Man-made UV radiation

Sunbeds with fluorescent lamps that emit in the UVA and UVB are used for indoor tanning. They are supposed to simulate the solar UV spectrum and have therefore similar effects on the human skin. However, the intensity of radiation is often not monitored, and excessive exposure may cause serious dermatological health problems. A more detailed analysis reveals that the long-wave UV (UVA) is mainly responsible for the tanning while UVB radiation tends to be more dangerous. 

UVC radiation can not only be used to sterilize tap water, but also for the treatment of air and sewage. Radiation between 250 nm and 265 nm is passes through water and is strongly absorbed by nucleic acids, i.e. any living creature present. This kind of radiation therefore efficiently kills all microorganisms in the water. It is a lucky coincidence that at 254 nm, the main emission line of mercury lamps lies within the range of effective UV sterilization. 

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