Which type of UV rays primarily reaches the earth's surface?

The type of UV rays that primarily reaches the earth's surface is UVA. Unlike UVB rays, which are partially absorbed by the ozone layer, UVA rays penetrate the atmosphere more effectively, making up a significant portion of the UV radiation that can cause skin damage and contribute to aging. Although UVB rays are responsible for sunburn and play a role in the development of skin cancer, UVA rays are often underestimated in their potential to cause long-term skin damage. They can reach the skin more deeply and are associated with oxidative stress and skin aging. The distinction between UVA and UVB rays is important, especially in the context of sun protection and tanning, emphasizing the need for broad-spectrum sunscreens that protect against both types of ultraviolet radiation. UVC rays, on the other hand, are mostly absorbed by the ozone layer and do not reach the earth's surface, making them irrelevant in this context.