Lucy Carpenter

You're absolutely right. We think of the ocean as this vast sink of things like CO2, carbon dioxide, but it does emit gases as well. And maybe that's been somewhat overlooked. It's quite hard to get out there into the open ocean. We all know the ocean is full of salt and there's a whole bunch of marine biology that's quite active. So they can act to produce aerosol particles that can influence clouds and influence the oxidizing capacity of our atmosphere as well.

We mentioned ozone. We're going to be talking about it quite a lot today. So it's worth getting a reminder of exactly what it is, because this molecule is both a protector and a pollutant, isn't it? That's right. So 90% of ozone in the atmosphere resides in the stratosphere. The stratosphere is the upper. Is the upper. So that's around 10 to 50 kilometers above our heads. That's not a fixed zone, but depends on temperature and latitude. So that's where the ozone layer is, the protective layer that protects us from harmful solar UV radiation.

Troposfeeri on täysin erilainen. Ozone on muuttunut troposfeeriin erilaisena. Stratosfeeriin se on muuttunut luonnollisesti oksigenfotolyysistä. Troposfeeriin se on muuttunut antropogeniasta. Troposfeeriin se on muuttunut maataloudesta? Maataloudesta stratosfeeriin. Sitten se menee suoraan stratosfeeriin. Troposfeeriin on luonnontuotantoa, mutta myös tuotantoa. Todella vahva tuotanto. Ozone on huono suuntaan ja hyvä stratosfeeriin.

and then began the phase-out of those harmful chemicals that gave rise to the ozone hole, the chlorofluorocarbons, the CFCs, that were used in fire protection, as deodorants, as hairspray. So once the Montreal Protocol was signed, the phase-out began, and thanks to that and the efforts of hundreds and thousands of people across the world, we are now starting to see the recovery of the ozone layer. So it's predicted to recover back to 1980 levels by about mid-century, somewhat later in Antarctica. So yes...

We have basically gone from ozone depleting gases. The CFCs are very ozone depleting. Then they were replaced by the HCFCs. They contain a hydrogen atom, so they're broken down more quickly. So they're not as dangerous. And then often replace them with HFCs. And most people will have an HFC-134A, for example, in their car as their air conditioning refrigerant. Many of them aren't actually more harmful than CFCs as greenhouse gases. But some of them are pretty potent. Right.

Now they are being swapped out for shorter-lived HFCs, called HFOs. They may bring their own problems as well. There is no perfect fluorinated chemical that you can put into the environment. We'll come on to possible ways of saving the planet, but just to ease ourselves in, let's hear the start of your story. You grew up in rural Wiltshire with mum, dad, three brothers. What were you like as a kid?

Olen ollut tommoisena. Olin koko ajan myyntiä. Olin lähtenyt paikalliseen kouluun ja tykkäsin kaikkia asioita kouluun. En oikeastaan tiedä, mitä halusin tehdä. Meillä oli erittäin hyvää kemisteriä, joka teki niitä vanhoja koulujen demonstraatioita, jotka ehkä eivät enää tapahtu. Säädettiin potasioita ja vettä. Luulen, että se saa minun kiinnostukseni kemisteriin menevään.

They did indeed. I don't think I was a natural in the laboratory to start with. So on my very first chemistry experiment in the labs, I ended up in A&E because I still have a slight scar actually on my finger. It's where I tried to put a teat on a burette and rather enthusiastically managed to get the glass into my finger. So I was never going to make an organic chemist, someone who was in the lab making chemicals, but I did like the...

Suurimmat halogenit ovat fluorina, kloriina, bromina ja iodina. Ne ovat erilaisia muotoja, esimerkiksi inorganisia muotoja. Olemme kuitenkin kuulleet hydrokloriikasta, HClista, ja inorganisista halogenista, jotka ovat volatileja ja olevat gas-fasassa.

to organic halogens, also volatile, also exist in the gas phase. So the organic halogens just being those that have carbon in them? Yes, so they can exist in a variety of forms, solid, liquid, gas, and a huge variety of reactivities as well. Well, you got involved with the project to measure organic halogens at Macehead Atmospheric Research Station on the west coast of Ireland.

Yes, so there was an idea that there could be some halogen chemistry in the troposphere. We knew that it would involve, if it was happening, more reactive halogens, iodine and bromine, but really very little was known. So I built a system to trap the halogens and we coupled it to a

gas chromatic mass spectrometer, a well-established way of measuring molecules, and put it on this station. It was part of a big experiment. In fact, I think it was one of the UK's first big consortium field experiments. So it was a great experience. And lo and behold, we found a much richer mixture of halogens that had been seen before. And at that site, you look out to Macehead and you can see seaweed everywhere.

Ja näimme hienoja taitoja halogenissa, jotka tuli olemaan syntyneiden takia. Ja ei vain se, koska se oli konsortointiprojekti, ja paljon erilaisia labeja tehtiin paljon erilaisia asioita. Aerosolipuolet, kun se oli lauantaina ja päivänä, näivät, mitä olimme usein kutsuneet, jotka olivat isoja taitoja uusia partikkoja, pieni nanometrin määrä aerosolipartikkoja. Ja se tuli olemaan, että kemistiikka liittyi iodin-suomalaisuuteen.

Kiitos kun katsoit.

A really key thing is how you sample. If a gas is very reactive, you might need an inlet that's only a centimeter long and a special way of making sure the gas or radical is not lost before it gets into your system. So for some very reactive things, we actually have to put the instrument itself on the roof or on the sampling tower. Other molecules, you can essentially have a great big manifold, suck the air down, you pump the air in, trap it, concentrate it often, because if you're measuring it that tiny, tiny level...

You can't just put something straight through into your instrument. You have to concentrate it until you've got enough of it. Get rid of the things you don't need, like the CO2 and the nitrogen and the oxygen, and then just inject what you want. So that's how we tend to do lots of science. And you're injecting it into this instrument, the mass spectrometer, which tells you what elements, what molecules...

So the seaweeds, they actually accumulate huge amounts of iodine and bromine sometimes as part of what biologists call the oxidative stress response. So they don't like being exposed to dry, sunny air. They like being in the sea. So when they're out, they actually have a whole reactive chemistry going on. And their release of these halogens is part of their response to get rid of things like hydrogen peroxide from their system. But yeah, the molecules that we're seeing are...

The chemicals that they are emitting, that then react with organic material in the seawater. And together those things make these very exotic, mixed organic halogens that we saw. And other halogens that we didn't see at the time, but later found out were being emitted as well.

But this was surprising. You weren't expecting to see these molecules. I mean, it was incredible. It was like nature telling us, look, there's a tidal cycle here. You guys can figure out what's going on. So that was nice. But, you know, these molecules are pretty reactive. So the sun comes down and breaks that bond through photolysis, photolytic decomposition. And then once you have that, your halogen atom is split off from the molecule, undergoes other chemistry.

Well, I was approached by some German colleagues that had the idea of having a station there. The main person who thought about it was an oceanographer. So he was really interested in that region, partly because a whole load of Saharan dust gets deposited in that part of the ocean every year, and that can stimulate ocean biological processes. So he approached me as someone who was active in this ocean air research and said, you know, we found this station. It would be a great place for you to do your research as well. What do you think?