A report published in the peer-reviewed journal’s October 2020 edition indicated that there is no conclusive evidence showing cloth masks help protect users against the coronavirus, suggesting the science on the subject is not yet settled.
The authors wrote: More research on cloth masks is needed to inform their use as an alternative to surgical masks/respirators in the event of shortage or high-demand situations. To our knowledge, only 1 randomized controlled trial has been conducted to examine the efficacy of cloth masks in healthcare settings, and the results do not favor use of cloth masks.
More randomized controlled trials should be conducted in community settings to test the efficacy of cloth masks against respiratory infections. In the report, the authors warned that cloth masks could provide users with a “false sense of protection.”
I am pretty sure this was published this May 2020. There are many peer reviewed papers that say N95 type masks are useless. There are federal guidelines for protection, and PPE always protects the eyes. The yes are the second best path for entry. This is what I do for a living, there is zero confusion on the subject.
Thank you, TerryK. Good to hear from one who does in fact know rather than a horde of supposers.
I think we wear the damn things because businesses say we have to in order to shop/dine there. It's relatively painless, costs nothing, and keeps the "Karens" from screaming at us.
I don't remember anyone saying the masks protect you. It has always been to keep you from spreading the virus. Not 100% but it does offer some.Seems all the naysayers conveniently forget this
Last edited by saddlesore; 10/29/20.
If God wanted you to walk and carry things on your back, He would not have invented stirrups and pack saddles
The virus from the lungs is mathematically complex. It is nanometer (10e-9 meters) to stuff you can see like fog on a cold day at 30X 10e-6 meters. So some of the droplets are 1000X smaller than a human can see. The super small stuff like that can be trapped in a hepa fllter pretty well because it travels like a pin ball. This is called browning motion and is well know mathematically. Most engineers do it for homework. Naturally smallest goop has a high probability of contact due to the circuitous path. Little bigger stuff goes straight, and contact trapping is very reduced. Particles are 100s time smaller than mesh. Like a mosquito going thru a chain link fence, and these are the super nasty ones for the cells. These also stay suspended in air due to heat etc, so again they are a triple threat. Bigger dudes that you can't even see may be trapped, but can become nebulized by the mask and breathing. So masks may trap bigger particles, and help disperse them as smaller more deadly units. There are other concerns like humidity, heat, electrostatics, etc, but size kinda dominates the pathways. Mask thing for virus is beyond silly. This stuff is in a zillion text books, and assigned as homework to engineers that make stuff like nano drugs and semiconductors. Transistors are really about the same size as a virus, so dirt on that size scale would kill your cell phone parts. So having a working phone means plenty of people know the physics of attenuating small particles, virus or any other material. Many drugs are actual copies of the virus, but have a different corona that may stick to cancer, or hide the drug from the bodies attack/removal system. Payload is usually a poison, not MRNA like a virus, but both are a trogen horse jelly donut. Again these things are well known. People make "virus" particles for drugs have to have a safe manufacturing environment. There are federal standards such as bio-safety level PPE procedures and enclosures. Again this is not my idea, this is OSHA ,FDA, ASTM compliance regulations and guidelines. Paid off my house knowing this stuff. Insulting to see the BS on this subject. Mask do nothing, and the virus is real, but somewhat rare. Best bet is to isolate the risk group and go for herd immunity. Masks are a teddy bear for physiological comfort, and that is why they are used.
I don't remember anyone saying the masks protect you. It has always been to keep you from spreading the virus. Not 100% but it does offer some.Seems all the naysayers conveniently forget this
Show me the particle flow math that proves this. Hint there is none. Industries run on these facts. Masks are transparent to nanoscale viral particles - period. 1 inch HEPA is even terrible. A McDonald napkin is effective for a coffe spill, not viral inhalation or transmission through the eyes.
Just look up cleanroom filters, and particle flow. The worst size is nominally 0.3 microns. Kinda a sweet spot for a lot of variables. Worst yet, this is also a sweet spot for cellular uptake. So in some way the virus, any virus is bad mojo due to free transport, and cellular scale. Perfect fit, that is why virus is a "thing". Scale.
