If we want to remove harmful substances from the air, such as PM10 dust, certain species of evergreen trees will help us, according to a study conducted by scientists from the University of Surrey in the UK. The article was published in “Science of The Total Environment”.
Scientists from the University of Surrey checked which of 10 trees growing on a busy street captures the most harmful substances from the air. Researchers initially assumed that species whose leaves had a rougher surface and fine hairs would capture more pollutants. However, the evidence did not support this.
– In order for the leaves to remove more harmful substances from the air, they must be washed by rainfall. It appears that the size and shape of the leaf is much more important than whether it is rough and hairy, said Yendle Barwise of the University of Surrey.
Scientists used evergreen trees in the study, which do not lose their leaves in winter, when air pollution is the highest. They placed them in pots alongside the A3 in Guildford, Surrey. On average, 80,000 vehicles pass through there every day.
Among the examined plants, common yew (Taxus baccata) was the plant that removed the most air pollutants. However, the most effective in the fight against harmful PM10 particles were the leaves of species such as Japanese cryptomeria (Cryptomeria japonica) and Lawson’s cypress (Chamaecyparis lawsoniana).
The research also showed that stomata, the so-called “pores” of the leaf, can help plants “catch” harmful particles from the air. In the case of the yew, more harmful dust accumulated on the porous underside of the leaf. – This is despite the fact that that the other side of the leaf is 47 percent rougher, Barwise noted. He added that the research should continue.
– We know that planting trees near busy roads improves the air quality in a given area. Our study shows that some species can capture more of these harmful substances, said Prashant Kumar, lead author of the study. “Our study shows that leaf shape and structure matter,” he added.
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