How Do Trees Reduce Pollution?

Air pollution is associated with an increase in respiratory diseases, heart disease, cancer, stroke, dementia, obesity, and even early death. However, we are regularly exposed to pollutants, such as car emissions and fossil fuels.¹ 

Data from the World Health Organization (WHO) show that the majority of the population breathes air exceeding their guideline limits. According to the WHO, one-third of deaths from stroke, lung cancer, and heart disease are as a result of air pollution.

How can plants help?

All leaves can capture small amounts of air pollution,¹ acting as a barrier against pollutants. Trees are not the only plants that can trap particles that are found in our streets, and research suggests that hedges are better than trees in trapping pollutions. This is because trees can create a canopy over streets, preventing traffic pollutants from escaping. However, hedges form a barrier at human height and acts as a filter.¹ 

Which trees are best at trapping pollution?¹

• Trees with hairy leaves, such as cotoneasters, are good at trapping pollution, as these leaves have a wider surface area than trees with smooth leaves. As a result, they capture more pollution. 
• Pollutants can also get trapped in scaly leaves, such as the leaves of red cedar.
• Ones with rough leaves, such as hawthorn, where particles get trapped in the ridges and grooves on the leaf’s surface.
• Waxy leaves, such as those from yew trees, are also beneficial, because pollutants get stuff in the waxy cuticle layer. Yew trees can also be grown as small or large hedges, and provide red berries and habitat for wildlife.

Read more:

1. Griffiths A, Keightley M. ‘Plants as potential pollution busters’, Your Wellbeing Garden: How to Make Your Garden Good for You (2020) London: Dorling Kindersley Limited, pp.20-2.