The next time you're in Carnegie Hall and the atmosphere seems stuffy, don't blame the upper crust in their box seats. Blame the building's air. It weighs almost 32,000 kilograms.

It's one of many little-known facts about the stuff we breathe that British science writer Gabrielle Walker packs into the engrossing, surprisingly light book, An Ocean of Air: Why the Wind Blows and Other Mysteries of the Atmosphere.

Though we take air pollution very seriously, we tend not to pay much attention to the air itself unless it's threatening us with harmful chemicals. Yet Walker's book tells the story of the inventive scientists who studied the air and came to fascinating conclusions.

"We live submerged at the bottom of an ocean of air," wrote Renaissance mathematician Evangelista Torricelli, whose experiments discovered atmospheric pressure.

Walker takes us on a buoyant tour of the brilliant, though often flawed minds that have probed a substance so difficult to study. The Sunday Star spoke to her about the weight of air, the good intentions behind CFCs, and the first man in space (it's not who you think it is).

In what way is the Earth's air an "ocean"?

It's because it's so big and heavy. It's so heavy that it's almost inconceivable that we walk around and brush it aside, but it's actually weighing down on us. Just like an ocean, it's also got currents that distribute warmth throughout the world, and it also has creatures moving through it. I had thought that we were living on the surface of a rocky planet. I had no idea I was living at the bottom of an ocean. I imagined shrimps and lobsters marching around on the sea floor who have no idea of the miraculous substance above their heads.

What made you write a book about the atmosphere?

Since working for Nature, I had to research the atmosphere and the oceans, and I found it really interesting. I found out this story about the amazing Capt. Joseph Kittinger. I discovered that this extraordinary man had actually fallen through the atmosphere.

He'd jumped out of a plane. And I found footage of him doing it. You can see what it was like when he jumped out, you can see him tumbling, and you see the balloon up overhead, and it's incredible. He could see the curvature of the Earth, and he could see that delicate, thin, blue curving line of the atmosphere. This is before the astronauts saw it. And as he was doing that, I was thinking, what would it feel like to be out in space, above the atmosphere and falling through it?

I mentioned Capt. Kittinger to several people, but no one believed the story.

It is incredible, and it is completely true. But what really struck me about his description was that he was only 20 miles (32 kilometres) up. He was above the part (of the air) that brings food and water and rain and oxygen to the air; it transforms the Earth. That's actually 99 per cent of the atmosphere. He didn't feel like he was in a vacuum, he didn't know the air was so thin there that he would have died if he hadn't had his pressure suit working. But he felt like there was something deadly, an incredibly hostile environment.

He said, in a quote that I have in the beginning of my book, "There's a hostile sky above me. Man will never conquer space. He may live in it, but he will never conquer it."

And as he fell through space he got more and more comfortable, and by the time he landed on the ground, even though he was in a desert, he felt like it was the Garden of Eden because it was so full of life and it was so nurturing. And the thing that made the difference between those two states was the air. Twenty miles of it.

The book mentions a lot of striking facts, such as the revelation that if levels of carbon dioxide in the atmosphere get high enough, there's a 1 per cent chance this planet could turn into another Venus. One per cent seems pretty high.

Venus is a very different planet, but it's (still) extraordinarily similar to the Earth. It would take a lot more than we have now for there to even be a chance. But we also know there's more carbon dioxide now than ever before in human history. We're changing the atmosphere beyond anything that we've ever experienced.

Why is Thomas Midgley, the American who invented such environmental hazards as leaded gasoline and Freon, a sympathetic figure?

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The thing that amazed me about him is that I really did think, let's look at the person who invented Freon. And I had this notion that this must be a bad guy who didn't care about polluting the planet as long as he made a profit. I couldn't believe it when I found out who it actually was – someone who was really trying to help. He was brilliant. He was so unlucky, yet everybody liked him.

Midgley was feted in his lifetime and died without knowing the true nature of his inventions ...

At least that meant that he never lived to find out how much damage he'd done. He'd certainly be heartbroken by it. I have this image of him: He's showing how safe Freon is, showing that it isn't toxic by breathing it in himself, and showing it isn't flammable by exhaling it out on a flame (and putting it out). He wanted it to be safe, he really did. It was just one of those tragedies. It showed that when we put things into the atmosphere, we get it wrong more than we get it right.