The circle in the background is a kind of mirror,

背景看到的圓圈就像是一個鏡子，

that, combined with a special photography technique,

這是結合一種特別的拍攝手法，

allows you to see the flow of air.

可以讓你們看到空氣中物質流動的影像。

In this case, it is showing how far air particles travel when someone breathes.

這個影像可以看到人在呼吸的時候，空氣微粒會傳播到多遠。

And when they cough — which makes the respiratory particles travel further, and faster.

而當他們咳嗽的時候－這樣使得空氣微粒飛得更遠更快。

This is what it looks like when someone coughs into their hand.

這就是有人用手或是手肘來

And into their elbow.

遮住咳嗽的影像。

And this shows the travel of air particles when coughing while wearing two types of masks:

而這邊可以看到戴兩種口罩咳嗽時的空氣微粒傳播的範圍：

a dust mask, and a surgical mask.

防塵口罩和醫療用口罩。

This isn't a scientific study. It simply shows something face masks do very well:

這個不是科學性的研究。這只是想讓你們知道戴口罩有多好：

They limit how far away from you respiratory particles can travel.

它們可以抑制你們飛沫微粒的傳播。

But whether you've been told to wear a face mask to prevent the spread of Covid-19,

但也可能要看你們是住在哪邊，是否你們都學會戴口罩

probably depends on where you live.

可以預防新型冠狀病毒的感染。

In some East Asian countries, it's already common practice.

在一些東方亞洲國家，這已經是一個普遍的習慣。

Some European countries have also started mandating face masks in public spaces.

有些歐洲國家也開始強制規定公共區域要戴上口罩。

But in the US, the message from the federal government has been inconsistent.

但美國的聯邦政府卻有不同的指示。

“There's no reason to be walking around with a mask...

「沒有理由要戴著口罩走路......

it's not providing the perfect protection that people think that it is.”

戴口罩並無法提供人們所認為的完美防疫。」

“The CDC recommends wearing cloth face coverings in public settings

「衛生福利部疾病管制署指出在難以保持

where other social distancing measures are difficult to maintain."

安全社交距離的公共空間時就該戴上布口罩。」

“This is voluntary. I don't think I'm going to be doing it.”

「這是自願性的。但我不認為我會因此開始戴口罩。」

Unless you live somewhere that mandates it, whether you wear a face mask is probably up to you.

除非你們住在一個強制規定的地方，要不然你們要不要戴口罩就看你們的決定。

But making that decision for yourself is a lot easier

但如果想要簡單地為自己做出決定，

if you understand what face masks can actually do.

就是要了解戴口罩實際上能預防些什麼，

And what they can't.

或是它們無法做到的是什麼。

Here's where the experts agree: If you are sick, and you leave the house,

這個是專家同意的一件事：如果你們生病，出門的話，

you should wear a face mask, because it keeps your germs in.

你們就該戴口罩，因為可以避免把病毒傳染給別人。

Most of the uncertainty around masks is related to a separate question:

但很多質疑戴口罩的另一個問題是：

whether healthy people should wear them too.

是不是健康的民眾也要戴口罩。

Right away, though, that distinction, between sick with covid-19, and healthy,

這邊感染新型冠狀病毒和健康無病的區別，

is more complicated than it sounds.

這個比聽起來還要來得複雜。

People who catch covid-19 don't feel symptoms for 5-6 days on average,

感染新型冠狀病毒平均 5 - 6 天是沒有任何不舒服的症狀，

and even up to 14 days,

甚至會高達 14 天之久，

but are contagious before that.

但這段期間都是具有傳染力的。

And based on what we know right now, about 25% of people who catch it never show symptoms at all,

根據我們現在所知道的，受到新冠病毒感染的人，大概會有百分之 25 的人是完全無症狀的，

but are also contagious.

但卻具傳染力。

In other words, especially with covid-19,

也就是說，特別有關這個新型冠狀病毒，

feeling healthy doesn't necessarily mean you don't have it.

你們感到健康並不代表你們沒受到感染。

"I think we should all be acting, and also all assume, that we're infected."

「我認為我們都應該要有所行動，也都要認為，我們都受到感染了。」

Shan Soe-Lin is an expert on global public health,

Shan Soe-Lin 是世界公共衞生專家，

and Robert Hecht is a professor of clinical epidemiology.

和臨床流行病學家 Robert Hecht 。

And they say the possibility of being asymptomatic is one of the best cases for universal mask wearing.

他們指出無症狀的可能性是大眾應該戴口罩的最佳原因之一。

"Those who are actually infected and don't know it, or showing almost no symptoms,

「這些真的受到感染的人，並不知道，也沒辦法看出任何的症狀，

it's not even primarily for their own health.

