演讲题目：Why do we have to wear sunscreen?

演讲简介：

你知道海滩之行可能会严重晒伤，但防晒的相关安全问题十分复杂。能造成皱纹的UVA紫外线和能诱导烧伤UVB的，可以对你的健康构成严重威胁（和你的外貌）。那我们怎么办呢？凯文P.博伊德告诉我们要每天多涂抹些物理性或者化学性的防晒霜。



中英文字幕

Most of us think of the Sun as our friend.

我们大多数人都把太阳当作朋友。

It helps plants grow, keeps us warm, and who doesn't love to lie on the beach on a sunny day?

它帮助植物生长，使我们暖和，谁不希望在阳光下躺在沙滩上呢？

But for all of it's good qualities, the Sun can also be harmful in large amounts.

不过出了它的好处外，阳光也可以造成很多伤害。

That's why we invented sunscreen.

所以我们发明了防晒霜。

The purpose of sunscreen is to shield the body from the Sun's ultraviolet rays, which have several harmful effects, including sunburn, aging,

防晒油的作用在于保护身体免受阳光中紫外线照射所带来的伤害，包括灼伤，皮肤老化，

and skin cancer promotion.

也可引发皮肤癌。

These rays are separated by their different wave lengths, into types such as UVA and UVB,

紫外线可以用不同波长来区分，可分为 UVA （长波紫外线）和 UVB （中波紫外线），

which exert a variety of effects in the skin due to the absorption patterns of chromophores, the parts of the molecules responsible for their color.

这会对皮肤产生各种影响，这是由于色基发色团的吸收方式中，部分分子对颜色产生反应。

The primary two chromophores are hemoglobin, found in our red blood cells, and melanin, which gives our skin its pigment.

两种主要的色基发色团是血红蛋白，存在于红学球中，以及黑色素，它使我们的皮肤产生色素。

We know that UVB rays cause the skin to burn.

我们知道 UVB 射线会导致皮肤晒伤。

The role of UVA rays is less well understood and appears to have an effect on our tanning response, carcinogenesis, and aging.

而对 UVA 射线的作用的了解还不够全面，不过会引发照射反应，癌变，和老化。

So, how does the sunscreen protect us from these rays?

那么，防晒霜如何保护我们免受这些射线的伤害呢？

There are two basic types of sunscreen: physical and chemical blockers.

常用的防晒霜有两种，物理防护型和化学防护型。

Physical blockers, like zinc oxide or titanium dioxide, reflect the Sun's rays by acting as a physical barrier.

物理防护型，例如氧化锌或二氧化钛，象物理性屏障一样反射太阳射线。

If you've seen lifeguards with noses covered in white, then you know what this looks like.

如果你见到过救生员的鼻子上覆盖着白色物体，那么你就知道这看上去象什么了。

The same ingredients are primary components of diaper creams, where the goal is also to create a physical barrier.

相同的配方被用作制作婴儿用痱子粉，目的也在于产生物理屏障。

Historically, they haven't always been easy to apply and were conspicuously visible on the skin,

一直以来，他们不是那么容易涂抹，而且在皮肤上也很显眼，

but new formulations have made this less of an issue.

不过新的配方减少了这些不便。

Chemical blockers, on the other hand, absorb the Sun's rays.

另一方面，化学型防晒霜，吸收阳光中的射线。

They deteriorate more quickly than physical sunscreens because their ability to absorb the Sun diminishes.

相对物理型防晒霜更快退化，因为他们吸收阳光的能力会逐渐消失。

Generally, these are more transparent when rubbed on the skin, but some people develop allergic reactions to some of the chemicals.

通常，这些物质在皮肤上摩擦时会更加透明，但有些人会对某些化学物质产生过敏反应。

Regardless of the type of sunscreen, all are subjected to testing to determine their sunburn protection factor, or SPF.

无论何种防晒霜，都需要经过测试，以衡量其防辐射系数，或简称SPF。

This is essentially a measure of the protection that the sunscreen will provide from UVB rays before one begins to burn.

这实际上是防护效果的单位，用来衡量防晒霜能提供的对于UVB射线的保护。当一个人开始受到照射时。

But even if you don't burn, you still need to use sunscreen because, unless you live in a cave, you're not immune to the effects of the Sun.

