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没有阳光就没有人类和人体的健康。但过度的照射日光,不仅会导致皮肤过早老化,还会发生日光性皮炎或日光疹、日光性皮肤角化症、日光性肉芽肿、皮肤癌等。阳光中对皮肤有伤害作用的主要是紫外线,科学家根据不同波长紫外线的生物学作用,将其分为长波紫外线(UVA)、中波紫外线(UVB)及短波紫外线(UVC)。UVA对皮肤有较强的穿透力,可造成皮肤色素沉着(晒黑),一般情况下不会引起皮肤的急性炎症;UVB的主要副作用是晒伤皮肤,轻者出现红肿、疼痛,重者会发生水疱等急性炎症;UVC绝大部分已被臭氧层所吸收,不会对人体产生危害。由上述可以看出,紫外线对人体有伤害的主要是UVA及UVB,伤害作用有以下几方面: 1.皮肤老化皮肤老化有内在和外在两方面的因素,即自然老化和光老化。前者是随着人体的老化,皮肤亦发生自然的不可避免的老化过程,属于自然老化现
There is no human and human health without sunshine. However, excessive exposure to sunlight, not only lead to premature aging of the skin, but also occur in solar dermatitis or solar eruption, solar keratosis skin, solar granuloma, skin cancer and so on. The sun is harmful to the skin mainly UV, scientists according to the biological effects of different wavelengths of UV, be divided into long-wave ultraviolet (UVA), ultraviolet (UVB) and short-wave ultraviolet (UVC). UVA has a strong penetrating power on the skin, can cause skin pigmentation (tanning), under normal circumstances will not cause acute inflammation of the skin; the main side effects of UVB is sunburn, mild swelling, pain, severe cases Blisters and other acute inflammation can occur; most of the UVC has been absorbed by the ozone layer, will not cause harm to the human body. From the above we can see that ultraviolet rays are harmful to human body mainly UVA and UVB, the injury has the following effects: 1. Skin aging Skin aging has both internal and external factors, that is, natural aging and photoaging. The former is with the aging of the human body, the skin also occurs naturally inevitable process of aging, is a natural aging