What if Everyone Wore a Mask?

[Lake-Effect]

Originally Posted by thinwater

If everyone wore [masks], healthy and sick alike, in specific circumstances which I am intentionally not detailing, would they help? Would they make the grocery store experience safer for everyone? Would they make it possible for some industries to get back to work, because we can't all sit at home. Infection rates are going to get high and we need some answers.

PDFs do what they're supposed to - float the wearer - with a very high degree of dependability.

Masks on the ill also work well, but I'll bet that their dependability at preventing the wearer from contaminating anything is less than that of a PDF to float the wearer.

Masks on the general public is like a PDF in a bathroom. It probably wont be that much help.

I do see where you're trying to go with this, but I don't think a 100% mask regime is (yet) an acceptable substitute for the current practices of staying home and social distancing.

[Trump's] not completely wrong about work. We're not going to get back to normal by Easter--that's a laugher--but we need the wheels to keep turning. We need to eat. We need food and electricity. My company supports several vital industries. Among other things, they suport soap and hand sanitizer. Can they quit? The office employees are all at home, but the plant workers must soldier on, and I feel for them. They can't stop and they can't wait for the best solution. We need to figure out a way to help them now. Shelter in place is good if it is an option for you. For many it is not. Not for the working man. These people, that must still work, will become an increasing part of the spread equation. How do you break the chain when social distancing is not practical?

I hear that as well (even said elsewhere that I agreed with Trump that it cannot continue indefinitely or for long).

You have a specific issue there - protecting essential workers. It's your plant; mandate the use of masks. Take the steps to protect your people to the best of your ability.

For the general public and all the possible public interactions and variables... the requirement and the benefits aren't as clear-cut. Maybe it can be considered on a case-by-case basis as a means of resuming a specific business.

[S/V Illusion]

Some elementary virus concepts - the Covid19 virus is 0.1 micron in size. The N95 filter blocks 2/3 of anything greater than 0.3 microns.

Might as well wear a kitchen colander

[Lake-Effect]

Originally Posted by thinwater

Mass General (and others) requiring EVERYONE to wear a mask.
https://www.wbur.org/commonhealth/20...-do-masks-work

I've done the whole hospital-borne-infection thing when visiting a relative with one or more of the fashionable superbugs. The masks are on visitors in a hospital to protect patients, not the wearer.

[Singularity]

Originally Posted by S/V Illusion

Some elementary virus concepts - the Covid19 virus is 0.1 micron in size. The N95 filter blocks 2/3 of anything greater than 0.3 microns.

Might as well wear a kitchen colander

Do you think it could be more complicated than this, and that N95s are indeed effective (if not perfect)....or do you think that you've stumbled upon evidence that the rest of the world is wrong?

[Chotu]

Originally Posted by S/V Illusion

Some elementary virus concepts - the Covid19 virus is 0.1 micron in size. The N95 filter blocks 2/3 of anything greater than 0.3 microns.

Might as well wear a kitchen colander

That's not how it works. It acts differently on that scale. There are direct impacts, a 3 stooges trying to get through a door effect, and a couple other effects that change the trajectory of the particle so it sticks in the mask.

Here's a great read on how air filtration actually works. From Wikipedia.org




HEPA filters are composed of a mat of randomly arranged fibres.[10] The fibers are typically composed of fiberglass and possess diameters between 0.5 and 2.0 micrometers. Key factors affecting its functions are fiber diameter, filter thickness, and face velocity. The air space between HEPA filter fibers is typically much greater than 0.3 μm. The common assumption[by whom?] that a HEPA filter acts like a sieve where particles smaller than the largest opening can pass through is incorrect and impractical. Unlike membrane filters at this pore size, where particles as wide as the largest opening or distance between fibers can not pass in between them at all, HEPA filters are designed to target much smaller pollutants and particles. These particles are trapped (they stick to a fiber) through a combination of the following three mechanisms:

