9 votes
Accepted

Does a KN95 that says 'non medical' helps to protect against COVID-19?

In the US, in order for a mask to be labeled "medical", that mask must be approved by the FDA as a medical device. With so many new people manufacturing masks coupled with the public demand ...
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  • 680
7 votes
Accepted

Why is a (simple) mask not recommended for asymptomatic COVID-19 patients?

TL;DR: please WEAR A MASK! (unless your nearby hospitals are out of it, in which case give your masks to them and stay at home) The link you mentioned provides the reason that the CDC likely has in ...
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5 votes

If tissue and kitchen paper masks achieve 90% of the filtering function of a surgical mask, why the CDC is not recommending them?

This is an early paper on the efficiency of different fabrics for virus filtration. (Lots of testing as gone on since then.) However, it nicely illustrates breathability, the other factor to consider ...
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4 votes

Are hand-made mask using HEPA safe to breath through?

Shop-vac, a major manufacturer of HEPA material strongly advises against using their vacuum bags to make a filter First, the filter materials used in the vacuum cleaners are for no purpose other than ...
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  • 13.2k
4 votes

What should you put on your face if you want to protect both yourself and others?

A mask. According to the FDA If worn properly, a surgical mask is meant to help block large-particle droplets, splashes, sprays, or splatter that may contain germs (viruses and bacteria), keeping it ...
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  • 680
4 votes
Accepted

Is repirator easier to breathe through than conventional medical mask?

Masks with exhalation valves are meant to be used to protect against particulates like sawdust or smoke. They must not be used in a pandemic because a large part of the usefulness of masks is ...
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  • 11.9k
3 votes

Does a KN95 that says 'non medical' helps to protect against COVID-19?

Typically for an N95 mask to be considered "medical grade" it must be compatible with a sterile environment, such as by filtering both inhaled and exhaled air. Surgical masks provide some ...
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  • 131
3 votes
Accepted

What are some medical conditions and disabilities that might prevent someone from wearing a face covering during the COVID-19 outbreak?

My interpretation of this advice is that it is creating a necessary loophole for, say, someone's physician to state that a patient should not wear a mask. Maybe it would include people on supplemental ...
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  • 11.9k
3 votes
Accepted

Is using a shield rather then a mask effective with COVID-19?

Some advantages of shields: Eyes are protected in comparison to masks (CDC considers this the main reason to wear a shield; source: https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/...
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  • 1,157
3 votes

Why wear half face disposable respirator inside full face powered air respirator?

Raymond J. Roberge (2008) discusses the rationale for concurrent use of N95 FFR masks and PAPR hoods. The primary benefit is to reduce the number of particles the wearer inhales, and secondarily to ...
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  • 218
3 votes

Alternatives other than face-mask-respirators for protection against COVID-19

Those are face shields to prevent primarily droplets reaching the eyes, and are worn as being more comfortable than goggles to protect the mucous membranes of the eyes, and they don't fog up like ...
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  • 13.2k
3 votes

Bike pump as a ventilator?

Even a cursory reading of the spec indicates that this will not work. Specification Must: Defines the minimum viable product clinically acceptable by clinicians [...] RMCPAP must ...
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3 votes

New Covid December 2020 mutation in UK and its consequences

The higher transmissibility of this VUI-202012/01 strain (if it is confirmed) is almost certainly due to mutations in the spike gene of the virus; see preliminary report from COG UK; another version ...
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  • 5,803
3 votes

What face mask with glowing LEDs on the back is this health worker wearing?

I guess it's some kind of compact PAPR in semi-mask form. Here's a similar product
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  • 5,803
3 votes

What is the difference between different mask standards?

The FFPx standards refer to the efficiency of the mask and the minimum particle size it filters out: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7248188/#:~:text=FFP1%20refers%20to%20the%20least,...
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  • 9,346
2 votes

How does a "normal" N95 respirators differ from a medical variant N95 respirator?

