SAN FRANCISCO — Ian MacDonald, a 14-year-old in Portland, Ore., got a treat from his parents the other day. He was allowed to go outside.
It was for less than five minutes. “I let him take out the garbage. We wore N95 masks,” said his father, Dr. Kelvin MacDonald, who has been insisting his family stay in the house as wildfires flare nearby. Dr. MacDonald is a pediatric pulmonologist, and he is concerned about the health risks to children from the ashen-thick air.
“It is unethical to expose them and find out what happens 50 years from now,” said Dr. MacDonald, who is also an associate professor of pediatrics at the Oregon Health & Science University. While the science is still emerging, he said, the thrust is already clear: “This does not look good for children.”
The fire that is breathing down the Pacific Northwest and parts of California poses particular peril to young lungs, and is especially acute for children with medical conditions like asthma, which afflicts one in 12 children. Their lungs can become so inflamed by the micro-particles that airways may close, creating — in extreme cases — mortal threat.
Healthy children exposed to wildfire smoke at the current levels, even for just a few weeks, can become vulnerable to infection, too, in some cases triggering latent asthma. Such exposures can heighten existing asthma symptoms and increase hospital visits, according to the Centers for Disease Control and Prevention and research from the Environmental Protection Agency.
In the short-term, smoke can kill immune system cells that protect the lungs from pneumonia and other disease. In the long run, doctors fear, such toxin exposure could prompt asthma in children with a genetic predisposition but who might otherwise not have contracted it.
Much of 2020 has been spent focusing on imperiled lungs of the older and the infirm, who are at greater risk of Covid-19, but these fires prey on developing lungs, experts said.
Dr. John McQueston, a pediatric pulmonologist who works for Randall Children’s Hospital in Portland and serves satellite clinics in some of the hardest hit regions in the state, predicted a spike in asthma-related illness.
“I would not be surprised if six months from now, when children have problems with asthma, I’ll ask their parents, ‘When did it start?’ And they’ll answer, ‘It happened right after the fires,’” he said.
The intensive care unit at the hospital where he works admitted a boy under the age of 5 who was having a severe asthma attack apparently made so by the smoke. Dr. McQueston said the boy recovered, in no small part by getting into the hospital’s clean air.
In recent days, Dr. McQueston has dealt with a handful of other cases involving asthmatic children living just downwind from fires; they had intensified symptoms but had been treated at home with medication. Dr. McQueston said there might well be more acute issues in the region if not for the coronavirus pandemic, which was already keeping so many children at home and less exposed to infection.
In Oroville, Calif., near some of the state’s worst fires, Dr. Sidharth Bagga, a pulmonary critical care specialist for children and adults, said he and his colleagues were receiving “drastically more phone calls” about lung health for people of all ages. He’s particularly concerned about the children, though, because many seem to be playing outside still.
“My fear is parents don’t realize it is unhealthy,” he said, and that the smoke can act as a “trigger” for long-term respiratory challenges.
“We’re creating the next generation of smoke or respiratory cripples by letting them be exposed to this without realizing this is what is actually happening,” Dr. Bagga said. To support this concern, he estimates that 5 to 10 percent of patients he sees regularly and who come in with new asthma or respiratory distress say they first felt symptoms after a fire.
Longstanding evidence from more polluted nations shows the risks of unhealthy air to developing lungs, with one estimate showing that, worldwide, 237,000 children under age 5 died in 2015 from asthma and other conditions associated with air pollution, mostly in Asia and Africa.
The research on wildfires is more recent, reflecting the fact that industrial pollution has been considered more common. But researchers say the differences might not be so pronounced in that the wildfire air carries tiny particulates that threaten lungs from scorched trees, cars, homes and businesses and industrial areas, Dr. MacDonald said. “It could be pretty bad if man-made objects are being burned.”
If the science remains murky, the bottom line seems plain, experts said.
“In the absence of a compelling reason, it’s best to keep the kids at home,” said Dr. David Cornfield, chief of pulmonary, asthma, and science medicine at Stanford Children’s Health. He was involved in cases of two children with severe asthma who died after exposure to smoke from wildfires, one in 2016 and one in 2013.
