Math

[Steve Sells]

could someone explain to me how using a 150 micron filter helps trap .2 micron and smaller particles?

[Frosty]

I see someone hasn't bought his 20 years worth of toilet paper. It would become clear if you did you know.

I suppose you don't understand borrowing your way out of debt either? 

Frosty The Lucky. 

[ThomasPowers]

Like those grocery receipts that tell you how much you saved buying stuff you wouldn't have bought if it wasn't on sale?

[Buzzkill]

As you know, the short answer is "it doesn't."

However, a longer answer starts with "it depends."   For instance, if your .2 micron particle is generally contained within a substance which has larger than 150 micron particles or droplets, then trapping the droplets or larger particles which contain the smaller particle is still somewhat effective.

[Steve Sells]

.. until that drop of moisture dries a bit and then gets breathed in anyway, I wear the stupid masks to make other people feel better but its nuts that people think it makes them safe.  According to CDC the effective life of a typical face mask is 20 minutes at best..

[Glenn]

By the numbers, it is like putting a chain link fence around your yard to keep out mosquitoes.  

The masks help keep some of the particles contained at the source and not allowing as many particles to escape beyond the mask.  The less particles out there the better and the concentration of particles is reduced. 

Yes, .2 micron is smaller than 5 microns but add multiple layers, moisture from your breath, trapping particles larger than 5 microns (think dirty masks) and many other factors and you have to adjust the thinking some.

[Buzzkill]

As a matter of principle I agree, but I didn't want to risk getting political.  I was just pointing out that there is a scenario, however limited, where the smaller particles can be slowed or stopped by a filter with bigger holes than those particles.

[SLAG]

Folks,

Effective Covid -19 masks usually have more than one layer. Ideally three layers.

The masks may have larger "holes" than some of the aerosolized particles. But other factors come into play. 

I can think of electrostatic charges, entanglement, and moisture could bar those particles from penetrating the mask and effecting the user.

(this is my conjecture, and not facts gleaned from the scientific press).

For example, most microbiological personnel know that missing a shave drops the mask's effectiveness by forty percent.

Masks that mold the face are more effective than standard masks. M-95 masks are examples of those.

(incidentally, the inventor of them,  also patented the first form fitting, uplifting bra).

People with facial hair require modified masks in the laboratories and surgeries.

There has been some published reports on the effectiveness of masks. But not nearly enough.

An on-line search turned up some pertinent references. (eg. google and wiki).

The forgoing is SLAG's two cents on the subject. Take it with a grain of salt.

SLAG.

p.s.  I just had a look on an article on wiki,

Try https://en.wikipedia.org/wiki/Face_masks_during_the_COVID-19_pandemic

[ThomasPowers]

There is another factor too: must something be 100% or not worth using?  My vehicles have never been 100% and yet I still drive them. Vaccines are not 100% and I still get them and had my children inoculated.  The question is: Do they work good enough to make an appreciable difference?  So far the studies I've read say yes on the masks.

Besides which; here in NM having folks enter businesses with Bandanas pulled up over their lower faces is rather *traditional*!

[Irondragon Forge ClayWorks]

Now I get to wear a mask and carry a gun legally. Our masks are made by my wife, 3 layers of close woven washable fabric + a replaceable inner liner of .2 micron HEPA filter fabric.

[SLAG]

Mister Dragon,

Are your wife's  masks for sale.

SLAG.

[Irondragon Forge ClayWorks]

They are just for personal use...sorry.

[George N. M.]

A few thoughts:  First I agree with Buzzkill that masks have an effectiveness in stopping the droplets that have entrained viruses in them and once the droplets have dried the viruses are, at least in part, tangled/attached to the fibers of the mask.  Second, is the psychological effect of a mask.  A person who wears a mask is more likely to practice social distancing and seeing someone else wearing a mask may remind another person to keep a proper social distance.  Third, a mask keeps you from touching your nose and mouth and cuts down on the possible cross contamination from your hands.

Also, if a person is covid-19 positive, even if asymptomatic, a mask will cut down on putting out infected droplets into the environment.  A mask is more to protect other people than the wearer.

