Current Journal of Applied Science and Technology

The article presents a system, including a multi-sensor instrument, for measuring, recording, processing and displaying the level of biologically active UV-B radiation. The multi-sensor instrument comprises of solar erythemal UV detectors distributed on a spherical (faceted) dome-like structure. Some of the detectors face upwards measuring the radiation emanating from the sky, while others face downwards, measuring radiation from reflected surfaces. The system displays UV-B radiation levels on billboards in real-time at recreation grounds, thereby warning of danger in instances of over-exposure to sun light. The displayed information includes the amount of sun exposure, in Minimum Erythema Dose, on different parts of the body in relation to the category of human outdoor activity, such as swimming, bathing, sport activity, and sitting in the sun (light) or in the shade. In addition, the system communicates and constantly updates the maximum recommended exposure time to sun light according to the different categories of outdoor activity, while displaying in colour-code, UV-B intensity and ultraviolet index (UVI).  It was found that during the period between 10:00 to 16:00, a person may absorb 15 times more UV-B than what is recommended. Sitting in the shade for that period of time is equally as dangerous as it is for sports activity. The vertex of the head and the nose receive the highest levels of UV-B radiation. The erythema onset time for skin type II may also be lower than 15 minutes at summer solar noon. The instrument is intended to be operated at recreation grounds, such as beaches, swimming pools, resort areas, etc., and to display dangerous levels of UV-B radiation.