An important study was published earlier this year that clearly demonstrates the benefits of spending time in nature and summarized in this article on NPR.
The source of the NPR article is a study by the National Academy of Sciences of the United States of America, published in their proceedings PNAS, on January 14, 2019. The study is titled “Residential green space in childhood is associated with lower risk of psychiatric disorders from adolescence into adulthood”. Their finding affirm that “integrating natural environments into urban planning is a promising approach to improve mental health and reduce the rising global burden of psychiatric disorders”.
So don't forget to take your children outside.