“In 2018, Dr. Aruni Bhatnagar, a University of Louisville medical school professor, decided that he wanted to “do something” about air pollution in Louisville, which has repeatedly earned 
failing grades for air quality from the American Lung Association. His contribution, he decided, would be to find the connection between trees and better heart health using the gold standard for evidence: clinical trials.”
“Bhatnagar collects an almost-obscene amount of data that includes blood panels, urine, hair samples, wastewater runoff, air pollution samples, soil and leaf samples, bat sounds, LiDar scans, temperature and humidity measurements, crime data, psychological surveys and sleep surveys. It is all being parsed, and relationships are starting to emerge, he said.”
Read on: A scientist in Louisville is compiling data on trees and human health