Coronavirus and homemade tools

[Jon]

My question is though since the virus has already proven to be transmitted either by touch or airborne from breathing in the air around you after someone has sneezed or coughed plus it is theorized to have a longer life in humidity's above 40% would it be too far fetched to think that it could be transmitted through air handling equipment like legionnaires disease? All of the triggers are there.

From what we know now, this is not too far-fetched at all, certainly if the air is moving over short distances. What is the best source of virus-filtering material to incorporate into homemade tools that handle air?

For example, I'm looking at this 3M air filter selection guide. Some of the filters are labelled as filtering viruses. What are those filters made from?

[Frank S]

From what we know now, this is not too far-fetched at all, certainly if the air is moving over short distances. What is the best source of virus-filtering material to incorporate into homemade tools that handle air?

For example, I'm looking at this 3M air filter selection guide. Some of the filters are labelled as filtering viruses. What are those filters made from?

The solution could be as simple as infusing common table salt in the filter media or mildly saturating the media with vinegar, or dusting the filters with powdered chinchona bark
Ok here is a tip for anyone who may have been infected. many viruses which attack the respiratory system can be halted slowed or in many cases completely stopped if the victim recognizes themselves as coming down with something early on.
When every preventative measure has failed to protect you from catching a virus and you start to feel a scratchy sensation in your throat a way to stop this is to gargle with a salt water and vinegar mixture. Tonic water table salt and vinegar works great but if you don't happen to have tonic water but have these ingredients you can make your own. "lemongrass, citric acid, chinchona bark, allspice, cardamom, star anise"
Any way mix the tonic water with table salt and vinegar then use as a gargle.
Since most viruses begin with an irritated throat and take several days to mastisize further down in the body if you can stop it before your fever becomes too severe In my opinion there is a better than average chance this virus could be stopped as well. I gargle simply salt and cheap vinegar when ever my wife used catch a cold from being around people where she used to work. I never catch a cold but then again I eat so much hot pepper sauce that I make out of a myriad of spices and chilis that could be another reason as well. I know that my wife used to suffer frequently from stomach viruses upset stomach and other gastro intestinal ailments that she ate quart sized bottles of indigestion tablets and drank Gaviscon like water until I finally talked her into eating more of my hot sauce, It has been 10 years since she has complained of heart burn or upset stomach

[Saltfever]

. . . For example, I'm looking at this 3M air filter selection guide. Some of the filters are labelled as filtering viruses. What are those filters made from?

The chart is misleading. Most likely because there is no accountability on a chart. Printing a label on a product is a serious matter and can subject you to "Truth in advertising" litigation.

This is the actual claim on the filter; "Particles that can carry a virus" is a big difference" from the insinuation in the chart that the filter can actually trap a virus. Most viruses are less than 200nm in size. The Filtrete 2200 is not even rated as a HEPA filter.



The text you see on the left (above) is what is printed inside my marked-up red circle on the Filtrete 2200 filter package.

Sorry about the pic orientation. Pics get flipped during uploading and I have no idea how to control it. I have no idea how a 3rd pic below was installed and a few attempts at edit could not delete it.

[Jon]

Frank S - salt gargles to slow viral infection may be questionable (although they can provide relief of symptoms), but, yes, salting masks is reasonable, and perhaps we can apply that to salting filtration media. More: https://www.nature.com/articles/srep39956

Here, we report the development of a universal, reusable virus deactivation system by functionalization of the main fibrous filtration unit of surgical mask with sodium chloride salt. The salt coating on the fiber surface dissolves upon exposure to virus aerosols and recrystallizes during drying, destroying the pathogens.

Also, this 1:25 video:

Good call Saltfever. Regarding pics, our forum software automatically flips them into what it thinks is correct orientation, but it doesn't always get it right.

