Scientific study finds clean, green public spaces make us happier and lessens depression

Restaurant Tech Live blog post 1 Restaurant Tech Live blog post 2 Restaurant Tech Live blog post 3

The Philadelphia Horticultural Society cleaned up and planted trees in several vacant lots in a study of how public spaces affect mental health.

A new study shows that removing litter and adding green spaces to empty lots helped people feel happier and reduced the symptoms of depression. In a scientific study of the effects of public spaces on mental health, a non-profit group in Philadelphia cleaned up trash-filled vacant lots and planted trees in others, primarily in low-income areas, and found that residents reported feeling happier.

The study looked at 541 empty lots around Philadelphia. In one third of them, trees and grass were planted, and litter was removed from another third, but the remainder were left untouched. 

Researchers from the University of Pennsylvania spoke to 342 local residents several times to track their emotional state over the three-year period of the cleanup study, between 2011 and 2014.

They found that residents of areas that had either the greening or rubbish removal projects reported a decrease in feelings of depression by about 40 percent, and in neighbourhoods below the poverty line, the drop was as high as 70 percent. Researchers also found reductions in feelings of worthlessness, hopelessness and overall poor mental health.

For residents near lots that were not cleaned up, the levels of depression stayed the same or changed only slightly.

Renee Holly, 54, is a lifelong resident of North Philadelphia. She said she loves the grass and trees that have replaced the trash in the vacant lot on her block. “It’s a beautiful thing to have a clean lot, it makes me happy,” she said. “Now, our neighbourhood kids don’t have to play in a lot with glass and trash.”

Holly, who works as a custodian, is a block captain in her neighbourhood, charged with keeping it in good condition. She said community residents take responsibility with help from the Pennsylvania Horticultural Society, which conducted the cleanups. "They helped us take it to a better place, and I'm so thankful," she said.

Dr. Eugenia South, an emergency room doctor at University of Pennsylvania Hospital and a corresponding author of the study, said she was not surprised by the results. “This is further evidence that where people live has an impact on their health,” she told NBC News. “The positive individual mental health effects the study found can also change behavior, and affect the community at large.”

“When the lots were cleaned up, needles and condoms were found,” South said. “The abandoned, cluttered spaces encouraged crime.”

Spaces that were already cleaned up will keep being cared for by The Pennsylvania Horticultural Society who return every two weeks, except during the dead of winter, for maintenance, South said.

But South hopes that the results of the study will resonate with physicians and city officials working in urban planning and public health, and inspire more projects to clean up public spaces. “Doctors can treat depression, drugs and wounds,” she said. “But we need to look at what brings the patients in, in the first place.”