UVC rays are the most harmful type of ultraviolet radiation. However, the good news is that the Earth's atmosphere completely filters them out, preventing them from reaching the ground. Therefore, the UV rays we need to be most concerned about are UVA and UVB.
Understanding the Different Types of UV Rays
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UVC: As mentioned, UVC rays are the most damaging. They possess the shortest wavelength and highest energy. Fortunately, the ozone layer absorbs nearly all UVC radiation before it reaches the Earth's surface. Sources of UVC exposure are limited to artificial sources like welding torches and UV sanitizing lamps. ([Source: WHO, NASA, UPMC HealthBeat, Stouch Lighting])
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UVB: UVB rays are shorter in wavelength and have more energy than UVA rays. They are primarily responsible for sunburns and are a major contributor to skin cancer. ([Source: American Cancer Society, CDC, UPMC HealthBeat, EPA])
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UVA: UVA rays have a longer wavelength and lower energy than UVB rays. While they don't cause sunburns directly, they penetrate deeper into the skin and contribute significantly to premature aging, wrinkles, and also play a role in skin cancer development. UVA rays are also used in tanning beds. ([Source: UPMC HealthBeat, MD Anderson Cancer Center, EPA])