這不是主要憂關他們自己的健康，

It's for the health of their family and neighbors."

而是他們家人以及鄰居的健康。」

But let's say you definitely, 100%, do not have the virus.

但我們說你們絕對百分之 100 沒有感染這個病毒。

The first thing you need to know is that no mask can actually guarantee that you won't get it.

主要的事情是你們必須要知道的是沒戴口罩一定保證你們都會受到病毒的感染。

Instead, the best way to think about face masks is as part of a larger set of protective measures,

而最好的觀念就是，戴口罩是最重要的預防措施，

along with social distancing and hand-washing.

也不要忘記社交安全距離和保持手的清潔。

Used together, they don't protect you completely,

有著這三個措施，不保證你能完全免於病毒的感染，

but they dramatically lower your odds of infection.

但它們能降你們受到感染的機率。

"I think of it as a protective triad, with the virus trying to get in.

「我認為這三個方式是一個保護金三角，能預防病毒的入侵。

And if you don't have one of the branches in it,

如果你們其中一個措施沒做好，

then you're not protecting the whole thing.

你們就無法擁有一個完建的保護層。

And if you didn't have a mask, could you do better with social distancing and hand-washing? Sure.

如果你們沒有戴口罩，那就維持好社交距離和手部清潔呢？當然也是可以。

But having all three is really, really important."

但能做到這三個措施是非常非常地重要。」

To understand how that works, let's look at the two ways covid-19 is transmitted.

來了解這金三角是怎麼保護我們的，這邊我們可以看到兩個新型冠狀病毒的傳染方式。

One way is by touching an infected surface and then touching your face.

一個機率是碰到受到感染的物品表面，然後在摸自己的臉。

This is called fomite transmission.

這就是所謂的環境污染傳播模式。

And frequent hand-washing is the best defense against this.

而時常清洗手是一個最好預防這個情形的發生。

But wearing face masks correctly can play a role too:

但正確地戴上口罩是也有幫助的：

"Masks do a really good job of keeping you from touching your face."

「口罩可以完全確保你們都不會碰觸自己的臉。」

The second way someone's respiratory particles can reach you is directly. Like this:

第二個機率是你會直接接觸到某人的飛沫微粒。像是這個：

This is a slowed-down recording of a sneeze.

這是一個慢動作打噴嚏的過程。

It shows the kinds of respiratory particles a sneeze emits,

可以看到飛沫粒子是如何傳播，

and how far they travel.

和它們會達到多遠。

From a sick person, these droplets are packed with millions of viral particles

一個病人的飛沫有著數百萬的病毒微粒子，

that fall in close range, and infect whatever they land on.

會附著在附近的東西上，然後感染每個接觸到的物品。

Social distancing protects us from droplets, by keeping you away from the particles emitted

保持社交安全距離可以保護我們接觸到飛沫，免於我們接觸到打噴嚏、

through sneezing, coughing, or even talking.

咳嗽、講話的飛沫粒子。

But face masks could help there, too:

戴口罩在這邊也有所幫助：

"If someone sneezes a couple of feet away from you, it'll protect some of the bigger splashes."

「如果某人在幾公尺遠的地方打了噴嚏，它可以阻止掉幾個較大的唾液粒子。」

That also means face masks are especially important

這也指出戴口罩對那些沒維持好

for people who don't have the privilege of being able to social distance:

社交安全距離的人有多重要。

"That would be cops. That would be grocery clerks."

「那些人可能會是警察。也可能會是量販店銷售員。」

"Taxis, Uber, FedEx, UPS..."

「計程車、優步、聯邦快遞、優比速．．．」

"Anyone who's coming into contact with a lot of people,

「時常需要接觸很多人的人，

and maybe can't always maintain that six-foot distance."

可能無法一直都維持六公尺的社交安全距離。」

Look at this video again, though,

再看看這個影片，

and you'll see that we also produce these longer-range, smaller particles,

你們可以看到，我們釋放出這些較長距離更小的粒子，

which evaporate, and can leave the virus hanging in the air.

蒸發並且空氣中散布著病毒。

These are called aerosols.

這些就是所謂的懸浮微粒。

And we still don't really know how infectious they are for the average person.

我們至今還無法知道它們對每個人會造成多少的影響。

But experts think they mostly pose a threat to medical workers,

但專家們認為，它們大多對那些經常近距離接觸

who work up close to patients with Covid-19.

