FlyBitcoin

Maybe for protection against measles (where a single dry virion infects you) if you are not immune, but this virus requires a very large load to get clinical infection AND is droplet spread. And in macaques, 700,000 PFU gets you an asymptomatic case, wtih 2.6 million needed for clinical infection: https://www.dhs.gov/sites/default/fi...2020_04_14.pdf
Droplets all have to compete to get through the holes in your mask and will coalesce to become bigger droplets during that process. Then if an edge of a droplet touches the edge of that passageway, the droplet gets absorbed and the viral load remains in the mask. Using any kind of virus particle measurements for a non-healthcare worker in a community environment or on an airplane simply does not hold water for THIS virus.

As a practicing physician I cannot think of a single medical contraindication to the ear looped, loose masks that airlines will be providing flyers. Your entire inhalation will be unimpeded as it will come from around the edges of the mask, while your exhale will lack the velocity and viral load that potentially harms others outside of your personal space. No OSHA contraindications to non-fitted, non-N95 masks for any medical condition, either. We will see that loophole closing up very soon. Moreover, if you can't wear that loose mask, then you cannot handle the air in a plane at cruising altitude either. Probably better to drive. Anyone within a row of me doesn't wear a mask, and one of us will be moved.

LonghornDXB

Thats correct, i.e. pollution is the main reason why many people used to wear masks in the Far East. Of course there are also people who would wear it when they have a cold, with symptoms. That has made it easier for the majority of the population to adapt in 2020.

But what you hear from some Americans is : "Oh, Asians are so considerate that most of them have been wearing masks throughout their lives, because they do not want to infect others- Asians so good, Americans so bad"

Massive sweeping generalizations being made by them, but not entirely unexpected. Just like you had Americans on one side of the political divide praising Russia and certain East European countries for protecting their culture, you have the other extreme where some Americans worship everything about China or the Far East

knownothing

You all are nuts the N99 masks that health care workers wear all have the valve. they give the greatest protection to the one wearing it

FlyBitcoin

In the age of coronavirus and asymptomatic spread, they DO NOT wear them in patient care without an additional covering on top.

Maybe you can find a video from last year or earlier with a HCW wearing one, but no more. While it is more likely the patient has more viral load than the provider, we can not be certain any HCW is NOT spreading the virus.

Not sure how this matters for "Coronavirus and Travel", the subject of this board, because no HCW on a flight needs the same protection that they need at work, and the cabin is not an ICU.

ajf87

1. Healthcare workers receive training on how to properly use N95s.

2. In the healthcare setting, N95s are worn when the patient has a confirmed or suspected contagious respiratory disease. Masks in public places for civilians serve a completely different purpose, as has been explained ad nauseum on this website and across many different mediums.

jmastron

Raises an interesting question -- for protecting OTHERS, is an N95 with a valve with additional covering better or worse than an N95 without a valve alone? I suspect an N95 without valve can't possibly maintain as good a seal under the positive pressure of exhaling as it can under the negative pressure of inhaling, but is the velocity/quantity of droplets that escape around the edges significant?

knownothing

knownothing

all n95 have a valve

ajf87

Username fits.

boerne

Umm, NO. I participated in an aerosol producing procedure with about 20 people in the OR today, Everyone had an inner N95 and an outer mask, with 100% eye protection. Not a single person was wearing a N95 Mask with a valve. If someone tried to wear one of those they would have been thrown out of the operating room if not the hospital. I was originally not on board with the valve restriction but my research tells me that it is a deal breaker. Go ahead and use them, but if I see someone with that, I am out of there

Loren Pechtel

Except they're in droplets that are big enough to be stopped. Masks aren't perfect but they're a lot better than no masks.

FlyBitcoin

Definitive FAQ regarding masks: https://www.fast.ai/2020/04/20/skeptics-masks/

jmastron

Yeah, in my garage I have a few 3M N95 masks without valves and a few 3M N95 masks with valves. I'll post a picture if any posters who don't "know" would like. The valve is literally a flap over a big hole that lets unfiltered <whatever> come out when you exhale; completely useless for containing anything. It does need to be called out explicitly and in training materials, otherwise it's going to open up whole new areas of conflicts between customers who know and who don't know. Just like it's now socially acceptable to tell someone behind you in line to back off where it might not have been before, I'm not going to let the guy with a valve mask sit in the middle seat next to me that the airline claimed they weren't allocating in the first place...

estnet

A properly fitted and used n95 does NOT allow "leakage" (hence part of the reason they are uncomfortable over long periods of time and can lead to face skin problems - do a search)- medical workers are trained to use them properly and test that the seals work (with a variety of tests) however among untrained people who don't have a clue how to even bend the nose clip, etc. the answer to improperly used anything is uncertain at best.

chrisl137

The largest viruses are around 0.3 microns across, about the same size as the smallest bacteria. The SARS-CoV-2 virus is 0.120 micron in diameter. But as already mentioned by Flybitcoin and Loren Pechtel, that doesn't really matter from a mask perspective, because they come out in much larger droplets that are easily caught on the way out by a mask.