1 . Conifers (针叶树) are generally better than broad-leaved trees at purifying air from pollutants. But deciduous (落叶的) trees may be better at taking in 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 pollutants involved.

Trees and other greener in cities provide many benefits that are important for the well-being of residents. Leaves and needled on trees filter air pollutants and reduce exposure to poisonous substance in the air. But which trees purify the air most effectively? Researchers from the University of Gothenburg have collected leaves and needle from eleven different trees growing in the same place in the Gothenburg Botanical Garden (GBG) to analyse which cub-stances they have absorbed.

“This tree collection provided a unique opportunity to test many different species of trees with similar environmental conditions and exposure to air pollutants,” said Jenny Klingberg, a researcher of the GBG

A total of 32 different pollutants were analysed, some of which are bound to articles of various sizes. Others are gaseous. This project has focused on paths (多环芳烃). In cities, traffic is the biggest source of these pollutants, which are released due to incomplete burning in engines.

“Our analysis show that different species of trees have different abilities to absorb air pollutants. Conifers generally absorb morn gaseous paths than broad-leaved trees. Another advantage of conifers is that they also act as air purifies in winter, when air pollution is usually at its highest,” said Jenny Klingberg.

“This study contributes to improving our understanding of the ability of trees to clean the air and which species are best at absorbing air pollutants,” said Jenny Klingberg. This known-edge is important for urban planning when designing sustainable cities. While trees and green-era can contribute to better air quality in cities, at the end of the day, the most important measure is to reduce emissions.

1. Which is the determining factor in choosing the most suitable tries to purify air?

A．Air quality.

B．Geographical location.

C．The height of plants.

D．The kind of pollutants.

2. Why did the researchers collect leaves and needled from GBG?

A．To compare their shapes.	B．To create a tree collection.
C．To figure out what they absorb.	D．To display them on exhibition.

3. What may cause more paths to be released?

A．Fuel vehicle’s.

B．Electric engines.

C．Traffic accidents.

D．Complete burning.

4. What is the most effective way to better air quality in cities?

A．Decreasing emissions.	B．Planting more conifers.
C．Raising public awareness.	D．Designing sustainable cities.