Which sunscreen should you choose? - Mary Poffenroth

譯者: Yun Chu Lin 審譯者: SF Huang

Sunscreen comes in many forms,

防曬品千百種，

each with its own impacts on your body and the environment.

每種都對身體及自然環境 帶來不同的影響。

With so many options,

在琳瑯滿目的品項中，

how do you choose which sunscreen is best for you?

如何挑選出最適合自己的防曬品呢？

To answer that question,

回答這些問題之前，

we first have to understand how sunscreens work.

我們必須先了解 防曬品是如何發揮功效的。

Sunlight is composed of electromagnetic waves

陽光是由不同波長的電磁波組成，

and is our primary source of ultraviolet radiation,

也是我們接收紫外線的主要來源。

which has a shorter wavelength than visible light and carries more energy.

紫外線的波長比可見光短， 並帶有更多的能量。

UVA,

紫外線 A、

UVB,

紫外線 B、

and UVC are classified according to their wavelengths.

及紫外線 C， 是依紫外線的波長而區分。

Short wavelength UVC never reaches the Earth's surface,

短波的紫外線 C 無法到達地球表面，

but UVB and UVA do.

但是，紫外線 B 和 A 可以。

Medium wavelength UVB rays can enter the skin's superficial layers

中波的紫外線 B 光可到達皮膚表層；

and long length UVA rays can penetrate into the deeper layers.

而長波的紫外線 A 光 可穿透至更深的真皮層。

UVB in small amounts actually helps us make vitamin D,

少量的紫外線 B 光 其實能幫助人體合成

which enables our bodies to build and maintain strong bones.

打造及維持強健骨骼 所需的維生素 D。

However, prolonged exposure to UVA and UVB can damage DNA,

但是長期暴露在紫外線 A、B 光下， 會破壞 DNA（去氧核醣核酸）、

age your skin,

造成皮膚老化、

and promote the development of potentially deadly skin cancer.

甚至增加得到致命性皮膚癌的機會。

Sunscreen protects your skin either physically by deflecting UV rays

防曬品能保護你的肌膚，物理性的： 像是氧化鋅及二氧化鈦，

with an inorganic blocker like zinc oxide or titanium dioxide,

作用在皮膚上形成無機的保護膜， 將紫外線反射出去；

or chemically by using carbon-based compounds to absorb UV photons

或化學性的：像是使用碳基化合物 來吸收紫外線的光子，

that are then harmlessly dissipated as heat.

並轉化成無害的熱能散發出去。

So, what differentiates one sunscreen from another?

所以，防曬品有什麼區別呢？

When we choose a sunscreen,

當我們挑選防曬品時，

we can compare application method,

我們可以比較使用方法、

the SPF,

防曬係數以及有效成分。

and the active ingredients.

Sprays can be convenient to put on, especially when you're wet,

噴霧型的防曬品方便使用， 尤其是當你全身溼答答時。

but a recent study found that most people don't apply a thick enough layer

但最近的研究顯示， 大多數民眾並沒有噴上足夠的用量，

to get full protection.

以致無法獲得全面的保護。

And the possible health risks of inhaling sunscreen compounds from a spray cloud

而且想到吸入飄來的防曬噴霧 可能造成的健康危害，

might make you consider reaching for that bottle of lotion instead.

你可能會考慮選擇瓶裝防曬乳。

Opt for a sunscreen with an SPF of at least 15, although 30 is better.

選擇防曬係數至少 15 的產品， 雖然防曬係數 30 的會更好。

SPF is a nonlinear scale of how much UVB radiation is needed

防曬係數是一種非線性係數， 計算要多少紫外線 B

to give protected skin a sunburn.

才會讓已受保護的皮膚曬傷。

SPF 15 does a pretty good job by blocking 93% of UVB rays.

