Something changed in around 2012. People started talking about the air. Perhaps they heard their children wheezing, or granny told them she couldn’t climb the stairs, or they were fed up with having constant headaches.

China woke up when the city of Beijing had to shut half its factories to make sure its coal-polluted air was safe enough for Olympic athletes to breathe. Two years later the great Sahara dust episode was the alarm call in Britain. After weeks of choking on traffic fumes, Londoners found their cars covered in a fine red dust. The prime minister, David Cameron, said it was fine because the pollution was natural, but nobody believed him and news desks at last started to tease out the biggest public health scandal of the past fifty years.

And what a scandal! The scale of this modern plague, we have begun to see, is staggering. We have long known that nearly three million people in poor countries die prematurely each year from inhaling wood smoke from open fires used for cooking, but we didn’t know until quite recently that many people in modern cities are having their lives cut short as a result of breathing in vehicle exhaust gases and industrial fumes. The official narrative has been that since the end of coal-burning in homes in the 1950s and the demise of heavy industry, urban air has been relatively clean, leaving us with nothing to worry about. The reality is shockingly different. We understand now that air pollution doesn’t just harm our lungs, as coal dust did, but also gets into the bloodstream. The World Health Organisation reckons that nine in ten people around the world breathe air containing ‘high levels’ of pollution; it is responsible for 26 per cent of premature deaths from heart disease, 24 per cent of those from strokes and nearly one-third of all deaths from lung cancer. It is linked to obesity in children, autism and dementia.

The plague does not strike all equally. The air in high-income cities like London and New York may be toxic and polluted to sometimes illegal levels, but it is very many times worse in most African and Asian megacities, where not only wood but also coal and old tyres are burned, and where cars are older and fuels may be contaminated. In such places there is little monitoring of air quality and health services are often minimal.

The cost, in wasted life and money, is crippling. The deaths attributed to air pollution are now triple those from AIDS, malaria and TB combined. Pollution already costs some countries as much as 4 per cent of their GDP – a figure likely to increase because children are the worst affected and deaths across much of the world are set to double within thirty years.

The worst air I ever breathed was in Kabul. At the height of the war in Afghanistan, I visited one of the city’s largest hospitals, expecting to hear stories of the wounded. Instead, I found wards full of people with cardiac and respiratory diseases. The doctors were adamant that one in four people there were dying from polluted air. The war? I asked. The air is much more dangerous, I was told.

A handful of scientists, campaigners, lawyers and journalists have spent years exposing the scandal. But while in the past ten years a ton of books has been published on climate change, the fall of forests and plastic pollution, only a few authors have stopped to consider the quality of modern air. We must now thank the journalists Beth Gardiner and Tim Smedley and the scientist Gary Fuller for taking up the story at length. They have written complementary books which together graphically show how air pollution has become so deeply embedded in everyday life that we barely notice it. They also go some way to explaining how governments did not just sleepwalk into the present crisis but knowingly condoned the mass poisoning of their peoples.

The story has few heroes and many villains. Politicians have flouted laws and UN guidelines; cynical oil and cheating car companies have made pollution worse; watchdog agencies and environment groups have been too weak or fixated on climate change to do much; consumer ignorance has been relied upon and encouraged by the authorities.

In Choked, Gardiner, an American living in London, travels to smoggy China, India, Germany and Poland, drops in on Malawi, compares bike-riding in Berlin and London, marvels at how California cleaned up its act and makes sense of some complex chemistry. Along the way, she weaves in her personal story, nails Dieselgate and produces some awkward but effective lyrical passages about the act of breathing dirty air.

Tim Smedley, who is described as a ‘sustainability’ journalist, follows a similar but more circuitous path through many of the same countries in Clearing the Air. He is honest enough to say that he knew air pollution was bad in London but paid little attention to it until his own child was born. While harrowing, his narrative is compromised by a surfeit of statistics and technical details, and the book is not helped by type-dense pages.

Gardiner’s and Smedley’s books both get glowing endorsements from Arnold Schwarzenegger, who of all Western politicians has most effectively demonstrated the link between air pollution and climate change, showing how if you want to solve one, you must address the other. Sadly, both authors treat air pollution in relative isolation.

Not so Fuller, who leads a team of air researchers at King’s College London. Fuller wears his learning lightly in The Invisible Killer, looks to history for context and shows how foul air has perplexed and angered societies for centuries. Importantly, he links it to recent forest fires, shipping, acid rain, farming, holes in the ozone layer and the whole way we live and burn.

Fuller is old-fashioned. He doesn’t offer a personal narrative or try to engage in fine writing. Instead, he tells a straight-up horror story, leavened with impressive detail. He, too, travels the now-familiar route to burgeoning Delhi and Beijing, but he also drops in on New Zealand, which boasts of having some of the cleanest air in the world. But instead of celebrating the pure Antipodean air, he heroically punctures the clean, green Kiwi image by revealing the amount of wood that is burned there.

The consensus of all three writers is that the air of the future will be more breathable as technologies improve and people understand the dangers. I am less sure. Many European cities have indeed taken up the challenge to reduce air pollution in their centres and are driving out petrol and diesel cars. But old cars and pollution-producing machinery often end up being exported to the poorest countries, and the air of Accra, Nairobi and Kathmandu is already close to being unbreathable.

The global health crisis resulting from air pollution will be with us for generations. The world’s urban population is set to double in the next forty years. Most of that growth will be in the kind of chaotic, lawless cities to which these writers have barely ventured. The full horror of how we are poisoning the world for profit has yet to be revealed.