The cooling provided by this single tree is equivalent to five average room air conditioners running 20 hours per day. An acre of urban forest or park will transpire more than 1,600 gallons of water per day. A large tree may have 200,000 to 400,000 leaves, which act like a continuous air filter. An acre of trees may remove as much as 13 tons of dust each year. Streets with trees have 3,000 particles per liter of air, compared with 10,000 to 12,000 in streets without trees.
Trees also remove heavy metals.
Trees serve as moderate filters of some gaseous pollutants such as sulfur dioxide and carbon monoxide. Each Iowa citizen uses the equivalent of a 100-foot tree each year. We use 600 pounds of paper each year for all uses. From 1900 to 1988, Americans grew and used the equivalent of 13 billion 100-foot trees. Building an average 1,800 square foot home uses 10,000 board feet of lumber, equivalent to 20 cords.