Natural UV Radiation

Most tight sources for artificial lighting have a UV component in their emission spectrum. Usually, the glass encapsulation absorbs all radiation below about 

330 nm. Light bulbs work as a blackbody radiator at a temperature of approx. 2800 K. Temperatures up to 3300 K can be reached by filling a bulb with haloge-nated gas. The spectral radiation distribution has a tail below A = 400 nm that strongly decreases at shorter wavelengths. Its magnitude rises with the temperature of the source of radiation. 

Fluorescent lamps generate light through a low-pressure mercury vapor discharge that has strong emission tines in the UV, namely at A = 254 nm and around 366 nm. The fluorescent layer is excited by the UV radiation and emits in the visible part of the spectrum. While remains of the 254 nm tine are efficiently rejected by the glass tube, some fraction of the 366 nm radiation can be measured in the emission spectrum of the lamp. 

---