What is UVA and UVB Radiation?
When sunlight penetrates the top layers of the skin, ultraviolet radiation (referred to as UVA or UVB) bombards the genetic material, the DNA, inside the skin cells and damages it. UVB radiation is the primary cause of sunburn and mainly affects the skin’s outer layers. UVB is most intense at midday when sunlight is brightest. It is interesting to note that slightly more than 70% of the yearly UVB dose is received during summer and only 28% is received during the remainder of the year. UVA radiation penetrates more deeply and efficiently, however, UVA’s intensity also tends to be less variable both during the day and throughout the year than UVB’s. For example, only about half of the yearly UVA dose is received during the summer months and the balance is spread over the rest of the year. UVA is also not filtered through window glass (as is UVB). Both UVA and UVB rays damage the skin, including genetic injury, wrinkles, lower immunity against infection, aging skin disorders and cancer,
