Study confirms wearable, filter-free, breathing device sterilizes inhaled air [pdf] | Hacker News Reader

Study confirms wearable, filter-free, breathing device sterilizes inhaled air [pdf]

medi-immune.com

21 points_8nvo21 comments

Apparently this is related to their ProtectivAir device: https://medi-immune.com/protectivair/

An actual article where the link came from: https://www.ptcommunity.com/wire/revolutionary-breathing-dev...

That seems a reasonable and cheap device. An improvement might be to sterilize the exhaled air as well.

That's a great idea. I hope somebody makes mass production of these. The disposable respirators are expensive (in the log run) and lead to pollution. At the end, for medical reasons, we just want germs to be inactivated. I wonder if this kills fungi as well, but I doubt it would do anything to fungal spores, but for those maybe a washable filter could be used.

I know just a little about sterilization. Because I worked on controls for sterilizers.

As a general problem killing spores is what's hard. With gas sterilization they 'precondition' product at 120 degrees and 80% humidity in order to encourage spores to activate. With CO60 gamma radiation the product comes out a bit warm. Steam sterilization is done at 258 degF. You get the idea.

Compared to spores influenza type viruses are trivial to kill.

Do you know what's the diameter of the spores? There's so much about reusing masks [0], but I read nowhere about the fungi concerns. Respirators can be breeding grounds for fungi when they get damp, and even though with N95 you can breathe them in, most probably, I'm sure they release toxic fumes. Fungi can "eat" pretty much anything - if they can live on stones and find "food" there, I'm sure there's enough "food" for them in the reused masks as well.

[0]: https://www.n95decon.org/

In ferrets!

(The article says: infection in ferrets, which are the standard animal model for human influenza infection.)

As someone with a fairly limited understanding of how these sterilizing UV rays work, I've wondered if it would be possible to install overhead UV lights that either came on at intervals or were on constantly to help sterilize surfaces in common areas that see high numbers of people. For example, inside of elevators.

Is something like that just not practical/possible or has it just not been seen as a priority prior to our current situation?

3 Problems with that:

1. UV light capable of sterilization destroys or degrades most materials very quickly, worse than leaving it out in the sun.

2. UV lights tend to be very energy-expensive, and there is not much advancement in green tech to mitigate that, unlike visible LEDs and such.

3. Damage to peoples eyes and skin, means you must have interlock systems to make sure nobody is around.

4. UV light will not sanitize something it does not directly shine on. Any shadow is a gap. An indoor space would have to be engineered in a certain way, not even postmodern architects would like it.

The only profitable UV sanitizers I ever see are in the medical/dental field anyway, used for autoclaving things. They do have UV rooms for things like hazmat suits, but they tend to be the domain of industrial accident response, EPA or FEMA types. Again, the power they require, and the grade of radiation they give off, they are too hazardous to allow ordinary people to be near them when operating.

People forget your first point way too often. I’ve had to deal with air handlers that were retrofitted with a UV systems that I’m sure sounded like a marvelous idea to my institution; however none of the insulation or wiring was rated for UV exposure. So after a few years it was a total mess.

Also, air treated with UV light smells terribly. I was raised in Bulgaria and like in most Soviet bloc countries, during the winter, all kids were getting irradiated daily at kindergartens and schools for 5 minutes to get vitamin D. That smell around the UV lamp is so strong in my memory! Of course, we all wore goggles.

You guys seem to be missing the best part. It automatically turns viral particles into a vaccine of sorts.

> Three doses (500 PFU each)of UV-treated aerosol through the IASD, given 9-10 days apart, protected against disease in terms of significantly reduced weight loss compared to the mock-treated group, although the ferrets were not protected against infection.

Thats a great side effect when dealing with being exposed to the virus, but I think health professionals would not recommend this instead of a vaccine.

Given that certain sterilizing UVC wavelengths are known to not penetrate the epidermis, could we just attach a bunch of LEDs tuned to that range to a headband or something instead of making people breathe through an enclosed apparatus?

>https://www.who.int/uv/faq/whatisuv/en/index2.html

>The three types of UV radiation are classified according to their wavelength. They differ in their biological activity and the extent to which they can penetrate the skin. The shorter the wavelength, the more harmful the UV radiation. However, shorter wavelength UV radiation is less able to penetrate the skin.

>Short-wavelength UVC is the most damaging type of UV radiation. However, it is completely filtered by the atmosphere and does not reach the earth's surface.

>Medium-wavelength UVB is very biologically active but cannot penetrate beyond the superficial skin layers. It is responsible for delayed tanning and burning; in addition to these short-term effects it enhances skin ageing and significantly promotes the development of skin cancer. Most solar UVB is filtered by the atmosphere.

I think this is a misunderstanding.

It won't penetrate deep into the skin, it will continuously cook the top layers.

https://hps.org/publicinformation/ate/q9450.html

Frequent exposure WILL cause damage to skin and eyes.

Creating and selling personal protective equipment should be taken very seriously.

Putting UVC light sources on a headband without controlling airflow is simply too risky, no one could safely guarantee that a stray air current and or virus from an unexpected angle would be exposed to enough light for enough time to be safe. Air flow must be controlled.

> It won't penetrate deep into the skin, it will continuously cook the top layers.

> Frequent exposure WILL cause damage to skin

This report seems to say that that is not true for 222nm https://journals.plos.org/plosone/article?id=10.1371/journal...

Glad I was wrong! Hopefully this can be certified and implemented in all kinds of sterilization devices ASAP.

Thank you for the link.

Looks like a cool device for high-virus areas like front-line health care workers.

How about a mask with filter and UV lights that periodically disinfect it? Could be cheaper.

And from other UV uses, it would be cool to use it for disinfecting bathrooms when nobody is inside.

That's really cool for immune compromised people! Way better than living in a bubble

I wonder if this is dangerous long term though in the "hygine hypothesis sense"?

A maker's implementation: https://www.youtube.com/watch?v=fzGrh2io9Ds&

Looks cool, not sure how well it works.

That mask uses UVA which doesn't kill germs. Only the horrifyingly dangerous UVC kills germs. Don't even think about making a DIY UVC device. You could blind yourself in seconds.

https://www.bbc.com/future/article/20200327-can-you-kill-cor...

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