COVID: what happens when you breathe

For a man who died ninety-seven years ago, Carl Flügge had a very big 2020 and 2021. We paid homage to him every time we waited in a socially distanced grocery line, used a homemade chute to deliver Halloween candy, or yelled “Six feet!” to a child wandering too close to a stranger. In an age of CRISPR and face transplants, one of the heroes of the coronavirus pandemic was a German doctor who, in 1897, measured how far bacteria-laden spittle could travel from the mouths of volunteers. Six feet, he determined, and so, in 2020, that became the recommendation offered by caution signs around the world. (In Sweden: “Please keep a distance about the size of a small moose between yourself and others.”) We’ve learned that our breath can sometimes carry the coronavirus much farther than six feet, but the number is still useful and seems permanently etched into our brains. We all  became Flüggeites.

Flügge was obsessed with hygiene, and for good reason. In his day, there was little to offer the sick in the way of effective medicines—beyond, say, opiates or quinine—and few vaccines were available. The best way to be of help, some physicians decided, was to try to find out how to keep patients from getting sick in the first place.

At the time that Flügge was measuring droplet travel, New York City was overcome by a terrible respiratory disease. Tuberculosis, the city’s leading killer, was claiming ten thousand lives a year. A local doctor, Hermann Biggs, proposed actions that he believed could save lives: reporting all TB patients to the health department, and tracking everyone with whom those patients had been in close contact. (Other physicians protested, calling the moves “aggressive tyrannies” and “offensively dictatorial,” so Biggs wasn’t able to implement them fully.) He also pushed for people to cover their mouths while coughing, and for patients infected with TB to be isolated from healthy people. Twenty years later, even with no advances in medication, Biggs’s careful attention to the sharing of air had helped cut the number of TB cases in the city in half.

Eventually, effective antibiotics were introduced, and by the nineteen-fifties TB was considered, in the United States, anyway, to have been more or less conquered by modern medicine. But, in the decades that followed, with the old precautions abandoned, the disease began to spread anew in New York, and there was an additional problem: incomplete treatment could lead to strains that resisted the drugs. The number of cases per capita doubled between 1980 and 1990. The pulmonologist Michael Stephen writes about the debacle in his wide-ranging, “Breath Taking: The Power, Fragility, and Future of Our Extraordinary Lungs”:

In a time when we had our most powerful antibiotics, New York was doing worse than Dr. Biggs had done ninety years before, with education and no antibiotics at all. The story is a reflection of the remarkable fact that, in the twentieth century, an era of astounding medical breakthroughs, simple – and relatively inexpensive – public-health interventions saved more lives than clinical medicine did.

As a doctor of the lungs, Stephen is plenty interested in cutting-edge cancer therapies and treatments for such harrowing illnesses as cystic fibrosis, but he clearly sees his philosophical forebears in the likes of Biggs and Flügge – and even their successor William Wells, who, in the nineteen-thirties, introduced sneezing powder and Balantidium coli into the lecture halls and air-conditioners of the Harvard School of Public Health, just to find out how far the bacteria could travel and still reach human lungs. All of them understood a basic truth, which, Stephen maintains, becomes more profound the more you think about it:

The atmosphere is a communal space, and lungs are an extension of it.

Our very breath ties us to one another and to the world around us. It’s a lesson that we seem to struggle to remember.

In countless languages and religions, breath is a synonym for life, as well as for the spirit or soul. And for good reason. The Earth spent some two billion years without oxygen in its atmosphere, bereft of life beyond a few anaerobic microorganisms. Slowly, blue-green algae generated a buildup of oxygen, and so created the conditions that allowed for the grand explosion of biology on which nearly everything and everyone we know depends. Stephen quotes the English physician William Harvey who wrote in the seventeenth century:

Life and respiration are complementary. There is nothing living which does not breathe, nor anything breathing which does not live.

He was overlooking anaerobes, of course, but the gist was right. Even plants respire, in a process separate from photosynthesis; animals such as jellyfish or earthworms, which lack respiratory systems, breathe through their skin. (A dried-up worm on the sidewalk is dead because it has suffocated.) Our very distant ancestors, having started with something more or less like a fish’s swim bladder, developed lungs—a highly efficient mechanism for exchanging internal gases for atmospheric ones—and took to the land. It’s a beginning we each reenact on the day we are born. Though other organs function in utero, independent life starts the moment that our fluid-filled lungs inflate, for the first time, with our own breath.

And yet, Stephen argues, we have consistently overlooked the importance of our lungs (and not just by giving hearts all the glory in love songs). The details of our ordinary breathing – pacing, depth, and so on – get little attention in modern medicine, but Stephen tells us that breathing exercises, of the sort long promoted in Buddhism and Hinduism, may improve not just respiratory conditions but also depression and chronic pain. Some studies suggest that they can combat the damaging effects of stress; Stephen says:

that mobilizing the power of the breath has also been shown to turn on anti-inflammatory genes and turn off pro-inflammatory ones, including genes that regulate energy metabolism, insulin secretion, and even the part of our DNA that controls longevity.

