Trees store air pollutants

I’ve written before about the role of urban trees. They contribute to a number of positive outcomes. A newer area of research is whether the trees actually absorb air pollutants.

Klingborn et al (2022) examined the levels of a specific type of pollutant in both deciduous (leafy) trees and coniferous (cone bearing) trees. They found that both types absorbed the pollutants based on how much was in the air. This means that trees are pulling potentially dangerous pollutants out of the air.

This is important data because we need to identify ways of working with nature to overcome the many stresses that we put onto the environment. This is similar to using spaces like wetlands to filter water, something called ecosystem services. The benefits of these are quite extensive and often result in cost-savings compared to industrial solutions.

However, I do have a question. What happens to the pollutants once they have been absorbed? Is the tree able to process the pollutants or do they just sit in the tree until it dies? This could have implications for how long term a tree purifier is. In addition, is the tree impacted by the pollutants? Does it change its growth at all?

Regardless, with yet another benefit of having urban trees, it’s important for cities to invest in trees and make sure that there is equitable distribution so that everyone, regardless of where they can live can experience the benefits.