PROBLEM: As we've seen again and again, people are generally happier when they have access to grass, trees, and flowers. In terms of the many other things required to have a satisfying life in urban settings, how important is living near parks and gardens?

METHODOLOGY: Researchers at the University of Exeter looked at 18 years of data covering almost 10,000 U.K. citizens living in urban areas. By conducting annual surveys, they quantified the participants' well-being through two measures: how satisfied they were with their lives (asking point-blank: "How dissatisfied or satisfied are you with life overall?"); and whether they had signs of depression, anxiety, or other psychological disorders. The researchers controlled for as many other factors known to significantly influence well-being as possible, like income, job and marital status, health, commute, and housing demographics.

RESULTS: As green space increased within a 2.5-mile radius of where they lived, overall well-being increased proportionally. Specifically, life satisfaction increased by 2 percent and psychological distress decreased by 4 percent.

In relative terms, living in a greener area was associated with mental health gains about 35 percent as significant as those one gets from being married. It was 12 percent as beneficial to mental health as employed.

In terms of "life satisfaction," the effect was equal to 28 percent that of being married and 21 percent that of being employed. 

IMPLICATIONS: The association of green spaces with well-being was small. But other factors you'd expect to impact well-being, like neighborhood crime rates and average neighborhood income, surprisingly, had no significant association at all with mental health or life satisfaction. 

Nature, on the other hand, seems to remain significant regardless of everything else going on. And as the authors point out, marriage only benefits two people. Planting more gardens has the potential to improve life for everyone, all at once.

"Would You Be Happier Living in a Greener Urban Area? A Fixed-Effects Analysis of Panel Data" is published in Psychological Science.