Diffusion Edit
An enhancing mechanism that is a result of the collision with gas molecules by the smallest particles, especially those below 0.1 μm in diameter, which are thereby impeded and delayed in their path through the filter; this behavior is similar to Brownian motion and raises the probability that a particle will be stopped by either interception or impaction; this mechanism becomes dominant at lower air flow
Interception Edit
Particles following a line of flow in the air stream come within one radius of a fiber and adhere to it.
Impaction Edit
Larger particles are unable to avoid fibers by following the curving contours of the air stream and are forced to embed in one of them directly; this effect increases with diminishing fiber separation and higher air flow velocity.
Diffusion predominates below the 0.1 μm diameter particle size, whilst impaction and interception predominate above 0.4 μm.[11] In between, near the most penetrating particle size (MPPS) 0.21 μm, both diffusion and interception are comparatively inefficient.[12] Because this is the weakest point in the filter's performance, the HEPA specifications use the retention of particles near this size (0.3 μm) to classify the filter.[11] However it is possible for particles smaller than the MPPS to not have filtering efficiency greater than that of the MPPS. This is due to the fact that these particles can act as nucleation sites for mostly condensation and form particles near the MPPS.[12]

CREDIT: Wikipedia.org

[S/V Illusion]

Originally Posted by Singularity

Do you think it could be more complicated than this, and that N95s are indeed effective (if not perfect)....or do you think that you've stumbled upon evidence that the rest of the world is wrong?

I think I “stumbled” upon proven epidemiology demonstrating that a .1 micron pathogen doesn’t have much trouble being sucked into a .3 micron filter when the wearer inhales.

These are somewhat more effective in positive pressure tests simply because that delta pressure difference is minimal when exhaling. Hence, doctors wear masks to minimize transmission of pathogens to patients, not to protect the doctor.

Diffusion is a convoluted argument based more on supposition than actual data.

[thinwater]

Originally Posted by S/V Illusion

Some elementary virus concepts - the Covid19 virus is 0.1 micron in size. The N95 filter blocks 2/3 of anything greater than 0.3 microns.

Might as well wear a kitchen colander

You've missed the point of a surgeon's mask entirely. It is to prevent him from spraying the patient, or in this case, from you spitting on me. You need a good mask to protect from aerosols in the air, but far less to reduce aerosols in the air.


You cough into your elbow, right?



Even a loose tend keeps your sanding dust off your neighbor's boat. True?

[NPCampbell]

Originally Posted by S/V Illusion

Some elementary virus concepts - the Covid19 virus is 0.1 micron in size. The N95 filter blocks 2/3 of anything greater than 0.3 microns.

Might as well wear a kitchen colander

From the studies online, an N95 mask is amazingly good at blocking particles .3 microns and higher but still pretty damn good for particles the size of the corona virus. https://www.tandfonline.com/doi/full...26.2013.829209

In a casual environment of passing someone in a grocery store that might be infected, my take is that an N95 mask provides very good protection if fitted correctly with the normal touching precautions. Since at least one study has shown that the virus spreads as an aerosol for up to 3 hours https://www.nejm.org/doi/full/10.1056/NEJMc2004973 I have worn a mask both times that I have had to shop since we were ordered to shelter at home. I come in contact with vulnerable elderly family members so after shopping I additionally let non-perishable goods sit for at least 24 hours and wipe down refrigerated goods.

It's almost zero inconvenience so if it reduces the risk of killing someone why wouldn't I?

[Lake-Effect]

Originally Posted by NPCampbell

Since at least one study has shown that the virus spreads as an aerosol for up to 3 hours https://www.nejm.org/doi/full/10.1056/NEJMc2004973

uh no, in that study they artificially aerosolized virus in a special environment and confirmed that IF aerosolized and maintained as an aerosol, the virus could survive there up to 3 hours. As far as I could tell, that study is NOT stating that expelled virus would stay in the air for 3 hours. As droplets the vast majority are most likely to fall to a surface.

Again, this is another reason why social distancing remains important. Masks are not a replacement for that.

[Singularity]

Originally Posted by S/V Illusion

I think I “stumbled” upon proven epidemiology demonstrating that a .1 micron pathogen doesn’t have much trouble being sucked into a .3 micron filter when the wearer inhales.

These are somewhat more effective in positive pressure tests simply because that delta pressure difference is minimal when exhaling. Hence, doctors wear masks to minimize transmission of pathogens to patients, not to protect the doctor.

Diffusion is a convoluted argument based more on supposition than actual data.

What proven epidemiological evidence are you referring to?

[pathlesschosen]

I’ve had the fun experience of wearing N95 for several weeks straight 12+ hrs per day during physically difficult work. You get used to the mask. Not a big deal.

