochemicals]

A bit late now.

https://www.bbc.co.uk/news/health-55537624

[alancalverd]

Let's go back to the HSE's actual findings mentioned by BC several months ago

[quote[Using separate tests to measure levels of inert particles and live aerosolised influenza virus, our findings show that surgical masks provide around a 6-fold reduction in exposure. Live viruses could be detected in the air behind all surgical masks tested. By contrast, properly fitted respirators could provide at least a 100-fold reduction.[/quote]

So: simple surgical masks, as they are intended to do and have done for umpteen years, reduce the probability of you infecting anyone else because they intercept projected aerosol in your exhalate. If everybody wears them properly, they are more effective than not in reducing new infections in public places. But if you have to work in a known infective environment, you need a fitted HEPA respirator and scrupulous hand hygiene.