[RFI] CFL's & UV - Hoax or Real? Real but Overstated?

Dan Zimmerman N3OX n3ox at n3ox.net
Mon Feb 23 22:53:45 EST 2009

On Mon, Feb 23, 2009 at 9:49 PM, kd4e <doc at kd4e.com> wrote:

> The claim of the researchers is 10x+ the UV radiation of a typical
> incandescent.

Sure, I buy that.

There's basically a vanishingly small amount of UV radiation in the thermal
light distribution coming off an incandescent.

Check out the Wikipedia graph of thermal emission spectra:


Seems like a regular incandescent filament is about 3000-3200K, so it's like
the red curve.

There's going to be a little tiny bit of UV in that, but it's only strong in
the visible and a LOT in the infrared!  Of course, that means a lot of the
energy goes into heating up the bulb and surroundings with IR emissions that
don't give you any useful light output...

So there's absolutely no question in my mind that a typical CFL gives off
much more UV than an incandescent.  CFL's need to generate UV to work,
incandescents just have a little tiny bit out on the high end of the
emission spectrum.

That doesn't necessarily mean a CFL gives off a dangerous amount.  After
all, wouldn't much matter if I was saying 10 grains of salt have 10x the
sodium of 1 grain of salt :-)


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