A study published in the journal Psychological Science has found people living in urban areas of the UK reported less mental distress and higher life satisfaction when they were living in greener areas.
The research has been led by Dr Mathew White from the University of Exeter Medical School's European Centre for Environment and Human Health, in Truro, Cornwall.
Dr White said: "We've found that living in an urban area with relatively high levels of green space can have a significantly positive impact on well-being, roughly equal to a third of the impact of being married."
This effect is also equivalent to a tenth of the impact of being employed, compared with being unemployed, Dr White said.
The scientists involved say the results show that even when stacked up against other factors that contribute to life satisfaction, living in a greener area has a significant effect.
Dr White said: "These kinds of comparisons are important for policymakers when trying to decide how to invest scarce public resources, such as for park development or upkeep, and figuring out what bang they'll get for their buck."
A university spokesman said: "Research published today does not prove that moving to a greener area will necessarily cause increased happiness, but it does fit with findings from experimental studies showing that short bouts of time in a green space can improve people's mood and cognitive functioning."
Dr White said the research could be important for psychologists, public health officials and urban planners who are interested in learning about the effects that urbanisation and city planning can have on population health and wellbeing.