No, masks are not bullet or virus proof shields but I'll keep wearing mine, thank you.  Any protection is better than none.  Is it inconvenient? Yes.  Does the inconvenience outweigh the benefits? No. IMO.

Again, my own opinion is that all the folk going to bars, parties, the beach/pool, etc. are textbook examples of Darwinian natural selection.  This will have the effect of partially thinning the irrational from the herd.  Stupidity is not a survival trait.  I'm missing my friends and family as much a anyone but I'm in several of the high risk groups and I don't want to die from doing something dumb.

"By hammer and hand all arts do stand."

[Irondragon Forge ClayWorks]

I was in a convenience store the other day and had my mask on. The only other person in the store at the time with a mask on was the cashier. There were about six other customers waiting to check out and not one of them were wearing masks. The guy behind me made a sarcastic comment about only she & I had masks on. My response was that's because we were the only one's that care (not my exact words) about other people, shut him right up.

[arkie]

1 hour ago, Irondragon Forge & Clay said:

They are just for personal use...sorry.

Randy, those will be great for coal smoke!!!!!  Be sure to use the black ones, LOL

BTW, I like your reaction to the folks in the store...we care too.

[ThomasPowers]

Dragon; doesn't being able to do that legally take some of the fun out of it?   I remember VIcopper telling me that he was required to carry a gun when he traveled by plane a lot of the time. 

[Steve Sells]

4 hours ago, Irondragon Forge & Clay said:

Now I get to wear a mask and carry a gun legally.

except there is a rule against wearing a mask while Concealed Carry.. so....

[Irondragon Forge ClayWorks]

I carry under the LEOSA, same as when on duty even though retired and I'm dead serious about it. Never has been fun for me.

[billyO]

On 6/26/2020 at 9:48 AM, SLAG said:

I can think of electrostatic charges,

This is a big part of the effectiveness of surgical masks.  Which is why you can't wash them and have them still be effective.

On 6/26/2020 at 10:14 AM, George N. M. said:

Again, my own opinion is that all the folk going to bars, parties, the beach/pool, etc. are textbook examples of Darwinian natural selection.

While I agree, the problem is that they can transmit the virus to others for days before they become symptomatic.   

Ignoring the medical experts on this is just like playing Russian roulette, most folks will probably be OK and possibly never even know they have the virus.  Unfortunately it's not just yourself that you're pointing the gun at, but everyone else you interact with.

[JHCC]

Also, just to be clear:

• N-95 (and KN-95, the Chinese equivalent of the US standard) masks with an exhaust valve for exhaled air protect the wearer, but not others.
• Surgical masks and homemade cloth masks protect others, but don't do much to protect wearer.
• N-95 and KN-95 masks without an exhaust valve protect everybody.

You sometimes see reports of people wearing both an N-95 AND a surgical mask, but that's almost always someone who's put a surgical mask over an N-95 with a valve.

[Buzzkill]

That is a fair point of course.  However, in general I still am of the opinion that to a large extent each person is responsible for his/her own safety.   If you think the risk is too great for you or others around you to leave the house, attend gatherings, or eat in public then don't do it regardless of whether it's "allowed."   It is very difficult to contract a contagious disease if you are never in close proximity to someone who has it.  We should pay attention to the medical experts about the best way to minimize our chances of becoming infected or infecting other people, but blindly following mandates is no guarantee of anything.  There is a phrase I heard some time ago which I have not forgotten, although I can't remember where I heard it:  "Compliance does not equal safety."

In your scenario, BillyO, you are only pointing the gun at other people who have also chosen to take the risk.  You won't be interacting with those who refuse to take the risk.

On the other hand if you decide to take the risk and you get the virus or pass it on to someone else, you have no business complaining about it - and you are responsible.

[ThomasPowers]

Ah; BK there are certain diseases where close proximity is not so close---look at Measles, from the cdc website: "You can catch measles just by being in a room where a person with measles has been, up to 2 hours after that person is gone."  Also you are contagious before you know you have measles.  A rather drastic example I will admit; one I deal with by vaccination (as well as previously having pretty much all the various types as a kid---one of which nearly killed me when it morphed into pneumonia.)

When dealing with something new; (The Novel in Novel Corona Virus 19), it is sometimes best to be on the safe side until we know all the possibly subtle things about it.

