How Climate Change Is Punishing Asthma Sufferers

A warmer world puts greater strain on already-struggling lungs.

Jillian Alfieri didn’t even make it through her first seven months before asthma started having its way with her. The now 13-year-old had just been placed in her stroller for an early evening walk when her parents noticed that she seemed to be battling to breathe. 

“At first, we thought she was choking,” says her father, Rob, a stay-at-home parent in New York City. “She couldn’t catch her breath or make a sound. She finally started to cry, and we looked at the base of her neck and saw it going in and out as she was trying to inhale.”

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Rob and his wife, Jaimee, an HR director for a Manhattan law firm, rushed Jillian to the pediatrician, who put her on a nebulizer mask to stabilize her breathing and diagnosed the episode either as a possible one-off that would not repeat itself or a first bout with asthma—depending upon whether the problem returned. It did, six months later, and with that, Jillian joined the nearly 4.7 million other asthmatic children in the United States—children who know the special fear of having to fight for their very breath.

It’s a bad time to have what is already a bad disease. The U.S. Centers for Disease Control and Prevention (CDC) reports that asthma diagnoses have not budged much in the past generation, going from 7.4% of the U.S. population in 2001 to just 7.7% in 2021. But the severity and frequency of asthma attacks is another thing entirely. Across the country, pulmonologists, pediatricians, and other doctors are reporting more and more visits to their offices and to emergency rooms by more and more people—especially children—suffering from worse and worse asthma torment. One of the biggest likely reasons: climate change.

Last summer was the hottest on record, according to the National Oceanic and Atmospheric Administration, and the 10 warmest years the Administration has tracked were all from 2010 to 2022. Before summer even officially arrived this year, the U.S. suffered through a Northeast and Midwest heat dome that saw temperatures records broken across the map. Weather like that is murder on the lungs, with pollen counts rising, ozone levels soaring, and diesel exhaust and other particulate pollution getting trapped by stagnant air.

“We understand a lot more about asthma, and we have great therapies to treat it,” says Maureen George, a registered nurse at the Columbia University School of Nursing and an expert in asthma in urban settings. “But we haven’t made good inroads in the incidence of it, and so we think climate change is one of several things that is going on.”

George is not alone in seeing a link between a warmer world and worsening breathing. “The peak of the complaints I see from patients are mostly happening as the seasons are getting hotter,” says Dr. Jessica Hui, an allergy and immunology physician at National Jewish Health in Denver. “With climate change, not only is our pollen season longer, but our pollens have become more allergenic.”

All age groups can suffer from asthma: Jillian’s mother, Jaimee, is 51 and has battled the disease on and off since she was 18. More than 20 million adults are diagnosed as asthmatics, according to the CDC, but children suffer more severe symptoms—for a number of reasons, not least being simple anatomy.

“Kids aren’t just little adults,” says George. “Their bodies are different. They have higher respiratory rates and take in a greater volume of air per kilogram of body weight, so they’re getting more exposure to inhaled allergens.”

What’s more, children are not only likelier to be playing outside than adults are, but they’ll roll and tumble close to the ground. “Ozone and allergens hang just above ground level,” says George. “So children’s smaller lungs and their pattern of breathing and their outdoor play all put them at greater risk.”

Asthma tends to run in families, as Jillian and her mother suggest. For reasons that are not yet clear, boys have a somewhat higher rate of asthma than girls: 8.3% to 6.7%. But in the 18 and above group, that differential flips, with 5.5% of men and 9.7% of women diagnosed with the disease, according to the American Lung Association.

“It would seem that it may be hormonally driven,” says George, “but I don’t know that anyone understands what the mechanism is.”

Read More: How Complementary Medicine Can Help People With Asthma

Why summer is the cruelest season

Even before the onset of climate change, summertime was always a punishing stretch for people with asthma. Hot, humid, sticky air not only leads to greater inflammation of sensitive airways, it also can also entrain pollutant particles, especially those measuring less than 2.5 micrometers—or millionths of a meter. So-called PM 2.5 particles easily penetrate deep into airways and lung tissue and lodge there, causing irritation and constriction. 

“Exhaust particles, particularly from diesel fuel, are carried into the body and retained by tissues,” says Hui. “The pediatric population is especially vulnerable because their airways are smaller.”

Tailpipe and smokestack emissions are not the only source of PM 2.5 particles. Pollen grains can be a problem too. Pulmonologists have long observed that asthma attacks often occur during summertime thunderstorms, partly because wind gusts can lead to greater dispersal of pollen, but also because lightning can rupture the grains, fragmenting them below the PM 2.5 threshold. 

“You see this during the most extreme storms,” says Dr. Jonathan Spergel, chief of the allergy program at the Children’s Hospital of Philadelphia. “You get really acute exacerbations of asthma because the fine particles are easier to breathe in.”

