The two basic types of ultraviolet (UV) rays that reach the earth’s surface are called UVA and UVB. UV radiation can cause considerable damage to unprotected skin. Long-term effects, such as premature aging, are predominantly caused by UVA rays, while sunburn and aggressive forms of skin cancer are caused by UVB rays.
UVA is a weaker but more prevalent form of UV radiation. UVA can affect cells in deep layers of the skin and trigger DNA mutations that can become cancerous. Further, overexposure to UVA can deplete collagen levels in the skin, which leads to wrinkles.
The shorter wavelength of UVB rays makes them more potent and capable of causing more immediate damage. In high doses, UVB causes sunburn, peeling, and blistering. UVB has also been linked to the two most common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma.