How to use your garden to fight pollution

An academic from Goldsmiths, University of London has published a guide to building an ‘air quality garden’, detailing which plants are best equipped to combat harmful pollutants.

The ‘Phyto-sensor’ toolkit was developed by the Citizen Sense research group that is led by Goldsmiths sociologist, Professor Jennifer Gabrys. 

Professor Gabrys said: “Recent news coverage has highlighted the serious issues this country faces both in pollution levels in towns and cities. This report provides timely advice for people who want to know how they can use vegetation to both mitigate and monitor pollutant levels. This is a citizen’s toolkit for planting air quality gardens.”

The toolkit includes instructions for identifying the best locations for air quality gardens, as well as different planting strategies and maintenance techniques.

The toolkit was tested and refined through a public workshop and walk held at the Museum of London in March to investigate ways in which vegetation can improve air quality. The Museum of London partnered with Citizen Sense to develop the toolkit, and a demonstrator garden of air quality plants was on display during the workshop and walk.

Plants in the toolkit have been selected for their suitability to reduce or ‘bioindicate’ different types of air pollution in the urban environment. Bioindication refers to plants’ changes in appearance when certain pollutants are present.

A number of plants highlighted by the report combat particulate matter, including the wallflower, or Erysimum, which combats particulate matter 2.5 and 10 – air pollutants with different-sized particles comprising dust, sand and soot.

The common ivy plant also traps particulates, and is described as ‘ideal for air purification’ due to the extensive surface area of its leaves.

Some of the plants also combat nitrogen dioxide, including Alchemilla mollis or ‘Lady’s Mantle’, which has hairy leaves that trap harmful particulates and can reduce nitrogen dioxide levels by up to 40%.

Among the best bioindicating plants are Aster, which reveals high levels of ozone by yellowing leaves, and Osmanthus, which displays ‘chronic’ leaf damage when exposed to sulphur dioxide. Some of these plants also take up heavy metals and phyto-remediate soils. 

The report’s other recommendations include planting particular trees to improve local air quality, and the installation of green walls and screens as barriers to busy roads. Examples of successful community projects that have used these planting scenarios are included in the toolkit.

Professor Gabrys said: “While reducing emissions at source is the best way to address air pollution, plants can play an important role in mitigating against it. This toolkit is designed to equip people with the knowledge and inspiration to plant gardens that can improve air quality and enhance the urban realm. The research builds on citizen monitoring of air quality in Deptford and New Cross, which found that good urban design can significantly improve air quality levels.”

For more information visit citizensense.net or follow @citizen_sense on Twitter.

Read and download the full Phyto-sensor report