Hedges can soak up London’s toxic air pollution better than trees, study finds

Pollution-busting plant: garden hedges: Shutterstock / Ivan Smuk
Pollution-busting plant: garden hedges: Shutterstock / Ivan Smuk

Greenthumbs will know that owning a hedge can be a high-maintenance task, but having one in your front garden could have one very important benefit for the environment.

Researchers have found that hedges are a brilliant natural filter for toxic air pollution in London, thanks to their short size and tight-knit foliage.

A paper published in the journal Atmospheric Environment has found that while tall trees are good at absorbing pollution in the open countryside, hedges are better at trapping harmful pollutants at exhaust pipe level.

The authors of the study say that hedges are unsung heroes in cleaning up the city, and that while trees still play an important role, these leafy barricades are better at absorbing toxins in city "canyons".

The research comes after the level of toxic air in London hit the highest black alert earlier this year and doctors warned time was “running out” to protect the capital’s children from air pollution.

London Mayor Sadiq Khan said in February that “nothing is off the table” when considering how to reduce air pollution.

Professor Prashant Kumar, who lead the study which looked into the best pollution-fighting plants, is urging local councils to plant hedges on busy pavements where the level of toxic air is high.

Apart from air pollution reduction, he says that the other benefits of urban green infrastructure include lowering heat, potentially reducing energy consumption and protecting homes from flooding.

He told The Evening Standard: “We all know air pollution is a major factor of everyday urban life.

“This comprehensive review highlights that trees and hedges, as well as other green infrastructure, must be used strategically to help create healthier, less polluted cities that are also more pleasant for everyone to live and work in.

“The strategic placing of hedges, trees and other green infrastructure can have a direct benefit as an air pollution control measure in cities.”