Schools Need More Trees

Protecting Children from Air Pollution

Air pollution is one of the most serious environmental health threats facing children today. Traffic emissions, industrial pollutants, wildfire smoke, and airborne microplastics affect developing lungs and can lead to lifelong health problems. While schools cannot control every pollution source in their area, one powerful and low-cost solution is available right on campus: trees. Research shows that increasing tree canopy around schools significantly improves air quality, reduces exposure to harmful pollutants, and protects children’s respiratory and cognitive health.

Children Are More Vulnerable to Air Pollution

Children breathe faster, spend more time outdoors, and have developing lungs and immune systems, making them more sensitive to air pollution than adults. Fine particulate matter (PM₂.₅), nitrogen dioxide (NO₂), and ozone (O₃)—common pollutants near roadways—can penetrate deep into the lungs and bloodstream.

Exposure to air pollution in childhood is associated with:

• Higher rates of asthma and respiratory infections

• Impaired lung growth

• Reduced cognitive development and attention

• Increased school absences

According to the World Health Organization (2018), 93% of children globally breathe polluted air that exceeds safe health limits.

Trees Reduce Pollution Around Schools

Trees act as natural air filters. Their leaves, needles, and bark trap harmful airborne particles and absorb gaseous pollutants. Urban forestry research shows that trees capture PM₂.₅, NO₂, O₃, and other contaminants linked to respiratory and cardiovascular disease (Nowak & Greenfield, 2018). When planted around schools—especially near playgrounds, sports fields, and drop-off zones—trees create a cleaner, healthier air space for students.

Vegetation barriers along roadways can reduce particulate pollution by up to 52%, depending on canopy density and species (Baldauf, 2017). This is especially important for schools located near highways or busy streets, where pollution concentrations are highest during morning drop-off and afternoon pick-up.

Cleaner Air Supports Better Learning

Air quality doesn’t just affect physical health—it affects brain function. Children exposed to air pollution show reduced attention, slower cognitive processing, and lower academic performance. Studies link increased PM₂.₅ and NO₂ exposure to poorer test scores and higher rates of developmental delays (Grineski et al., 2020).

By improving air quality, trees support better learning environments. Nature exposure also boosts focus, reduces stress, and improves memory and attention in children (Berman et al., 2008). Green schoolyards provide dual benefits: cleaner air and improved student well-being.

Green Schoolyards Encourage Healthier Lifestyles

Schools with trees encourage outdoor play, physical activity, and positive social interactions. Green schoolyards help reduce stress and anxiety, improve mood, and create calming spaces during recess or outdoor learning (Markevych et al., 2017). These benefits are especially important for students with ADHD, anxiety, or behavioral challenges.

Adding trees to campuses also provides shade, reducing heat exposure on playgrounds—an increasing concern with rising temperatures and climate change. Cooler outdoor areas make recess safer and more enjoyable, especially during warm months.

A Simple, Low-Cost Solution With Long-Term Benefits

Planting and protecting trees around schools is a cost-effective strategy with long-lasting impact. Mature trees provide exponentially greater benefits than newly planted ones, so schools should prioritize both preserving existing canopy and planting for the future.

Effective green-campus actions include:

• Tree buffers along roads and parking lots

• Shade trees near playgrounds and outdoor seating

• Green barriers between sports fields and traffic

• Nature-based outdoor learning spaces

Partnerships with local urban-forestry programs, parent-teacher associations, and community groups can accelerate school greening efforts.

Conclusion

Children deserve safe, healthy places to learn and play. Trees offer a natural and scientifically proven way to reduce air pollution, support cognitive development, and create more nurturing school environments. By planting and protecting trees, schools invest in student health, academic success, and long-term community well-being.

Planting a tree on campus may seem simple—but for a child, it can mean breathing easier, learning better, and growing healthier.

References (APA 7th Edition)

Baldauf, R. (2017). Roadside vegetation design characteristics that can improve local, near-road air quality. Atmosphere, 8(6), 111. https://doi.org/10.3390/atmos8060111

Berman, M. G., Jonides, J., & Kaplan, S. (2008). The cognitive benefits of interacting with nature. Psychological Science, 19(12), 1207–1212. https://doi.org/10.1111/j.1467-9280.2008.02225.x

Grineski, S. E., Collins, T. W., Adkins, D. E., & Morales, D. X. (2020). School-based exposure to hazardous air pollutants and grade point average: A multi-level study. Environmental Research, 185, 109368. https://doi.org/10.1016/j.envres.2020.109368

Markevych, I., Schoierer, J., Hartig, T., et al. (2017). Exploring pathways linking greenspace to health: Theoretical and methodological guidance. Environmental Research, 158, 301–317. https://doi.org/10.1016/j.envres.2017.05.030

Nowak, D. J., & Greenfield, E. J. (2018). U.S. urban forest statistics, values, and projections. Journal of Forestry, 116(2), 164–177. https://doi.org/10.1093/jofore/fvx004

World Health Organization. (2018). Air pollution and child health: Prescribing clean air. World Health Organization.