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Can ultraviolet lightbulbs end the next pandemic before it starts?

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Re: Can ultraviolet lightbulbs end the next pandemic before it starts?

#41
post #31

"haha, only serious" question: Can we use something like CFCs to break down the ozone?

Doesn't sound likely to me.

I looked it up and what happens is that over long time periods in sunlight, CFCs lose a chlorine radical, and that chlorine radical lives for a long time and catalyzes ozone to turn into normal oxygen molecules.

So it would only even possibly be effective if you have so much CFCs and so much light that it builds up a bunch of chlorine, enough to get rid of all of the ozone. My guess is that even if those reactions occur in the context of a home (which seems like a big if) they'd be so slow and require so much chlorine and CFCs around that you'd be dead before you could celebrate.

Not to mention you'd have to be releasing CFCs in ~every building constantly, which would destroy the ozone layer orders of magnitude worse than we did decades ago.

Re: Can ultraviolet lightbulbs end the next pandemic before it starts?

#42

What does HN think of Naomi Wu's far-UVC lights? https://cybernightmarket.com/products/mini-far-uvc-lights-se... I just ordered a set to check them out for myself, although I don't know how I could possibly measure their efficacy in killing pathogens or their risk to humans.

Pretty sure these are based on (relatively) inexpensive KrCl excimer lamps, which are available on Aliexpress and such. The big question in my mind is whether or not it's a big enough dose to actually sterilize a room.

Re: Can ultraviolet lightbulbs end the next pandemic before it starts?

#43
I sterilize my N95/KF94 masks with UV light for reuse.

If anyone wants to follow suit, beware fake UV bulbs. Test your product / bulb with a banana.

Put masking tape on the banana, then expose the banana to the light for a few hours. If the band develops a suntan except for under the tape, you've got a good bulb. It should kill any bacteria and certainly any viruses on your mask.

But still throw out your masks when the fit gets bad; a mask is useless if the COVID is slipping in through the sides.

Re: Can ultraviolet lightbulbs end the next pandemic before it starts?

#44
Having posted this article, I must say it's disappointing the number of people who appear to be expressing knee-jerk reactions to the headline alone. I guess anything related to pathogens and public health are a hot-button topic these days and perhaps that's why?

I just found it interesting and exciting to read an overview of where this research is going. The ozone issue is unfortunate, as I was originally very excited to read the results showing no direct impact on skin or eyes, but then that aspect does put a bit of a damper on it. But still, perhaps that can be addressed somehow, or with further study might turn out not to be a major issue, and regardless it seems there will at least be niche applications. And perhaps widespread ones. Anyway, it would be nice if we could engage on this topic with the same spirit of open mindedness and intellectual curiousity as we're accustomed to here.

Re: Can ultraviolet lightbulbs end the next pandemic before it starts?

#45

Having significant air movement (like an actual felt breeze) is really all we need, so I'd consider this an accesory. And this would be super nice anyway in places like elevators and restrooms which are rarely ventilated to a good level.

Good circulation definitely helps, but it's not a panacea, unless very well designed. I recall a case from the early covid days where contact tracing showed a bunch of people catching it in a restaurant; it turned out what they had in common is that they were all downwind of the carrier from the relevant HVAC vent.

Some restaurants retrofitted fancy setups with individual vents or even partial center enclosures for each table, but obviously that gets quite expensive, especially compared to a UV bulb.

I do generally agree with you though that proper circulation and filtration can be very beneficial in limiting spread of pathogens.

Re: Can ultraviolet lightbulbs end the next pandemic before it starts?

#46
the answer is no, I was reading the linked documents and:

1. yes UVC of that frequency kill virus but they don't provide results about human safety, the say "potentially": "Germicidal ultraviolet light, typically at 254 nm, is effective in this context but, used directly, can be a health hazard to skin and eyes. By contrast, far-UVC light (207–222 nm) efficiently kills pathogens potentially without harm to exposed human tissues."

