UV Light Safety Whilst Mothing

I’m not too familiar when it comes to the use of uv lights, but I have some questions. I’ve seen many people use uv lights when mothing. Yet, they don’t seem to be concerned about the dangers that come with uv light. What are the affects that come from mothing when using uv lights if any? What precautions could be taken? Should uv light even be used anymore? I’ve looked around and was surprised by the lack of discussion on this topic. I’ve seen people recommend blue uv lights over purple uv lights aswell. Is the blue light less dangerous? Does the blue light attract more moths? Maybe I’m looking at this all wrong, but have y’all had this question come up before?


I have no experience regarding this, but I did take a college Chemistry class recently so I have my 2 cents.

Not all UV light is the same:

So you see, on one end you can have UV light that is close to visible spectrum (“wimpy” ones, as my professor would put it. On the other you can have those nearing X-ray spectrum, which have way more energy. High energy UV waves are the most damaging ones. I would assume that most handheld UV lights are towards the “wimpy” side and should not do much harm?

Edit: also dosage as well, I’d think that the intensity of those UV lights are relatively low. I could be wrong though.


Take it from my Chem professor’s book: https://mccord.cm.utexas.edu/chembook/page.php?chnum=3&sect=4

Read the section on ultra-violet on that page, which should explain it well enough.

the effects would generally be the same as any exposure to any UV light. how much danger there is depends on how intense the light / exposure is, how long you are exposed, what part of the body you’re exposing, and which wavelength(s) are involved.

i would think that most people would be using UV lights somewhere in the UVA/B or near ultraviolet (roughly, >300nm) range, and the intensity of the light would be relatively low compared to the UV exposure you would get just on a sunny day. (if you’ve ever seen a tanning bed, you’ll see that they use a lot of light just to match the sun’s power.)

if somehow you’re getting a suntan, or worse, a sunburn, then you’ve definitely been overexposed to UV. if your vision is suffering, then you’ve definitely been overexposed to UV.

if you’re using a UV flashlight, definitely don’t point that in someone’s eye. if using a tube light or something similar, i would generally try looking away from the bulb, too. if you’re concerned about your eyes, wear eye protection. (anything with acrylic lenses should be fine. if in doubt, sometimes i’ll put the lens between my ID card and the light to see if my card fluoresces as it would when exposed directly to UV light. if not, the lenses are blocking the UV.)

for your skin, clothing and / or sunscreen could offer protection, if you desire it.

usually, the lights that we perceive as purple are operating just under 400nm, on the boundary between UV and human-visible light. below that, the UV really should be invisible to your eyes, but sometimes some sort of fluorescence allows you to indirectly perceive the light. so i assume that’s what you mean by a blue light.

as long as the wavelength is not below 300nm – i don’t think using a lower wavelength would ever make sense, since i believe that’s the boundary for most insect vision – you probably shouldn’t need to take any special precautions other than noted above.

but if you’re talking about using something like a UVC germicidal light (<280nm), then that seems like a bad idea, since there’s probably not any safe exposure to that kind of light.

in practice, i think this just depends on what you’re attempting to attract. it seems to me like many moths are attracted just fine to visible light, as you know if you’ve ever looked at a street light at night. when people use a UV light, it seems to me like what’s often happening there is that they’re attracting insects less to the bulb (which is putting out UV) and more to a nearby sheet (which would be fluorescing visible light). so if the point is just to minimize the amount of visible light coming from the bulb, then going with a bulb that emits closer to, say, 365nm (definitely outside human visible range but still relatively long wavelength for UV) should be fine for that purpose. if you’re really looking to specifically attract insects that have vision in that lower range of insect vision closer to 300nm (which i think would be things like midges and such), then you’ll want to use a bulb that emits light in whatever range you’re interested in.

i don’t think there are insects whose vision range includes only UV (and does not also extend into the human visible spectrum), but i could be wrong about that.


Wow, this has all been very helpful! Thank you all very much for your help! I also forgot to pose another question. What would be the optimal amount of exposure to be safe? I would think no more than a couple of hours. Also, what about long term. If I’m going to be doing this on a regular basis for the foreseeable future, what would be the effects from years of using the uv light?

When talking about blue light I was referring to what was mentioned by twan3253

I think I looked at his message wrong. I guess that when he was talking about blue light, I lumped it with uv light.

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this is hard to know for sure. again, it depends on many factors mentioned above… and it depends on your own body, too.

i think the intensity of most UV lights that people would be using would be relatively low. so i don’t think most adults should be overly worried about occasional exposure. but if you’re going to be under UV lights for a long time very often, then i don’t see how it could hurt to take some extra precautions.

if you’re going to protect something, i think you should protect your eyes, because it’ll be harder to reverse any damage from UV exposure. and the younger you are, the more important it’ll probably be to protect your eyes (because people’s lenses will naturally yellow and and block out more light on the blue end of the spectrum as they age).

if you know you’re susceptible to sunburn, then maybe you would want to take more precautions for your skin. cover up with long sleeves, pants, sunscreen, and a cap, as appropriate.

if you’re not already very melanistic, you’ll be able to tell that you’re overexposing if you cover up a few otherwise exposed spots on your skin. for example, if you’re exposing you hands to the UV light, and you put a dab of sunscreen on the back of each hand, and you notice that your hands get tanned except for the spots where the sunscreen was, then you know that you’re getting a enough of a UV dose that your skin is concerned about the exposure.


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