Properly fit tested N95 respirators filter out 95% of 0.35 micron particles that the wearer would otherwise inhale. N95 respirators without an exhalation valve filter out 95% of 0.35 micron particles ...
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  • 159
2 votes

Do surgical masks effectively protect me against passive smoking and off-gases from cars?

Keep in mind that surgical masks are designed primarily to protect the patient from the surgical staff, not the other way around. They prevent aerosols exhaled by the surgeons and nurses from ...
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  • 9,346
2 votes

How does a sanding mask compare with a disposable medical mask?

Particle Size-Selective Assessment of Protection of European Standard FFP Respirators and Surgical Masks against Particles-Tested with Human Subjects The tested FFP respirators and SMs in this ...
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  • 13.2k
2 votes
Accepted

Is there any upside of using N95 masks instead of N99 or N100 to protect against COVID-19?

Yes, there are several "upsides" as you put it. It's cheaper It's easier to breath in It's sufficient for catching particles smaller than it's actually designed for... Now, that last point is what'...
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  • 150
2 votes

Why don't we use complete white medical suits to have full protection instead of only masks?

In an ideal world everyone would have full body Ebola type protection. In the world of practicality, the WHO has advised that this is a droplet, and surface spread infection. However, it is not ...
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  • 13.2k
2 votes

How much more protection does doubling up masks offer for COVID-19?

The CDC published a study on this recently, but it's not doubling the same mask. Double mask refers to a three-ply medical procedure mask covered by a three-ply cloth cotton mask. A knotted and ...
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  • 5,803
1 vote

Is the efficacy of N95 respirators or surgical masks reduced when wet (COVID-19)?

This paper tested Ebola penetration of wet and dry surgical masks and N95 respirators. It found, "A difference in virus penetration was observed between dry (5%, 1/21 tests) and saturated (33%, 7/...
1 vote

Do oxygen and carbon dioxide move with Brownian motion? And, if so, do they get trapped by N95 masks?

From what I can tell, yes, both oxygen and carbon dioxide gas particles will follow brownian dynamics as they move through the air on both sides of an N95 mask. And, yes, studies (on people wearing ...
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1 vote

Does a KN95 that says 'non medical' helps to protect against COVID-19?

The mask protects people from the person wearing the mask. In surgery, my colleagues and I wear a mask to protect the patient's open wound from me. Do not make the mistake of thinking that you, as ...
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  • 817
1 vote

What is the difference between medical grade and non-medical grade disposable masks?

Offhand it would appear that surgical masks of the type you have cited would be regulated by the US government if they were to be used in a medical setting. Check out this FDA page, you will see that ...
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  • 680
1 vote

Why wear half face disposable respirator inside full face powered air respirator?

It's not clear that they are actually wearing a 3M powered air purifying respirator system as those have a valve and filter at the front of the mask. Anyway, even if it is a 3M PAPR the data suggests ...
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  • 13.2k
1 vote

Could a face masks prevent droplets even though it does not avoid virus infection?

There has been a lack of masks outside Asia. Instead of saying: We don't have enough masks the governments and health authorities announced: masks are not to protect the one who wears it but all ...
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1 vote

Bike pump as a ventilator?

Airway pressure is a lot less than what a bike pump produces during a single pump action (in the usual setting of how its used). Even though ventilators work in a similar way (cf. https://i.stack....
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  • 1,157
1 vote

Which studies have shown that UV radiations fail to reach some part on the mask and therefore may not be suitable for sanitizing masks?

This may not be the exact issue alluded to in your source, as it’s not caused by the shape of the mask directly, but Fisher, Williams, & Shaffer (2010) finds that the effectiveness of UV ...
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  • 218
1 vote

How resistant to moist heat is SARS-CoV-2

Regardless of whether high-temperature steam kills SARS-CoV-2, a technical bulletin from 3M notes specifically that they do not recommend sterilizing N95 FFR masks using high temperature, autoclave, ...
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  • 218

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