Irina Petropadlovskikh

So they're also quite essential for this depletion to occur.

And the reason for that is that they actually set up this activation of the chlorines that are typically not very active.

So they set them up such that there will be only chlorines and bromines released once the sun comes back.

And so then those chemicals are released, and then they will start to destroy ozone very, very rapidly.

But there are also other chemicals that get frozen into the polar stratospheric clouds that typically neutralize these reactions.

And so there is nothing to stop those chemicals to destroy ozone for some period of time until the polycystic clouds disappear.

Right, exactly.

So they started to present their findings to the public, to the governments.

And so eventually they got enough people to listen to their worries that the Vienna Convention happened, where the representatives from many, many countries got together and they discussed these issues.

Wow.

And then the Montreal Protocol in 1987, actually signed by every country, I mean, this is really amazing, agreed to stop production and use of those ozone-depleting substances.

Some chemicals actually can leave, once they get into stratosphere, they can live up to 100 years.

So once they're released, let's say they've been released in the 50s and even before that, they have quite a long way to go before they get completely removed from the stratosphere.

So the ozone hole is recovering, but very slowly because we still have a lot of these chemicals in the atmosphere still.

No, we are very lucky.

We still have a lot of observations.

So, yes, I mean, we still need to monitor it.

And the reason for that is that...

There are some other chemicals that have been released in the atmosphere.

They're not really destroying ozone.