Too many trees 'spoil air quality', says study

Planting too many trees in the central reservation of roads can have a detrimental effect on air quality, according to a new study.

ScienceDaily reports that the environmental analysis, conducted by International Journal of Environment and Waste Management, shows that streets with too many trees planted in close proximity to one another along a central strip could lead to the entrapment of more vehicle exhaust fumes than if there were no trees at all.

The wind tunnel research concentrated on the way in which air flows along city streets known as "urban canyons", focusing in particular on the impact of a central line of trees that are separated by varying distances and the effect of moving traffic on the air flow.

Further air monitoring also discovered that separating trees by at least the width of their crowns allows the street level air to clear much faster.

In recent news, a study published by the Columbia Center for Children's Environmental Health revealed that exposing pregnant mothers to poor air quality can have a negative effect on the IQ of their unborn child.

Written by Claire Manning