Lavender, marjoram and ivy improve clean air from green walls
New research from the University of Surrey has revealed the best species for purifying the atmosphere.
Studying 10 individual plant types on a custom-built 1.4metre green wall situated at the A3 in Guildford, the team drew a number of conclusions which could help maximise the impact of future infrastructure.
Evergreen, candytuft, and ivy leaves were all found to perform best at catching large and small particulate matter. Lavender, meanwhile, was able to clean particles off easiest in the rain, although candytuft and marjoram also did well at this.
‘We hope that town planners and infrastructure experts can use our findings to think more carefully about what they plant,’ said Professor Prashant Kumar, director of the Global Centre for Clean Air Research (GCARE) at the University of Surrey. ‘Having a green wall is a great way of removing pollution – but what you plant on it can make a big difference to how successful it will be.’
‘By planting vertically on a green wall, communities can clean up their air without taking up too much street space,’ said Mamatha Tomson, postgraduate researcher at the University of Surrey. ‘Our study suggests that this process depends not only on the shape of its leaves but on the micromorphological properties of their surfaces. We think a good mixture of species will produce the most effective green walls – and look forward to carrying out further research to see if we’re right.’
Last year, Professor Kumar spoke to the Environment, Food and Rural Affairs Select Committee, advocating ‘well-placed trees‘ in urban areas as a solution to air pollution. Last week, our sister title, Air Quality News, hosted the Northern Air Quality Conference in Manchester. Read the full report.
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Image: Daiga Ellaby