BALANCING BENEFITS WITH EXPOSURE RISKS OF ULTRAVIOLET EMISSIONS FROM LAMPS

Ultraviolet lamp products are used for a variety of applications, from excitation of fluorescent pigments in fabrics, paints and paper to insect traps and germicidal radiation. We examined the UV emissions of a wide variety of lamp products with an analysis of irradiances and exposure durations at typical use distances for realistic exposures of the eyes and skin. It was found that the UV-A (315-400 nm) emitted from lamp products posed no realistic health risk when considering the time-weighted exposures. Safely installing ultraviolet germicidal irradiation (UVGI) can pose practical problems for upper-air disinfection; proper fixture design and lamp height becomes critical. It is also concluded that lamp safety standards should also better clarify the risks of UV-A exposures and the essence of time-weighted averaging of potential exposures. The risks of ocular exposure UV-A radiation require a better understanding and it is emphasized that UV-A absorbed by the eye's crystalline lens is reemitted as harmless fluorescence, thus protecting the retina and protecting the lens from direct photochemical damage and over-heating.