Trees are often called the lungs of our planet. That’s because they absorb carbon dioxide from the atmosphere and release oxygen through photosynthesis. But their contribution doesn’t end there. Trees also play a vital role in cleaning the air by removing pollutants from the atmosphere. Air pollution comes from many sources, such as industry, intensive agriculture, (air) traffic, and wildfires. This pollution can cause serious health problems, including respiratory issues, cardiovascular and lung diseases, and even cancer. In this blog, we look at how greenery contributes to air purification.
Trees as Natural Air Purifiers
Trees are natural air filters that help reduce the harmful effects of pollution. In terms of health, the focus is on reducing fine dust, soot, nitrogen dioxide, and ozone. Trees directly influence the concentrations of these substances through deposition (settling), dispersion (absorption), and by altering airflow.
Trees purify the air in several ways:
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Absorbing pollutants: Plants have pores in their leaves that can absorb harmful gases such as carbon monoxide, nitrogen oxides, and sulfur dioxide—common causes of respiratory problems.
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Filtering polluted particles: Trees trap airborne particles like soot and fine dust on their leaves, twigs, and bark. These tiny particles, often from industry and combustion, are linked to diseases such as dementia and cancer.
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Releasing oxygen: Oxygen is essential not only for breathing but also helps oxidize and neutralize pollutants, reducing their harmful effects.
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Breaking down pollutants: Through a process called phytoremediation, plants can break down harmful substances, converting them into less harmful compounds. Promising studies are even exploring how plants could help remove PFAS from soils.
Smart Species Choice and Hay Fever
While trees improve air quality, pollen allergies (hay fever) can affect some people. Species choice is therefore important, and good advice is essential. Generally, pollen-related allergies occur during a limited period in spring, especially in dry weather. A diverse and carefully chosen planting scheme can help limit hay fever problems.
Behavior and Smart Planning
Many studies show that green environments significantly improve air quality—not only through purification but also by changing behavior. Green surroundings encourage cycling instead of driving, reducing emissions. Greenery can also slow down traffic, further lowering pollution. Strategically planting trees where pollution originates provides direct compensation.
The biggest gains come from planting trees, thanks to their large leaf surface and volume. Trees along roads, for instance, reduce nitrogen dioxide levels right where it matters most. Capturing fine dust is one of the primary functions of trees in improving air quality.
In Summary
Trees play a crucial role in absorbing pollutants such as carbon monoxide, nitrogen oxides, and sulfur dioxide, directly benefiting human health. They also help reduce greenhouse gas concentrations in the atmosphere. The importance of trees in air purification cannot be overstated. Protecting forests and planting trees wisely must remain a priority to prevent human activities from further damaging the climate.
This blog is part of the series Trees and Their Ecosystem Services, which explores the many benefits trees provide to people and the environment. Upcoming articles will focus on how trees help address today’s environmental challenges, including water management, heat stress, CO₂ storage, air quality, biodiversity, and livability.
