Low pressure UV germicidal lamp is a kind of short wave low pressure mercury vapor discharge lamp. The excited atom of mercury vapor emits short waves of ultraiolet light under the low pressure in the sealed glass tube.

Germicidal lamps should not be confounded with fluorescent lamps for while transmit small amount of ultraviolet, the coated phosphor powder inside the glass tube converts the ultraviolet into visible light to illuminate the lamp, while germicidal lamps can not be confounded with sun tanning lamps or black either, for while these are also ultraviolet lamps, the ultraviolet produced is of longer wavelength and is not useful for germicidal purpose. Germicidal lamps emit short wave ultraviolet that is lethal to microorganism.