2. A study on rats is linked, but it doesn't prove the human safety;

3. The author of the study is economically interested to exploit commercially that sterilisation technique. further reason to wait for serious verifications: “The authors declare the following pending patent: Patent Title: “Apparatus, method and system for selectively affecting and/or killing a virus”. Applicant: The Trustees of Columbia University in the City of New York. Inventors: Gerhard Randers-Pehrson, David Jonathan Brenner, Alan Bigelow. Application #: US20180169279A1. Aspect of manuscript covered in patent application: Use of filtered 222 nm UV light to kill viruses URL: https://patents.google.com/patent/US20180169279A1/en?oq=2020... “D.J.B has a granted patent entitled ‘Apparatus, method and system for selectively affecting and/or killing a virus’ (US10780189B2), that relates to the use of filtered 222 nm UV light to inactivate viruses. In addition, D.J.B has an ongoing non-financial collaboration with Eden Park Illumination, and the authors’ institution, Columbia University, has licensed aspects of UV light technology to USHIO Inc.”

4. Invisible light is dangerous, you can injury your eyes, without realizing it and, devices from unreliable resellers could hide more serious risks.

Re: Can ultraviolet lightbulbs end the next pandemic before it starts?

#48
post #31

"haha, only serious" question: Can we use something like CFCs to break down the ozone?

it's not the cfcs themselves but their chlorine breakdown product (in uv light). certainly there are disadvantages to adding free halogens such as fluorine and chlorine to your air (chlorine used to be a major chemical warfare agent, and fluorine wasn't only because there's no practical way to carry it around, it being the closest real equivalent to the legendary alkahest), but unlike cfcs halogens are not persistent in the environment, and it's not unimaginable that the required levels of halogens would be less harmful than the ozone they removed

platinum, though, can catalyze the same decomposition that chlorine does, so i suspect that a much more reasonable approach is to use platinum catalytic converters, so the catalyst remains contained with a box instead of going into your lungs

Re: Can ultraviolet lightbulbs end the next pandemic before it starts?

#49
post #33
post #16

Earlier quoted context omitted.

The far UV spectrum being talked about here is not the same as conventional UVC germicidal lamps, nor the same as UVA/B from the sun. UV is only dangerous because at UVC wavelengths it penetrates cell nucleii and damages DNA. The interesting thing about far UV though is that while it will still damage DNA, it can't penetrate regular cells - it's blocked by the cell membrane/proteins. But viral particles don't have a…

Personally I feel the use of the term "far uv" is very misleading because the 220 nm wavelength is within UVC, and not too far away from 254 nm germicidal UVC. It is always helpful to consult a chart: http://www.drb-mattech.co.uk/uv%20spectrum.html So, from a public health/public education standpoint, I find it troubling that scientific research, which the article points out, is limited in this area. For decades, gen…

As I understand it, the point of 222nm is NOT to sterilize organic tissue directly.

The point of 222nm is to able to use it for sterilization in things like air return ducts, industrial cleaning equipment, etc.

Since 222nm is relatively "safe", you don't have to worry some idiot opening up a system, giving himself a gigantic flux of UV in the face, and winding up in the ER for cornea burns.

Consequently, your maintenance people don't need special equipment or extra training.

Re: Can ultraviolet lightbulbs end the next pandemic before it starts?

#50
post #46

the answer is no, I was reading the linked documents and: 1. yes UVC of that frequency kill virus but they don't provide results about human safety, the say "potentially": "Germicidal ultraviolet light, typically at 254 nm, is effective in this context but, used directly, can be a health hazard to skin and eyes. By contrast, far-UVC light (207–222 nm) efficiently kills pathogens potentially without harm to exposed hu…

P.s. Reading patent details: "to prevent the at least one radiation from having any wavelength that is outside of the range can be provided or which can be substantially harmful to cells of the body". What means "substantially harmful" radiation ? That is harmful but not so much ? A little bit harmful, maybe? Tell me if I'm wrong, because, for me, if something can't damage anything is "harmless", not "probably harmless" or "not substantially harmful". That is the language of the lawyers or the sellers. They simply don't know yet.

P.S.2 What about photochemical effects ? You put this inside a home and UVC start to discolor everything around. Besides piss off customers, could create serious legal problems to the seller. You know, damage to expensive furniture, paintings, etc.

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