For wearing surgical or similar less effective mask. If the slight inconvenience for me prevents spreading the virus at the grocery store before I know that I’m sick. Excellent idea. Hope the other person in the isle does the same.

Not the only solution but perhaps one of the solutions in a new normal.

Maybe track the transmittal rates in countries that employ masks vs not.

Cheers.

[GordMay]

The Centers for Disease Control and Prevention (CDC) does not recommend that the general public wear N95 respirators, to protect themselves from respiratory diseases, including coronavirus (COVID-19).

The "N95" is one of three types of filters - N, R and P. These refer to the type of resistance they have to the degrading of their filtering efficiency, when exposed to different kinds of airborne particulates, mists, etc. To help people remember which filters can be used for protection against different kinds of airborne particulates (e.g., dust, fume and mist). NIOSH provides the following guide:
N - Not resistant to oil
R - Somewhat Resistant to oil
P - Strongly resistant to oil (oil Proof)

The "95" in N95 refers to the filter efficiency. There are three levels of filter efficiencies - 95% (N95), 99% (N99), and 99.97% (N100 or HEPA filter) tested against aerosol (fine mist) droplets 0.3 microns in diameter.

The COVID-19 virus is approximately 0.125 Microns in diameter. However, it often travels in biological aerosols from coughing and sneezing which range in “clump’ size from 0.5 to 3.0 Micron.

N95 type respirators are the respirators recommended by the Government of Canada and the U.S. Centers for Disease Control and Prevention (CDC) for use by health care workers, in contact with patients with infections, that are transmitted from inhaling airborne droplets (e.g., tuberculosis (TB); also recommended for health care staff working with patients having or suspected of having SARS, severe acute respiratory syndrome).

[Chotu]

Originally Posted by GordMay

The Centers for Disease Control and Prevention (CDC) does not recommend that the general public wear N95 respirators, to protect themselves from respiratory diseases, including coronavirus (COVID-19).

The "N95" is one of three types of filters - N, R and P. These refer to the type of resistance they have to the degrading of their filtering efficiency, when exposed to different kinds of airborne particulates, mists, etc. To help people remember which filters can be used for protection against different kinds of airborne particulates (e.g., dust, fume and mist). NIOSH provides the following guide:
N - Not resistant to oil
R - Somewhat Resistant to oil
P - Strongly resistant to oil (oil Proof)

The "95" in N95 refers to the filter efficiency. There are three levels of filter efficiencies - 95% (N95), 99% (N99), and 99.97% (N100 or HEPA filter) tested against aerosol (fine mist) droplets 0.3 microns in diameter.

The COVID-19 virus is approximately 0.125 Microns in diameter. However, it often travels in biological aerosols from coughing and sneezing which range in “clump’ size from 0.5 to 3.0 Micron.

N95 type respirators are the respirators recommended by the Government of Canada and the U.S. Centers for Disease Control and Prevention (CDC) for use by health care workers, in contact with patients with infections, that are transmitted from inhaling airborne droplets (e.g., tuberculosis (TB); also recommended for health care staff working with patients having or suspected of having SARS, severe acute respiratory syndrome).

All good stuff for people working on boats to know as well.

The bold is what I jokingly referred to as the 3 stooges effect.

In any case, if one reads the Wikipedia article on how HEPA filters actually work, it's not like a strainer. There are complex dynamics as play that allow them to stop smaller particles than the "holes" in the mask.

[slug]

Originally Posted by letsgetsailing3

Masks didn't break the contagion. Strict social distancing did.

Yes

Social distancing is the best defense

Masks are for infected persons, to prevent them from spreading the virus



Masks for non infected persons can provide some defense in that they prevent you from touching your mouth with your hands


Obviously masks are needed for health care workers , to protect their patients and themselves

[slug]

Originally Posted by pathlesschosen

I’ve had the fun experience of wearing N95 for several weeks straight 12+ hrs per day during physically difficult work. You get used to the mask. Not a big deal.

For wearing surgical or similar less effective mask. If the slight inconvenience for me prevents spreading the virus at the grocery store before I know that I’m sick. Excellent idea. Hope the other person in the isle does the same.

Not the only solution but perhaps one of the solutions in a new normal.

Maybe track the transmittal rates in countries that employ masks vs not.

Cheers.

There is a shortage of masks

People who wear them without a need are depleting the supply for those who must wear them