How does UV radiation cause damage?
UV radiation consists of three different wavebands: UVA, UVB and UVC. The UVC waveband is the highest-energy UV but has the shortest wavelength, meaning it does not reach the earth’s surface and does not cause skin damage to humans.
However, UVA has a long wavelength and accounts for 95% of solar UV radiation that reaches the earth’s surface, while UVB – with a middle-range wavelength – accounts for the remainder. Tanning beds and tanning lamps primarily emit UVA radiation, sometimes at doses up to 12 times higher than that of the sun.
Both UVA and UVB radiation can damage the skin by penetrating its layers and destroying cellular DNA. UVA radiation tends to penetrate deeper layers of skin, known as the dermis, aging the skin cells and causing wrinkles. UVB radiation is the main cause of skin reddening or sunburn, as it damages the outer layers of the skin, known as the epidermis.