So a mask for virus is like a fish net condom, eh?
Better yet it can be a spray bottle trapping bigger stuff and dispersing it on a smaller more dangerous scale. I don't think that is mush of a deal, but it is a small factor.
Ideas like this dispersion are critical in containing spills etc, not really masks per say. So rags and mops become spreaders, if not used properly. That is a more central tenant when looking at think cloth material and the potential to minimize transmission in an industrial environment.
Anyway I said enough, I usually like to avoid these discussions.
The virus from the lungs is mathematically complex. It is nanometer (10e-9 meters) to stuff you can see like fog on a cold day at 30X 10e-6 meters. So some of the droplets are 1000X smaller than a human can see. The super small stuff like that can be trapped in a hepa fllter pretty well because it travels like a pin ball. This is called browning motion and is well know mathematically. Most engineers do it for homework. Naturally smallest goop has a high probability of contact due to the circuitous path. Little bigger stuff goes straight, and contact trapping is very reduced. Particles are 100s time smaller than mesh. Like a mosquito going thru a chain link fence, and these are the super nasty ones for the cells. These also stay suspended in air due to heat etc, so again they are a triple threat. Bigger dudes that you can't even see may be trapped, but can become nebulized by the mask and breathing. So masks may trap bigger particles, and help disperse them as smaller more deadly units. There are other concerns like humidity, heat, electrostatics, etc, but size kinda dominates the pathways. Mask thing for virus is beyond silly. This stuff is in a zillion text books, and assigned as homework to engineers that make stuff like nano drugs and semiconductors. Transistors are really about the same size as a virus, so dirt on that size scale would kill your cell phone parts. So having a working phone means plenty of people know the physics of attenuating small particles, virus or any other material. Many drugs are actual copies of the virus, but have a different corona that may stick to cancer, or hide the drug from the bodies attack/removal system. Payload is usually a poison, not MRNA like a virus, but both are a trogen horse jelly donut. Again these things are well known. People make "virus" particles for drugs have to have a safe manufacturing environment. There are federal standards such as bio-safety level PPE procedures and enclosures. Again this is not my idea, this is OSHA ,FDA, ASTM compliance regulations and guidelines. Paid off my house knowing this stuff. Insulting to see the BS on this subject. Mask do nothing, and the virus is real, but somewhat rare. Best bet is to isolate the risk group and go for herd immunity. Masks are a teddy bear for physiological comfort, and that is why they are used.
Thanks for that.
The news article states an oct 2020 publication, FWIW.
This is 3rd or 4th flip on mask reco.
If you take the time it takes, it takes less time. --Pat Parelli
American by birth; Alaskan by choice. --ironbender
yes. Classic multivariable analysis with heat, humidity, materials, etc, etc. Good homework for most engineers. Cool curves. But cooper bracelets and good intentions invalidate those math models. Wishful thinking trumps physics.
May 2020 peer reviewed CDC publication.
The reference is: “Nonpharmaceutical Measures for Pandemic Influenza in Nonhealthcare Settings—Personal Protective and Environmental Measures.” Published in: “Emerging Infectious Diseases, Vol.26, No. 5, May 2020.” (That journal is published by the CDC.)
I quote from the abstract: “Here, we review the evidence base on the effectiveness of nonpharmaceutical personal protective measures and environmental hygiene measures in non-healthcare settings and discuss their potential inclusion in pandemic plans. Although mechanistic studies [*] support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza. We similarly found limited evidence on the effectiveness of improved hygiene and environmental cleaning.”
Here are quotes from pages 970-972 of the review: “In our systematic review, we identified 10 RCTs [randomized controlled trials] that reported estimates of the effectiveness of face masks in reducing laboratory-confirmed influenza virus infections in the community from literature published during 1946–July 27, 2018. In pooled analysis, we found no significant reduction in influenza transmission with the use of face masks…”
