9

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 for masks, it is likely not profitable to delay to seek FDA approval. The FDA also is unlikely to approve a new manufacturer's mask without ASTM testing. Thus, ...


7

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 mind (though I agree it doesn't identify it clearly as the reason): The worldwide supply of masks is limited. It's critical that we use them appropriately. [...


5

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 when making a mask: They summarize nicely here: Although the dish towel and the vacuum bag captured the most particles, they were also the hardest to breath ...


4

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 to protect the end users of Shop Vac products from particles or debris being expelled back into the ambient air during operation. They are in no way designed ...


4

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 preventing people who are infected and don't know it from spreading the virus. If you have an exhalation valve on your mask you're exposing everyone around you. Public ...


4

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 from reaching your mouth and nose. Surgical masks may also help reduce exposure of your saliva and respiratory secretions to others. Other types on masks may ...


3

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 oxygen or with respiratory difficulties. Could also include people with injuries on the face. The point is that it is vague on purpose; it doesn't intend to ...


3

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 filtration of exhaled air, which is why they're useful in surgury (e.g. keep saliva off an operating region). I have an N95 mask advertised for environments with ...


3

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/cloth-face-cover-guidance.html). Disinfection may be easier for reusable variants. Some disadvantages of shields: There are varieties of shields that are very ...


3

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 provide backup protection in the event of power loss in the PAPR. PDF link: https://www.ajicjournal.org/article/S0196-6553(07)00594-9/pdf


3

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 goggles can. However, they don't protect against droplet nuclei which float in the air, and there is no regulated design. Face shields are PPE that are commonly ...


3

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 of that with slightly more analysis confirms that one of the (17) mutations involved had been previously confirmed as causing higher transmissibility in a mouse ...


3

I guess it's some kind of compact PAPR in semi-mask form. Here's a similar product


2

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 reaching the sterile surgical field, and do very little to filter the air the staff breathes. In order to do that, you need a tight seal on the face with no gaps, and ...


2

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 study were observed to have the worst protection against particles between 0.263 and 0.384 μm. The protection factors of FFP respirators against particles in the ...


2

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's important. According to 3M's own documentes on various types of filters and masks, it seem that there's an electrostatic effect between the layers of the ...


2

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 discounting the possibility of aerosols especially during some medical procedures eg. induced coughing, and then a potentially ill fitting mask and goggles may not ...


2

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 deliver inspired oxygen concentration in the range 35 – 80% to the patient, selectable by the user. [...] All gas connectors and hoses must comply with BS EN ISO ...


2

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 tucked medical procedure mask is created by bringing together the corners and ear loops on each side, knotting the ears loops together where they attach to the mask, ...


1

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 the mask wearer, are conferring a degree of protection that provides safety.


1

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%, 7/21 tests) samples of PPE."


1

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 N95 masks, not on the mask itself--which more directly answers the concern) have shown that carbon dioxide does get trapped in the mask and builds-up over time. (...


1

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 masks to be used in medical setting must conform to 21 CFR 878.4040. It is entirely possible that there is no physical difference between the medical and non-...


1

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 you get a lot more protection Objective: To determine if using an N95 filtering face-piece respirator concurrently with a loose-fitting powered air-purifying ...


1

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 others in the environment of an infected person who wears it. Other arguments have been: wearing a mask gives a false security folks of western civilization don'...


1

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.imgur.com/PgmEZ.png), CPAP by definition needs to maintain a continuous airway pressure (CPAP = continuous positive airway pressure). The pressure to be held should ...


1

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 germicidal irradiation is limited by the accumulation of soil (skin residue) on N95 FFR masks, which decreases the penetration of UVGI. See: https://www.cdc.gov/niosh/...


1

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, or steam as these methods cause significant filter degradation: https://multimedia.3m.com/mws/media/1824869O/decontamination-methods-for-3m-n95-respirators-...


1

Apparently yes. The South China Morning Post reports that Professor Yuen Kwok-yung of HKU has been using ozone for respirator sterilization: https://www.scmp.com/news/hong-kong/health-environment/article/3078195/coronavirus-hong-kong-scientists-look


1

Some hospitals are sanitizing (not sterilizing) their N95 respirators (not masks) already. Coronavirus Update: Massive N95 Mask Sterilizing Machines Now Running on Long Island Doylestown Hospital has solution to coronavirus mask shortage - WHYY As others have pointed out, for an item that is usually $2-3 at most, the time and effort involved had not ...


Only top voted, non community-wiki answers of a minimum length are eligible