Ultraviolet penetration ability is strong, can reach the dermis, the skin tanned, very harmful to the skin, even in the non-summer period, although the intensity of ultraviolet light is weak, it still exists, but long time accumulation is easy to make skin injury, melanin precipitation, skin aging and relaxation problems. So women who want to be beautiful must wear sunscreen every day.
The statement 'The amount of ultraviolet radiation in an indoor space half a meter away from a window is about 40 percent of that in an outdoor space, and 15 percent of that in an indoor space 1.5 meters away from a window. Therefore, sunscreen is not necessary when staying indoors' is the most likely to undermine the conclusion.