LED lights with UV spectrum dangerous for our health?

[Billyreef-ita]

Hi everybody,
I see that many lamps are now providing some leds whose spectrum is below 400nm, the so called UV light (such as 395nm).

I’m fully aware the UV lights that are dangerous are UV-C that are in the range 100-280nm.
However the UV-A are in the range 315-400 and also exposure to UV-A could be harmful for the skin, they are the same we protect against using sun-cream.

I understand what really counts is the length of exposure to them, but considering that our lights are on for many hours in our homes, and we spend quite some time working very close to the tank, don’t we run some risks?

Thanks for your feedbacks

 

[JNalley]

Hi everybody,
I see that many lamps are now providing some leds whose spectrum is below 400nm, the so called UV light (such as 395nm).

I’m fully aware the UV lights that are dangerous are UV-C that are in the range 100-280nm.
However the UV-A are in the range 315-400 and also exposure to UV-A could be harmful for the skin, they are the same we protect against using sun-cream.

I understand what really counts is the length of exposure to them, but considering that our lights are on for many hours in our homes, and we spend quite some time working very close to the tank, don’t we run some risks?

Thanks for your feedbacks

most of the lights that employ the 365nm, 370nm, 380nm, and 385nm LEDs (different manufacturers choose a different peak wavelength, you have to check which ones are which, Kessil, for instance, is 385nm, while GHL I think is 370nm), are only doing a maximum of 2 LEDs that I have seen. The output of these are probably 0.01% or even less of what the sun puts out on a daily basis, and loads of people are out working in the sun 12 hours a day...

 

[LARedstickreefer]

These LEDs are really low (relatively) power and the majority of their output is directed towards the tank. I wouldn’t worry at all about them. I’m betting that they do very little (if anything) anyways.

-Matt

 

[oreo54]

Hi everybody,
I see that many lamps are now providing some leds whose spectrum is below 400nm, the so called UV light (such as 395nm).

I’m fully aware the UV lights that are dangerous are UV-C that are in the range 100-280nm.
However the UV-A are in the range 315-400 and also exposure to UV-A could be harmful for the skin, they are the same we protect against using sun-cream.

I understand what really counts is the length of exposure to them, but considering that our lights are on for many hours in our homes, and we spend quite some time working very close to the tank, don’t we run some risks?

Thanks for your feedbacks

Well first UV-C is non-existant in leds AFAICT and only a teeny bit in HID lamps not designed to emit UV-C.
It is also filtered out by the atmosphere.

Second it is more UV-B that is "the" issue. Again none in LEDs used in reef lighting.
You can get specialty t5's for this though. Reptile lights.
Also some in HID lamps, probably little to zero in "normal" t5's .

As to UV-A well you could probably build a better argument about the perils of like royal blue leds than the little UV-a emitted in the uv containing led -fixtures. A long time ago the output of the Kessil UV was measured and found to be quite low.

Kessil and Aqua Illumination Tested - Kessil gives of 7.5 Times as much UV as AI LED

Kessil and Aqua Illumination LED's were tested for UV using an Apogee UV Meter. The Kessil gives of 7.5 Times as much UV as AI LED. Kessil A160we LED spotlight review: the best gets even better I wish there were more tests like this. All I ever see are PAR Comparisons on LED Lights.

www.reef2reef.com

Just so you're aware, the difference between 2mW of UV and 15mW of UV is like comparing a speck of dust to another speck of dust. Both are so incredibly low that there is a zero percent chance of them having any effect on color or growth...These intensities would not even be enough to activate the photosynthetic process, much less add anything to them. In addition, light decreases in intensity as an inverse square. If this reading was taken at, say, 6" away, if it's hung 8" over a 16" tall tank, the bottom of the tank would be down to microwatts of intensity..

Kessil and Aqua Illumination Tested - Kessil gives of 7.5 Times as much UV as AI LED

Kessil and Aqua Illumination LED's were tested for UV using an Apogee UV Meter. The Kessil gives of 7.5 Times as much UV as AI LED. Kessil A160we LED spotlight review: the best gets even better I wish there were more tests like this. All I ever see are PAR Comparisons on LED Lights.

www.reef2reef.com

HID lamps do have a larger quantity of UV-A (well some ). T5's not so much.

There is no definitive proof that UV-A is a "critical" component needed for coral growth. Maybe a bit in forcing protection and concurrent "some" pigment production.
Want to go down that rabbit hole you can start here..

UV spectrum & reef lighting.

Now that I'm figuring out the dynamics of using my lights in an Apex environment I'm wondering... Has anyone adjusted their uv spectrum to be higher then the other blue channels. Effectively lowering whites and blues proportionally to allow the uv to be more dominant? It's already been well...

www.tcmas.org

https://reefs.com/magazine/playing-with-poison-ultraviolet-radiation/

Plenty of lights without it..if it is bothersome to you.
Daily outdoor exposure is like Watts. Not milliwatts, not micro watts.
I'm not going to say one way or another as to ANY possible health effects.. excet to say that exposure is likely very minimal in normal situations.

THAT said don't LOOK at the diodes while ON. Goes for any led really.

Looking into exposure data of uv-a:
1.0 mW/cm2 for periods lasting greater than 1000 seconds.

At 365Nm, the sun's intensity is typically less than 6 mW/cm2.

A MH may push 1.1mW/cm2.

 

[Billyreef-ita]

Thanks, I went through the docs and this is fascinating. I assume everything is on the safe side also because led producers wouldn’t receive approvals from guardian authorities

 

[gbroadbridge]

Hi everybody,
I see that many lamps are now providing some leds whose spectrum is below 400nm, the so called UV light (such as 395nm).

