隔離紫外線 歡樂度夏日

導讀：夏季烈日炎炎，日光中的紫外線(ultraviolet)會對皮膚造成嚴重傷害，而防晒產品又頻頻被曝含有害成分。防晒用品應該怎樣選？本文為您的夏日防晒計劃支招。

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.隨著夏日的到來，我們都喜歡進行一些戶外運動。但因為日照愈加強烈，我們應避免將自己的皮膚直接暴露在太陽下。

Ultraviolet (UV) radiation can cause damage such as premature aging (wrinkles and age spots), skin cancer, damage to the eyes and even blindness.紫外線（簡稱UV）輻射會導致皮膚過早衰老（產生皺紋和老年斑）、皮膚癌、還可能會傷害眼睛甚至導致失明。

Sunscreen, in the form of lotion, spray or cream, provides a chemical barrier which reflects or absorbs UV radiation.防晒乳液、防晒噴霧或防晒霜等防晒產品都能通過反射或吸收紫外線，為皮膚提供化學防護。

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，有報道稱防晒護膚品中含有致癌或有毒的化學成分。在中國，一些產品被查出含有鉛、砷、汞等重金屬。醫學專家提醒這些重金屬會對腎臟造成傷害。

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，美國有線電視新聞網CNN報道稱，在由美國環保機構「環境工作小組」發布的一項報告中，美國國內800種送檢的防晒產品中，有75%含有潛在危害成分。僅有1/4的產品既不含任何毒素，又能有效保護皮膚。

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%的產品含有能夠吸收紫外線的氧苯酮。但研究表明，氧苯酮可被皮膚吸收，人們認為該物質會導致內分泌紊亂，細胞損傷，甚至可能誘發皮膚癌。

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.美國食品藥物管理局則表示這一成分安全無害。此外，一種維生素A也被認為存在安全風險，但目前尚無確切證據。

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.那麼該如何選擇最佳防晒霜呢？除了要選用那些不含有毒化學成分的產品之外，明智之舉是使用防晒係數（SPF）達到15或30以上的防水廣譜防晒霜。

This will protect you against both types of ultraviolet radiation (UVA and UVB), says the Environmental Working Group.美國環境工作小組稱，這種防晒霜可以抵禦兩種紫外線輻射：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.紫外線輻射中主要包含兩種射線：波長較長的UVA可以穿透皮膚導致細胞損傷，而波長較短的UVB則影響皮膚表層，主要會導致皮膚髮紅和晒傷。

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.防晒產品的防晒係數範圍很廣。防晒係數SPF值越高，抵禦導致晒傷的紫外線的效果越好。如果長時間暴露在日光下，你用的防晒品SPF值至少要在30-50之間。

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的防晒霜可以抵禦93%的UVB射線，而SPF 30的則可抵禦97%，SPF50的能達到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.美國皮膚病學會會長丹尼爾?M?西格爾在該學會官方網站寫道：「皮膚科醫生建議在使用防晒產品的同時，也要結合採取其他的防晒手段。」

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