[HN Gopher] Two-Twenty-Two ___________________________________________________________________ Two-Twenty-Two Author : _Microft Score : 69 points Date : 2022-10-10 18:13 UTC (1 days ago) (HTM) web link (www.science.org) (TXT) w3m dump (www.science.org) | kurthr wrote: | I love me some Derek Lowe, but this one really beat around the | bush. | | Article is about disinfection with 222nm light, which has some | very useful and well tested properties. | at_a_remove wrote: | As someone with a photosensitivity disorder, anything shorter | than 405 nm spells trouble for me. This is kind of a nightmare | scenario really. | jefftk wrote: | Are you sure something as low 220nm would? This is short enough | that the chemical changes it causes are very different than | longer UV. | at_a_remove wrote: | It sure will be exciting to find out. | tln wrote: | Sorry to hear that :( | | Is there anything you use to detect light like this? Digital | spectrum meters or UV detector keychain etc. | at_a_remove wrote: | Pain, really. Anything shorter than "purple" is enough. | | I just can't imagine how I would function if this sort of | thing became commonplace. | _0ffh wrote: | According to the article, 222nm would already be stopped by | the thin coat of dead cells on the skin. So it shouldn't | penetrate far enough to cause any trouble. | mig39 wrote: | Would organisms eventually evolve to be resistant to 222nm light? | thaumasiotes wrote: | Yes, of course. | chromatin wrote: | Given that the articled discusses 222 nm light being harmless to | humans, and acknowledging that 254 nm is known to be dangerous, I | am concerned that wide/universal deployment of such systems might | lead to situations where poorly constructed or serviced equipment | might emit dangerous wavelengths. | _tom_ wrote: | This needs more informative title. | jiggawatts wrote: | > "...led them to conclude that at the current OSHA regulatory | standard for continuous 222 nm light exposure that you would see | 90% viral inactivation at 8 minutes and 99% inactivation in about | 16 minutes." | | Something I learnt about disinfection protocols is that they're | measured on a logarithmic scale, much like volume (decibels), | earthquakes, etc... | | So when you see marketing saying things like "kills 99.9% of | germs", think of that as "strength 3" because it has three nines. | | The article mentions strengths from 1 to 2, which is about as low | as it gets and still have "some" effect. | | Hospital grade disinfectants are more like 99.99% to 99.999% ("4" | and "5" strength), for comparison. Autoclaves and the like can go | to "12"! | | This is because bacteria grow exponentially, so to remove "one | doubling" time, you have to halve the numbers. To remove "two | doublings", you have to quarter the numbers, and so forth. In | other words, every unit of safety time you want to buy requires | an exponential increase in disinfection. | | Keep this in mind when shopping for cleaning products! The | difference between "99%" and "99.9%" is just "one" doubling time, | not a tenfold improvement. | | More reading: | https://static1.squarespace.com/static/5f42a255876c3361a6189... | divbzero wrote: | > _What 's even better than [effective drugs and vaccines] are | public health measures that are taken even more broadly and don't | require individual actions. In the industrialized world, we took | many of these a long time ago, things like providing clean water | without pathogens floating around in it. It comes as a shock to | us when that layer of defense breaks down, because we're so used | to it that we take it as part of the natural order of things._ | | If disinfection with 222nm light or a similar safety measure | becomes so commonplace that we take for granted, that would be a | remarkable shift and a small silver lining to the COVID pandemic. | anikan_vader wrote: | The Atlantic article that this one links to admits that negative | side-effects of UV-C have been known since at least the 40's: | | >> But though Wells and other early pioneers of this technology | could shine their 254 nm lamps aloft to clean the air floating in | the upper portion of rooms, or use the light inside vents or | ducts, they couldn't actually shine them downward, directly onto | the occupants of rooms, without ill effect. That's because, | although 254 nm inactivates pathogens, it also causes skin and | eye damage at certain doses. | | This is a very contradictory tone with the article, which | essentially claims UV-C is totally safe for humans. EDIT: The | author of the article explicitly acknowledges this. | high_pathetic wrote: | Additionally, the UV radiation produces ozone, which is harmful | to breathe. | BoppreH wrote: | Dr Lowe explicitly mentions the danger of 254 nm: | | > That's very much as opposed to (say) 254 nm light, which | starts doing damage immediately due to greater penetration into | animal tissue. | | and that 200-222 is safer because of lower penetration. | | > down in that range, the penetration of such light is only a | few microns, and it doesn't even get past the dead cells on the | surface of the skin and the cornea of the eye! | anikan_vader wrote: | My bad, thanks for the correction. I am surprised though - I | thought higher frequency waves were more dangerous, but | clearly that is not universally so. | tingletech wrote: | the article (titled Two-Twenty-Two presumably because it is | about this specific wavelength vs the whole UV-C range) does | say "222 nm light does not induce DNA damage in mice, even at | much higher flux than would be used for disinfection. That's | very much as opposed to (say) 254 nm light, which starts doing | damage immediately due to greater penetration into animal | tissue." | 1970-01-01 wrote: | Seems like we should add ~222 UV light to many more home | appliances. Home water tanks with lower temperatures, dishwashers | with water-free sanitization cycles, refrigerators could include | a self-cleaning option, etc. If it holds bacteria and shouldn't, | use UV to sanitize. | zasdffaa wrote: | How about we stop worrying so much about germs unless killing | them wholesale is shown to produce a _significant_ increase in | health. I am pretty sure bactericides etc. are being pushed by | industry for their profit not our wellbeing at all. | tourist2d wrote: | I don't know why you want a significant increase in health. | I'd switch over even if it were a mild increase. | 1970-01-01 wrote: | Killing germs is part of modern daily life. You shower, do | dishes, brush your teeth, and wash clothes. It's much, much | cheaper to shine a UV light onto a surface for a few minutes | compared to using soap and other chemicals. UV toothbrushes | and toothbrush cleaners are already sold online. | zasdffaa wrote: | Me: let's not do <thing> unless we have a reason. | | You: We should continue doing <thing> because we already do | <thing> | | "carry on" is not a reason to do anything. I literally | can't understand how you are thinking to post such a non- | justification. | 1970-01-01 wrote: | Sorry, I don't understand where you are going with this | comment. I was explaining how UV can be used to save | energy. You're arguing against that? | funnymony wrote: | GP argues against killing microbes. (With some nuance) | zasdffaa wrote: | If you're talking cost then maybe. In the right places | such as hospitals, very likely. I'm questioning that we | should do that indiscriminately in other places such as | in homes. We have highly developed immune systems, let's | not risk weakening them. And not doing it costs nothing | at all. | bobsmooth wrote: | Germs cause disease. I know germ theory is pretty new but | its established science. | zamalek wrote: | Germs _also_ cause immunity. You do need exposure | (vaccines help, but aren 't enough). | shard wrote: | Agreed. More sterilization also goes against what we should | do per the hygiene hypothesis | (https://en.wikipedia.org/wiki/Hygiene_hypothesis, which | states that early childhood exposure to germs is necessary | for the development of a healthy immune system), especially | around children in non-hospitalization situations. ___________________________________________________________________ (page generated 2022-10-11 23:01 UTC)