It is leant that the types of ultraviolet radiation of concern to our skin are ultraviolet A and ultraviolet B (UVA and UVB for short). In natural sunlight, there is 90% UVA and 10% UVB. However, majority of our skin reactions from ultraviolet radiation and sun exposure are from UVA. Research has shown that UVA is responsible for what we called photoaging, meaning it can penetrate deeper into our skin and destroys our elastic tissue and collagen. UVA is also a contributor to the development of skin cancer and may affect our sebaceous glands to grow and become lumpier and prominent in our skin, we may call this condition as sebaceous hyperplasia, i.e. an unsightly condition as there are sometimes many lesions on the face.
According to studies, tanning booths provide approximately 95% UVA and 5% UVB. The lower in concentration of the UVB has been held responsible for burning and may contribute to skin cancer formation.