“What is happening?” a young father asked me in the summer of 2018, as he sat on the hospital bed of his three-year-old son. He was looking out the window at a blanket of gray smoke covering Reno for a third week; in front of him, gauzy shadows of downtown buildings came and went in the slow-moving haze.
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The smoke had flowed over the mountains from the Carr and Mendocino Complex fires in Northern California, filling our pediatric ward with coughing children. His son and the other child in the room, my four-year-old patient Liam, were both on oxygen, delivered through a nasal cannula. The thin clear tube crossed from ear to ear, with prongs in both nostrils and a circle of tape on each cheek, holding it in place. Neither boy had ever wheezed, or needed oxygen, before.
I was standing between their beds, unsure if the father’s question was really directed at me. Suddenly to my right, Liam rubbed his face, crying, and pulled the nasal cannula out. A beep beep beep signaled that his oxygen level had dropped; his mother calmed him and put the prongs back in his nose.
There was no way to protect their own children without fighting for all children. The only medicine we had was each other.
“You’ll be home soon, buddy.” I smiled, then caught myself: soon meant something very different to a preschooler than it did to me. He looked defeated as his small rebellion failed.
It had been five years, almost exactly, since Anna’s visit to my clinic during the Rim Fire. Though smoke had pulsed through the city every fire season, this was our worst air quality crisis since.
For most of that month, we had not seen the sky; our world had shrunk to a few feet. All of our nerves were fraying. Driving to the hospital that morning I had been startled to see a teenage girl in a fast-food uniform emerge from the smoke as I passed. She was walking on the sidewalk, clutching a large white towel over her face. In the rearview mirror I watched her dissolve again as if she’d been an illusion.
Now, in the hospital room, I wondered what lay ahead of her and these two little boys. I looked at Liam, who normally couldn’t stay still, limp in his bed, connected to the oxygen pump and monitor, a few spikes of sweaty hair stuck to his forehead. His mother was side-saddled next to him, gently rubbing his chest. He had snuck outside to play one day, and it had landed him here.
His roommate, the three-year-old, in his tiny pediatric gown, was staring at the television on the opposite wall. It was perched among glossy, bright-colored geometric shapes, beneath overhead light panels that looked like blue sky and clouds. From the TV a reporter in a windbreaker looked back at the little boy. She was holding a microphone in one hand and pointing, with the other, to a hillside of burning trees.
His father was still mesmerized by the Twilight Zone episode outside.
A moment ago, he had told me he was a landscape worker—and that this past month, with its ugly air and record-setting temperatures, had been hell. Then he’d coughed into a muscular arm bent over his face, both darkened by the sun.
What is happening. His question hung in the room. I glanced at the television, wanting the reporter to answer. But she wouldn’t name this crisis, even as she pointed to it.
My head ached and my eyes stung after the short walk through the smoke from my car. With my background in forestry and environmental science, I was better equipped than most pediatricians to explain what we were living through. Since the Rim Fire, more than a hundred scientific studies have all pointed at the same cause. I knew why 129 million trees had died to our west, and now dotted the mountains like brown pox. Why heat was rising, making those dead trees explosively dry. How forest managers and utility companies had neglected this growing danger, allowing tinder to accumulate. Why wildfires were much bigger, longer lasting, and erupting more months of the year. Why his son and Liam were here.
I don’t usually dodge difficult topics, even when parents and I disagree. But decades of propaganda and partisan warfare had made climate science political. Saying out loud what we could all see happening—out the window, on television, in this pediatric ward—risked something I treasured: my relationship with patients’ families.
Yet as I stood there I realized another reason the words were stuck in my throat. Naming what gripped our city would make it real—and there was no medicine I could offer to fight it. For every other problem I discussed with parents, I could give advice or a prescription, an order for a lab test or a referral to a specialist. I could tell them what to do to help their own child. But for this, what could I say?
There was no way to protect their own children without fighting for all children. The only medicine we had was each other. The only thing we could do was speak up, together, against the corporations whose decisions had led us here. Because this smoke, these sick children, our learned helplessness and silence—all were a measure of their strategy, and the billions they had spent to get their way. And we were behaving like passengers in their car, failing to grab the wheel as they drove the world’s children, faster and faster, down this slope.