I’m fully aware the UV lights that are dangerous are UV-C that are in the range 100-280nm.
However the UV-A are in the range 315-400 and also exposure to UV-A could be harmful for the skin, they are the same we protect against using sun-cream.

I understand what really counts is the length of exposure to them, but considering that our lights are on for many hours in our homes, and we spend quite some time working very close to the tank, don’t we run some risks?

Thanks for your feedbacks

If they were in any way hazardous I'm sure they'd be illegal in CA

 

[strich]

So I spent the past few weeks reading quite heavily into this specific topic, with the specific goal of understanding whether I can use 365nm light to maximise coral fluorescence and minimise visible blue light as I dislike the look of it. The thought here being that I can light the tank in typical daylight style, and add some 365nm to have it really pop. I have yet to test this theory.

Here are my notes, some of these are backed up by actual papers I read (though I did not save them sorry):

• Peak fluorescence is considered to be at 365nm, which is why it is a popular watermark in products. Unclear if that holds true for actual coral vs whatever materials they set that upon.
• Corals do react to UV - The more UV they detect, the more time and energy they spend creating a form of sunblock for which I forget the name of. If you'll allow me to loosely summarise the paper I read, it was observed that coral grew less if lit with a lot of UV-B. I believe the same held true for UV-A too but to a lesser extent. I do not believe a small amount of 365nm got from home LED lights would effect growth though as the study was simulating UV amounts close to actual outdoor sun amounts, to simulate global warming conditions. IE a lot more than a home LED array.
• With regards to human hazards - I am not a professional but as mentioned by someone else 365nm is really on the upper edge of UV-A and in the amounts we're talking about here it should not be of concern. That said, the same caution with any bright light should be used here.
  • I'm fairly certain, though have not properly Googled it, but I think one can buy 365nm "black lights" for clubs etc, which if true would help settle any undue concern.

 

[JNalley]

to simulate global warming conditions. IE a lot more than a home LED array.

What does the amount of UV Light (and its ability to reach corals) have to do with climate change/Global Warming? It's not like we're warming up because of more short-wave radiation reaching the planet, we're heating up because long-wave radiation is getting trapped by greenhouse gases... This is the whole basis for Anthropomorphic climate change AKA global warming... do you still have the link to it? I'd like to read it so I can get a clear/better understanding.

I'm fairly certain, though have not properly Googled it, but I think one can buy 365nm "black lights" for clubs etc, which if true would help settle any undue concern.

Yes, this is totally true. The Blacklight fixtures you see in novelty shops and inside nightclubs are indeed 365nm peak UV Light. I brought this up in another thread, I think it was either in the lighting or the experiment forums, where the person had purchased a 365nm flashlight and shined it onto their coral at night and saw a bunch of colors they had never seen before. Long story short, they wanted to see about getting a fixture in that same wavelength so I directed them to buy a T8 or T12 Blacklight + Fixture, they can be had for less than $100 in most cases.

 

[strich]

What does the amount of UV Light (and its ability to reach corals) have to do with climate change/Global Warming? It's not like we're warming up because of more short-wave radiation reaching the planet, we're heating up because long-wave radiation is getting trapped by greenhouse gases... This is the whole basis for Anthropomorphic climate change AKA global warming... do you still have the link to it? I'd like to read it so I can get a clear/better understanding.

Heating/warming is neither here or there. I believe the paper more specifically considered UV changes due to ozone layer changes either due to human activity or geographical location. But it wasn't important so I don't remember clearly.

I'm sorry I don't have the specific paper. However I did a quick google and I think you can at least start here. The linked paper may or may not be what I read - I couldn't find the growth charts I remember seeing. Take a look at the linked/similar papers below this one maybe.

Yes, this is totally true. The Blacklight fixtures you see in novelty shops and inside nightclubs are indeed 365nm peak UV Light. I brought this up in another thread, I think it was either in the lighting or the experiment forums, where the person had purchased a 365nm flashlight and shined it onto their coral at night and saw a bunch of colors they had never seen before. Long story short, they wanted to see about getting a fixture in that same wavelength so I directed them to buy a T8 or T12 Blacklight + Fixture, they can be had for less than $100 in most cases.

Good to know, and I know the thread you speak of! I believe his conclusion on whatever he did buy had no visible effect for him, but I think he just didn't buy enough Watts of UV - It probably needs a decent amount due to the quick loss in the water column. And I'd expect it to be subtle as well.

 

[JNalley]

Heating/warming is neither here or there. I believe the paper more specifically considered UV changes due to ozone layer changes either due to human activity or geographical location. But it wasn't important so I don't remember clearly.

gotcha

I'm sorry I don't have the specific paper. However I did a quick google and I think you can at least start here. The linked paper may or may not be what I read - I couldn't find the growth charts I remember seeing. Take a look at the linked/similar papers below this one maybe.

thanks, I'll see if I can drum it up, it's an interesting topic (My minor is in Geology/Geosciences)

Good to know, and I know the thread you speak of! I believe his conclusion on whatever he did buy had no visible effect for him, but I think he just didn't buy enough Watts of UV - It probably needs a decent amount due to the quick loss in the water column. And I'd expect it to be subtle as well.

Yeh, he bought some cheap 365nm LED strips, I arrived at the same conclusion, probably not enough watts/light output to make any difference. But 2 T12 tubes at 45 watts each should be more than enough to punch through