不过即便你没有晒伤，也应该使用防晒霜，因为除非是居住于洞穴中，你还是不能免于阳光的影响。

It is true that darker skinned people and those who tan easily have more built-in protection from sunburns,

事实上深色皮肤的人和那些容易晒黑的人不容易被晒伤，

but they are still vulnerable to the effects of UVA.

不过他们仍然无法幸免于UVA带来的伤害。

Children under the age of six months, on the other hand, should have almost no sun exposure as their protective mechanisms are not fully functioning,

六个月以下的儿童，从另一方面来说，应该完全避免阳光照射，因为他们的保护机能还没有完全发育，

and their skin is more likely to absorb any sunscreen that is applied.

而且他们的皮肤更有可能吸收任何涂抹的防晒霜。

Wearing sunscreen helps protect against the development of all three types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma.

涂抹防晒霜有助于避免这三类皮肤癌：基底细胞癌，鳞状细胞癌，以及黑色素瘤。

On a daily basis, the DNA in your cells is developing mutations and errors that are generally handled by machinery within your cells,

日常情况下，你细胞中的DNA产生的突变和错误，通常都会在细胞中自动处理，

but ultraviolet rays from the Sun lead to mutations that the cell may not be able to overcome,

不过阳光中紫外线引发的大量变异使细胞的自我修复无法承受，

leading to uncontrolled growth and eventual skin cancer.

导致不受控制的生长并最终导致皮肤癌。

The scariest thing about this is that usually you can't even see it happening until its too late.

最可怕的是，通常你甚至看不到它的发生，直到为时已晚。

But if these concrete risks to your health are not enough to convince you to use sunscreen, there are aesthetic reasons as well.

如果这些危害健康的事实还是无法说服你使用防晒霜，还有一个审美上的原因。

Along with cigarette smoking, sun damage is the leading cause of premature aging.

出了吸烟以外，阳光伤害是提早老化的主因。

Photoaging from chronic sun exposure leads to a loss of elasticity in the skin, in other words, making it look saggy.

长期暴晒在阳光下会导致皮肤失去弹性，或者说，使皮肤看上去下垂。

Take a look at this truck driver who's left side was chronically exposed to the sun and notice the difference.

看看这位左侧长期暴露在阳光下的卡车司机，注意到其中的区别。

This is an important point.

这是重要的一点。

Car windows block UVB, the burn rays, but not UVA, the aging rays.

车窗可以隔绝 UVB，烧伤射线，不过挡不住 UVA，老化射线。

It is recommended to use sunscreen daily,

建议每天都使用防晒霜，

but you should pay special attention before prolonged sun exposure or when at the beach or among snow since the reflectivity of water and ice amplifies the Sun's rays.

不过你也要特别注意，在长时间暴露在阳光下时，或在沙滩上，或在雪地中，因为水和冰的反射会放大阳光中的射线。

For these cases, apply about an ounce 15 to 30 minutes before you go out and once again soon after you get outside.

在这些情况下，于出门前十五到三十分钟前涂抹大约一盎司防晒霜。而且在出门后再涂抹一次。

After that, you should reapply it every two to three hours, especially after swimming or sweating.

然后，每隔两到三小时再涂抹一次，特别是在游泳和出汗之后。

Otherwise you should wear protective clothing with ultraviolet protection factor, or UPF.

否则就应该穿上防护服，具有防止紫外线系数（UPF）的防晒服。

Stay in shaded areas, such as under trees or an umbrella, and avoid the sun at the peak hours of 10 a.m.

尽量待在有阴凉的地方，例如树下或伞下，避免日照强烈的时段如上午10点

to 4 p.m.

到下午4点。

And what's the best kind of sunscreen?

那么最好的防晒霜是什么呢？

Everyone will have their preference, but look for the following things: broad spectra, SPF of at least 30, and water-resistant.

每个人都有自己的偏好，不过请考虑以下几点：广谱，防晒系数SPF至少30，并且防水。

A light moisturizer with SPF 30 should be good for daily use.

防晒系数SPF 30的少量润肤霜就很适合日常使用。

Take note if you decide to use a spray.

如果你决定使用防晒喷雾，请记得，

They take several coats to effectively cover your skin, like painting a wall with a spray can versus a paint brush.

需要不少涂层才能有效保护皮肤，就像在墙壁上的喷雾绘画同画笔绘画的区别。

So, enjoy the sun, but enjoy it with sunscreen.

好，享受阳光吧，不过要记得涂抹防晒霜。