Professor Matthew Cobb

It's made me much more sensitive, I think.

I notice, I try to notice smells.

We've had some very wet weather recently.

Going out straight afterwards and smelling the petrichor, the geosmin, this odour that's released by bacteria in the ground after it rains.

Fantastic, amazing smell, cheers you up, makes you feel more alive.

So this is the thing we talk about, the smell of rain.

What exactly are we smelling?

After it's rained, when the rain stopped, you go outside, there's a kind of incredibly rich, fresh smell coming up from the earth.

And one of the main ingredients of this is something called geosmin, which is an odour that is produced by bacteria, which as soon as it starts raining will start, you know, respiring.

And one of the byproducts of their respiration is this geosmin odour that's marvellous.

Thank you very much.

It's been great.