Why do we have to wear sunscreen? - Kevin P. Boyd

為什麼要擦防曬乳？ - Kevin P. Boyd

譯者: Szu-Ting Yang 審譯者: Marssi Draw

Most of us think of the Sun as our friend.

大多數的人認為太陽是我們的朋友

It helps plants grow,

陽光滋養植物成長

keeps us warm,

讓我們感到溫暖

and who doesn't love to lie on the beach on a sunny day?

誰不喜歡在陽光普照的日子裡 躺在沙灘上曬太陽呢？

But for all of it's good qualities,

但就算太陽有很多好的性質

the Sun can also be harmful in large amounts.

太陽在很多方面也會造成傷害

That's why we invented sunscreen.

這就是發明防曬乳的原因

The purpose of sunscreen is to shield the body

防曬乳的功用是保護皮膚

from the Sun's ultraviolet rays,

隔離太陽的紫外線

which have several harmful effects,

紫外線有不少害處

including sunburn,

包含曬傷

aging,

and skin cancer promotion.

皮膚老化

也可能造成皮膚癌

These rays are separated

這些輻射光

by their different wave lengths,

因為有不同波長

into types such as UVA

而分散成UVA（長波紫外線）

and UVB,

與UVB（中波紫外線）

which exert a variety of effects in the skin

這對皮膚產生了各種影響

due to the absorption patterns of chromophores,

因為在色基發色團的吸收模式中

the parts of the molecules

其部分分子

responsible for their color.

產生了顏色所造成

The primary two chromophores are hemoglobin,

主要的兩個色基是血紅素

found in our red blood cells,

在血液細胞中可發現

and melanin, which gives our skin its pigment.

以及黑色素，在我們的皮膚上產生色素

We know that UVB rays cause the skin to burn.

我們知道 UVB 會導致皮膚曬傷

The role of UVA rays is less well understood

但對 UVA 就比較少了解了

and appears to have an effect

而對皮膚造成影響

on our tanning response,

例如曬傷

carcinogenesis,

癌症病變

and aging.

以及老化

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

那麼防曬乳如何保護我們 免於輻射光的危害呢？

There are two basic types of sunscreen,

常見的防曬乳有兩類

physical and chemical blockers.

物理性防護和化學性防護

Physical blockers, like zinc oxide

物理性防護，像是氧化鋅

or titanium dioxide,

或是二氧化鈦

reflect the Sun's rays by acting as a physical barrier.

藉由物理性阻隔物 反射了太陽的輻射光

If you've seen lifeguards with noses covered in white,

如果你有看過救生員的鼻子上 塗了一層白白的東西

then you know what this looks like.

你就會知道物理性防曬的樣子

The same ingredients are primary components

相同的成分主要用來製作

of diaper creams,

嬰兒用的痱子粉

where the goal is also to create a physical barrier.

目的是要用來產生物理性阻隔物

Historically, they haven't always been easy to apply

照理說，物理性防曬並不容易塗抹

and were conspicuously visible on the skin,

而且在皮膚上會明顯的看到

but new formulations have made this less of an issue.

但新的配方已經不會造成以上問題

Chemical blockers, on the other hand,

另一方面，化學性防護

absorb the Sun's rays.

吸收了太陽的輻射光

They deteriorate more quickly than physical sunscreens

會比物理性防曬乳更快退化掉傷害

because their ability to absorb the Sun diminishes.

因為化學防曬有能力 吸收太陽光的微小分子

Generally, these are more transparent

一般而言，化學防曬

when rubbed on the skin,

塗抹在皮膚上比較透明

but some people develop allergric reactions

但也造成有些人

to some of the chemicals.

對某些化學成分的過敏反應

Regardless of the type of sunscreen,

不管防曬乳的型態

all are subjected to testing

所有的防護產品都需要經由測試

to determine their sunburn protection factor,

來決定能防止曬傷的防曬係數

or SPF.

就是常見的 SPF

This is essentially a measure of the protection

判斷防護能力的主要辦法

that the sunscreen will provide from UVB rays

是防曬乳能在被曬傷前阻隔 UVB

before one begins to burn.

是防曬乳能在被曬傷前阻隔 UVB

But even if you don't burn,

但即使你並未感到皮膚燒燙

you still need to use sunscreen

你仍須使用防曬乳

because unless you live in a cave,

因為除非你住在洞穴裡

you're not immune to the effects of the Sun.

不然你對太陽所產生的影響沒有免疫力

It is true that darker skinned people

不可否認的是，皮膚比較黝黑的人

and those who tan easily

和那些容易曬黑的人

have more built-in protection from sunburns,

比較不容易被曬傷

but they are still vulnerable

但對於 UVA 還是很容易受到傷害

to the effects of UVA.

