Conifers are generally better than broadleaved trees at purifying air from pollutants. But deciduous tree may be better at capturing particle-bound pollution. A new study led by the University of Gothenburg shows that the best trees for air purification depend on the type of pollutant involved.
Trees and other greenery in cities provide many benefits that are important for the well-being of residents. Leaves and needles on trees filter air pollutants and reduce exposure to hazardous substances in the air. But which trees purify the air most effectively? Researchers from the University of Gothenburg have collected leaves and needles from eleven different trees growing in the same place in the Gothenburg Botanical Garden’s arboretum (tree collection) to analyse which substances they have captured.
“This tree collection provides a unique opportunity to test many different tree-species with similar environmental conditions and exposure to air pollutants,” says Jenny Klingberg, a researcher at the Gothenburg Botanical Garden.
A total of 32 different pollutants were analysed, some of which are bound to particles of various sizes. Others are gaseous. There is a proven connection between exposure to air pollutants and increased risk of cardiovascular diseases and airway problems. This project has focused on polycyclic aromatic hydrocarbons (PAHs). In cities, traffic is the biggest source of these pollutants, which are released due to incomplete combustion in engines. Our analyses show that different tree species have different abilities to absorb air pollutants. Conifers generally absorbed more gaseous PAHs than broadleaved trees. Another advantage of conifers is that they also act as air purifiers in winter, when air pollution is usually at its highest,” says Jenny Klingberg.
Journal article: Differences in accumulation of polycyclic aromatic compounds (PACs) among eleven broadleaved and conifer tree species
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Posted On: 07/03/2023