Asthma is the most common chronic disease for children. Swapping out polluting rides to school can lead to cleaner, healthier air for communities.
West Oakland, a neighborhood of less than 30,000 people on the northwestern tip of Oakland, Calif., is encircled by three major highways. In the latter half of the 20th century, construction of a postal service distribution center, a Bay Area Rapid Transit public transit line and a highway overpass sliced across once-bustling thoroughfares, dismantling a hub of Black culture and a burgeoning Black middle class. By the early 2000s, increased vehicle traffic from freeways, maritime activity from the port and local industry resulted in average diesel emissions more than 90 times greater than the rest of California.
Decades later, the legacy lives in the lungs of West Oakland’s youngest generation. Lisa Patel, a Bay Area pediatrician and executive director at the Medical Society Consortium on Climate & Health, has seen the impacts of chronic air pollution in real time.
“When a 2-year-old or 3-year-old comes into our emergency room, their lungs are so inflamed from that pollution that I can't even hear air pass,” Patel explained. “What that looks like on their face is just terror. Because they can't breathe, and they don't know why they can't breathe.”
Asthma is the most common chronic disease for children, and the symptoms are frequently exacerbated by air pollution entering children’s lungs. But in the shadows of highways and overpasses that bring air pollution into the East Bay, a solution is taking shape. Electric school buses are increasingly being deployed as a method to reduce children’s exposure to air pollution, with California leading the way.
The typical school bus runs on fossil fuels, releasing dangerous tailpipe exhaust while on the roads or idling outside schools and homes. Electric school buses, which run on electric battery technology that powers the vehicles through charging, have zero tailpipe emissions and are the only school buses on the market that don’t release harmful tailpipe pollution, removing a harmful irritant from a student’s commute.
Oakland is one of thousands of communities working to remove dangerous pollutants by switching to electric school buses. In 2024, Oakland Unified School District made history as the first major school district in the United States with an all-electric school bus fleet, transporting up to 1,300 special education students daily on 74 electric school buses.
Students with Asthma Suffer the Most
Eliminating daily exposure to diesel exhaust from school transportation is particularly important to the roughly 5 million children in the U.S. with asthma. Rates of disease vary by race and income level; 11% of all children living in poverty and 14% of all Black children have asthma. Pediatric asthma rates are 7.5 times higher in communities of color than most white communities in the U.S. The same population groups most likely to suffer from asthma and air pollution impacts — Black and low-income students — are also those most likely to rely on school buses.
“Often these are children of color, children who are experiencing poverty, and these kids will come in again and again with another asthma exacerbation,” Patel said of her patients. “What possibility is there for them to be healthy when they're constantly exposed to this pollution that we know is damaging their lungs?”
When air pollution is inhaled, it can trigger inflammation in the lungs, causing an asthma attack. Air struggles to move through inflamed passageways, and without enough oxygen, the cascading impacts are quick and sometimes life-threatening.
Asthma is one of the top causes of absenteeism, which in turn can influence a student’s success. Students who attend school regularly see higher academic achievement rates than those who do not.
Patel said she has heard from other doctors and nurses about children suffering from asthma attacks after riding the school bus. As an asthmatic, she always brings her inhaler along when she joins her own kids on field trips. That’s because the typical diesel-burning school bus releases diesel exhaust that contains particulate matter, gases like carbon dioxide and volatile organic compounds — all pollutants that can trigger asthma symptoms. Studies show that even a nine-minute bus ride can cause severe wheezing for children with asthma. Research increasingly highlights the dangers of air pollution on the lungs, brain and development.
What Makes Diesel So Dangerous?
When you stand beside a diesel-burning yellow school bus, the black smog that enters the air includes particulate matter. Particulate matter can be soot wafting off a campfire, dust and debris from far-off wildfire, tree pollen or the trails of smoke coming from a cigarette. Particulate matter is often classified into two categories: PM10 (smaller than 10 micrometers) and PM2.5 (smaller than 2.5 micrometers, or tinier than the widest part of a piece of human hair).
Fine particulate matter rates inside older diesel-burning school buses can reach 10 times the level of ambient air, which means that even short rides to school can account for high levels of PM2.5 exposure for students.
