Planting healthy air: a global analysis of the role of urban trees in addressing particulate matter pollution and extreme heat

Planting trees is a cost-effective way to tackle urban air pollution, which is a growing problem for many cities. A study by US-based The Nature Conservancy (TNC) reported that the average reduction of particulate matter near a tree was between 7% and 24%. Particulate matter (PM) is microscopic particles that become trapped in the lungs of people breathing polluted air. PM pollution could claim an estimated 6.2 million lives each year by 2050, the study suggests. Lead author Rob McDonald said that city trees were already providing a lot of benefits to people living in urban areas. The average reduction of particulate matter near a tree is between 7-24%, while the cooling effect is up to 2C (3.6F). There are already tens of millions of people getting those kinds of benefits. Dr McDonald said the study of the use of trees in 245 cities around the world compared the cost-effectiveness of trees with other methods of cooling and cleaning air.