“It’s climate change,” I said.
The father froze. Then he turned to his son and, smiling faintly, squeezed the small foot poking up through the sheets. “Yeah,” he said. He knew the answer to his own question. He didn’t want to say it, either. But Liam’s mother leapt at the realization that we were all thinking the same thing. “Haven’t you heard, Dr. Hendrickson?” she asked, extending one palm toward the window, and the other to her son and his machines.
“We don’t need to worry. It’s not real!”
*
I said my good-byes and left—feeling suddenly, weirdly, hopeful. Instead of an argument, I had found an ally. And with just a few words of sarcasm, she had pulled aside the bleak curtain of those weeks to expose the obvious: the climate crisis wasn’t only tragic, it was absurd.
I walked down the gleaming hallway, past more rooms of coughing and crying and beeping machines. I knew that pediatricians across the West were witnessing similar scenes. When I was a child, the country had never seen a wildfire bigger than 100,000 acres; now these “megafires” cursed cities from Seattle to Los Angeles to Missoula, and over 7 million children breathed smoke for part of every year. “Fire season” had joined “flu season” on my mental calendar of cyclical illness, and I had begun to dread the warmest months—previously a time when my schedule slowed.
But what, exactly, was in the smoke that was making these children sick?
At one level, the answer to that question was obvious. When the television reporter pointed at those burning trees, or later stepped through ashen neighborhoods, she was showing us what we were breathing. Megafires vaporize nearly everything they touch, and their smoke is packed with all of it.
In most fires, the people downwind never get a full accounting of what they’ve inhaled. But during the Rim Fire, special aircraft had collected samples of our dark air for analysis. Almost four years later, we were told that the smoke held 3 times more particle pollution than previously thought, as well as elevated levels of about ninety other compounds—including formaldehyde, benzene, and hydrogen cyanide.
Of these, particles—tiny fragments and droplets from trees, houses, cars, and whatever else has burned—are usually considered a wildfire’s most dangerous pollutant. Smoke is dense with sooty debris, but the ash and cinders we see are not as harmful as what we can’t: enormous quantities of microscopic “particulate matter.” The smallest particles regulated by law, PM2.5, are less than 2.5 micrometers in diameter—only about 1 ⁄30 the width of a human hair. Wildfire smoke also carries huge amounts of even smaller “ultrafine” particles, less than 0.1 micrometer wide.
Bits of what once was, particles can be carried for thousands of miles in the wind. Because of their minute size, they can also be pulled deep into the lungs; the smaller the particle, the more invasive and hazardous for human health. The finest particles easily cross the alveoli, enter the bloodstream, and wreak havoc on multiple organs, including the heart and brain.
Particle pollution is not exclusive to wildfires. Fossil fuels—whether burned in coal-fired power plants, diesel trucks, airplanes, or cars—are the most important source. Over the last half century, the Clean Air Act reduced emissions from tail pipes and smokestacks across the country. Yet scientists estimate that in 2018 an astounding 13 percent of all deaths in the United States, and 8.7 million deaths worldwide, were caused by particles from fossil fuels.
Now, as wildfires intensify, airborne particles are surging, especially in the western US, becoming a major health threat tied to the climate crisis. Between 2017 and 2021, both the severity of smoke pollution and the number of Americans exposed to it rose; at the end of that period nearly 64 million people lived in counties badly affected by wildfire particles, the most ever.
Almost all the cities with the worst “short-term particle pollution” are in the West. But as wildfire smoke from Canada engulfed the Northeast and Great Lakes regions in 2023, giving New York, Chicago, and other previously spared cities their worst air quality in history, many Americans saw that the health impacts of burning forests won’t stay confined to western states.
Wildfire smoke causes more health problems for children than just brief coughing and wheezing.
The implications of these trends are sobering. As many as 3,000 Californians over the age of sixty-five were likely killed by PM2.5 during the record wildfires of 2020—many times the number of people who died in the flames. In adults, particle pollution increases the risks of heart attacks, strokes, lung cancer, chronic obstructive pulmonary disease (COPD), diabetes, kidney disease, and dementia.
