No, I didn't know what it is either. Flipping the Switch on Far-UVC by Richard Williamson guesting at the Works in Progress Newsletter, which reports on biotech, replicability and fraud, and the intersection of tech and social problems.
Well, that got my attention. Is there another side to this story I don't know about? There was a specific link to research on the air in night clubs, which go out of business quickly under any kind of restriction, and I would think that restaurants and indoor arenas would want to be on this as well. The article, admittedly by someone from a nonprofit that is advocating for this, describes some of the reasons why this can't get off the ground.
Opinions welcome, as always. Informed opinions even more.
9 comments:
You sure don't want UVC in your eyes. Not great for your skin either.
I assume they're circulating the air through some separate system. It'll generate some ozone, which you don't want to breathe, but probably running the air through a catalyst filter would reduce that. If you run an intense enough system you could cycle the room air through it in reasonable time.
I got a small UVC unit in 2020 for fluorescence demonstrations, and tried it out as a disinfectant by just sitting it in the bathroom and running it for 15 minutes. The ozone was a bit harsh. FWIW, you couldn't find those things on Amazon the day after I bought mine; everybody was buying them for room disinfection.
I have had an in-duct UVC system since before the pandemic because I'm one of those stupid people who still smoke. It turns on when the fan is running and it does make a difference. It's not the same as this far-UVC and I don't know that I'd be comfortable in a room with that system without the research this guy is talking about.
I can tell that it makes a difference because of the few months a year that I don't need much AC or heat where I live, mostly that dust becomes noticeable quickly.
I do not attribute my never having contracted Covid to having that installed. Social distancing is quite natural for me except with close family. They were so afraid I'd get it that my granddaughters drew life-size "hugs" for me. I got vaccinated as soon as I could and set up an open air "living room" with widely-spaced seating in my garage.
One of many things where I've long thought is "we already know how to do this with standard UV-C safely, cheaply, and effectively".
Potentially eye-safe 'far'-UV-C would be, in my view, an incremental improvement.
I'm wary of how eye-safe it really is long-term. And somehow my university system (a distant campus) managed to install 'upper air' UV lights for COVID in such a way that they were shining 257nm UV-C light right into the lecturers' eyes, so maybe I shouldn't think that basic safety with UV-C is well known.
I've actually been running HEPA air cleaners with UV-C light in my office since I returned, but I'm pretty sure that the airflow's time and intensity of exposure to UV-C in these consumer home air cleaners is insufficient to do anything other than add a supposed feature to help marketing.
Peanut allergy theory suggests making this widespread might have some pretty negative side effects.
We had some black mold starting to establish itself in our air handler ductwork, in the central AC. In Gulf Coastal Texas, that's fairly normal over time, given our humidity here. The technician suggest installing UV lights just downstream of the coil - it's on full time, inside the air handler, so all of the air is treated as it blows by. It also has a negative ion generator, which gives airborne particles a tendency to clump together electro-statically, and either drop out or be caught by the filter. I noticed a difference in air quality right away, an improvement. It worked, killing off all the mold, but what I noticed was that the filters, on the regular 3 month rotation, were black, and I mean, black - where they are usually just noticeably gray, compared to the new 'white' condition. The next month, it wasn't so bad. But a couple of years in, having installed them on both systems now, the filters still pick up a lot more. I think it's a great way to passively treat the air - the cost is not insignificant, but I would endorse the benefits gained, for sure, and I can see the application for HVACs in crowded venues for disease control. I think there are UV systems for water treatment, too.
This is all excellent. Is there anyone else out there that knows a lot more than me about this?
I don't know that I know a lot more, but I do want to point out that most of us above are talking about UV-C light for disinfection that is very likely all the 253.7 nm that is a convenient-for-us-to-make wavelength with really strong bacteriocidal effect (but that is also really damaging for our skin and eyes, so it should always be in places where we're not exposed to it directly), but the article is about far-uv-c light, which is wavelengths shorter than 220 nm (higher frequency, farther up the light spectrum) which are less strong in bacteriocidal effect but also according to some research 'safe' for long-term exposure we are exposed to it.
Also want to point out that the wikipedia article on this is pretty good:
https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation
True, if it can't readily penetrate the dead skin layer it won't do as much damage to live skin. If Figure 1 https://pmc.ncbi.nlm.nih.gov/articles/PMC3797730/ is correct, absorbance rises by an order of magnitude. The paper talks about cornea protecting the lens (and that surgical staff already have eye protection), though the UV would still be dumping energy into that layer.
Post a Comment