The breath of life, indeed.

Meanwhile, diseases of the lungs, which have often been stigmatized as “dirty,” have trouble attracting research money and attention. (“Ignored, underfunded, and forgotten: this is the medical history of lung diseases,” Stephen writes.) You’ve likely never heard of idiopathic pulmonary fibrosis, though it affects more Americans than cervical cancer and has a much lower survival rate. Lung cancer is by far the deadliest cancer in America, but other cancers receive significantly more funding. Even as deaths from traditional killers such as heart disease and cancer are largely in decline in the United States, mortality from respiratory diseases is rising.

NOTE: And this was true before we lost hundreds of thousands of Americans to COVID-19, which kills most of its victims through acute respiratory failure.

Cases of asthma increase every year, and, globally, so do cases of chronic obstructive pulmonary disease, which is associated with smoking but also afflicts people who have never smoked. Lung cancer, too, is becoming more common among nonsmokers; in the United States, someone is diagnosed roughly every two and a half minutes. Worldwide, respiratory problems are the second most common cause of death, and the No. 1 killer of children under five.

We tend to think of a lung as a simple pump: one gas is pulled in, another is pushed out. In fact, Stephen writes:

It is an organ alive with immunology and chemistry, one that does an extraordinary amount of work under extreme stress from the moment we enter this world.

With each of the roughly twenty thousand breaths we take in a day, air travels through convoluted passages that can stretch for fifteen hundred miles, to one of the approximately five hundred million alveoli – tiny, clustered air sacs – that each of our lungs holds. Oxygen moves from the lungs to the bloodstream, as carbon dioxide flows back to the lungs. The brain stem controls the balance, which must be just right. Gas exchange has a remarkably immediate and intense effect on the body; one reason cigarettes are so addictive is the speed with which inhalation delivers drugs to the brain.

When you hold your breath, what feels like hunger for oxygen is really your body’s reaction to too much carbon dioxide, which turns blood acidic. When you breathe into a paper bag to quell a panic attack, it works because hyperventilating has tipped the balance in the other direction, leaving you without enough CO₂.

Lungs are a paradox. They are so fragile that an accumulation of the tiniest scars can rob them of their elasticity and function, so delicate that one of the pioneers of pulmonology solved a long-standing mystery about a deadly neonatal lung disease in part by reading a book about the physics of soap bubbles. Yet, unlike our other internal organs, nestled away inside us, they are open, like a wound, to the outside world. The respiratory system is regularly attacked by pathogens, to say nothing of allergens and pollutants. As a result, our lungs are home to vast numbers of protective cells that patrol them like sentries, and a lining of tiny hairs that constantly move a layer of cleansing mucus upward, ejecting all the invaders they can. Our lungs are both protection and portal, the nexus of our relationship with an environment that can heal us as well as harm us. In their deepest recesses, a wall as thin as a single cell is all that separates us from the world.

In December of 1952, a temperature inversion, a relatively common wintertime meteorological event, developed in the skies above London, trapping cold air under a layer of warmer air. Because the air could not escape, the already terrible pollution of the city grew so concentrated that, in some areas, people could no longer see their feet. Buses and cabs stopped running because of the poor visibility, and some people blindly wandered into the Thames and drowned. The air quality was such that even indoor events had to be cancelled, and the press reported cows dying of asphyxiation.

For five days, amid what became known as “the Great Smog”, Londoners got to know, too intimately, everything that the city emitted into the communal atmosphere – including coal smoke, from factories and homes, which mixed with fog and generated sulfuric acid. Enormous numbers of people were hospitalized, and, in the weeks and months that followed, an estimated twelve thousand died. Undertakers ran out of caskets.

For centuries, there had been failed attempts to reduce coal burning in England – among them a ban in 1306 by Edward I, who turned to fines, torture, and death threats; and, in the sixteen-sixties, a report written for Charles II that warned about the effects of “filthy vapour” on “this frail Vessell of ours which contains it.” But the region’s famous air pollution was dismissed as simply the cost of modern life. Four years after the Great Smog, though, Britain finally passed a Clean Air Act and began its long, slow transition away from coal. (In 2020, Britain set a national record by going sixty-seven days, twenty-two hours, and fifty-five minutes without burning any coal for power – a first since the Industrial Revolution.)

In the U.S., several years before the Great Smog, a winter inversion trapped the residents of Donora, Pennsylvania, in a cloud of emissions from local zinc and steel factories, sickening nearly half the town. The resulting outcry led to the first federal efforts to address air pollution, although America’s Clean Air Act wasn’t passed until 1963. People learned the hard way about the lack of separation between themselves and what they breathed.