COVID-19 appears to be more easily transmitted, and causes greater illness and mortality, in areas with higher particle pollution; Reno saw an 18 percent rise in cases tied to the 2020 fires. Exactly how much worse the pandemic’s toll was in the West, because of smoke, is unknown. What is clear is that when particle levels jump in a city, the non-accidental death rate does, too.
Very few studies have examined the impact of wildfire smoke on children. It’s a difficult question to answer fully because smoke’s contents are complex and differ from one fire to the next. But three studies that focused on the particulate matter in smoke—from Southern California wildfires in 2003, 2007, and 2017—found that it alone had a significant impact on children’s respiratory health. Children and teens downwind suffered higher short-term rates of asthma, bronchitis, pneumonia, sinus infection, and allergy symptoms. The bigger the dose of smoke a community got—the more days of bad air, or the higher the particle levels—the more respiratory illness among its kids. One of the studies found that children under five years old were most affected.
Based on these findings, I assumed that particles were the main culprit behind Anna’s and Liam’s coughing, wheezing, and shortness of breath during the fires. Further evidence would come a few months after Liam’s hospitalization, when health researchers from our state university showed me local air quality data plotted against daily all-ages medical visits for asthma. Every major wildfire leapt from their graph: a wave of particle pollution, rising and falling over a string of days, and a second wave, of illness, mirroring the first but lagging by a day or two. I knew my young patients were somewhere in those curves.
When the smoke cleared, so did their symptoms. But I have reason to worry that their exposure to wildfire particles might have lasting effects. In recent research from Stanford University, blood tests on school-age kids in central California revealed that particulate matter from a single, nearby 2015 megafire had actually changed their DNA. Specifically, the pollution had altered a gene needed to form T cells, a vital part of the immune system. As a result, the children made fewer, less healthy immune cells, raising their later odds of allergies and infections.
Not all particles are created equal. Particles from wildfires cause more lung inflammation and hospital admissions than those produced by fossil fuels. In fact, a multiyear study in San Diego County found that PM2.5 from wildfires was roughly 10 times more likely than particles from other sources to cause breathing problems in children, especially if they were under five years old. And particles from megafires seem to inflict more damage than those from smaller, controlled fires. This may be because megafires’ intense heat and destructiveness produce more ultrafine and toxic particles, including “black carbon,” an irritating microscopic soot that binds to chemicals and heavy metals in the smoke. Climate change is thus increasing not just the quantity of particles but also, apparently, their toxicity.
This creates another outsized threat to the young. Take, for example, polycyclic aromatic hydrocarbons (PAHs), cancer-causing chemicals that are often bound to particle pollution. Although PAHs are a threat to everyone, an adult’s liver contains enzymes that break down these chemicals so they can be excreted. Other adult enzymes repair pollutant-damaged DNA in our cells, reducing the odds of cancer. But in fetuses, babies, and children, these defenses are immature, so exposure to the same “dose” of PAHs is more likely to cause harm.
Some of my patients’ families have tried to escape smoke’s dangers by moving from the West; since megafire pollution disperses across the country, however, and since wildfires are spreading to other regions, it is difficult to avoid completely. Others forget about the smoke when our skies return to blue, or believe next year will be better. The rest of us are trying to adapt to our new, seasonal reality. Even before COVID-19, I recommended N95 face masks for my patients during wildfires. If they are too young to wear one, I recommend a fabric cover over the car seat. Air purifiers are now found in any home that can afford them, though some families make their own from instructions available online.
Schools keep kids inside on “smoke days” or cancel classes altogether; some have installed special ventilation systems to filter both viruses and particulates. We are all doing our best to cope. Yet most parents in my clinic are understandably anxious about the fires. No one really knows how repeated exposure to smoke is affecting their children’s long-term health. Will its toxic chemicals increase childhood cancers? Will its particulate matter cause local kids to have more heart disease as adults?
Data on these questions are basically nonexistent. But we have good reason to believe that wildfire smoke causes more health problems for children than just brief coughing and wheezing. That’s because of a large body of research on particles from other sources—namely, fossil fuel burning.
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Excerpted from The Air They Breathe: A Pediatrician on the Frontlines of Climate Change by Debra Hendrickson. Copyright © 2024 by Debra Hendrickson. Reprinted by permission of Simon & Schuster, Inc. All rights reserved.
