Pollution Protection with Greenery

For many years now, understanding how greenery might absorb air pollution in urban areas has been a priority for many scientists, as it is thought that flora can help eliminate 50% or more of two kinds of air especially on streets featuring many tall buildings.

The strategic planting of the right plants, in the right places, should go a long way toward not only cleaning urban air but also reducing related threats to human health from such pollution. German Karlsruhe Institute of Technology atmospheric scientist Thomas Pugh conducted the new UK study at Lancaster University.

Previous studies showed these so-called street canyons, where tall buildings abound, allow pollutants to accumulate by trapping air within them, especially when traffic is heavy. His team created a computer model of just such a basic street canyon – taking into variables such as wind speed and vegetation coverage – focused air pollutants nitrogen dioxide and particulate matter measuring less than 10 micrometers (0.0004 inches) in diameter.

Both of these are known to be commonplace in cities world-wide, and linked to heart and lung diseases. The findings were that, at low wind speeds, just the simple addition of shrubbery to walls cut nitrogen dioxide concentrations by 40% and particulate matter by 60%. This should mean, the researchers say, that if very high pollution levels apply to particular streets, they can be targeted for greening and thus rendered healthier.

The new findings challenge traditional thinking, which has long held that greenery could only remove small amounts of air pollutants, when the true potential in using greenery might actually be much more effective, giving planners another tool to fight urban air pollution, known to be today world-wide a major cause of illness and premature death in cities around the world.

Urban plantings come along with several other bonus features, including reducing  both the so-called urban heat island effect and noise pollution, as well as providing habitats for birds and wildlife, and making the whole street outlook a more pleasant experience all-round.