[Buzzkill]

No one is suggesting to be on any side other than the safe side.   I'm suggesting that each person needs assess the risk for him/herself and those close to them and then, using the best information available, make decisions on how to proceed. 

I'm not a big fan of mandates from on high, nor do I think that many things have a "one size fits all" solution.  If we relate this to smithing, I would suggest that each person needs to assess the risks based on what he is doing in his surroundings, and then determine appropriate PPE, policies, and procedures to minimize his chances of injury, death, and/or property damage.  While there would certainly be some basics that would apply to nearly everyone, just blindly following someone else's recommendations would not likely produce minimal risk.  For instance, in sections of California the risk of unintentionally setting fire to the surroundings may be far greater than in Seattle or the Midwest, and extra precautions should be taken with that in mind.

Nothing we ever do is honestly "safety first."  If safety were indeed the primary concern, none of us would ever start a fire or pick up a hammer. We wouldn't drive a car on the road.  We'd never swim in the ocean or ski down a mountain. What we strive for is minimal risk while engaging in an inherently risky activity, but participating in that activity is obviously more important to us than completely eliminating risk.  Safety is actually second, or even third in the hierarchy, but it is still very important.

[George N. M.]

BK:  The problem is that the equation is fairly simple when it involves yourself, when you decide whether the risk is worth the pleasure/reward.  That is a personal decision which involves only yourself. (That's not strictly true since your own decisions affect others, your family, EMTs, doctors, your employer, etc..  None of us live in a vacuum.  "No man is an island.")  When you make decisions involving public health things like Covid-19 the equation has a lot more variables because it involves other people besides the individual.  And because you don't have the true input on everyone else's value of the risk/benefit ratio it is very difficult to make a decision.  A person may say that they value their pleasure or convenience more than the risk to other people but the other people are unlikely to agree with that analysis.

Having a general rule is not ideal but it applies to everyone the same and takes the personal part of the analysis out of the equation.  However, I do agree with you that local situations should be evaluated and taken into consideration.  What is required in an urban area may not be necessary in a rural environment and vice versa.

If everyone were coldly rational and had the same analytical skills and abilities things might work a lot better but, unfortunately, there are a lot of folk out there who are rationally impaired and make decisions, which may impact thee and me, which are based on emotion, politics, personal feelings at the moment, and an imperfect grasp of a situation.

"By hammer and hand all arts do stand." 

[Buzzkill]

Some valid points, but it's not as different as you suggest.  Whether you drive on the road does not affect only you.  It potentially affects family members, others on public roads, EMT's, doctors, etc. etc.

Those who decide they will not venture out into public will not be interacting with those who choose to do so. They will have minimum risk of being infected or passing on an infection to someone else.  Those who choose to take the risk are more likely to become infected or infect other people who have chosen the same risk.  Yes, it can impact other people, but that will mainly be other people who chose exactly the same risk level.

One thing that seems to be missed in all of this is a simple truth:  All of us WILL be exposed to this virus at some point.  There is no scenario where it just goes away.  If we slow the spread enough it is possible that there will be a viable vaccine manufactured and distributed before the vast majority of the population has been exposed. Also, the more time that passes, the better the understanding of, and treatments for, the virus.  Those things decrease the percentage of fatalities per capita, but they do not change the likelihood of exposure.  That approaches 100% likelihood over time.  This pandemic ends with herd immunity, whether that be natural immunity due to exposure and survival or manufactured immunity due to immunization.  That still will not completely eliminate the virus.  Polio is much harder to transmit and still exists in the world after decades of vaccine distribution.

All I'm pointing out is that all of the measures do not changes whether you will be exposed to the virus; they just have the potential to change when you will be exposed.  Certainly the risks of serious illness or death are greater for those in high risk categories, but for 99+% of the population this virus is not fatal, and we will continue to drive the mortality rate down as time passes.  

I'm guessing we could agree that we would assess situations where a disease has an 80% transmission rate and is 50% fatal differently than those where the disease has a 99% transmission rate and is 0.001% fatal.  This is somewhere in the middle.  Regardless, each of us still needs to make decisions for ourselves and those close to us based on the best information available and our particular situation rather than to assume if we follow some set of instructions given to us that everything will be just fine.