Wendy Zuckerman

Stephen thinks it's perhaps some very unlucky genetic predisposition.

But what Stephen did know was that every time little Ella breathed in all that pollution, it kept irritating her lungs more and more and more until it destroyed them.

Rosamund started researching about pollution.

And she realized that in the UK and the US, pollution levels tend to be higher in black and brown communities.

And that's partly because the government and industry have gotten away with building things like highways through black and brown neighbourhoods.

And the thing is, the neighbourhood where Rosamund lives, it has a pretty large black population.

Rosamund herself is black.

And once Rosamund knew that air pollution had played this big role in killing her daughter...

Her next question was, why didn't any of Ella's doctors know about this?

Like, why didn't they even suggest that air pollution could have been triggering her asthma?

There'd been heaps of studies, even at the time, showing that air pollution could make asthma worse.

But despite that, it just wasn't on the radar of some of the best doctors in London.

How is that possible?

That answer is coming up just after the break.

Welcome back.

We just heard that pollution was a major trigger for Ella's asthma.

But until Stephen and the team came along, none of her doctors had even suggested it as a possibility.

So why is that?

Well, some researchers told us that it could be because these days you often can't see the pollution around us.

It's a little out of sight, out of mind.