但對於 UVA 還是很容易受到傷害

Children under the age of six months,

另一方面，六個月以下的孩童

on the other hand,

另一方面，六個月以下的孩童

should have almost no sun exposure

不適合直接曬到太陽

as their protective mechanisms

因為身體上的保護機制

are not fully functioning,

還未完全產生作用

and their skin is more likely to absorb

以至於孩童的皮膚更容易吸收

any sunscreen that is applied.

塗抹在皮膚上的防曬乳

Wearing sunscreen helps protect

塗抹防曬乳可以加強保護

against the development of all three types of skin cancer:

避免三種皮膚癌產生：

basal cell carcinoma,

基底細胞癌

squamous cell carcinoma,

鱗狀上皮癌

and melanoma.

黑色素瘤

On a daily basis, the DNA in your cells

每天，細胞裡的 DNA

is developing mutations and errors

都會產生細胞運作可以控制的變異和差錯

that are generally handled

都會產生細胞運作可以控制的變異和差錯

by machinery within your cells,

都會產生細胞運作可以控制的變異和差錯

but ultraviolet rays from the Sun lead to mutations

但太陽的紫外線會導致

that the cell may not be able to overcome,

細胞可能無法克服的變異

leading to uncontrolled growth

而產生無法控制的成長

and eventual skin cancer.

最後成為皮膚癌

The scariest thing about this

最可怕的情況

is that usually you can't even see it happening

是你不太會看到這一切變化的過程

until its too late.

直到為時已晚

But if these concrete risks to your health

但如果這個危害到健康的事實

are not enough to convince you to use sunscreen,

還不足以說服你使用防曬乳

there are aesthetic reasons as well.

還有審美觀的原因

Along with cigarette smoking,

除了吸菸以外

sun damage is the leading cause of premature aging.

陽光傷害是造成提早老化的主因

Photoaging from chronic sun exposure

長期在陽光下曝曬所產生的皮膚老化

leads to a loss of elasticity in the skin,

導致皮膚失去彈性

in other words, making it look saggy.

另外，也讓皮膚看起來下垂

Take a look at this truck driver

看看這位卡車司機

who's left side was chronically exposed to the sun

他的左側長期在陽光下曝曬

and notice the difference.

你可以看出兩邊的差異

This is an important point.

這是一個很重要的要點

Car windows block UVB, the burn rays,

車窗可以阻擋 UVB 燒燙的光

but not UVA, the aging rays.

而不是 UVA，造成老化的光

It is recommended to use sunscreen daily,

建議每天都使用防曬乳

but you should pay special attention

需要特別注意的是

before prolonged sun exposure

在長時間的陽光曝曬之前

or when at the beach

或是待在海邊

or among snow

在雪地中

since the reflectivity of water and ice

因為水和冰

amplifies the Sun's rays.

也會反射太陽輻射光

For these cases, apply about an ounce

因為上述情況

fifteen to thirty minutes before you go out

外出前 15 分鐘到 30 分鐘 塗抹大約一盎司的防曬乳

and once again soon after you get outside.

並在你出門後再次塗抹

After that, you should reapply it every two to three hours,

之後，你應該每 2 到 3 小時就重新塗抹一次

especially after swimming or sweating.

尤其是游泳或流汗之後

Otherwise you should wear protective clothing

否則，你也應該穿上

with ultraviolet protection factor, or UPF.

有防曬係數 UPF 的防曬外套

Stay in shaded areas,

待在有遮蔽物的地方

such as under trees or an umbrella,

像是大樹或雨傘底下

and avoid the sun at the peak hours

同時避免上午 10 點到下午 4 點間的烈日

of 10 a.m. to 4 p.m.

同時避免上午 10 點到下午 4 點間的烈日

And what's the best kind of sunscreen?

哪個是最好的防曬乳？

Everyone will have their preference,

每個人都有不同的喜好

but look for the following things:

但記得注意以下幾點：

broad spectra,

用途廣泛的

SPF of at least 30,

防曬係數至少 30

and water-resistant.

還有防水

A light moisturizer with SPF 30

有防曬係數 SPF30 的輕量潤膚霜

should be good for daily use.

蠻適合每天使用

Take note if you decide to use a spray.

如果要使用防曬噴霧，請記得

They take several coats to effectively cover your skin,

噴霧需要不少塗層 才能有效蓋住你的皮膚

like painting a wall with a spray can

就像用噴漆的方式彩繪牆壁

versus a paint brush.

與用油漆刷彩繪牆壁的不同

So, enjoy the sun,

所以，盡情享受陽光

but enjoy it with sunscreen.

但也請在使用防曬乳的情況下享受