It is important to plant different types of trees to clean the urban air as each tree can have different capacity. Photo: File
Sweden: A study has shown that trees of different species but native species can clean the air of the city better. This is because each tree has a different capacity to absorb different types of pollutants.
Experts from the University of Gothenburg in Switzerland have said that cypress (conifer) trees have a greater ability to absorb polluted air than broad-leaved plants, while deciduous trees absorb pollution particles better. That is, each tree has a different ability to absorb different pollutants.
According to scientists, the leaves and pointed thorns of the tree not only clean the air in a better way but also reduce the toxic components in the air. But experts also wanted to know which tree might prove to be the best. In this regard, Gothenburg scientists have investigated 11 types of plants.
All trees were kept in the same environment and condition. A total of 32 types of pollutants including various gases and particles of different sizes were thrown on the trees. Also included are polycyclic aromatic hydrocarbons (PAHs).
Cypress trees were found to absorb more pollutants, including PAHs. These trees also act as a filter in winter when pollution and fog are high. Then it was also found that the pointed ridges, thorns and stalks on the tree also absorb the atmosphere more. But broad-leaved trees are no less, and because of their large surface area, they capture more of the pollutant particles.
The same study found that pollution of any kind does not reduce the amount of chlorophyll in plants. This is the reason why different types of trees can clean the air of the city in a better way.
However, experts have said that indiscriminate planting of trees in narrow streets can cause harm instead of benefit. This will reduce the absorption of pollution, but due to the stoppage of air circulation, dirty air can be trapped there for a long time.
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