Hi Gizzy NIck
Take a look at this very detailed analysis of measuring the output of a petshop lights. You are not allowed to view links.
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LoginThe % measurement merely tells you the % UVB as a part of the total UV output, it doesnt really tell you what the dose is that you are getting, of course it is useful but doesnt really tell you the whole story. By way of background Im an engineer by training, Ill expand on that, I am not a guy who fixes telephone lines or boilers. I have an honours degree in Electical Engineering and am a Chartered Engineer, Ive designed / built mobile phone networks, been involved in new technology developments at the bleeding edge. Been doing it for 30 odd years. Thought I just put that in to give a bit of credibility to my technical capability!
The report above gives you a pretty good analysis, in my humble opinion, showing you the dose that you can get according to distance, also according to the position in the beam, relates the output to UV Index, relates the UVB spectral output of the lamp to the Action Spectrum of 7-DHC to pre-D3 conversion (by the way reference to none other than Holick), compares it with solar radiation. They also look at the decay of output from the lamps over time. Measures UVC also.
Aside from the methodolgy which looks good the million dollar question is, are their instruments properly calibrated? They question that themselves, very good sign, so whether they are right or wrong we will never know unless someone else attempts to replicate the same set of measurements independently.
Anyway getting past all the tech chatter and making the assumption that their instruments were good then you can expose yourself to a UV Index of 1 to 3 if you are a good distance away from the lamp or by placing yourself too close in danger of giving yourself a nasty burn with UV Index in excess of 10.
In my books UVB is UVB, but you can see from the analysis that these lamps are very spiky in their UVB output, Im not aware of any light that replicates the sun's broadband spectrum output, they provide output in the part of the spectrum that will produce D3 in your skin. I dont think any of us would worry about going about our business outside unprotected when you have a low UV Index.
Holick, and others who research Vit D by the way is saying that the current advice on Vit D maximum supplements is way too low. Holick also is open in saying that D3 vit supplements help but they dont address all the other chemicals produced in the skin in the D3 synthesis and he doesnt know what role they play either could be good or bad. Believe the Canadian health authorities just increased the maximum daily supplement.
So inconclusion, Im not advocating anyone doing this, make your own decisions based on informed opinion either your own, or your derms. Not all of us can afford the very high price of the marketed lamps. Pity you cant find similar data for the lamps produced for humans.
Cogs
