A research team from Portland State University (PSU), in Oregon, has created the Trees and Health App, which can help urban planners manage the impact of poor air quality by showing where a lack of vegetation corresponds with poverty.

In cities, tree cover is one of the most visible indicators of neighborhood income, and vegetation density is directly tied to health outcomes, especially for the vulnerable group, such as kids, the elderly, and people living below the poverty line.

To establish a baseline for the impact of trees in a neighborhood, the research team placed 144 pollution sensors across the city of Portland, and cross-referenced maps from the Forest Service and U.S. Geological Survey for tree cover. Next, the team  overlaid pollution sources like factories, mass transit, and sinks, "such as parks that soak up ambient pollutants," in neighborhoods where there was a high density of older adults, children under 18, and people living below the poverty line. These three social factors were chosen from census data because they are "known to be important for impacting public health."

Those three factors are commensurate with places that are hot and dirty. We know that trees can help to mitigate air pollutants, and we've also seen thermal regulation through tree planting.

Vivek Shandas, the PSU professor who spearheaded the project, claims that the pattern of vegetation in cities isn't random, and compares it to the "chicken and egg."

The Trees and Health App itself breaks down research into three actionable steps: "assess," "prioritize," and "plan." Selecting "assess" allows users to examine vulnerable neighborhoods based on social factors, and indicates the amount of tree cover, while "prioritize" can break down at-risk groups by specific factors. The "plan" function is where the app really can lead to action--users can set specific goals for pollution levels, and the app then provides maps of planting projects that would be needed to achieve them. 

The research team has received a National Science Foundation grant to expand the program to 13 other cities, including Albuquerque, Denver, Pittsburgh, Baltimore, and Cincinnati. The program only includes urban areas with a population between 400,000 - 700,000 people, "because these cities are big enough to have a voter base to push for more trees, but small enough that planting efforts would make a difference." 

To read more about the project, read the full coverage on Smithsonian.com >>