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Question

What does SPF do in sunscreen?

Answer

The higher the SPF rating, the more protection from the sun. SPF refers to the ability of a sunscreen to block ultraviolet B (UVB) rays, which cause sunburns, but not UVA rays, which are more closely linked to deeper skin damage, according to WebMD. Both UVA and UVB contribute to the risk of skin cancer, the Web site reports.

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