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Black Lights and plain CFL and Cancer?

  1. Apr 3, 2015 #1

    so I have just learned that CFL bulbs fall in to the category of producing UV light, including perhaps some UVB in the case of black lights.

    I have had a black light bulb and a blue CFL running in my bedroom for almost two years now. I often fall asleep with the lights on, sometimes nude or nearly so...

    Given what I have read about these in relation to cancer, I am now feeling very worried about the health risks. I am a 22 year old male from Canada, in otherwise pretty good standing. I have had fluoroscopic exposure to x-rays when I was younger during 5-6 voiding cystourethrograms which adds to my worry. That's on top of average amounts of other plan x-rays and things like that.

    Anyways, this is the only link to some info on the exacta bulb I had in my room for the time:

    http://reviews.canadiantire.ca/9045/0525146P/blue-planet-blue-planet-13w-mini-cfl-bulb-black-reviews/reviews.htm [Broken]

    Can anyone help me to better understand how (or how not) dangerous being exposed to two of these bulbs for hours each day is?
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Apr 3, 2015 #2


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    The skin shows an indication of the amount of UV received: did you get a sunburn?

    The sun at zenit leads to ~30W/m^2 UV radiation. The value is lower if the sun is lower.

    If your light bulb would convert 10% of its electric input power to UV light (probably a large overestimate) and emits it in all directions, and if you are 2m away, this corresponds to ~0.025 W/m^2. 3 orders of magnitude below the power of the sun. The frequency spectrum could be different, but I think that is a large safety factor.
  4. Apr 3, 2015 #3


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    Where did you learn this? What is the source?

  5. Apr 4, 2015 #4
    I know Wikipedia isn't the best source of information always, but it says that some of the escaping light falls under UVB.

    "Although black lights produce light in the UV range, their spectrum is mostly confined to the longwave UVA region, that is, UV radiation nearest in wavelength to visible light, with low frequency and therefore relatively low energy. While low, there is still some power of a conventional black light in the UVB range."

    mfb, thank you for your response. Can you elaborate more on what you meant by the frequency spectrum being a large safety factor? Keep in mind i had two of these things running at the same time for a couple of years.
  6. Apr 4, 2015 #5
    Another thing I am trying to make sense of is this statement:

    "Since black light, for the most part, is not visible, it is very difficult to gauge its intensity. According to a study conducted by the International Radiation Protection Association, the limit for exposure to an ultraviolet wave of 60 joules/meter is eight hours. Considering that the average 40-watt black light bulb produces 40 joules each second (which we then divide by the walls and ceiling of the space) this puts the average "exposure rate" being reached within a half hour or less."

    From this article: http://www.ehow.com/about_5566929_black-lights-dangerous.html
  7. Apr 4, 2015 #6


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    Even better.
    That's not what I meant. The huge safety factor is the different intensity. Walking around outside on a really cloudy dark day still gives more UV intensity than the light.
    The UV power is negligible.

    The numbers on the ehow site do not make sense at all, a clear indication that you can ignore what they write.
  8. Apr 4, 2015 #7


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    UV sources that are used in clubs and parties do not have any visible effect when used outside during the day. That, to me, is pretty good evidence that the amount of UV they produce must be quite a bit less than what is present in normal sunlight. But, of course, a lot of exposure directly to the Sun is dangerous.
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