Potential Health Risks of Blacklights: A Scientific Analysis

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Discussion Overview

The discussion revolves around the potential health risks associated with exposure to black lights, specifically the fluorescent tubes commonly found in novelty stores. Participants explore the types of ultraviolet (UV) radiation emitted by these lights and their possible effects on health, particularly in relation to skin and eye damage. The conversation includes both theoretical and practical considerations regarding safety and exposure limits.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that black lights primarily emit UVA radiation, which is generally considered less harmful than UVB or UVC radiation.
  • One participant warns against prolonged exposure to black lights, citing the risk of malignant melanoma, despite the lower danger associated with UVA.
  • A participant references the importance of dose and wavelength, indicating that UVA is not dangerous if not stared at for long periods, and that the dose from black lights is low.
  • Another participant expresses uncertainty about the safety of UVA, noting recent links to melanoma and discussing exposure limits based on technical sources.
  • Concerns are raised about the potential for eye damage from UV exposure, with a reference to "snow blindness" as a related risk.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the health risks associated with black lights. While some argue that the risks are minimal, others express concern about potential long-term effects and eye damage, indicating a range of opinions on the topic.

Contextual Notes

Limitations include varying interpretations of safety based on exposure duration and intensity, as well as differing opinions on the significance of recent findings related to UVA and melanoma. The discussion also reflects uncertainty regarding the calculations of UV exposure limits and their practical implications.

Who May Find This Useful

Individuals interested in the health effects of UV radiation, safety considerations for using black lights, and those involved in discussions about lighting technology and its implications for health.

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My roommate and I have set up a couple fairly strong black lights in our dorm room. They're forty watt fluorescent tubes about three feet tall, and look quite cool.

However, we are both wondering whether there's any health risk associated with being exposed to the black lights for an extended period of time. They're the sort of light you purchase at a novelty store like Spencer's Gifts. I would expect that nothing sold under those circumstances would emit any significant radiation at potentially harmful wavelengths, but perhaps I'm too trusting.

So, is there a health risk here?
 
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Interesting question. I think most "blacklight" is longer wavelength ultraviolet, which is less dangerous than the shorter UVB or UVC radiation. You probably won't get a sunburn!

Maybe someone in the biology forum can give a more authoritative answer.
 
Blacklight like ones you see over in clubs are UVA. Those arent as dangerous as germicidal light - UVC. My UVC light burned down plants in a few hours. I won't recommend sitting under blacklight for extended periods of time though.. you may get a malignant melanoma so why risk it?
 
"It all depends on the dose and wavelength of the radiation. UVA (315 - 400 nm) is pretty harmles. This is what you get from those black-light disco tubes. It is not dangerous if you don't stare to the tubes for long periods. The dose remains so low that you don't even get suntan."

http://www.usenet.com/newsgroups/sci.optics/msg01878.html
 
I'm not sure what to think. UV-a, being non-ionizing, was intially thought to be safe. Apparently, however, it has recently been linked to melanoma (skin cancer)

For hard figures, we have some exposure limits at

http://www.icnirp.de/documents/UV1989.pdf

The wikipedia puts the wavelength of the typical mercury vapor fluorscent lamp at 254 nm, which is fairly near the peak of the weighting curve.

http://en.wikipedia.org/wiki/Fluorescent_lamp

There is some additional radiation at 185 nm, but this is lower in magnitude and off the peak of the weighting curve.

The limit at that freqency is 60 joules/meter^2 in an 8 hour period, which really isn't a lot. A 40 watt UV bulb would generate 40 joules/second at 100% efficiency. Without a meter, I guess you could (over)-estimate the radiation flux by assuming 100% efficiency on the part of the UV bulb, and divide the power (joules/sec) by the total area of the walls and ceiling (in m^2) to get (joules/m^2) / sec.

If we had 100m^2 of area that would reach the above limit in a couple of minutes, unless I'm making a major calculational error (?!).

For less technical sources, we have

http://wolfstone.halloweenhost.com/TechBase/blttip_BlackLightTips.html#Safety

which I thought intially was over-conservative, but having looked up their referred technical sources and run the numbers above, perhaps it is not as over-conservative as I thought.

On the other hand, I would still expect that walking outside with sun-screen for a few minutes would generate much more UV exposure than your UV lamps would.

Anyway, that's about the best I can do - look up some of the sources and make up your own mind.
 
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UV-A will damage your eyes: look up "snow blindness".