UV radiation is categorized into three types: UVA, UVB, and UVC. UVA has the longest wavelength and penetrates deeply into the skin, while UVB primarily affects the outer skin layers. UVC is mostly absorbed by the Earth's atmosphere and does not play a significant role in photodamage. UV radiation can cause direct DNA damage and generate reactive oxygen species (ROS), leading to oxidative stress. This can result in mutations, impaired cellular functions, and skin aging.