新型冠狀病毒病患的醫療人員都具有威脅性。

"If you're a foot away from the patient, who's coughing as you're trying to intubate them,

「如果你們要幫一直在咳嗽的病患插管，只維持一公尺的社交安全距離，

aerosols are going everywhere.

而那距離中就已有懸浮微粒在四周漂浮著。

For you and me, just walking around, walking your dog, going to a grocery store,

對於你們和我，就只是到處走走、溜狗、到超級市場，

your risk is way higher from fomites."

你們受到傳染源的感染率非常高。」

A common mask that protects against aerosols is called an N95 respirator.

一個常見阻止懸浮微粒的口罩就是 N95 拋棄式口罩。

Its name comes from its material's ability to filter out 95% of aerosol particles.

它的名字是來自它的防護材質，可以阻擋百分之 95 的懸浮微粒。

It's also fitted to form a seal around your mouth and nose, so there's no leakage.

而且它能夠包覆好你們的嘴巴和鼻子，沒有任何的外漏。

In lots of places, N95s are in short supply, because of diminished government stockpiles

在很多地方， N95 有短缺的現象，因為政府庫存的短缺，

and disruptions in the supply chains.

和供應商的中斷。

And that's true for all disposable masks, not just N95s.

而不只是 N95 而言，其他拋棄式的口罩也都是如此。

That's why the US Center for Disease Control says that unless you're a health care worker,

這就是為什麼美國疾病管制中心指出，除非你們是醫療健康人員，

you shouldn't be using either N95s or regular surgical masks.

你們都不應該用 N95 或是一般型的手術口罩。

They're needed in hospitals, and the level of protection most people need can come from

醫院需要它們，而大多數人的防疫可以

a simple cloth mask.

就用一條簡單的布口罩就好。

The CDC recommends any kind of tightly woven cotton for the mask, or even a T-shirt.

美國疾病管制與預防中心建議任何一種密集縫製的口罩布料，甚至是短 T 。

You can make them by consulting the countless internet tutorials out there,

你們可以自己做，可以從網路上搜尋到很多的教學影片，

or buy them from the many vendors who manufacture them.

或是從製造商們那邊買到。

But they only work if you wear them correctly.

但你們必須正確地戴上，才會有效果。

"So what kind of masks are you wearing? Do you have them handy? Could you show us?"

「所以你們戴的是什麼種類的口罩呢？你們手邊就有口罩了嗎？可以讓我們看一下你們的口罩嗎？」

"We thought you might ask."

「我們就知道你可能會問。」

"This is all it takes to put it on:

「這就是你們戴口罩的方式：

Just grab it by the loops. Keep your hands off the central part.

抓住口罩的線，不要碰到口罩中心處，

Put it over your nose and mouth. Loop it around the ears.

蓋住你們的鼻子和嘴巴，並把繩子套在兩隻耳朵後面。

Be careful not to touch it when you're outside. Keep your hands away from your face.

你們出去的時候，要注意不要碰口罩。不要摸你們的臉。

When you come back in, after walking the dog,

當你們回到家後，溜完狗後，

or doing the groceries, do the same thing in reverse.

或是購物完後，就把剛剛戴口罩的步驟倒著做拿下來就好。

Put it off to the side. Don't start playing with it.

把它放一邊，不要玩弄它。

And then at the end of the day, pop it in the washer."

然後一整天過後，把它丟進洗衣機裡面洗。」

"You wash it every day?"

「你們每天都要洗它嗎？」

"I wash them every night. And, you know, if you don't have a washer,

「每個晚上我都會洗它們。另外，如果你們沒有洗衣機的話，

you can hand wash them every night. They're very small and they'll be dry by the next morning.

你們可以每晚親手將他們洗乾淨。它們很小，隔天早上就會乾。

So if people can have a couple, it would be better.

但如果民眾能有幾片口罩可以替換的話，會更好。

But if you only have one, then just wash it at night."

但如果你們只有一個，那晚上就要清洗它。」

Face masks highlight something important in the fight against covid-19:

口罩是抵抗新型冠狀病毒的一件非常重要的東西。

That it isn't always about protecting yourself.

這不是就為了保護你們自己而已。

It's about protecting the people around you.

這是保護你們周圍的人們。

And if everyone is doing it, we all protect each other.

而且如果每個人都這麼做，我們都是在彼此互相保護著。

"There's a visual messaging that comes from wearing a mask:

「這裡有一個戴口罩的實際成果：

A reminder to everybody, that we're not in normal times now.

一個對每個人的警示，我們並不是處在一個正常時期，

Everyone needs to be doing everything they can to protect themselves, and other people."

每個人都應該要竭盡所能保護自己，以及他人。」