If you're a city-dweller feeling a bit blue, you may want to consider going somewhere that's more green—even if it's still in a city. Because moving to greener urban areas provides both immediate and sustained mental health benefits. So says a study in the journal Environmental Science and Technology. The effort is one of the few to look at the effects of green spaces over an extended period of time. Researchers analyzed data from the British Household Panel Survey over a five-year period, splitting participants into two groups: those who moved to greener urban areas and those who moved to less green urban areas. In the year after people moved to greener spaces, they experienced a significant boost in mental health markers, such as mood and confidence. And the benefits persisted for the next two years, indicating a shift in their baseline mental health. People who wound up moving to less green areas experienced a temporary, but significant decrease in mental health. The researchers say these findings should inspire urban planners and policy makers. Because it's uneasy being not green.