“Research on PM2.5 is harrowing,” said Amanda Millstein, a pediatrician in Northern California. “The more we learn about PM2.5, the scarier I think it becomes, and the more urgent it becomes to minimize exposure.”
Because PM2.5 is so small, it’s easier to inhale and more dangerous to health. And because kids have higher respiratory rates than adults as they develop, they’re breathing in more of these dangerous pollutants. In addition to PM2.5, the diesel exhaust released from fossil fuel-burning school buses contains volatile organic compounds (VOCs) and nitrogen oxides (NOx) at levels that are unsafe for inhalation. Diesel exhaust is a carcinogen and the chemicals in diesel exhaust are associated with respiratory conditions, heart conditions, central nervous system issues and impaired brain function, among other issues.
The Clean Air Task Force estimates that in 2023, diesel exhaust from all sources led to nearly 9,000 deaths, 4,000 heart attacks, 6,000 cases of acute bronchitis and over 105,000 cases of exacerbated asthma in the U.S.
Globally, air pollution is responsible for millions of premature deaths and millions of metric tons of greenhouse gas emissions that contribute to climate change and worsening heat, storms, droughts and wildfires that threaten lives. And air pollution is not equally experienced: People of color have disproportionately higher exposure to PM2.5. In California, for example, an analysis of air pollution found that communities of color are exposed to 21% to 43% more vehicle particulate matter air pollution than white Californians.
Neelu Tummala is an ear, nose and throat doctor in New York City. Her practice handles the impacts of inhaled pollutants on upper airways. Pollutants can cause inflammation in the nasal mucosa and lead to headaches, congestion and facial pressure. When kids breathe in exhaust waiting for the bus or while boarding it, it can cause irritation and congestion that make it hard to focus; when caregivers are exposed to the same pollutants, it can impact their workday, and the impacts for individuals at any age can hamper sleep quality.
“The story behind air pollutants is not a one-and-done story,” she said.
It’s not limited to the upper airway or the lower airway. Pollutants enter the blood stream and can increase cardiovascular disease risk, and when they cross the blood-brain barrier, they can impact mental health and increase risk of stroke. The dangers of diesel exhaust and air pollution extend to pregnant woman and fetuses, increasing risk of pre-term birth and low birth weight.
“[These pollutants are] going everywhere in the body,” Tummala said, “The part of the body that I take care of is the first entry point of these air pollutants. Even starting right there, when they first entered the nose, they're already causing inflammation, they're already causing symptoms.”
Family Impacts and Greater Consequences
Asthma also impacts the whole family, Millstein explained. Watching a child struggle to breathe is upsetting. Logistical uncertainty of crowded emergency rooms, long waits and inconsistent appointments can keep caregivers up late and out of work. Depending on their workplace, caregivers can find their job security and wages threatened if they miss time to address a child’s illness.
And these issues aren’t one-off occurrences for most families, Millstein added. It’s much bigger than an isolated breathing treatment.
“This is just part of their life where every few weeks, every few months, their kid’s asthma flares and they need medication that they can't give that home, like oral steroids, magnesium, continuous albuterol,” she said. “And then they're dealing with the real impacts of what that does to a whole family.”
To make matters worse, the U.S. healthcare system is strained across the system, and treatment of children has taken a measurable hit. An analysis of 3,000 hospitals between 2003 and 2022 found that the number of hospitals providing the lowest level (offering only minimal services) of pediatric care doubled in that time, with corresponding decreases in hospitals with high pediatric capability. There was a 41% drop in hospital capability for asthma hospitalization.
On the other hand, research has shown that swapping out diesel-burning buses for electric school buses can provide substantial positive health and climate benefits, to the tune of $1.6 billion annually in societal benefits. The numbers consider the reduction in excess mortality caused by PM2.5 exposure that is minimized when diesel-burning buses are replaced by electric school buses.
“Increasingly, we don't have resources to care for children in our hospitals as more hospitals close and pediatrics wards are shut down. We should do everything we can to keep children from getting sick and requiring hospitalization in the first place,” Patel said.
“At the least, we shouldn't be making the burden of pollution worse for kids that are having to live around this pollution all the time. Because as it is, that pollution is already setting them up for lungs that can be asthmatic.”
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