A single tree can absorb 10 pounds of air pollutants a year, and produce nearly 260 pounds of oxygen — enough to support two people.

Children have lower rates of asthma when they live in neighborhoods with more trees. Researchers found that an increase in tree density of 343 trees per kilometer would be associated with a 29% lower prevalence of early childhood asthma.

Researchers have valued the human health benefits of trees’ reduction of air pollution at 6.8 billion dollars a year.