Air quality is measured by the density of pollutants; when a widely used index of air quality developed by the E.P.A. reads below 50, conditions are considered safe. That index has well exceeded 400 in the areas around Portland, causing them to be labeled “hazardous” and an “emergency situation,” while the levels in the San Francisco Bay Area, hovering between 200 and 300, are “very unhealthy.”
Dr. Cornfield said he didn’t want to be too prescriptive about what precise level should keep children inside but said a decent guideline is to cease outdoor activity at 100. Above 150, he said, “you don’t really want to have people sitting outside.”
That puts a major crimp in school reopening plans, which are predicated on keeping windows open, having ventilation, even holding outdoor classes to stanch the spread of the coronavirus. That, too, preys on the lungs, so administrators are now caught between wildfires that would call for tightly insulated schools and the threat of the virus, which argues for open air.
“The schools are playing with fire — literally,” said Rachel Murphy, who teaches special education at a private preschool in Portland. The school closed for air-quality reasons but Ms. Murphy and her husband, Jeff Jensen, have a challenge at home, too: Their 5-year-old daughter, Cora, has asthma so severe that, even in ordinary circumstances, she coughs her way through sentences.
Now, the air outside has smelled “like a campfire,” Ms. Murphy said, and thanks to the aging windows in their fixer-upper home in the Portland suburb of Tigard, they “are getting lots of smoke in the house.”
For the last few days, Cora hasn’t seemed like her usual chipper self, her parents said. She has been sleeping in later than usual and falling asleep at night without a fight. “Usually at bed time, when I go to lay down with her, she’s flapping all over the place,” her mother said. “But yesterday, she laid down next to me and went right to sleep.”
It has left Cora’s parents to wonder if lethargy could be tied to the fires and the asthma, but so far Ms. Murphy said she was trying not to panic. Ms. Murphy said she would take the girl to the doctor is she developed pronounced symptoms.
The couple also has a 2-year-old son, Benjamin, who does not have asthma and has clamored to go outside, to no avail.
“We bought a swing set during Covid so they could go outside,” said the children’s father, Mr. Jensen. “Now they can’t go into the backyard.”
During fires in 2008, researchers in Northern California allowed infant rhesus macaque monkeys to be exposed to 10 days of wildfire smoke and compared their lung function at the time and in the years that followed with the lung function of a group of rhesus monkeys that had not been exposed to the smoke.
The exposed animals “had significant reduced inspiratory capacity,” the researchers reported. There was a drop in immune-system functions, which could predispose the primates to infection. That can lead to “less ability to clear virus and bacteria,” said Dr. Ngoc Ly, division chief of pediatric pulmonology at the University of California at San Francisco.
Research shows that human children face challenges, too, from pollution over all and wildfire. A study of a fire that burned 4,200 acres in San Diego in 2017 — a blaze far smaller than the ones in the West today — found sharp increases in emergency room visits — 16 excess visits per day — at a children’s hospital in the region during a span of around 10 days during the fire.
A study of hospital visits during and just after wildfires in San Diego in 2007 found a 136 percent increase in asthma-related emergency-room visits for children ages 4 and under. The study concluded: “Young children appear at highest risk for respiratory problems during a wildfire, which is cause for particular concern because of the potential for long-term harm to children’s lung development.”
Children have been less well studied than adults but experts said the challenges of youth are very likely intensified by at least three key differences: children’s lungs remain in development, which means their immune systems may be altered; their airways are narrower; and they simply breathe more often and faster. That leads to more toxic intake for their body mass. “Infant respiration may be double or triple adults,” said Dr. Cornfield of Stanford.
At the particularly high levels of smoke in places like Portland, Dr. Cornfield said, at the least, families should consider getting an air filter or using air conditioning to the clear the air inside. In a perfect world, he would urge stronger measures, at least for the short term.
“I honestly think that if there’s the potential to relocate to a less challenged environment, one should really do that,” he said. “Most people are not so blessed with a plethora of options.”