Coronavirus: effectiveness of types of masks and manufacture of a homemade respiratory mask

[Christophe]

Bin then shut up!

[Flytox]

Hello,
with decathlon masks, why not put UVC leds (280nm germicide) in a tube, to pass the air you breathe, with a lipo battery in a small backpack !!
does anyone know if they have already tested it ??

UV rays, especially at this wavelength, are rather dangerous ..... at the top of the eyes and more ... in a DIY ...... AMHA is to be forgotten urgently !!!

https://fr.wikipedia.org/wiki/Ultraviolet

Difference between UV-A, UV-B and UV-C

The three types of UV radiation, A, B and C, are classified according to their biological activity and their power to penetrate the skin. They correspond to three conventional wavelength intervals (see below). The longer the wavelength of UV radiation (the closer it gets to visible light), the less energy it has and therefore the less harmful it is, but the more it has a significant skin penetrating power. Conversely, the shorter the wavelength of UV radiation (the closer it gets to X-rays), the more energy it has and therefore the more destructive it is, while having less power of skin penetration45.
UV-A (400-315nm)

UV-A, which has a relatively long wavelength, accounts for almost 95% of the UV radiation reaching the Earth's surface. They can penetrate into the deeper layers of the skin.

They are responsible for the immediate tanning effect. In addition, they also promote skin aging and the appearance of wrinkles, disturbing the balance of protein synthesis (in particular the breakdown of collagen and increasing the destruction of elastin) and in cells they are at the origin of the production of free radicals, which are very harmful to them. For a long time, it was thought that UV-A could not cause lasting damage. In reality UV-A seems to favor the emergence of skin cancers by several mechanisms46,47, but with a much lesser effect than UV-B48.
UVA excites the DNA molecule and promotes links between certain bases, especially when the DNA is in the form of a double helix, which can be a source of mutations, or even cancers49. Another carcinogenic mechanism seems to exist through the reactive oxygen derivatives that UV-A generate inside cells, in greater quantity than UV-B50. UV-A is also likely to potentiate the cellular toxicity of UV-B by penetrating deeper into the skin, by having an immunosuppressive activity51 and by damaging the DNA repair systems52.

UVA rays are dangerous for the eyes of children whose lens only partially acts as a filter. 90% of UV-A reaches the retina in infants and another 60% before the age of 13. In adults over 20, the lens stops (and experiences) UV-A almost 100%.
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This section does not cite its sources enough (March 2017).
UV-B (315-280nm)

UV-B, of medium wavelength, has an important biological activity, but does not penetrate beyond the surface layers of the skin, they are relatively absorbed by the stratum corneum of the epidermis (melanin). Part of the solar UV-B is filtered by the atmosphere.

They are responsible for tanning and delayed burns. They are capable of producing very high quantities of oxygenated free radicals in the skin cells, which are responsible in the short term for sunburn and inflammation. In addition to these short-term effects, they promote aging of the skin (by damaging the collagen fibers) and the appearance of skin cancers because even if UV-B represents a minority of the light which reaches the surface of the Earth, they are much more carcinogenic than UV-A48.

High UV-B intensities are dangerous for the eyes and can cause a "welder's flash" or photokeratitis, since they are only stopped by 80% by the crystalline lens of the adult. In children, half of UV-B reaches the retina of infants and 75% before the age of 10. [ref. necessary]

However, they can be beneficial for certain types of skin pathologies such as psoriasis. They are also important for the synthesis of vitamin D.
UV-C (280-100nm)

UV-C, of ​​short wavelength, is the most energetic as well as the most harmful UV (energy increases when the wavelength decreases), but they are completely filtered by the ozone layer of l atmosphere and therefore theoretically do not reach the surface of the Earth.

However, UV-C lamps are used in the biology laboratory for germicidal effects, in order to sterilize parts or devices (laminar flow hood, for example).

The UV-C spectral band consists of three sub-bands:

UV-C from 280 to 230 nm.
V-UV from 200 to 140 nm, i.e. UV propagating only in a vacuum (Vacuum Ultra-Violet).
X-UV from 140 to 100 nm, wavelengths which approach those of X-rays and which are therefore the most energetic wavelengths of ultraviolet. According to the institutions53, the light whose wavelength is located between the end of ultraviolet and the beginning of X-rays (124 to 10 nm) is sometimes called extreme ultraviolet radiation, or EUV. It is sometimes included in the UV-C category, sometimes distinct54.

[belladonna]

who said "besides the eyes", sorry, me, my eyes are not in the back, nor in a tube

[Leo Maximus]

The "dynamics" of micro-particles, NHK video document:

[Christophe]

Hello,
with decathlon masks, why not put UVC leds (280nm germicide) in a tube, to pass the air you breathe, with a lipo battery in a small backpack !!
does anyone know if they have already tested it ??

Very good note, it is certainly easier to manufacture than a thermal mask that I proposed yesterday here: health-pollution-prevention / virus-covid19-the-thermal-disinfectant-mask-t16392.html

1st question: what energy (duration of exposure) UV is necessary to kill the covid19 ??

But one does not prevent the other: filtration + thermal + UV! There we would be sure that it is HS! !!

[Ahmed]

In either case, it would be essential to smooth the air flow to optimize the neutralization of the virus: respiration is an alternative phenomenon which therefore leads to an aspiration phase followed by a period of rest (from point of view of the device which supports only the inspired air). A addition such as there is on bagpipes would be able to play this role (albeit in the opposite direction to breathing). This device, besides (sic) its functionality would certainly have a powerful comic effect, which would not constitute its least advantage in this rather resolutely gloomy period ...

[sicetaitsimple]

This device, besides (sic) its functionality would certainly have a powerful comic effect, which would not constitute its least advantage in this rather resolutely gloomy period ...

Wearing a kilt is becoming compulsory, in that it allows certain parts of the body to be "deconfined" during the short moments when an outside exit is authorized.

[Ahmed]

It seems to me an excellent idea and that would go entirely in the direction of greater clothing consistency, very interesting point in these times of loss of benchmarks ...

[GuyGadebois]

I have just returned from shopping (Carrouf), the first time I have been out of confinement. In the store, 1 in 10 people wear a mask, 2 in 10 people wear gloves, I have not seen anyone wear both and the cashiers just have gloves, no mask. 20 outbound terminals, 20 return terminals, not a policeman on the horizon.

[Christophe]

I have just returned from shopping (Carrouf), the first time I have been out of confinement. In the store, 1 in 10 people wear a mask, 2 in 10 people wear gloves, I have not seen anyone wear both and the cashiers just have gloves, no mask. 20 outbound terminals, 20 return terminals, not a policeman on the horizon.

Same thing, I was at the casino yesterday: out of the 20/30 people we crossed, there were 3 of us with a mask ...

By cons all employees had gloves and masks ...
All the cashiers were coughing!

Air conditioning worked