Or not. In today’s world, episodes like the Great Smog are less famous but more common. In recent years, residents of cities from São Paulo to Sydney have watched as smoke from record fires, fuelled by climate change and deforestation, has blotted the sun from the sky. In November, 2017, air quality in New Delhi—a city that, like Seattle and Salt Lake City, is prone to winter inversions – was so bad that sensors tracking air pollution, including the level of particulates under 2.5 micrometres, which are small enough to travel deep into the lungs and even into the bloodstream, couldn’t keep up. (Levels above 200 are considered “very unhealthy”; most sensors maxed out at 999.) Poor visibility caused a huge pileup of cars on a highway, and Delhi’s chief minister tweeted that the region had become a gas chamber. But it wasn’t an isolated event. Last winter, government officials in Delhi cancelled flights, shut down schools, and declared a health emergency because of air pollution. Millions of children are now believed to have irreversible lung damage, and a local surgeon told reporters that he no longer sees pink lungs, even among young nonsmokers.

We’re still learning all that air pollution can do to our bodies. It can cause not just lung diseases and impaired lung development (in Los Angeles, researchers found that they could track the progress of anti-pollution measures by the increasing size of children’s lungs) but also, indirectly, heart attacks and osteoporosis. For first responders who breathed in clouds of dusty air following the 9/11 attacks on the World Trade Center, many of them without wearing protective masks, health problems often came in three waves. First, there were persistent coughs, and then, a few years later, asthma, sinus inflammation, acid-reflux disease, C.O.P.D., and pneumonia. Finally came cancer, heart disease, and stroke.

Nearly 3,000 people died during the deadliest terrorist attack on U.S. soil. But in the two decades since then, the number of deaths among survivors and responders – who spent months inhaling the noxious dust, chemicals, fumes and fibers from the debris – has continued creeping up. Researchers have identified more than 60 types of cancer and about two dozen other conditions that are linked to Ground Zero exposures. As of September 2021, at least 5,100 responders and survivors enrolled in the World Trade Center (WTC) Health Tracking Program have died from conditions directly attributed to conditions linked to Ground Zero exposures.

In the U.S. today, the bad air comes not just from industry but from industrial agriculture (with its emissions of ammonia, hydrogen sulfide, methane, and the like); according to some research, the two cause about the same number of air-pollution-related deaths each year. Forty-six per cent of Americans live in counties where the air is considered unhealthy, raising the risk of disease and early death, with the brunt borne by poor people and people of color, who are likeliest to live in the most polluted areas.

We know the dangers, and we also know that, according to the World Health Organization, more than ninety per cent of human beings live in places where we breathe substandard air. Yet this knowledge doesn’t much stir us. It feels symbolic that, according to the E.P.A., air pollution has decreased the distance and clarity of our vision—even in protected natural areas and even in our post-Clean Air Act country—by as much as eighty-three per cent, depending on where we live. We fail to notice how much the air we breathe is literally shrinking our own horizons.

In the summer of 2020, U.S. streets erupted in protest after a white police officer slowly and calmly asphyxiated a Black man named George Floyd by restraining him with a knee to the neck. Floyd repeated a phrase that other victims of police violence had said before him, and that took on an extra resonance amid a respiratory pandemic in which people of color, in part because they were already breathing the nation’s most dangerous air, have suffered disproportionately. In the Annals of Surgery, Sanford E. Roberts, a Black surgical resident in Pennsylvania, wrote that the parallels of the situation – of patients gasping for air while protesters chanted “I can’t breathe” – were “striking and suffocating.” The atmosphere may be a communal space, but its risks aren’t evenly shared.

2020 was full of grim jokes about what an awful year it was – sentient almost, weaponized against us. It began with fires in Australia that suffocated untold numbers of animals and sent coughing people fleeing into lakes, as well as an announcement that a pneumonia of unknown cause was circulating in Wuhan, China. As the year went on, the dangerous imbalance of gases that we’ve created in the planet’s atmosphere contributed to the most active Atlantic hurricane season in history, along with record rainfall in some places and punishing droughts in others. In Brazil, rain forests and wetlands burned. It was a relentless litany of news that began to seem united not just in awfulness but in theme. There is no escaping the air that we share.

On the West Coast of the United States, wildfires sent the smoky remains of trees and houses and lives swirling across thousands of miles. You could drive for hours and never see anything but smoke, which turned usual bluebird summer skies disquieting shades of orange and gray, and rendered the air toxic.

It was another grim joke: it wasn’t safe to breathe outside, because of the smoke, but it wasn’t safe to breathe inside, either, because of the pandemic. The air had never felt so communal, nor these vessels of ours which contain it so frail.