As millions of children return to school this August, parents and teachers are thinking about the year ahead. Are classrooms safe? Is the drinking water clean? Are buildings prepared for another year of learning?
There is another question we should be asking: What are our children breathing while they are at school?
Air quality is one of the most overlooked factors in creating a healthy learning environment. We have established clear expectations around clean drinking water, but we have been much slower to recognize that the air children breathe for six or more hours a day deserves the same attention.
This is especially true for schools located near major roads and freeways.
The freeway next door
Across the United States, thousands of schools are located near busy highways and major transportation corridors. A nationwide study of more than 114,000 U.S. public and private schools found that about 15% of those studied were within 250 meters, or roughly 820 feet, of a major roadway. The study estimated that 6.4 million students attended those schools.
The EPA has similarly highlighted that nearly 17,000 schools are within one-tenth of a mile, or 100 meters, of a major road. Vehicle pollutant concentrations tend to be higher closer to roadways, with the highest levels generally occurring within the first 500 feet.
These numbers represent millions of children spending their school days near a significant source of air pollution.
Vehicles produce pollutants including fine particulate matter and nitrogen dioxide. These pollutants can enter school buildings through ventilation systems, open doors and windows, cracks, and other pathways. A child can spend most of their school day indoors and still be exposed to pollution generated just outside the school walls.
I’ve seen this firsthand in Boyle Heights, California. Surrounded by major interstate freeways, schools in the area bear a disproportionate pollution burden compared with schools farther from major roadways. IQAir installed air quality monitors and filtration systems in schools there because we recognized the importance of understanding what students were breathing and taking action to improve the air.
Boyle Heights is one example of a much larger challenge.
The same nationwide study found that schools serving predominantly Black students were 18% more likely to be located within 250 meters of a major roadway. Schools serving more economically disadvantaged students were also more likely to be located near major roads.
The burden of traffic-related air pollution is not distributed equally. For many communities, where a child goes to school can influence the quality of the air they breathe.
Map A displays the number of students attending a US school within 250 meters of a roadway in 2014, while Map B shows total percentages. Source: National Institutes of Health National Library of Medicine
Children are more vulnerable
Children are not simply small adults. Their lungs are still developing, they breathe more air relative to their body size, and they spend a significant portion of their day in schools.
The World Health Organization estimates that 99% of children worldwide breathe air that exceeds its air quality guidelines. In the United States, the EPA estimates that children spend approximately 90% of their time indoors.
Exposure to air pollution during childhood has been associated with respiratory problems, including asthma, and can affect developing lungs. If a school is next to a freeway, understanding outdoor air quality should be part of understanding indoor air quality.
We can't manage what we don't measure
Air pollution is difficult to address because much of it is invisible. A classroom can look clean while containing elevated levels of particulate matter or other pollutants.
That is why schools need reliable air quality monitoring. Monitoring can help identify changes throughout the day, reveal differences between indoor and outdoor conditions, and determine whether ventilation and filtration strategies are effective.
For schools near freeways, this information is particularly valuable. Pollution levels can vary based on traffic patterns, weather, and other conditions. Continuous monitoring can help identify when and where exposure risks may be greatest.
But monitoring is only the first step. Schools also need the ability to improve the air they measure through proper HVAC maintenance, effective ventilation, reducing indoor pollution sources, and high-efficiency filtration.
For schools affected by outdoor particulate pollution, filtration can be particularly important. Medical-grade filtration technologies, such as HyperHEPA, are designed to capture extremely small particles and can help reduce fine particulate matter indoors.
The objective is simple: Reduce children's exposure to harmful pollutants wherever we can.
Clean air is part of learning
Children are at school to learn, and the physical environment can influence their ability to focus and perform. Poor indoor air quality can contribute to headaches, fatigue, and respiratory symptoms, while research has connected better ventilation with improved cognitive performance.
We invest enormous resources in teachers, technology, curriculum, and school facilities because we understand that the environment in which children learn matters. Clean air should be part of that equation.
It should not be acceptable for a child attending a school next to a freeway to face a greater pollution burden simply because of where their school happens to be located. Communities near major transportation corridors and other pollution sources are often disproportionately low-income communities and communities of color, creating a significant environmental justice concern.
We cannot accept a system where access to clean air depends on a school's ZIP code.
We have rightly made clean drinking water a basic expectation for schools. Clean air deserves the same level of attention.
As students return to classrooms this fall, every school should be asking three questions:
- What is the quality of the air our students are breathing?
- How does the air outside affect the air inside?
- What can we do to make that air cleaner?
The answers will be different for every school. But the responsibility is the same.
We need to know what children are breathing. We need to understand the risks. And we need to act.
Every child deserves the opportunity to learn in a healthy environment. Clean air should not be an added benefit for schools that can afford it. It should be a fundamental part of what we consider a safe school.
When we send our children back to school, we should think not only about what they will learn, but about the air they will breathe while they’re learning.