Summertime ozone levels are another pulmonary irritant. A three-atom oxygen molecule, ozone is found naturally in the upper atmosphere, but can form closer to the ground when nitrogen oxides, produced by smokestacks and tailpipes, and volatile organic compounds, produced by consumer products like paint and household chemicals, combine in the presence of sunlight. Exposure to the gas, like exposure to PM 2.5 particles, can be an acute airway irritant. The problem is worse in urban settings and especially in lower-income communities, which are likelier to be situated hard up against highways. Just shy of 11% of Black, Native American, and Native Alaskan communities have asthma, compared to 7.7% of whites, according to the American Lung Association.

“We see this interplay between ozone and hot weather,” says George. “That leads to lung inflammation, and it’s all kind of tied up in global warming.”

Wildfires fueled by climate-change related droughts and heat waves are another increasing problem for people with asthma. Last year’s Canadian blazes put 71,000 square miles of land north of the border to the torch and caused a yellow haze to descend across much of the U.S., from the Midwest to the Northeast to the mid-Atlantic states. California’s wildfire season now runs from April through October, peaking in the summer. Of the state’s 20 largest fires, half occurred from 2017 to 2022. 

“Smoke is a big trigger for me,” says Jillian’s mom, Jaimee. “When we had those wildfires last year I was on my [rescue] inhaler quite a bit.”

Mold is yet another asthma trigger, one that is especially common in hot, humid air. And while closed windows and air conditioning can keep ozone and PM 2.5 particles at least partly outside, mold is often an indoor scourge. Indeed, the mere fact of trying to shelter in place indoors when heat and humidity are at their worst can expose kids to a range of asthma triggers, including exhaust from gas stoves, formaldehyde given off by furniture fabrics, indoor pests and pesticides, and secondhand smoke. 

“People think, ‘Hey, just don’t go outside today,’” says Hui. “But indoor conditions can actually be much worse.”

September, which technically spells the end of summer, is by no means the end of asthma. Indeed, the Asthma and Allergy Foundation of America (AAFA) warns patients of what it calls the September Asthma Epidemic. For one thing, summer heat can easily persist straight through the month—and well into October as global temperatures climb. What’s more, ragweed pollen peaks in September, and falling leaves, often made sodden by rain, can cause mold to grow. And as schools reopen, kids are exposed to more respiratory illnesses like colds, RSV, and COVID-19.

“Whenever Jillian gets a cold, it goes straight to her chest,” says Rob, her dad. “When she was little, the doctor would tell us to pull up her shirt to see if her stomach was going in, as if she was digging deep, trying to breathe.”

Read More: What to Know About the Latest Advances in Managing Severe Asthma

Easing the breathing

Asthma patients are hardly without recourse. More medications than ever are available both to treat acute flares and prevent them before they happen. So-called rescue inhalers are more technically known as short-acting beta-agonists, because they bind to beta receptors surrounding the airways, causing them to relax. More prophylactically, patients can take corticosteroids, which reduce inflammation in the lungs, keeping airways clear in a more consistent way. Those drugs too are commonly dispensed by inhalers.

“Corticosteroids work to reduce swelling inside the lungs, while rescue inhalers relax the muscles that are squeezing airways from the outside,” says George. Increasingly, doctors are prescribing combination inhalers that include both drugs in a single dose. “That’s one of the big paradigm changes in asthma treatments,” George adds. “The new products have come on the market just in the last year.”

Other medications include what are known as leukotriene modifiers, which block the action of inflammatory chemicals the immune system produces in the presence of allergens. Also increasingly used are drugs known as biologics. They target a class of inflammatory white blood cells known as eosinophils, which are also produced in the presence of dust mites, pet dander, and other allergenic triggers.

“Sixty percent of kids who have asthma have the allergic variety, and the same is true of 40% of adults,” says George. In many people, asthma is part of what’s known as an atopic march—a genetically driven cascade of disorders culminating in pulmonary symptoms. “People first develop eczema as a child, and then later develop hay fever and seasonal allergies, and then the next thing they do is get asthma. It’s pretty much a clear pathway.”

That march may be slowed or even stopped, however. The simple passage of time can often help. As children pass into their teens and young adulthood, asthma will often go quiescent. But about half of people who had asthma in childhood will manifest it again in their 30s and 40s, according to the AAFA.

Taking medications as prescribed is, of course, another critical tool. So too is staying active. That can be a challenge in summer—the very season in which non-asthmatic kids are outside the most. But timing outdoor activities for early in the morning or closer to sundown, when temperature and pollen counts are lower, can help.

“Being active and having the ability to go outside is still a mainstay for treatment,” says Hui. 

Jillian’s parents planned to keep her indoors when the June heat dome descended over New York, but otherwise are mindful of her need for exercise and freedom. And as she enters her teens, her symptoms have subsided at least a little. 

“She’s not on steroids right now,” says Rob. “We wanted to see if she still needs it because she’s 13. Luckily, she hasn’t had to go to the hospital or go back on the medication.” Like any parents of an asthmatic child, Rob and Jaimee can only hope their luck—and Jillian’s—will continue to hold.