As summer approaches we all enjoy outdoor activities. But with sunlight becoming more intense we should protect our skin from harmful direct exposure to the sun.随着夏日的来临，我们都讨厌展开一些户外运动。但因为日照愈发反感，我们不应防止将自己的皮肤必要曝露在太阳下。Ultraviolet (UV) radiation can cause damage such as premature aging (wrinkles and age spots), skin cancer, damage to the eyes and even blindness.紫外线（全称UV）电磁辐射不会造成皮肤过早衰老（产生皱纹和老年斑）、皮肤癌、还可能会损害眼睛甚至造成失聪。Sunscreen, in the form of lotion, spray or cream, provides a chemical barrier which reflects or absorbs UV radiation.美白乳液、美白喷雾或防晒霜等美白产品都能通过光线或吸取紫外线，为皮肤获取化学防水。

However, there are reports that sunscreen contains toxic or cancer-causing chemicals. In China, some products have been found to contain heavy metal elements such as lead, arsenic and mercury. Medical experts warn that they can damage the kidneys.然而，有报导称之为美白护肤品中所含致癌物或剧毒的化学成分。在中国，一些产品被追查所含铅、砷、汞等重金属。医学专家警告这些重金属不会对肾脏导致损害。In May, CNN reported that, according to the Environmental Working Group, 75 percent of 800 sunscreens tested in the US contained potentially harmful ingredients. Only one-fourth of them were effective at protecting our skin without any toxicity.本月，美国有线电视新闻网CNN报导称之为，在由美国环保机构“环境工作小组”公布的一项报告中，美国国内800种检验的美白产品中，有75%所含潜在危害成分。

仅有1/4的产品既不不含任何毒素，又能有效地维护皮肤。For instance, 56 percent of the products contained oxybenzone, which serves to absorb UV. But studies show that oxybenzone can be absorbed through the skin, and it is believed to be linked to hormone disruption, cell damage and may lead to skin cancer.例如，56%的产品所含需要吸取紫外线的氧苯酮。但研究指出，氧苯酮可被皮肤吸取，人们指出该物质不会造成内分泌失调，细胞受损，甚至有可能所致皮肤癌。

The US FDA (Food and Drug Administration) says the ingredient is safe. Besides, a type of Vitamin A is also considered to be risky, but there is no conclusive evidence yet.美国食品药物管理局则回应这一成分安全性有害。此外，一种维生素A也被指出不存在安全性风险，但目前尚不清楚证据。So, how do you choose the best sunscreen? Apart from picking up those with no toxic chemicals, it’s wise to apply a water-resistant, broad-spectrum sunscreen, with a sun protection factor (SPF) of at least 15 or 30.那么该如何自由选择最佳防晒霜呢？除了要搭配那些不所含毒化学成分的产品之外，明智之举是用于美白系数（SPF）超过15或30以上的透气广谱防晒霜。

This will protect you against both types of ultraviolet radiation (UVA and UVB), says the Environmental Working Group.美国环境工作小组称之为，这种防晒霜可以抵挡两种紫外线电磁辐射：UVA和UVB。UV radiation has two primary types of rays: UVA that has relative long wavelengths can deeply penetrate the skin and cause cell damage, and UVB are shorter-wavelength rays that affects the out layer of skin and chiefly cause reddening and sunburn.紫外线电磁辐射中主要包括两种射线：波长较长的UVA可以击穿皮肤造成细胞受损，而波长较短的UVB则影响皮肤表层，主要不会造成皮肤发红和晒伤。Sunscreens are made in a wide range of sun protection factors. The higher the SPF indicates better protection against sunburn-causing rays. For extended higher exposure, you may want a minimum of SPF of 30 to 50.美白产品的美白系数范围很广。美白系数SPF值越高，抵挡造成晒伤的紫外线的效果就越好。

如果长时间曝露在日光下，你用的防晒品SPF值最少要在30-50之间。Sunscreen with SPF 15 can block about 93 percent of all UVB rays, while SPF 30 blocks 97 percent and SPF 50 blocks 98 percent.SPF 15的防晒霜可以抵挡93%的UVB射线，而SPF 30的则可抵挡97%，SPF50的能超过98%。“Dermatologists recommend using sunscreen in conjunction with other sun-safe practices,” wrote Daniel. M. Siegel, president of American Academy of Dermatology on its official website.美国皮肤病学不会会长丹尼尔M西格尔在该学会官方网站写到：“皮肤科医生建议在用于美白产品的同时，也要融合采行其他的美白手段。

本文来源：中欧体育-www.cjsb158.com