Did you know trees help rid the atmosphere of contaminants and reduce air pollution? The effect isn’t great – trees only remove about one percent of airborne pollution – but a new study from the U.S. Forest Service concluded that trees in the U.S. save more than 850 lives a year by performing this important function. They estimate the reduction in pollution prevents 670,000 occurrences of acute respiratory symptoms, adding up to an impact on human health valued at nearly $7 billion. The investigation showed that while pollution removal by trees is higher in rural areas, the impact on human health is greater in urban centers where more than 80 percent of us live. The study looked at four pollutants for which the U.S. Environmental Protection Agency has established air quality standards: nitrogen dioxide, ozone, sulfur dioxcide and particulate matter less than 2.5 microns in aerodynamic diameter. Pollution related to particulate matter was linked to 130,000 deaths, while deaths related to ozone totaled 4,700 in 2005, the study found. In addition to being a primary environmental concern, air pollution is linked to a number of negative effects on health, including increased risks of pulmonary, cardiac, vascular and neurological diseases.
David Nowak et al, “Tree and Forest Effects on Air Quality and Human Health in the United States," Environmental Pollution, doi: 10.1016/j.envpol.2014.05.028