防曬係數15 的防曬品 可有效阻隔 93％ 的紫外線 B 光。

You get a slight increase as SPF goes up,

隨著防曬係數越高， 阻隔效果也會略微增加。

with SPF 30 blocking 97%,

防曬係數 30， 可阻隔 97％ 的紫外線；

and 50 blocking 98%.

防曬係數 50， 可阻隔 98％ 的紫外線。

SPF is based on the quantity of solar exposure.

防曬係數取決於陽光下的曝曬量。

So how much time you have before you start to burn

所以多久時間才會曬傷，

really depends on a long list of factors,

取決於很多因素：

including your genetics,

包含你的基因、

and when, where, and how you spend your time in the sun.

時間、地點及用什麼方式待在陽光下。

Even though US marketed sunscreens have been deemed safe by the FDA,

儘管美國市售防曬品 都有食品藥物管理局的安全標章，

scientists are still researching the effects of many active ingredients

科學家仍在研究

許多現行成分對人體帶來的影響。

on the human body.

So if you're worried about potential irritants,

所以如果你擔心有潛在的刺激物，

look for mineral-based formulas with zinc oxide or titanium dioxide.

就選擇礦物性配方，含有 氧化鋅或二氧化鈦的防曬品。

Even though they may go on a bit thick at first,

儘管剛塗抹時會覺得有點厚重，

they're less irritating than carbon-based chemical sunscreens.

但和碳基化學性的防曬品相比， 較不具刺激性。

These mineral-based sunscreens are preferential for the environment, too.

這些礦物配方的防曬品， 對自然環境也比較友善。

If you plan on catching rays while splashing in a river or the ocean,

如果你打算到河邊 或海邊玩水、享受日光，

keep in mind that carbon-based chemical sunscreens

請記住碳基化學性的防曬乳，

can harm marine life.

對水中生物有害。

Take coral reefs, for example.

舉珊瑚礁為例，

Although they cover less than 1% of the Earth's underwater surface,

雖然他們只覆蓋了 不到 1％ 的地球水域，

they're home to nearly 25% of all fish species,

但他們是地球上約 25％ 魚類的家，

making them the most diverse and productive marine ecosystems.

這使得珊瑚礁成為最富生物多樣性、 也最具生產力的海洋生態系統。

Research shows that carbon-based chemical sunscreen ingredients,

研究顯示，碳基化學性的防曬成分，

like oxybenzone, butylparaben, octinoxate, and 4MBC

像是羥苯甲酮、羥基苯甲酸丁酯、 桂皮酸鹽和甲基亞芐亞基樟腦，

contribute to a stress condition called coral bleaching in corals,

會導致珊瑚白化，

which are living creatures.

而珊瑚是活生生的動物。

Exposure to these organic compounds

接觸這些有機化合物，

results in the death of the coral's symbiotic algae.

會讓與珊瑚共生的藻類死亡。

In addition to providing a reliable food source,

除了提供可靠的食物來源，

these algae give coral their brilliant rainbow of colors.

這些海藻也讓珊瑚擁有 彩虹般的色澤。

Without them, corals turn a bleached white

沒有了海藻，珊瑚就會白化，

and are susceptible to disease and possibly death.

可能會生病，甚至是死亡。

And once the coral dies,

一旦珊瑚死亡，

the entire reef ecosystem is not far behind.

所有的珊瑚礁生態系統 也會隨之瓦解。

So you're now ready to make an informed choice when picking out your next sunscreen.

所以現在你應該知道如何明智地 選擇下一個防曬品。

SPF is clearly labeled on the front.

防曬係數通常都清楚的標示在前面。

On the back under "active ingredients,"

背面有效成分的那欄，

you can find whether zinc oxide,

你可以找看看有沒有氧化鋅、

titanium dioxide,

二氧化鈦

and those coral-harming components are present.

或是那些會危害珊瑚的成分。

Taking a bit more time to check can be well worth it

多花點時間查看，

for both you and the environment.

對你、對自然環境來說， 都是值得的 !