Breathing is the most fundamental thing we do as living beings. Breath gives us life and stops only when we die.

Yet breathing kills millions of people every year. According to the World Health Organization, air pollution is responsible for 8.8 million premature deaths per year globally. Ninety per cent of the global population breathes air that's polluted enough to damage health. In some of the poorest parts of the world, people are forced to inhale a toxic stew of chemicals from their cooking fires or at their workplaces — poisoning themselves in the name of day-to-day survival.

But even in the world's richest countries, air quality can be so bad that kids can't play outside and adults who would otherwise be healthy suffer from sore throats and burning eyes, and can't climb more than a couple flights of stairs without wheezing.

Beth Gardiner is an environmental journalist, formerly with The Associated Press, who's also written for the New York Times, The Guardian, Time magazine and National Geographic. She travelled around the world to understand the sources of — and solutions to — air pollution and the toll it is taking on the health and lives of millions of people.

She spoke to The Sunday Edition's guest host Peter Armstrong about her new book Choked: Life and Breath in the Age of Air Pollution. Here is part of their conversation.

The book is full of these alarming statistics about air pollution and its impact on our health. What struck you or surprised you the most as you put them together?

Journalist Beth Gardiner says the health effects of air pollution go far beyond our lungs. (Suzanne Plunkett )

Millions of people die every year from the health effects of air pollution, and I think part of what is so striking about that is how invisible it is. These deaths are scientifically very well understood, and the research behind those numbers is rigorous. But at the same time, we can't make out the links with the naked eye, as it were, between cause and effect. You know, if I have a heart attack tomorrow, I'll never know that it was because of the fact that I've lived in London for 18 years and the air here is terrible, thick with diesel fumes.

But I think what surprised me as I began digging into this was the range of illnesses that are linked to air pollution. Most people would find it fairly intuitive that dirty air can trigger an asthma attack, or it can cause emphysema or other kinds of breathing problems or even lung cancer.

But actually the effects go so far beyond our lungs and our breathing — to everything from heart attacks and strokes to Alzheimer's and Parkinson's and premature births and miscarriages, now, are very strongly linked by the science to air pollution. We've come a long way in understanding how profound the effects are.

There are so many components to air pollution, such as benzene, fine particulate matter, ozone and carbon monoxide. We hear about acceptable or safe levels of contaminants in the air and we get warnings about air quality when those levels are exceeded. But how safe, really, are those levels?

The more that scientists understand the effects of air pollution on our health, the more they understand that there is actually no safe level. There's really a very tight correlation, particularly when you're talking about the tiniest particles — they call them PPM 2.5 — which are the most dangerous. As the levels go up, the rates of all these illnesses go up, and death rates go up. But the converse is that when pollution comes down, and usually that's down to government action and regulation making the air cleaner, you see people's health improving almost immediately and death rates going down.

Environmental journalist Beth Gardiner's book, Choked: Life and Breath in the Age of Air Pollution, explores the dangers of air pollution. (University of Chicago Press)

As I was growing up we were always told that whether you're rich or poor, whether you're powerful or powerless, we all breathe the same air and that's why we need to care about it. One of the things the book did for me is illustrate the extent to which that's not necessarily true. I mean, do the poor or the marginalized end up breathing the same air as the more affluent?

Both are true, actually. It is certainly true that air pollution affects us all. If you live in a city that has poor air quality, that will affect everyone who lives there. But at the same time, it affects some more than others. People who are poor, communities of colour, immigrant communities, tend to live, because of real estate prices, in areas that are closer to a busy highway or closer to a polluting factory or a power plant. And, in a sense, air pollution really intersects with all the biggest issues that we're grappling with today — with economic inequality, with racial justice, with climate change, with questions of corporate power and how do we balance private profit against public good and government power. I think that air pollution tracks all the fractures that run through our modern societies.

When most of us think about the worst air, we think about Beijing. But it is a shocking picture that you paint of just how bad the air is in Delhi, India. How bad does it make life for people there?

It's just awful. Upwards of a million and a half Indians every single year die from the effects of air pollution. That is a mind-boggling number even in such a big country, and unlike China, where the air is famously also awful, India is not making any progress in dealing with it.

What really amazed me there was the unbelievable multitude of pollution sources in India — it's garbage fires and diesel generators that people have to use because the power supply is not reliable. And it's unregulated old cars with very dirty fuel, and it's fields northwest of Delhi where there's no way of getting rid of the stalks and stuff that are left over after the harvest, so farmers just light them on fire, and the smoke that comes off of those fields and drifts towards Delhi.

And it just sends pollution there absolutely off the charts. They use the phrase,"the world's greatest pediatric health emergency." And it's really true, and not just pediatric. It affects everyone who lives there.

A village man walks carrying a child on his shoulders on a foggy day in Greater Noida, near New Delhi, India, on Nov.5, 2018. (R S Iyer/Associated Press)

Coal is still a big part of the energy mix here in Canada and the U.S., not to mention China and India. You went to Poland where coal is still king. Tell me about the role that coal plays in Poland and what it does to people's health?

Poland is one of the most coal-dependent countries on Earth. It's not just power plants that are using coal, but people are also burning it for heat at home. And as bad for the air quality as power plant coal burning is, it's so much more egregious in people's homes, because they're getting access only to the sort of cheapest, dirtiest kinds of coal. When you burn it in a home furnace, you don't have any kind of scrubbing or filtration. So when you walk around cities and towns in Poland in the winter, coming out of every chimney, you see this thick, thick smoke. And the effects on people's health, pretty predictably, are terrible. But there's resistance on the governmental level to move towards other options.

Something that emerges from your book is that governments need to regulate this — that the private sector and industry and business aren't going to clean up of their own accord.

That was really something that I saw as a theme throughout the book. We've seen that when it comes to pollution, companies are very happy to outsource the costs — just spew their pollution into the air or the water or whatever, and let the costs be borne by the public in terms of effects on our health. And it is only government power in the form of regulation that has changed that.

I grew up with unleaded gasoline. You'd pull up and ask for unleaded. Until I started working on this, I just never thought about it. I thought that lead was naturally in gasoline. And then, you know, we took it out. And that's where unleaded gas came from right. What I learned is that tetraethyl lead was added intentionally to gasoline in the 1920s because it was seen as a way to make engines run a little bit more efficiently. It was very well understood at the time that it was a neurotoxin. You had some of the biggest companies in America, including GM, intentionally putting it into gasoline. It stayed there for decades until the 1970s, when the American Clean Air Act forced the sale of unleaded gas to become more widespread.

The book is downright scary in parts, but it's still full of hope — the notion that this is not an impossible dream. Where do you see hope?

This is really fixable. We were talking about the American Clean Air Act — you know the U.S. did this in recent memory and just a few years ago was still making progress on clean air. So it's not impossible. The thing with air pollution is that even incremental progress brings results. It brings health benefits; if you can even improve the air quality by 15 per cent, you will literally save a lot of people's lives.

That's really powerful and it's doable. I think, though, it's a matter of choice and it's the same as the situation that we're in with climate change right now, which is that we could do it. It's up to us: are we going to do it, or are we not? The technologies exist now — the wind and the solar and the electric cars and all of that. But is that political will there?

Click 'listen' near the top of this page to hear the full conversation.

Q&A has been edited for length and clarity.