手把手教你夏日防晒妙招
夏季烈日炎炎，日光中的紫外线(ultraviolet)会对皮肤造成严重伤害，而防晒产品又频频被曝含有害成分。防晒用品应该怎样选？本文为您的夏日防晒计划支招。
As summer approaches we all enjoy outdoor activities. But withsunlight becoming more intense we should protect our skin fromharmful direct exposure to the sun。
随着夏日的到来，我们都喜欢进行一些户外运动。但因为日照愈加强烈，我们应避免将自己的皮肤直接暴露在太阳下。
Ultraviolet (UV) radiation can cause damage such as prematureaging (wrinkles and age spots)， skin cancer, damage to the eyes andeven blindness。
紫外线(简称UV)辐射会导致皮肤过早衰老(产生皱纹和老年斑)、皮肤癌、还可能会伤害眼睛甚至导致失明。
Sunscreen, in the form of lotion, spray or cream, provides achemical barrier which reflects or absorbs UV radiation。
防晒乳液、防晒喷雾或防晒霜等防晒产品都能通过反射或吸收紫外线，为皮肤提供化学防护。
However, there are reports that sunscreen contains toxic orcancer-causing chemicals. In China, some products have been foundto contain heavy metal elements such as lead, arsenic and mercury.Medical experts warn that they can damage the kidneys。
然而，有报道称防晒护肤品中含有致癌或有毒的化学成分。在中国，一些产品被查出含有铅、砷、汞等重金属。医学专家提醒这些重金属会对肾脏造成伤害。
In May, CNN reported that, according to the EnvironmentalWorking Group, 75 percent of 800 sunscreens tested in the UScontained potentially harmful ingredients. Only one-fourth of themwere effective at protecting our skin without any toxicity。
本月，美国有线电视新闻网CNN报道称，在由美国环保机构“环境工作小组”发布的一项报告中，美国国内800种送检的防晒产品中，有75%含有潜在危害成分。仅有1/4的产品既不含任何毒素，又能有效保护皮肤。
For instance, 56 percent of the products contained oxybenzone,which serves to absorb UV. But studies show that oxybenzone can beabsorbed through the skin, and it is believed to be linked tohormone disruption, cell damage and may lead to skin cancer。
例如，56%的产品含有能够吸收紫外线的氧苯酮。但研究表明，氧苯酮可被皮肤吸收，人们认为该物质会导致内分泌紊乱，细胞损伤，甚至可能诱发皮肤癌。
The US FDA (Food and Drug Administration) says the ingredientis safe. Besides, a type of Vitamin A is also considered to berisky, but there is no conclusive evidence yet。
美国食品药物管理局则表示这一成分安全无害。此外，一种维生素A也被认为存在安全风险，但目前尚无确切证据。
So, how do you choose the best sunscreen? Apart from pickingup those with no toxic chemicals, it’s wise to apply awater-resistant, broad-spectrum sunscreen, with a sun protectionfactor (SPF) of at least 15 or 30.
那么该如何选择最佳防晒霜呢？除了要选用那些不含有毒化学成分的产品之外，明智之举是使用防晒系数(SPF)达到15或30以上的防水广谱防晒霜。
This will protect you against both types of ultravioletradiation (UVA and UVB)， says the Environmental WorkingGroup。
美国环境工作小组称，这种防晒霜可以抵御两种紫外线辐射：UVA和UVB。
UV radiation has two primary types of rays: UVA that hasrelative long wavelengths can deeply penetrate the skin and causecell damage, and UVB are shorter-wavelength rays that affects theout layer of skin and chiefly cause reddening and sunburn。
紫外线辐射中主要包含两种射线：波长较长的UVA可以穿透皮肤导致细胞损伤，而波长较短的UVB则影响皮肤表层，主要会导致皮肤发红和晒伤。
Sunscreens are made in a wide range of sun protection factors.The higher the SPF indicates better protection againstsunburn-causing rays. For extended higher exposure, you may want aminimum of SPF of 30 to 50.
防晒产品的防晒系数范围很广。防晒系数SPF值越高，抵御导致晒伤的紫外线的效果越好。如果长时间暴露在日光下，你用的防晒品SPF值至少要在30-50之间。
Sunscreen with SPF 15 can block about 93 percent of all UVBrays, while SPF 30 blocks 97 percent and SPF 50 blocks 98percent。
SPF 15的防晒霜可以抵御93%的UVB射线，而SPF 30的则可抵御97%，SPF50的能达到98%。
“Dermatologists recommend using sunscreen in conjunction withother sun-safe practices,” wrote Daniel. M. Siegel, president ofAmerican Academy of Dermatology on its official website。
美国皮肤病学会会长丹尼尔•M•西格尔在该学会官方网站写道：“皮肤科医生建议在使用防晒产品的同时，也要结合采取其他的防晒手段。”