Anja Murray: We need more trees to improve Ireland's air quality

A mature leafy tree can produce enough oxygen for 10 people to inhale in a year and during rush hour, trees significantly reduce highly hazardous substances in the air

Trees, like sessile oak (pictured) dramatically help improve urban air quality.

May is here. Bealtaine, an ancient Irish festival traditionally celebrated on May 1, marks the crossing over to the bright half of the year. It’s a time to breathe deep, inhale the freshness of unfurling leafy canopies on trees. This is the point where we transition to more outdoor activities as the summer begins.

At this time of year, trees are in the process of growing a whole new canopy of green leaves. Each leaf uses energy directly from the sun to divide molecules of carbon dioxide and water, before recombining the atoms as carbohydrates and oxygen. The carbohydrates are used by the tree to grow new twigs, bigger branches, stronger roots and more leaves. The food that trees make is passed up through the food chain, for example by the caterpillars who feed on the leaves and in turn provide essential protein-rich food for nesting birds.