Anyway, our question remains: what fabric or bulk filter material can we use to make virus-filtering tools? Is there a rating system we should be looking at? MERV rating? Also, how do we reconcile this with the fact that viruses generally travel through the air encased in droplets that are much larger than viruses. Is filtering those droplets enough?

What are peoples' plans if a household member gets infected? Our plan is to use our master bedroom as a ward. Leave adjoining master bathroom door open, and turn on bathroom fan; this should provide negative pressure. Because of what we know - and don't know - about airborne spread, our plan is to either unplug our forced-air propane furnace, or seal off the vents in the bedroom, and to heat the room with portable electric heaters if it's cold. If I can find a good furnace filter, we might be able to keep the furnace running, which is important because it's also connected to our whole house steam humidifier (Colorado mountains are very dry).

The household viral attack rate is enough such that infection of other household members is still likely, but I'd like to stagger our illnesses (a "flatten-the-curve" strategy, but within a household), so that if one of us becomes extremely ill, the other person will at least be less ill at that time, and can care for the sick person, or drive them to the hospital if need be.

[Crusty]

The major usage for N95 masks (the surgical standard) is not to block pathogens coming in but rather to protect others from pathogens going out which might be inadvertently expelled by the wearer. The masks are intended to potentially protect others from aerosolized pathogens. Wearing one's a caring and responsible thing to do but not very effective at blocking an incoming infection.

[Jon]

The major usage for N95 masks (the surgical standard) is not to block pathogens coming in but rather to protect others from pathogens going out which might be inadvertently expelled by the wearer. The masks are intended to potentially protect others from aerosolized pathogens. Wearing one's a caring and responsible thing to do but not very effective at blocking an incoming infection.

This is a valid point, but note that, yes, this is true for surgical masks, aka "procedure masks", but N95 masks are also worn to protect healthy people.

Unfortunately, because covid infected people can be asymptomatic and contagious for - what we now believe - to be a median of 5 days, if we encourage widespread mask-wearing, then people who are unknowingly ill but feel healthy will not be transmitting the virus.

Reusable respirators with P100 filters will filter even more than N95s, and lots of our guys will have those in their shops already. 3M actually manufactures a P100 filter that is specifically designed for viral outbreaks. PDF is here. A single pair of filters is expected to last for a full pandemic wave. Note the 6035 filter model number; I believe this is a 7093 model in the US market - good luck finding any of those now! However, any P100 filter will work, and the plastic encapsulated ones can be removed, wiped down, and then the respirator can be submerged to be sterilized.

[old kodger]

Maybe making the virus deviate around half an orange wasn't so silly after all.

[Saltfever]

. . . 3M actually manufactures a P100 filter that is specifically designed for viral outbreaks. PDF is here.

Another PDF here for your viewing pleasure. Remember, "PN" is the filter efficiency in trapping particles equal to or GREATER than 0.3 microns. Anything smaller might get through depending on the entrapment scheme used by the manufacturer.

Of the more than 5,000 known viruses only a few are larger than 0.25 micron. Covid-19 is spherical and about 125nm in diameter (Wikipedia). It seems PN95 to PN100 work fairly well. Information is offered here so those who are thinking of home-brew solutions know the difficulty of the problem. How do you effectively trap a 0.125 micron diameter particle?

[Jon]

As I understand it (as an amateur of course), we mostly just need to trap the respiratory droplets within which the virions are transmitted in coughs, sneezes, and the breath of infected people. Fortunately, these droplets are much larger, which is why even homemade fabric masks offer a significant advantage.

People who study these viruses in labs wear positive pressure personnel suits. I don't think that those even filter outside air; they provide breathing air from overhead lines. For example, here's a person studying the Ebola virus (50% fatality rate) in a lab:



And note how some of the suits puff out significantly from the positive air pressure. This is analogous to a negatively-pressured hospital room. If there's a breach in the suit, the air ejecting out of the tear protects the wearer from virions entering.

[old kodger]

Gee Jon,
I thought that they were Sumo wrestling game suits