Study: Research Shows Trees and Exposure To Nature Help Overall Human Health
By ScientificAmerican.com // July 26, 2015
(ScientificAmerican.com) – Trees are known to improve air quality by capturing six common air pollutants and toxic gases: ground-level ozone, particulate matter, carbon monoxide, nitrogen oxides, sulfur dioxide and lead.
In fact, a single tree can absorb 10 pounds of air pollutants per year.
In a study published in 2014, U.S. Forest Service scientists and collaborators calculated that trees are saving more than 850 human lives a year and preventing 670,000 incidents of acute respiratory symptoms.
The researchers valued the human health effects of the reduced air pollution at nearly $7 billion every year.
“We found that, in general, the greater the tree cover, the greater the pollution removal, and the greater the removal and population density, the greater the value of human health benefits,” says Dave Nowak of the U.S. Forest Service.
More recently a 2015 study from the Centre for Research in Environmental Epidemiology (CREAL) in Barcelona, Spain found that children exposed to more greenery—as measured by satellite imagery of their schools and neighborhoods—demonstrated better attention skills and memory development.
While the association was partly mediated by reductions in air pollution, Mark Nieuwenhuijsen, one of the study’s authors, noted that he and the study’s other researchers don’t think it’s all air pollution: “I think it’s also some kind of direct effect… you see quite a beneficial effect of green space on mental health.”
Numerous recent studies have focused on the positive effects that exposure to trees and nature has on our mental health.
A recent study published in the journal Nature combined satellite imagery, individual tree data, and health surveys from 31,109 residents of the greater Toronto, Canada area, and found that people who live in areas with higher street tree density report better health perception compared with their peers living in areas with lower street tree density.