Children who live along tree-lined streets have lower rates of asthma, according to new research.
Researchers based their findings on rates of asthma among 4 to 5 year olds, and hospital admissions for the disease among children up to 15, in 42 health service districts of New York City.
The medical data were then plotted against city data on the number of trees in each area. Asthma rates fell by almost a quarter for every standard deviation increase in tree density, equivalent to 343 trees per square kilometer. This pattern held true even after taking account of sources of pollution and population density.