The leaves are covered in tiny hairs and ridges which help trap the pollution particles.
When it rains, the particles that have come to rest on the leaves are washed off so the cleaning/filtration process can begin again.
Silver birch foliage is sparse which means the air can easily circulate up through its branches and pollution can escape.
A young tree such as Betty can:
• Produce 12 lbs of oxygen allowing 6 people to breath for an entire day.
• Stores 4 lbs of carbon, equal to 71 ft. travelled in a commercial plane.
• 119 gallons of water evaporation which in turn has the cooling effect of 5 air conditioners working for 20 hours.
*Facts calculated by 8billiontrees.com