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People tend to take their skin for granted and let it fry in the sun. Using gobs of sunscreen helps prevent the damage. But how exactly does it work? The aptly named "Howstuffworks" explains that sunscreen absorbs or blocks ultraviolet light, thanks to several "absorption chemicals" like para-aminobenzoic acid (PABA). You shouldn't let the word "acid" scare you off, but it's worth noting that PABA may cause irritation in folks with sensitive skin. The Library of Congress offers a more in-depth explanation. Essentially, sunscreen works "by combining organic and inorganic active ingredients." Zinc oxide and titanium oxide are inorganic. They "reflect or scatter
ultraviolet (UV) radiation." Meanwhile, organic ingredients such as octyl methoxycinnamate and oxybenzone "absorb UV radiation" and dissipate it as heat. This may be verging on too much information, but according to the Library of Congress, there are three forms of ultraviolet wavelengths: UV-A, UV-B, and UV-C. UV-C is absorbed by the atmosphere. UV-B causes sunburns, and it is these rays that sunscreen helps protect against. UV-A penetrates skin to an even deeper level than UV-B. However, a sunscreen's sun protection factor (SPF) "doesn't measure UV-A." Folks seeking protection from UV-A rays should purchase a sunscreen with "broad-spectrum protection." Or you could just stay indoors for the rest of your life. Either way works.
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