Plants are our third line of defence for air pollution in cities

Around the world, there is an active conversation about the importance of plants and what they bring to the planet. As discussion builds, plant research is delivering fresh guidance that will help to create realistic change. When it comes to air pollution, after reducing emissions and increasing distance from pollution sources, plants are the third line of defence.

Putting research into practice and how that practice informs policy to make a difference on a local, city-wide and global scale was the topic of the latest City of London Green City Briefing that addressed Air Quality in Cities.

Hosted by AIPH in collaboration with the Worshipful Company of Gardeners, the briefing took place in November with presentations from Henrik Sjöman, Scientific Curator, Researcher and Teacher at Gothenburg Botanic Garden and the Swedish University of Agricultural Science, and Dr Tijana Blanusa, RHS Principal Horticultural Scientist.

Henrik Sjöman believes that the most effective means of mitigating urban problems is to strategically increase the diversity of tree species across the urban landscape. He said: “25% to 40% of trees that have been planted that didn’t perform well and need to be removed, are not replaced by new trees. Around the world there is active conversation about the importance of plants and what they bring to the planet. As discussion builds, plant research is delivering fresh guidance that will help to create realistic change. This means we seldom get a second chance when it comes to
tree selection.”

Tree data also shows the unnecessary risks being taken by cities around the world through the limited number of tree species being used for urban greening. “We should move away from the quantity perspective of tree planting and move more towards the quality of tree species”, urged Henrik.

Dr Tijana Blanusa’s presentation on ‘Plant traits associated with good delivery of ecosystem services’ supports this thinking. Tijana leads and delivers RHS research on the environmental benefits of urban green infrastructure, and is working to understand what underlying plant traits are most successful. In the webinar, she outlines the means whereby plants help reduce airborne pollutant
concentrations, but also how they are impacted by pollution.

To conclude, research confirms that differences in plant structure and function lead to differences in the delivery of ecosystem services. Yes, there is a role for plants in mitigating urban climate change, but it’s now for us to discover and grow the best genetic material of the species to truly benefit from the power of plants.

Watch the briefing on-demand