And now a few years removed from a pandemic lockdown, and it's still kind of weird to think about.

突然、空気そのものが私たちを殺そうとしているように感じた。

Viruses and bacteria are these invisible enemies that we just kind of deal with day to day, and they leave us coughing and sneezing our way through winters.

そして今、パンデミックの封鎖から数年が経った、

So we wield our sprays and wipes and sanitizers.

考えてみると、いまだに奇妙なことだ。ウイルスとバクテリア

But there is a powerful disinfectant that we've known about for a century and it still isn't part of this tool kit.

私たちは日々、目に見えない敵と向き合っている、

At least not consistently.

咳やくしゃみをしながら冬を過ごすことになる。

Light.

This is the electromagnetic spectrum.

だから私たちはスプレーやウェットティッシュ、除菌剤を使う。

You've seen it before, literally here where visible light is.

しかし、100年前から知られている強力な殺菌剤がある、

The light we're talking about as a disinfectant occurs here: Ultraviolet light.

しかし、このツールキットにはまだ含まれていない、

There are actually three different types of UV light that occur at different wavelengths.

少なくとも一貫性はない。

The one shining down on us from the sun is mostly UVA and some UVB.

軽い。

And that UV does all the things that people think UV is going to do so we can't shine it on people. Ok?

これが電磁スペクトルだ。目に見える光は、文字通りここにある。光は

It hurts your skin, it hurts your eyes, it gives you cancer.

ここで言う殺菌剤とは、紫外線のことである。紫外線だ。

It does that by damaging the DNA in our cells, but ironically, those same properties that cause cancer also break down viruses and bacteria and stop them from replicating.

UVには3つのタイプがある。

And we've known this since the late 1800s.

異なる波長で発生する光。

So researchers have been experimenting with low wavelength UV or UVC as a germicide for decades.

太陽から降り注いでいるのは、ほとんどがUV-Aで、UV-Bもある。

In the 1940s, researchers placed UV irradiation chambers in classrooms.

そしてUVは、人々がUVがやると思っていることをすべてやってくれる。

Now, don't worry, the UV light was being safely projected into the air above the children so they weren't being directly exposed to it.

だから、私たちはそれを人に当てることはできない。

But as air circulated the room, it could be cleansed.

肌を傷つけ、目を傷つける。

Researchers ultimately found that it was effective at stopping the measles virus.

ガンになる。

Very effective.

それは細胞のDNAを傷つけることによって行われる。

Under 15% of the kids in classrooms with UV were infected, compared to over 55% of those in classrooms without it.

しかし皮肉なことに、同じ性質が癌を引き起こすのである。また、ウイルスや細菌を分解し、複製を阻止する。

Later studies used rodents to test UVS effectiveness with other diseases like tuberculosis.

このことは1800年代後半からわかっていたことだ。

The air was irradiated with ultraviolet light first and the hamsters in the treatment group did not get tuberculosis.

そこで研究者たちは、低波長の紫外線を使った実験を行ってきた。

But these lights needed to be kept above people or hamsters and installed carefully using a costly process called upper room UV.

Because even though they operate at a low wavelength, it still isn't great to directly blast humans with it day in and day out. You know, because the cancer thing.

またはUV-Cを殺菌剤として何十年も使用してきた。

This method is actually used in a lot of hospitals, paired with ventilation to help reduce infection rates.

1940年代、研究者たちは教室に紫外線照射室を設置した。

But having UV at the top part of the room can't do much to stop the germs being spread between people.

ご心配なく、紫外線は空気中に安全に投射されています。

So more recently, researchers began looking for a better way to kill pathogens all around us.

子供たちは直接それを浴びることはなかった。

They ran studies to determine the most UV light that could be used to kill bacteria and viruses but also minimize harm to humans, which brings us to a type of UVC called Far UV.

しかし、空気が部屋を循環することで、浄化される可能性がある。

Far UV has a very low wavelength that can't penetrate skin deeply enough to cause damage, even in mice, specifically bred to be susceptible to cancer.

研究者たちは最終的に、麻疹ウイルスを阻止する効果があることを発見した。

This is a field full of tuberculosis hamsters and cancer mice, and I feel really bad about it.

非常に効果的だ。紫外線を浴びた教室の子供たちの15％以下が感染していた、

In test chambers, Far-UV is really effective at killing pathogens.

それに対して、それがない教室では55％以上であった。

This study is from 2020 when, well, you know what happened in 2020.

その後の研究では、げっ歯類を用いて他の病気に対する紫外線の有効性を検証している。

It showed that Far-UV was able to kill 99% of Coronavirus in a test chamber.

And this study found that it was 98% effective at reducing the bacteria that causes staph infections.

結核のように。

So why isn't it everywhere?

まず空気に紫外線を照射した、

In order to understand effectiveness, you first have to understand safety.

治療群のハムスターは結核にならなかった。

While it's generally accepted that Far-UV won't give you cancer, there are other consequences to bring a UV light so close to the ground.

