Counting the Earth

Counting the Earth

21: The invisible pollutant: 200 million

Sep 2, 2026 · 44 min · 9 segments

Most nitrogen is a harmless gas that makes up 78% of the air we breathe. Reactive forms of nitrogen are more of a challenge, such as those found in fertilisers essential to help our crops grow. When…

Most nitrogen is a harmless gas that makes up 78% of the air we breathe. Reactive forms of nitrogen are more of a challenge, such as those found in fertilisers essential to help our crops grow. When excess nitrogen escapes into the environment, it can become a major pollutant, damaging ecosystems, air quality and human health. In this episode, Alice and Sue visit Whim Bog, a peatland research site 20 km south of Edinburgh that is globally unique and managed by UKCEH. There, site manager Dr Matt Jones explains how 25 years of research have revealed the impacts of nitrogen pollution on the environment. Nearby at the woodland experiment site, Glencorse, Dr Ajinkya Deshpande discusses research on the effects of ammonia throughout the woodland canopy, including mosses and lichens. They also hear about a sister project in Sri Lanka investigating how tropical species respond to nitrogen pollution. UKCEH environmental physicist Professor Mark Sutton highlights the global significance of the issue, explaining how changes to agricultural practices can reduce nitrogen losses to the environment while conserving resources and reducing pollution. He also outlines solutions that could help deliver a future where pollution mitigation and food security go hand in hand. Hosts: Sue Nelson and Alice Hope Producer: Rachael Buchanan Counting the Earth is a Boffin Media Production for the UK Centre for Ecology & Hydrology. **Find out more:** LicheN app Download via Google Play Download via the Apple Store UNEP facts about nitrogen pollution

Most nitrogen is a harmless gas that makes up 78% of the air we breathe. Reactive forms of nitrogen are more of a challenge, such as those found in fertilisers essential to help our crops grow. When…

Top entities: Sri Lanka×14 Scotland×7 Alice Hope×5 Peatland Scottish Borders×4

Show signals: Audience≈39k followers

A Peat Bog Nitrogen Experiment0:02 – 2:16

0:02

There are house martins overhead.

0:04

I've heard a stone chat, a meadow pipit.

0:07

And in front of me is beautiful, rich, brown soil.

0:13

Hello, I'm Sue Nelson.

0:14

And today, Alice Hope and I are recording this episode of the Counting the Earth podcast from a peat bog, just 20 kilometres south of Edinburgh in the Scottish Borders.

0:26

Both of us are wearing these sort of rather fetching midgenets over our faces.

0:30

Yes.

0:31

It feels a little bit like those nets that you put over cake in the summer to stop the flies.

0:36

And that's exactly why we have them.

0:38

Scotland is famous for many things, shortbread, kilts, bagpipes, but also its midges.

0:44

And we are desperately trying to protect ourselves.

0:46

But I do feel a little bit like a beekeeper, I have to say.

0:48

We've also got a large wooden shed behind us, a series of boardwalks stretching across the peat bog and covered with all sorts of different types of heather.

1:00

And there are three sections dividing up into smaller plots with pipes connecting each plot back to the shed building behind us.

1:10

This is UKCH's research station at Wim Bog, a globally unique study of how peatland ecosystems respond to different levels and mechanisms of nitrogen coming from the atmosphere and landing on the ground.

1:23

We're here to discover what's been learnt from the two and a half decades long experiment at this site.

1:28

As always, we look at nature through the lens of one number, and our number for this episode is 200 million.

1:32

That's 200 million tonnes.

1:36

the annual amount of reactive nitrogen lost to the environment globally, leaching out into soils, rivers, lakes and emitted into the air.

1:43

Our guides today are Dr Matt Jones, Head of Air Quality Impacts and Responses for UKCH and the manager of this facility, as well as his colleague, environmental physicist, Professor Mark Sutton.

1:56

Later, we'll be popping a few kilometres up the road to see Wimbog's younger sibling, a woodland version of this experiment.

2:03

But first, Wimbog with Matt Jones.

2:06

Thank you so much for inviting us here.

2:07

You run this research facility.

2:10

Explain to us how you go about testing the effects of nitrogen on a habitat like this.

2:14

Give us the full works, the full tour.

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