HN Explorer

Ask HN: Can aquarium UV lights be used to kill coronavirus?

3 points by sgroppino ↗ HN
The below paper suggests that with approx 2.4mWsec/cm2 it's possible to inactivate 99% of viruses. No specific mention of coronavirus, but could we use 13W aquarium UV lamps (are they UVC?) for an effective solution?

https://www.researchgate.net/profile/Chun_Chieh_Tseng/publication/239392662_Inactivation_of_Virus-Containing_Aerosols_by_Ultraviolet_Germicidal_Irradiation/links/54f823b80cf2ccffe9dce501/Inactivation-of-Virus-Containing-Aerosols-by-Ultraviolet-Germicidal-Irradiation.pdf

8 comments

[ 3.5 ms ] story [ 34.6 ms ] thread
rolph
the overhead lamps are not what you want, you want the bulb for the UV sterilizer that is normally used for UVirradiation of water circulating through a manifold.

you dont want to use this as normal illumination, it is damaging to the eyes.

there is a system where microbiological labs are under constant intense illumination with UV while they are unoccupied. you would be doing something similar i suppose?

have look here as an example of what you would need to do a proper job:

https://www.light-sources.com/solutions/germicidal-uvc-lamps...

https://www.light-sources.com/solutions/germicidal-uvc-lamps...

sgroppino
I was thinking something like this https://www.ebay.co.uk/itm/283782783926 or even this https://www.amazon.co.uk/gp/product/B00J3EUJPA to build some kind of wand to sterilize packages or clothes as I walk through the door. Just checked your links - I'm surprised the output is super low: 48W only yields 120uW/cm2. Does it mean a 12W UVC lamp would yield ~30uW/cm2? In terms of virus sterilization, would I need to expose the surface to a 12W for 80sec to get the 2.4mWsec/cm2?
rolph
ahh ok its not like a light sabre :)

its like a half life thing, the energy from the UV radiation makes the molecules of the virus shimmy and shake until it breaks, and this is time dependent so for a given |dosage| of UV you need wattage over time at distance from the source. it might be better to hang the garment in a closet or enclosure and expose it for a period of time.

in particular, the cuffs, and the upper chest lapel area, and the hip/pocket area these are typical hotspots.

sgroppino
just pictured myself with a Darth Vader mask and a UVC portable sabre to kill covid-19... re-reading those specs "Measurements were performed on a high-frequency, current limited electronic ballast and represent average values at 1 meter" - this means the output could be considerable higher at a few inches and it'll take only a few seconds to sterilize small garments (and mobile phones). It could work.
rolph
you just have to be carefull about repeated exposure of skin and eyes. light energy dissipates as a square function of distance the general idea is quarter the energy for 1 foot distance increase a quarter of that again when you get to 4 feet away...

maybe this is more concise:

https://en.wikipedia.org/wiki/Inverse-square_law

rolph
that sounds right the distance is the variable to get here its inverse square dependent. usually flux is at 1 foot distance to keep the measurements in a standard framework.

have a look here re inverse square:

https://en.wikipedia.org/wiki/Inverse-square_law

davismwfl
What's the usage idea?

UV sterilizers do work on most all viruses from what I understand but the issue is the the further from the light source the less effective it becomes and time, temperature and humidity are all factors which can affect the effectiveness. A UV-C light strong enough to clean a 100 sq ft room would be dangerous to humans so it could only be used as a sanitary item and not on all the time. At least as far as I understand it.

edit: just saw your usage idea. Not sure it would be doable and safe for humans but packages seems totally fair game.

sgroppino
Correct - the idea is mostly for ebay/amazon small packages, gloves, mobile phones and glasses (maybe even shoes though I don't see them as a big threat). Never directly applied to skin nor pointed at face/eyes; I'd probably use some tin foil to reflect part of the light, and use sunglasses as precaution though I need to check if they filter UV-C. Any ideas of sensors that could be used to measure W/cm2?