In this paper, a relation between the ultraviolet index (UVI) as a Sun exposure time and its effects in the form of burns according to the skin type has been elaborated. Moreover, we present a new expression that relates the intensity of solar radiation and the UVI, as well as expressions to obtain the percentage of population affected both by first and second degree lllsunburn for every skin-type. The results have been adjusted and validated through experimental results taken from the bibliography. Finally, this paper presents a table where the population can easily interpret the UVI values and calculate the maximum time one can be exposed to solar radiation without getting sunburn. In addition, this article aims to raise awareness of the potential harm caused by solar radiation by indicating the percentage of population affected by different types of sunburn depending on skin-type. Moreover, ultraviolet exposure to sunlight could not just result in sunburn, but also have long-term effects on eyes, or even cause immune system disorders or melanoma. Therefore, managing risk perception with this useful table could familiarize the population with actual harm prevention.