Scientists from the U.S. Forest Service have discovered that trees save more than 850 human lives per year and prevent 670,000 cases of respiratory symptoms annually in the first broad-scale study analyzing the removal of air pollution by trees.

Researchers involved with the study, published in the journal Environmental Pollution, discovered that the impact of the removal of pollution by trees was significant. The value of health effects from lowered air pollution was estimated to be almost $7 billion per year, as is documented in “Tree and Forest Effects on Air Quality and Human Health in the United States.”

Tree coverage in the U.S. is estimated at approximately 33.3 percent, though this number varies from state to state.

Michael T. Rains, Director of the Forest Service’s Northern Research Station and the Forest Products Laboratory, stresses the importance of vegetation to human lives.

“With more than 80 percent of Americans living in urban area, this research underscores how truly essential urban forests are to people across the nation. Information and tools developed by Forest Service research are contributing to communities valuing and managing the 138 million acres of trees and forests that grace the nation’s cities, towns and communities,” Rains said in a statement.

The location of trees has a significant impact on human lives – trees in urban areas are much more beneficial as compared to those in rural areas because of how much closer they are to people. The greater the tree coverage, the greater degree of air pollution removal.