“Going Green” Reduces City Street Pollution

Observing that street-level concentrations of nitrogen dioxide (NO2) and particulate matter (PM) exceed public health standards in many cities – contributing to increased rates of disease and death, European researchers submit that pollution concentrations may effectively be reduced by increasing the numbers of trees, bushes, grass, ivy, and other greenery growing amidst the concrete  and glass that dominate city real estate.  Thomas Pugh, from Karlsruhe Institute of Technology (Germany), and colleagues report that green plants can improve urban air quality by removing NO2 and PM pollutants from the air. The researchers found that judicious placement of grass, climbing ivy and other plants in urban settings can reduce the concentration at street level of NO2 by as much as 40%, and PM by 60%, much more than previously believed. The study authors propose that cities build plant-covered “green billboards” to increase the amount of foliage, concluding that: “judicious use of vegetation can create an efficient urban pollutant filter, yielding rapid and sustained improvements in street-level air quality in dense urban areas.”