1. Why is artificial light a concern?
Single envelope CFL
In general, artificial lights are very unlikely to cause any harm. However, some light sources emit blue light and ultraviolet radiation and these can aggravate the symptoms experienced by people with diseases such as chronic actinic dermatitis and solar urticaria. Some single-envelope compact fluorescent lamps (CFLs), , emit UV-radiation in amounts that can exceed the recommended limits set to protect from skin and retinal damage if they are used in close quarters and for extended periods of time. Lamps with a second glass envelope emit much less UV.
Some associations of light sensitive individuals claim that energy-saving lamps (mainly CFLs) aggravate the symptoms of a wide range of diseases and dispute the efficiency of second lamp envelopes. There are also reports that screw-base halogen lamps and LEDs aggravate symptoms. Recent measurements show that a large proportion of the UV radiation from tungsten halogen lamps is in the UVC range, which is particularly harmful.
There are concerns that artificial light with a strong blue component could affect human circadian cycles and the hormonal system, and be involved as a result in a wide range of conditions ranging from sleep disorders, immune system disorders, and macular degeneration, to cardiovascular diseases, diabetes, osteoporosis and breast cancer. More...