しかし、これらの照明器具は人間やハムスターの上に設置する必要があった。

We know really well that when you shine UV light on air, it can cause chemistry to happen.

アッパールームUVと呼ばれる高価なプロセスを使って慎重に。

UV light produces a molecule called ozone, which can be harmful for humans to breathe in.

If you're exposed to lots of ozone, if you're exposed to lots of particles that your, sort of, risk for respiratory ailments goes up.

なぜなら、低波長で動作しているとはいえ、まだあまり良くないからだ。

But just how much of it is being produced by these lights in a real world environment is still up in the air.

それを毎日毎日、人間に直接浴びせるのだ。

So in what ways can we use it?

癌のことがあるからだ。この方法は実際に

That's a UV light behind you.

多くの病院では、感染率を下げるために換気とペアになっている。

Yes, it is. Yeah.

しかし、部屋の上部にUVがあっても、それを止めることはできない。細菌が人々の間に広がっているのだ。

So this is a Far-UV light predominantly putting out 222 nanometer wavelength light, which is shown to be very effective in eradicating everything from viruses to bacteria to mold, allergens, and more.

そこで最近、研究者たちはは、私たちの身の回りにある病原体を殺すより良い方法を探し始めた。

PJ Piper is the CEO of a company called Far UV Technologies that develops all types of UV devices.

彼らは、使用可能な紫外線量を決定するための研究を行った。

He believes that far UV will become more widely used in tandem with other layers of protection.

細菌やウイルスを殺すだけでなく、人体への害も最小限に抑える。

I don't really look at this as displacing HVAC or filtration.

そこで、遠紫外線と呼ばれるUV-Cの種類を紹介しよう。

Those are important things.

遠紫外線は波長が非常に低く、皮膚に深く浸透しない。

They just do different things.

癌になりやすいように特別に飼育されたマウスでさえ、損傷を引き起こす。

HVAC is predominantly for climate control.

これはハムスターの結核畑だ

It also has a slight benefit of potentially removing the viral load.

私は本当に申し訳なく思っている。

Filtration, similarly, doesn't change the climate control, but it's really important for getting rid of inorganic pollutants like smog or wildfire smoke or something like that.

試験室では、遠紫外線は病原菌を殺すのに実に効果的である。この研究は2020年のものだ、

But there's nothing anywhere near as efficient as light as a source to eradicate the pathogens that might be in the room.

2020年に何が起こったかご存じだろう。

So pairing UV with other systems could help reduce pollutants too.

その結果、遠紫外線は、以下の物質を殺すことができることがわかった。

But Barbara and other researchers suggest we think about the cost-benefit.

試験室内のコロナウイルスの99％。そしてこの研究では、98％の効果があった。

I think we could run into trouble. Is if people want to install these lights as a replacement for ventilation?

A hospital where the risk of infection is very high, it could probably benefit from this, but an old school building on an average day, probably less so.

It might be some time before we start seeing Far-UV everywhere.

スタフ感染症の原因となる細菌を減少させる。では、なぜどこでもそうしないのか？

The odds of a of a next pandemic, it seems to me that it's more a question of when rather than if, and so having technologies like this, I think is super important.

有効性を理解するために

I just want to be careful that we don't get so excited about this kind of technology that we wind up missing something.

まずは安全性を理解しなければならない。

Look, anyone trying to sell you a single miracle cure for anything is likely bending the truth.

一般的に、遠紫外線でガンになることはないと言われている、紫外線をこれほど地表に近づけることには、他にも影響がある。

When it comes to fighting disease, whether that be the common cold or a full pandemic, there's no singular approach.

We need a toolbox of options from vaccines to mask to chemical disinfectants.

私たちは、空気に紫外線を当てようが当てまいが、紫外線の影響を受けないことをよく知っている、

And in time, it's likely that Far-UV could be one more addition.

化学反応を引き起こす可能性がある。

Maybe in various forms that we could bring with us to public spaces or installed somewhere above us without us even knowing as an extra invisible layer of protection against those invisible enemies in the air.

So if you want more info on UV light and germs, you can check out Unexplainable, Vox's Science podcast about unanswered questions.

紫外線はオゾンと呼ばれる分子を発生させるが、これは人間が吸い込むと有害である。

They're working on an episode that goes deeper into everything we don't know about UV light and disease.

オゾンにたくさんさらされている場合、

And they'll take you through that original experiment where researchers just decided that kids were better guinea pigs than actual guinea pigs.

たくさんの粒子にさらされている場合、

It'll come out next Wednesday, February 20th.

呼吸器疾患のリスクが高まる。

But in the meantime, here's a quick preview.

しかし、どれだけの量が生産されているのだろうか？

In 1937, 2 researchers had a kind of dangerous idea.

現実の環境におけるこれらの照明の効果は、まだ未知数である。

So they figured the perfect place to test it out was in an elementary school on kids on the eve of a massive epidemic.

では、どんな使い方ができるのか？