Which sunscreen should you choose? - Mary Poffenroth

翻译人员: Cissy Yun 校对人员: Jiawei Ni

Sunscreen comes in many forms,

防晒霜有各种形式的

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

每一种对于你的身体和大环境都有着不同的影响

With so many options,

有这么多的选择

how do you choose which sunscreen is best for you?

你应该如何选择最适合你的防晒霜呢？

To answer that question,

为了解答这个问题

we first have to understand how sunscreens work.

我们首先需要知道防晒霜是如何起到它的作用的

Sunlight is composed of electromagnetic waves

太阳光是由电磁波组成的

and is our primary source of ultraviolet radiation,

也是我们接收到的紫外线的主要来源

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

它有相较可见光更短的波长 也带有更多的能量

UVA,

a波紫外线

UVB,

b波紫外线

and UVC are classified according to their wavelengths.

和c波紫外线是由它们的波长来区分的

Short wavelength UVC never reaches the Earth's surface,

短波长的c波紫外线 到不了地球表面

but UVB and UVA do.

但是a波和b波紫外线可以到达

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

中等波长的b波紫外线 可以进到皮肤的表层

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

而长波长的a波紫外线 则可进入皮肤的深层

UVB in small amounts actually helps us make vitamin D,

少量的b波紫外线可以帮助人体产生维他命D

which enables our bodies to build and maintain strong bones.

它能让我们的身体保持强壮的骨骼

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

然而，过长的暴露在a波和b波紫外线下 会损坏DNA

age your skin,

并使皮肤衰老

and promote the development of potentially deadly skin cancer.

还会增加得致命性皮肤癌的可能

Sunscreen protects your skin either physically by deflecting UV rays

防晒霜保护皮肤 一是以物理护肤的方式偏转紫外线

with an inorganic blocker like zinc oxide or titanium dioxide,

运用的是一种无机的阻隔物 例如二氧化锌或二氧化钛

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

二是通过化学方式 用碳化物类吸收紫外线中的光子

that are then harmlessly dissipated as heat.

使它们以热的形式消散

So, what differentiates one sunscreen from another?

那么，是什么区分一种防晒霜于另一个？

When we choose a sunscreen,

当我们选择防晒霜时

we can compare application method,

我们可以比较它们的使用方法

the SPF,

比较SPF

and the active ingredients.

和其他的成分

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

防晒喷雾使用起来很方便 尤其在你的肌肤是湿润的时候

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

然而，最近的一个研究发现大多数人 并不会喷上足够

to get full protection.

保护皮肤的量

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

而且，也存在不小心吸入防晒喷雾而产生的 健康隐患

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

这也许使你想去换用那瓶防晒乳液

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

选择至少有SPF15的防晒产品 当然SPF30的会更好

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

SPF是一种非线性的比例 关于的是造成晒伤的

to give protected skin a sunburn.

b波紫外线的量

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

SPF15的防晒可以阻挡93%的b波紫外线

You get a slight increase as SPF goes up,

SPF值的升高，它的阻挡力也会稍许增加

with SPF 30 blocking 97%,

SPF30可以阻挡97%

and 50 blocking 98%.

而SPF50则可以阻挡98%

SPF is based on the quantity of solar exposure.

SPF值根据的是太阳曝光的量

So how much time you have before you start to burn

所以你是否容易被晒伤

really depends on a long list of factors,

有很多的因素

including your genetics,

包括你的基因

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

你在哪里，多长时间，如何晒太阳的

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

虽然美国认证的防晒霜被美国食品药品监督管理局 认可为安全的

scientists are still researching the effects of many active ingredients

科学家仍旧在继续研究 许多成分

on the human body.

对人体会产生的影响

So if you're worried about potential irritants,

所以如果你担心潜在的刺激

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

可以选用矿物配方以及有二氧化锌或二氧化钛的 防晒产品

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

它们一开始可能会有一些厚

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

但是它们相对于碳配方的防晒霜 对皮肤少刺激

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

矿物配方的防晒产品对 环境也有保护

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

如果你想要在沐浴着阳光 又想在河或者海洋中戏水

keep in mind that carbon-based chemical sunscreens

要记住 碳配方的化学防晒霜

can harm marine life.

对海洋生物有害

Take coral reefs, for example.

就拿珊瑚礁来说

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

虽然它们只覆盖了百分之一的地球水下面积

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

但是它们是百分之二十五的鱼类的家园

making them the most diverse and productive marine ecosystems.

让它们成为了最多样的和生产力最强的海洋生态系统

Research shows that carbon-based chemical sunscreen ingredients,

研究显示 碳配方的化学防晒中的一些物质

like oxybenzone, butylparaben, octinoxate, and 4MBC

例如说氧苯酮，尼泊金丁酯，桂皮酸钠和4MBC

contribute to a stress condition called coral bleaching in corals,

会给海洋带来很不好的影响 比如说珊瑚漂白

which are living creatures.

而它们都是有生命的生物

Exposure to these organic compounds

当珊瑚暴露在这些有机化合物前

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

会导致珊瑚的共生藻的死亡

In addition to providing a reliable food source,

这些共生藻除了提供食物源

these algae give coral their brilliant rainbow of colors.

它们还带给珊瑚彩虹般绚烂的色彩

Without them, corals turn a bleached white

没有了它们， 珊瑚就像被漂白过一样

and are susceptible to disease and possibly death.

而且很容易会有疾病，和死亡的可能性

And once the coral dies,

一旦珊瑚死去后

the entire reef ecosystem is not far behind.

整个珊瑚礁生态系统都将会崩溃

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

你现在一定可以在选防晒霜时 做出有所依据的选择

SPF is clearly labeled on the front.

SPF值在防晒产品上都会清楚地标明

On the back under "active ingredients,"

在背后的“成分表”中

you can find whether zinc oxide,

你可以发现防晒产品是否含有二氧化锌

titanium dioxide,

二氧化钛

and those coral-harming components are present.

或是对珊瑚有害的成分

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

花稍微多一点的时间来做出

for both you and the environment.

一个对你，对环境都好的选择