
Ask HN: Can aquarium UV lights be used to kill coronavirus? - sgroppino
The below paper suggests that with approx 2.4mWsec&#x2F;cm2 it&#x27;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?<p>https:&#x2F;&#x2F;www.researchgate.net&#x2F;profile&#x2F;Chun_Chieh_Tseng&#x2F;publication&#x2F;239392662_Inactivation_of_Virus-Containing_Aerosols_by_Ultraviolet_Germicidal_Irradiation&#x2F;links&#x2F;54f823b80cf2ccffe9dce501&#x2F;Inactivation-of-Virus-Containing-Aerosols-by-Ultraviolet-Germicidal-Irradiation.pdf
======
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?

------
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/uv-
light-applications/uv-light-sterilization/)

[https://www.light-sources.com/solutions/germicidal-uvc-
lamps...](https://www.light-sources.com/solutions/germicidal-uvc-lamps/uv-
germicidal-lamps/low-pressure-mercury-lamps/high-output-quartz/)

~~~
sgroppino
I was thinking something like this
[https://www.ebay.co.uk/itm/283782783926](https://www.ebay.co.uk/itm/283782783926)
or even this
[https://www.amazon.co.uk/gp/product/B00J3EUJPA](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](https://en.wikipedia.org/wiki/Inverse-square_law)

